U.S. patent application number 17/605434 was filed with the patent office on 2022-05-12 for systems and methods for estimating concrete thickness.
The applicant listed for this patent is FDH INFRASTURCTURE SERVICES, LLC. Invention is credited to Ethan Loewenthal, David Milligan, Armita Mohammadian, Akash Nikam, Klarissa Ramos, Joshua Scott, Matthew Sharpe.
Application Number | 20220146259 17/605434 |
Document ID | / |
Family ID | 1000006300420 |
Filed Date | 2022-05-12 |
United States Patent
Application |
20220146259 |
Kind Code |
A1 |
Milligan; David ; et
al. |
May 12, 2022 |
SYSTEMS AND METHODS FOR ESTIMATING CONCRETE THICKNESS
Abstract
The present disclosure provides systems and methods for
non-destructively estimating the thickness of buried concrete
without excavation. An example method may include placing one or
more first accelerometers at a plurality of vertical positions
below the surface of the ground at an approximate first distance
from a vertical edge of the buried concrete each time. The method
may further include, for each position in the plurality of vertical
positions, generating a dispersive wave in the buried concrete and
determining a time of arrival of the dispersive wave at the one or
more first accelerometers. The method may further include
estimating the thickness of the buried concrete based on at least
the times of arrival of the dispersive waves at the one or more
first accelerometers.
Inventors: |
Milligan; David; (Raleigh,
NC) ; Mohammadian; Armita; (Raleigh, NC) ;
Scott; Joshua; (Raleigh, NC) ; Nikam; Akash;
(Raleigh, NC) ; Sharpe; Matthew; (Raleigh, NC)
; Ramos; Klarissa; (Raleigh, NC) ; Loewenthal;
Ethan; (Durham, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FDH INFRASTURCTURE SERVICES, LLC |
Raleigh |
NC |
US |
|
|
Family ID: |
1000006300420 |
Appl. No.: |
17/605434 |
Filed: |
March 25, 2021 |
PCT Filed: |
March 25, 2021 |
PCT NO: |
PCT/US21/24223 |
371 Date: |
October 21, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62994607 |
Mar 25, 2020 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2291/011 20130101;
G01N 29/07 20130101; G01B 17/02 20130101; G01N 2291/0232 20130101;
G01N 2291/02854 20130101; G01N 29/44 20130101; G01N 33/38
20130101 |
International
Class: |
G01B 17/02 20060101
G01B017/02; G01N 29/07 20060101 G01N029/07; G01N 33/38 20060101
G01N033/38; G01N 29/44 20060101 G01N029/44 |
Claims
1. A method of estimating the thickness of buried concrete, the
method comprising: placing one or more first accelerometers at a
plurality of vertical positions below a surface of a ground at an
approximate first distance from a vertical edge of the buried
concrete; for each position in the plurality of vertical positions,
generating a dispersive wave in the buried concrete; and
determining a time of arrival of the dispersive wave at the one or
more first accelerometers; and estimating the thickness of the
buried concrete based on at least the times of arrival of the
dispersive waves at the one or more first accelerometers.
2. The method of claim 1, wherein placing one or more first
accelerometers at a plurality of vertical positions below the
surface of the ground at a first distance from a vertical edge of
the buried concrete comprises: determining a depth of a top of the
buried concrete relative to the surface of the ground; placing a
substantially-cylindrical tube having a channel into the ground
substantially parallel to the vertical edge of the buried concrete,
wherein the tube is placed such that it extends beyond an estimated
bottom of the buried concrete; placing the one or more first
accelerometers into the channel and in contact with the tube; and
moving the one or more first accelerometers to incremental
positions within the channel, wherein the incremental positions
include at least a position between the top and a bottom of the
buried concrete and a position below the bottom of the buried
concrete.
3. The method of claim 2, wherein placing the one or more first
accelerometers into the channel and in contact with the tube
comprises placing the one or more first accelerometers into a
casing dimensioned to slidably engage the channel and placing the
casing into the channel.
4. The method of claim 1, wherein generating a dispersive wave in
the buried concrete comprises: placing a rod into contact with the
buried concrete at a second distance from the vertical edge of the
buried concrete; and exciting the rod to generate a dispersive
wave, wherein the dispersive wave is transmitted from the rod to
the buried concrete.
5. The method of claim 4, wherein determining a time of arrival of
the dispersive wave at the one or more first accelerometers
comprises: removably coupling a second accelerometer to the rod;
and determining a time elapsed for the dispersive wave to travel
from the second accelerometer to the one or more first
accelerometers.
6. The method of claim 1, wherein estimating the thickness of the
buried concrete based on at least the times of arrival of the
dispersive waves at the one or more first accelerometers comprises:
correlating each time of arrival with each vertical position of the
one or more first accelerometers when the time of arrival was
determined; grouping the times of arrival that are substantially
equal; and estimating the thickness of the buried concrete based on
the vertical positions that correspond to the grouped times of
arrival.
7. A method of estimating a thickness of buried concrete without
excavation, the method comprising: placing a
substantially-cylindrical tube having a channel into a ground
substantially parallel to, and at a first distance from, a vertical
edge of the buried concrete, wherein the tube is placed such that
it extends beyond an estimated bottom of the buried concrete;
placing a rod into contact with the buried concrete at a second
distance from the vertical edge of the buried concrete; placing one
or more first accelerometers into the channel and in contact with
the tube such that the one or more first accelerometers are capable
of receiving a dispersive wave transmitted from the tube; removably
coupling a second accelerometer to the rod; placing the one or more
first accelerometers at a plurality of vertical positions within
the channel, for each position in the plurality of vertical
positions, exciting the rod to generate a dispersive wave, wherein
the dispersive wave is transmitted from the rod to the buried
concrete; and determining a time elapsed for the dispersive wave to
travel from the second accelerometer to the one or more first
accelerometers; correlating each time elapsed with each vertical
position of the one or more first accelerometers when the elapsed
time was determined; grouping the elapsed times that are
approximately equal; and estimating the thickness of the buried
concrete based on the vertical positions that correspond to the
grouped times.
8. The method of claim 7, wherein placing the one or more first
accelerometers at a plurality of vertical positions within the
channel comprises: placing the one or more first accelerometers at
a first vertical position that is approximately above a top of the
buried concrete; and incrementally lowering the one or more first
accelerometers in the channel to a plurality of positions that
include a vertical position that is approximately below an
estimated bottom of the buried concrete.
9. A system to determine a thickness of a buried concrete
structure, the system comprising a computing device configured to:
receive a first group of motion data from one or more first
accelerometers at a first group of vertical positions below a
surface of a ground at an approximate first lateral distance from a
vertical edge of the buried concrete structure; receive a second
group of motion data from one or more first accelerometers at a
second group of vertical positions below the surface of the ground
at an approximate second lateral distance from the vertical edge of
the buried concrete structure; determine a first group of times of
arrival at the one or more first accelerometers corresponding to
the first group of vertical positions from a first group of
dispersive waves emanating from the buried concrete structure;
determine a second group of times of arrival at the one or more
first accelerometers corresponding to the second group of vertical
positions from a second group of dispersive waves emanating from
the buried concrete structure; determine an inflection depth from
the first and second groups of times of arrival; generate a first
best fit line along a first set of data values from the first group
of motion data, wherein at least some of the depths corresponding
to the first set of data values are above the inflection depth;
generate a second best fit line along a second set of data values
from the second group of motion data, wherein at least some of the
depths corresponding to the second set of data values are below the
inflection depth; identify an intersection point between the first
and second best fit lines; and calculate or estimate a thickness of
the buried concrete structure based on the intersection point or
the first and second best fit lines.
10. The system of claim 9, wherein the one or more first
accelerometers generate one or more signals comprising the first or
second set of data values based on the times of arrival of the
first or second groups of dispersive waves and transmit the signals
to the computing device, wherein the computing device is further
configured to determine whether a quality of the one or more
signals satisfies one or more signal quality thresholds.
11. The system of claim 10, wherein the computing device is further
configured to determine whether data from the one or more signals
satisfies one or more data quality thresholds sufficient to
identify an inflection depth.
12. The system of claim 11, wherein the computing device is further
configured to reject one or more of the first or second sets of
data if the signal quality or data fail to satisfy the one or more
thresholds.
13-20. (canceled)
Description
CROSS REFERENCE
[0001] The present application claims the benefit under 35 U.S.C.
.sctn. 119(e) of U.S. Provisional Patent Application Ser. No.
62/994,607 filed Mar. 25, 2020 and titled "Systems and Methods for
Estimating Concrete Thickness," the disclosure of which is
incorporated herein by reference in its entirety and made a part of
this specification.
FIELD
[0002] The present disclosure generally relates to systems and
methods for estimating the thickness of below-grade concrete. More
particularly, the disclosure is directed to systems and methods for
non-destructively estimating the thickness of below-grade concrete
using dry parallel seismic testing.
BACKGROUND
[0003] Concrete structures often include both above- and
below-grade portions. The above-grade portion is exposed above the
surface of the ground (i.e., exposed concrete), while the
below-grade portion is buried beneath the surface of the ground
(i.e., buried concrete). The exposed concrete is often referred to
as a pier or a pedestal, or less commonly, as a column. The buried
concrete is often referred to as a pad, a footing, a foundation, or
an anchor block. Concrete structures having both above- and
below-grade portions are used in many industries for diverse
purposes, including to support infrastructures such as cellular
telephone towers, transmission line towers, and wind turbines.
[0004] In many circumstances, it is desirable to determine or
estimate the thickness of the below-grade portion of such concrete
structures. This will help to evaluate, for example, whether the
concrete structure is suitable for new, updated, or adapted uses as
well as any increased load capacity for such uses. Knowing the
thickness of below-grade concrete is particularly useful in the
telecommunications field because the recently-adopted 5G cellular
standard may require different or additional equipment than that
required for predecessor technologies. Thus, existing cellular
telephone towers may be retrofitted with the different or
additional equipment, which could pose different load conditions on
the towers.
[0005] In some circumstances, the thickness of the below-grade
portion of such concrete structures may be unknown. For example,
the engineering plans for such structures may be lost, destroyed,
or unable to be located. Other times, the structure may not have
been built according to design specifications. Uncertainty about
the thickness of below-grade concrete is also common in countries
that lack rigorous inspection guidelines or regulations.
[0006] Current methods for determining or estimating the thickness
of below-grade concrete are inefficient. Known methods require
excavating around the concrete structure to expose the buried
concrete portion, which can lie several feet or more below the
surface of the ground. Excavation requires manual labor and/or the
use of heavy machinery, both of which are expensive,
labor-intensive, time-consuming, and potentially dangerous.
Further, excavation is not always practical or possible. When a
concrete structure to be investigated is located on a mountain or a
hill, it may be difficult or impossible to transport the excavating
machinery to the structure. When a concrete structure is located in
a rocky area, it may be challenging and expensive to excavate in
such areas to expose the concrete.
[0007] Another inefficiency in current methods is the risk that
while excavating, underground utilities may be inadvertently
damaged, causing disruption to nearby residents and business
owners. Also, the infrastructure supported by the concrete
structures to be excavated, such as cellular telephone towers,
often have to be shut down during the excavation, resulting in
service disruptions.
[0008] A more efficient way of estimating the thickness of
below-grade concrete is therefore needed.
SUMMARY
[0009] The present disclosure provides systems and methods for
non-destructively estimating the thickness of below-grade concrete.
The inventive systems and methods disclosed or described herein do
not require excavating around a concrete structure, thereby
eliminating the inefficiencies and safety hazards of current
methods.
[0010] These and other features and advantages of the present
invention will be apparent from the following detailed description,
in conjunction with the appended claims.
DRAWINGS
[0011] The foregoing and other objects, features, and advantages of
the systems and methods described herein will be apparent from the
following description of particular embodiments thereof, as
illustrated in the accompanying figures, where like reference
numbers refer to like structures. The figures are not necessarily
to scale, emphasis instead being placed upon illustrating the
principles of the systems and methods described herein.
[0012] FIG. 1 is a schematic diagram illustrating an example
concrete structure.
[0013] FIG. 2 is a schematic diagram illustrating an example setup
of a system for estimating the thickness of buried concrete.
[0014] FIG. 3 is a schematic diagram illustrating an example setup
of a system for estimating the thickness of buried concrete.
[0015] FIG. 4 is a schematic diagram illustrating an example setup
of a system for estimating the thickness of buried concrete.
[0016] FIG. 5 is a schematic diagram illustrating an example setup
of a system for estimating the thickness of buried concrete.
[0017] FIG. 6A is a front profile view illustrating an example
casing and cover.
[0018] FIG. 6B is a side profile view illustrating an example
casing and cover.
[0019] FIG. 6C is a rear profile view illustrating an example
casing and cover.
[0020] FIG. 6D is a perspective profile view illustrating an
example casing and cover.
[0021] FIG. 6E is a close-up perspective view illustrating an
example cover and a partial view of an example casing.
[0022] FIG. 6F is a top perspective view illustrating an example
casing and cover.
[0023] FIG. 6G is a bottom profile view illustrating an example
casing and cover.
[0024] FIG. 7A is a simplified block diagram illustrating sensors
in signal communication with a receiver according to some
embodiments.
[0025] FIG. 7B is a simplified block diagram illustrating sensors
in signal communication with a receiver, and a receiver in signal
communication with an external system, according to some
embodiments.
[0026] FIG. 7C is a functional block diagram illustrating an
example receiver according to some embodiments.
[0027] FIG. 8 is a schematic diagram illustrating example positions
for an accelerometer near buried concrete.
[0028] FIG. 9A is a graph diagram illustrating an example plot for
estimating the thickness of buried concrete.
[0029] FIG. 9B is a graph diagram illustrating an example plot for
estimating the thickness of buried concrete.
[0030] FIG. 10 is a perspective view illustrating an example casing
and conduit that can be used to estimate the thickness of buried
concrete.
[0031] FIGS. 11A and 11B are perspective views illustrating an
example casing that can be used to estimate the thickness of buried
concrete.
[0032] FIG. 12A is a perspective view illustrating an example
casing that can be used to estimate the thickness of buried
concrete.
[0033] FIG. 12B is a profile view illustrating an example casing
that can be used to estimate the thickness of buried concrete.
[0034] FIG. 13 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete.
[0035] FIG. 14 is a flow diagram illustrating an example method for
placing an accelerometer at a plurality of vertical positions below
the surface of the ground.
[0036] FIG. 15 is a flow diagram illustrating an example method for
generating a dispersive wave in buried concrete.
[0037] FIG. 16 is a flow diagram illustrating an example method for
determining a time of arrival of a dispersive wave at an
accelerometer.
[0038] FIG. 17 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete based on at least times
of arrival of dispersive waves at an accelerometer.
[0039] FIG. 18 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete.
[0040] FIG. 19 is a flow diagram illustrating an example method for
placing an accelerometer at a plurality of vertical positions.
[0041] FIGS. 20-24 are graph diagrams illustrating example plots
for estimating the thickness of buried concrete.
[0042] FIGS. 25-27 are flow diagrams illustrating an example method
for estimating the thickness of buried concrete.
[0043] FIGS. 28A and 28B are perspective profile views illustrating
an example casing, cover, and conduit.
[0044] FIG. 29 is a perspective view illustrating an example
collar.
[0045] FIG. 30 is a perspective profile view illustrating an
example conduit.
[0046] FIG. 31 is a perspective profile view illustrating an
example cable tie-down.
[0047] FIG. 32 is a perspective profile view illustrating an
example conduit coupler.
DESCRIPTION
[0048] References to items in the singular should be understood to
include items in the plural, and vice versa, unless explicitly
stated otherwise or clear from the text. Grammatical conjunctions
are intended to express any and all disjunctive and conjunctive
combinations of conjoined clauses, sentences, words, and the like,
unless otherwise stated or clear from the context. Recitation of
ranges of values herein are not intended to be limiting, referring
instead individually to any and all values falling within the
range, unless otherwise indicated herein, and each separate value
within such a range is incorporated into the specification as if it
were individually recited herein. In the following description, it
is understood that terms such as "first," "second," "top,"
"bottom," "side," "front," "back," and the like are words of
convenience and are not to be construed as limiting terms unless
otherwise stated or clear from context.
[0049] As used herein, the terms "about," "approximately,"
"substantially," or the like, when accompanying a numerical value,
are to be construed as indicating a deviation as would be
appreciated by one of ordinary skill in the art to operate
satisfactorily for an intended purpose. Ranges of values and/or
numeric values are provided herein as examples only, and do not
constitute a limitation on the scope of the described embodiments.
The use of any and all examples, or exemplary language ("e.g.,"
"such as," or "the like") provided herein, is intended merely to
better illuminate the embodiments and does not pose a limitation on
the scope of the embodiments. The terms "e.g.," and "for example"
set off lists of one or more non-limiting examples, instances, or
illustrations. No language in the specification should be construed
as indicating any unclaimed element as essential to the practice of
the embodiments.
[0050] As used herein, the term "and/or" means any one or more of
the items in the list joined by "and/or". As an example, "x and/or
y" means any element of the three-element set {(x), (y), (x, y)}.
In other words, "x and/or y" means "one or both of x and y". As
another example, "x, y, and/or z" means any element of the
seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y,
z)}. In other words, "x, y, and/or z" means "one or more of x, y,
and z."
[0051] As used herein, the terms "exemplary" and "example" mean
"serving as an example, instance or illustration." The embodiments
described herein are not limiting, but rather are exemplary only.
It should be understood that the described embodiments are not
necessarily to be construed as preferred or advantageous over other
embodiments. Moreover, the terms "embodiments of the invention,"
"embodiments," or "invention" do not require that all embodiments
of the invention include the discussed feature, advantage or mode
of operation.
[0052] As used herein, the term "data" is a broad term and is to be
given its ordinary and customary meaning to a person of ordinary
skill in the art, and refers without limitation to any indicia,
signals, marks, symbols, domains, symbol sets, representations, and
any other physical form or forms representing information, whether
permanent or temporary, whether visible, audible, acoustic,
electric, magnetic, electromagnetic, or otherwise manifested. The
term "data" is used to represent predetermined information in one
physical form, encompassing any and all representations of
corresponding information in a different physical form or
forms.
[0053] As used herein, the terms "memory" and "memory device" are
broad terms and are to be given their ordinary and customary
meaning to a person of ordinary skill in the art, and refer without
limitation to computer hardware or circuitry to store information.
Memory or memory device can be any suitable type of computer memory
or other electronic storage means including, for example, read-only
memory (ROM), random access memory (RAM), dynamic RAM (DRAM),
static RAM (SRAM), ferroelectric RAM (FRAM), cache memory, compact
disc read-only memory (CDROM), electro-optical memory,
magneto-optical memory, masked read-only memory (MROM),
programmable read-only memory (PROM), erasable programmable
read-only memory (EPROM), electrically-erasable programmable
read-only memory (EEPROM), rewritable read-only memory, flash
memory, or the like. Memory or memory device can be implemented as
an internal storage medium and/or as an external storage medium.
For example, memory or memory device can include hard disk drives
(HDDs), solid-state drives (SSDs), optical disk drives, plug-in
modules, memory cards (e.g., xD, SD, miniSD, microSD, MMC, etc.),
flash drives, thumb drives, jump drives, pen drives, USB drives,
zip drives, a computer readable medium, or the like.
[0054] As used herein, the term "network" is a broad term and is to
be given its ordinary and customary meaning to a person of ordinary
skill in the art, and refers without limitation to any
communication network including, for example, an extranet,
intranet, inter-net, the Internet, local area network (LAN), wide
area network (WAN), metropolitan area network (MAN), wireless local
area network (WLAN), ad hoc network, wireless ad hoc network
(WANET), mobile ad hoc network (MANET), or the like.
[0055] As used herein, the term "processor" is a broad term and is
to be given its ordinary and customary meaning to a person of
ordinary skill in the art, and refers without limitation to
processing devices, apparatuses, programs, circuits, components,
systems, and subsystems, whether implemented in hardware, tangibly
embodied software, or both, and whether or not it is programmable.
The term "processor" includes, but is not limited to, one or more
computing devices, hardwired circuits, signal-modifying devices and
systems, devices and machines for controlling systems, central
processing units, microprocessors, microcontrollers, programmable
devices and systems, field-programmable gate arrays (FPGA),
application-specific integrated circuits (ASIC), systems on a chip
(SoC), systems comprising discrete elements and/or circuits, state
machines, virtual machines, data processors, processing facilities,
digital signal processing (DSP) processors, and combinations of any
of the foregoing. A processor can be coupled to, or integrated
with, memory or a memory device.
[0056] In one aspect, a method of estimating the thickness of
buried concrete includes placing one or more first accelerometers
at a plurality of vertical positions below the surface of the
ground at an approximate first distance from a vertical edge of the
buried concrete. The method further includes, for each position in
the plurality of vertical positions, generating a dispersive wave
in the buried concrete and determining a time of arrival of the
dispersive wave at the one or more first accelerometers. The method
further includes estimating the thickness of the buried concrete
based on at least the times of arrival of the dispersive waves at
the one or more first accelerometers.
[0057] In another aspect, the step of placing one or more first
accelerometers at a plurality of vertical positions below the
surface of the ground at a first distance from a vertical edge of
the buried concrete can include determining a depth of the top of
the buried concrete relative to the surface of the ground. The step
can further include placing a substantially-cylindrical tube having
a channel into the ground substantially parallel to the vertical
edge of the buried concrete. The tube can be placed such that it
extends beyond an estimated bottom of the buried concrete. The step
can further include placing the one or more first accelerometers
into the channel and in contact with the tube. The step can further
include moving the one or more first accelerometers to incremental
positions within the channel. The incremental positions can include
at least a position between the top and the bottom of the buried
concrete and a position below the bottom of the buried
concrete.
[0058] In another aspect, the step of placing the one or more first
accelerometers into the channel and in contact with the tube can
include placing the one or more first accelerometers into a casing
dimensioned to slidably engage the channel and placing the casing
into the channel.
[0059] In another aspect, the step of generating a dispersive wave
in the buried concrete can include placing a rod into contact with
the buried concrete at a second distance from the vertical edge of
the buried concrete. The step can further include exciting the rod
to generate a dispersive wave, which should cause the dispersive
wave to be transmitted from the rod to the buried concrete.
[0060] In another aspect, the step of determining a time of arrival
of the dispersive wave at the one or more first accelerometers can
include removably coupling a second accelerometer to the rod and
determining the time elapsed for the dispersive wave to travel from
the second accelerometer to the one or more first
accelerometers.
[0061] In another aspect, the step of estimating the thickness of
the buried concrete based on at least the times of arrive of the
dispersive waves at the one or more first accelerometers can
include correlating each time of arrival with each vertical
position of the one or more first accelerometers when the time of
arrival was determined. The step can further include grouping the
times of arrival that are substantially equal and estimating the
thickness of the buried concrete based on the vertical positions
that correspond to the grouped times of arrival.
[0062] In one aspect, a method of estimating the thickness of
buried concrete without excavation includes placing a
substantially-cylindrical tube having a channel into the ground
substantially parallel to, and at a first distance from, a vertical
edge of the buried concrete. The tube can be placed such that it
extends beyond an estimated bottom of the buried concrete. The
method further includes placing a rod into contact with the buried
concrete at a second distance from the vertical edge of the buried
concrete. The method further includes placing one or more first
accelerometers into the channel and in contact with the tube such
that the one or more first accelerometers are capable of receiving
a dispersive wave transmitted from the tube. The method further
includes removably coupling a second accelerometer to the rod. The
method further includes placing the one or more first accelerometer
at a plurality of vertical positions within the channel. The method
further includes, for each position in the plurality of vertical
positions, exciting the rod to generate a dispersive wave and
determining the time elapsed for the dispersive wave to travel from
the second accelerometer to the one or more first accelerometers.
The method further includes correlating each time elapsed with each
vertical position of the one or more first accelerometers when the
elapsed time was determined. The method further includes grouping
the elapsed times that are approximately equal and estimating the
thickness of the buried concrete based on the vertical positions
that correspond to the grouped times.
[0063] In another aspect, the step of placing the one or more first
accelerometers at a plurality of vertical positions within the
channel can include placing the one or more first accelerometers at
a first vertical position that is approximately above the top of
the buried concrete and incrementally lowering the one or more
first accelerometers in the channel to a plurality of positions.
The plurality of positions can include a vertical position that is
approximately below an estimated bottom of the buried concrete.
[0064] In one aspect, a system to determine a thickness of a buried
concrete structure includes a computing device configured to
receive a first group of motion data from one or more first
accelerometers at a first group of vertical positions below a
surface of the ground at an approximate first lateral distance from
a vertical edge of the buried concrete structure. The computing
device is further configured to receive a second group of motion
data from one or more first accelerometers at a second group of
vertical positions below the surface of the ground at an
approximate second lateral distance from the vertical edge of the
buried concrete structure. The computing device is further
configured to determine a first group of times of arrival at the
one or more first accelerometers corresponding to the first group
of vertical positions from a first group of dispersive waves
emanating from the buried concrete structure. The computing device
is further configured to determine a second group of times of
arrival at the one or more first accelerometers corresponding to
the second group of vertical positions from a second group of
dispersive waves emanating from the buried concrete structure. The
computing device is further configured to determine an inflection
depth from the first and second groups of times of arrival. The
computing device is further configured to generate a first best fit
line along a first set of data values from the first group of
motion data, wherein at least some of the depths corresponding to
the first set of data values are above the inflection depth. The
computing device is further configured to generate a second best
fit line along a second set of data values from the second group of
motion data, wherein at least some of the depths corresponding to
the second set of data values are below the inflection depth. The
computing device is further configured to identify an intersection
point between the first and second best fit lines and calculate or
estimate a thickness of the buried concrete structure based on the
intersection point or the first and second best fit lines.
[0065] In another aspect, the one or more first accelerometers
generate one or more signals that include the first or second set
of data values based on the times of arrival of the first or second
groups of dispersive waves and transmit the signals to the
computing device. In some aspects, the computing device is further
to determine whether a quality of the one or more signals satisfies
one or more signal quality thresholds.
[0066] In another aspect, the computing device is further
configured to determine whether data from the one or more signals
satisfies one or more data quality thresholds sufficient to
identify an inflection depth.
[0067] In another aspect, the computing device is further
configured to reject one or more of the first or second sets of
data if the signal quality or data fail to satisfy the one or more
thresholds.
[0068] In one aspect, a system to determine a thickness of a buried
concrete structure includes a hollow tube to be driven into the
ground adjacent the buried concrete structure. The system further
includes a casing to house an accelerometer. The system further
includes a conduit configured to extend into the hollow tube and
support the casing arranged at a first end of the hollow tube. The
system further includes a collar that includes an opening shaped to
accept the conduit in one or more distinct orientations, the collar
arranged at an opening of the hollow tube at a second end opposite
the first end to receive one or more conduits.
[0069] In another aspect, the system can further include an
accelerometer housed within the casing and configured to generate
data associated with a plurality of dispersive waves emanating from
the buried concrete structure. The system further can further
include a receiver communicatively coupled to the accelerometer.
The receiver can include a display, at least one input module to
receive data from the accelerometer, a processor, and memory
coupled to the processor. In some aspects, the memory stores
instructions that, when executed by the processor, cause the
processor to receive data from the accelerometer associated with a
plurality of dispersive waves and process the received data to
determine a thickness of the buried concrete structure.
[0070] In another aspect, processing the received data to determine
a thickness of the buried concrete structure can include performing
one or more quality checks on the received data.
[0071] In another aspect, the one or more quality checks can
include a pre-trigger noise check on data as it is received from
the accelerometer.
[0072] In another aspect, the one or more quality checks can
include a dead gauge check.
[0073] In another aspect, the one or more quality checks can
include a pre-trigger noise check on all of the received data.
[0074] In another aspect, processing the received data to determine
a thickness of the buried concrete structure can include
determining an inflection depth.
[0075] In another aspect, processing the received data to determine
a thickness of the buried concrete structure can further include
determining a first best fit line for data above the inflection
depth, determining a second best fit line for data below the
inflection depth, determining an intersection of the first and
second best fit lines, and determining a thickness of the buried
concrete structure based on the intersection.
[0076] FIG. 1 is schematic diagram illustrating an example concrete
structure 100 to which the inventive systems and methods may be
applied. The structure includes a buried concrete portion 102
having a thickness T, and that lies beneath the surface of the
ground 106. The structure further includes an exposed concrete
portion 104, wherein the top of the exposed concrete portion 104
extends above the surface of the ground 106 and the bottom of the
exposed concrete portion 104 is in contact with the buried concrete
portion 102. As illustrated, the concrete structure 100 is
generally surrounded by Earth 108, which can be any Earth material,
including soil, dirt, sand, gravel, clay, rocks, etc. The concrete
structure illustrated in FIG. 1 may be used to support a cellular
telephone tower, for example. It should be noted, however, that the
structure of FIG. 1 is provided for illustrative purposes only. The
inventive systems and methods can be applied to any buried concrete
and are not limited to the type of structure illustrated in FIG.
1.
[0077] FIG. 2 is a schematic diagram illustrating an example setup
of a system 200 for estimating the thickness of buried concrete
102. The system 200 can include a first sensor S.sub.1 240 that can
be removably secured in a casing 210, which is explained further
below. The system 200 can include a substantially-cylindrical
hollow tube 230 having a channel 232 formed by an inner wall of
hollow tube 230. Hollow tube 230 is driven into the Earth 108,
preferably in a vertical direction, to a depth that is beneath an
estimated bottom of the buried concrete 102. Although the depth of
the bottom of buried concrete 102 may not be known (as one purpose
of the invention is to estimate the thickness of the buried
concrete 102), the top of the buried concrete 102 can be
determined, for example, by driving a rod through the Earth 108
until it reaches the buried concrete 102 (not shown in FIG. 2).
Hollow tube 230 can then be driven a sufficient distance beneath
the known distance of the top of buried concrete 102. For example,
it may be estimated that the thickness of buried concrete 102 is
within the range of one to four feet. Thus, hollow tube 230 can be
driven to a depth that is greater than the depth of the surface of
buried concrete 102 plus the estimated maximum thickness of buried
concrete 102. Preferably, hollow tube 230 is driven to about two
feet below the estimated bottom of buried concrete 102.
[0078] Hollow tube 230 can be driven parallel to, and at a distance
D.sub.1 from, a vertical edge of buried concrete 102. Distance
D.sub.1 can be any distance that permits a dispersive wave to be
transmitted from the buried concrete 102 to hollow tube 230.
Preferably, distance D.sub.1 is within the range of about 6 to 10
inches. Hollow tube 230 can be driven into the Earth 108 using any
method familiar to those of ordinary skill in the art. For example,
hollow tube 230 can be driven into the Earth 108 by inserting a rod
(not shown) into channel 232 and striking the rod to drive hollow
tube 230 into the Earth 108. Hollow tube 230 can have a pointed tip
as illustrated in FIG. 2 to help facilitate being driven into the
Earth 108.
[0079] Sensor S.sub.1 240 can be configured to slidably engage
hollow tube 230 directly (not shown in FIG. 2) or can be configured
to slidably engage hollow tube 230 indirectly, for example, by
being encased in casing 210, which can be dimensioned to slidably
engage hollow tube 230. For example, hollow tube 230 and casing 210
can be made of plastic, polyvinyl chloride (PVC), metal, or any
other suitable material such that casing 210 is capable of sliding
within channel 232 to different vertical positions while remaining
in contact with hollow tube 230. Casing 210 preferably remains in
contact with hollow tube 230 to better enable dispersive waves to
be received by sensor S.sub.1 240 as explained further below.
[0080] Casing 210 can be positioned at different vertical positions
within channel 232 using conduit 220. Conduit 220 can be removably
coupled to casing 210, for example, using a male/female interface.
Alternatively, conduit 220 can be permanently coupled to casing 210
thereby forming one solid piece. Conduit 220 can have a length
generally long enough to extend casing 210 to the bottom of hollow
tube 230. Alternatively, and preferably, conduit 220 can comprise
sections that can be removably coupled to one another, for example,
using male/female interfaces, to extend the length of conduit 220.
This may help make it easier to transport conduit 220. Conduit 220
can include a scale having incremental markings that indicate the
length of conduit 220. For example, the incremental markings can be
spaced one inch apart. The scale can help identify the depth of
casing 210.
[0081] FIGS. 6A-6F illustrate different views of an example casing
210 and related cover 218 that can be used, for example, in the
system 200. FIG. 6A is a front profile view illustrating casing 210
and cover 218. As illustrated, casing 210 can have a generally
cylindrical body 211 and a pointed tip 212. Casing 210 can include
a cavity 213 configured to house sensor S.sub.1 240 (not shown).
Casing 210 can further include a longitudinal channel 214 to route
a transmission line (not shown) from sensor S.sub.1 240 (not shown)
through casing 210. Casing 210 can further include a groove 215 to
facilitate routing the transmission line from cavity 213 to channel
214. Cover 218 can be used to cover cavity 213 to help protect
sensor S.sub.1 240 when casing 210 is in use. Cover 218 can be
removably coupled to casing 210, for example, with tab 217, which
is configured to engage notch 216 in casing 210. Other means
familiar to those of ordinary skill in the art can be used for
coupling cover 218 to casing 210.
[0082] FIG. 6B is a side profile view illustrating casing 210 and
cover 218. FIG. 6C is a rear profile view illustrating casing 210
and cover 218. FIG. 6D is a perspective view illustrating casing
210 and cover 218. FIG. 6E is a close-up perspective view
illustrating cover 218 and a partial view of casing 210. FIG. 6F is
a top perspective view illustrating casing 210 and cover 218. As
previously explained, channel 214 can be used to route a
transmission line from sensor S.sub.1 240. As illustrated in FIG.
6F, channel 214 can also be used as a female interface for coupling
casing 210 to conduit 220. For example, conduit 220 can have a male
stem configured to snugly engage channel 214. Other means familiar
to those of ordinary skill in the art can be used for coupling
casing 210 to conduit 220 such as a threaded male/female interface.
For example, channel 214 can have a female threaded portion
configured to engage a male threaded stem of conduit 220.
Alternatively, casing 210 can have a male threaded stem configured
to engage a female threaded portion of conduit 220. FIG. 6G is a
bottom profile view of casing 210 and cover 218. As best
illustrated in FIGS. 6C, 6E, and 6G, cover 218 can have a
half-cylindrical shape, which provides sensor S.sub.1 240 with
sufficient room when housed within cavity 213.
[0083] FIGS. 28A and 28B illustrate another example system 2800 for
providing a sensor S.sub.1 240 through hollow tube 230 to perform a
sampling event. As shown, casing 2810 includes a base portion 2808
configured to house sensor S.sub.1 240 and support transmission
line 2814 through and out of casing 2810. The transmission line
2814 can extend into a "U" shaped tube or conduit 2802 connected to
casing 2810 via a connection extension 2806 with one or more
fasteners 2816. Further, two or more conduits 2802 can be coupled
together via one or more couplers and/or cable tie-downs 2804,
secured by one or more fasteners 2818, to extend the reach of
casing 2810 (and therefore sensor S.sub.1 240). Casing 2810 can
have a removable cover 2812, which allows access to sensor S.sub.1
240. The cover 2812 can be secured by snap fit, fasteners,
adhesive, welding, etc., and can further include one or more
gaskets (e.g., foam, rubber, polymer, etc.) to seal the casing
interior from moisture, dirt, etc. In some examples, sensor S.sub.1
240 can be molded within casing 2810. In still other examples,
sensor S.sub.1 240 can be encased and/or molded within casing 2810
such that no cover 2812 is needed.
[0084] Casing 2810 and conduit 2802 can be configured to slidably
engage the hollow tube 230 directly, which can be dimensioned to
slidably engage hollow tube 230. For example, one or more of hollow
tube 230 and casing 2810 can be made of plastic, polyvinyl chloride
(PVC), metal, or any other suitable material such that casing 2810
is capable of sliding within channel 232 to different vertical
positions. In some examples, casing 2810 remains in contact with
hollow tube 230 to enable dispersive waves to be received by sensor
S.sub.1 240 housed within.
[0085] As disclosed herein, casing 2810 can be positioned at
different vertical positions within channel 232 by securing casing
2810 to conduit 2802, and inserting one or more connected conduits
into hollow tube 230. One or more such conduits 2802 can include a
scale having incremental markings that indicate the length of each
conduit. For example, the incremental markings can be spaced one
inch apart. The scale can help identify the depth of casing
2810.
[0086] In some examples, casing 2810 is fully or partially housed
within hollow tube 230, either in advance of driving hollow tube
230 into the ground and/or inserted following driving hollow tube
230 into the ground. In some examples, casing 2810 is configured to
extend beyond an end of the hollow tube 230, and can itself be
encased in an additional tip or other supportive structure (not
shown) to facilitate driving hollow tube 230 and/or casing 2810
into the earth. In some examples, casing 2810 is dimensioned to fit
within channel 232 and provided with a pointed tip 2820. In some
examples, casing 2810 is dimensioned larger than channel 232,
and/or may be fixed relative to hollow tube 230, such that
extensions to hollow tube 230 and conduit 2802 together extend the
reach of the sensor S.sub.1 240.
[0087] Conduit 2802 can further include a longitudinal channel to
route a transmission line 2814 from sensor S.sub.1 240 through
casing 2810 and to receiver 270. Further, the structure of conduit
2802 (e.g., the "U" shape), allows for directional orientation of
sensor S.sub.1 240, even when inserted into hollow tube 230 at a
substantial depth. FIG. 28B provides a view of the system 2800 with
hollow tube 230 removed, exposing the conduit 2802.
[0088] In order to indicate the directionality of the sensor within
hollow tube 230, a collar 2900 can be provided at an opening of one
or more sections of hollow tube 230, as shown in the example of
FIG. 29. Collar 2900 has a rectangular opening 2902 in the center
that ensures that the U-shaped conduit 2802 cannot spin inside the
tube, thereby ensuring that the orientation of sensor S.sub.1 240
is known and controlled during a sampling event. Collar 2900
includes direction arrows 2904 to orient the operator to place a
sensing face of sensor S.sub.1 240 towards the foundation. Although
described as a U-shaped conduit and substantially rectangular, any
geometry and/or shape can be employed while maintaining the
benefits of the disclosed system. For example, a generally
cylindrical conduit with one or more flat surfaces can be employed,
or a triangle or other shape with a flat or protruding surface to
prevent unwanted turning of the sensor, and the shape of the
opening 2902 can be adjusted accordingly.
[0089] FIG. 30 illustrates another view of the example conduit
2802. As shown, the conduit 2802 has a generally U-shape, with
channel 2824 providing access for the transmission line 2814. The
transmission line 2814 can be secured within the channel 2824 via
one or more cable tie-downs 2804, as shown in FIG. 31. In examples
employing multiple conduits 2802, the ends thereof can be joined by
a coupler 2826, as shown in FIG. 32. One or more of the cable
tie-downs 2804 and/or coupler 2826 can be secured to conduit 2802
via one or more fasteners and/or openings 2822 of the conduit
2802.
[0090] Returning to FIG. 2, system 200 can include a second sensor
S.sub.2 250. Sensor S.sub.2 250 can be removably coupled to rod
260, which can be driven through the Earth 108 and into contact
with buried concrete 102. Sensor S.sub.2 250 can be removably
coupled to rod 260 using, for example, a magnet. Other means of
removably coupling sensor S.sub.2 250 to rod 260 can be used. For
example, adhesives such as tape or glue, or wax can be used. Rod
260 can be driven into contact with buried concrete 102 at a
distance D.sub.2 from a vertical edge of buried concrete 102.
Distance D.sub.2 can be any distance that permits a dispersive wave
to be transmitted from the buried concrete 102 to hollow tube 230.
Preferably, distance D.sub.2 is within the range of about 1.5 to 3
feet, though other distances are possible and contemplated herein.
The location of the vertical edge of buried concrete 102 can be
determined or estimated using any method familiar to those of
ordinary skill in the art. For example, although not illustrated,
several rods can be driven into the Earth 108 in the proximity of
the concrete structure to map out an estimated geometry of buried
concrete 102.
[0091] Sensors S.sub.1 240 and S.sub.2 250 can be any type of
sensors or transducers capable of or suitable for capturing and/or
providing data relating to dispersive waves. In some embodiments,
sensors 240 and 250 can be accelerometers that output data
proportional to acceleration. For example, sensors 240 and 250 can
be capacitive micro-electro-mechanical systems (MEMS)
accelerometers, piezoresistive accelerometers, piezoelectric
accelerometers, or the like, or any combination thereof. In other
embodiments, sensors 240 and 250 can be velocity sensors that
output data proportional to velocity. For example, sensors 240 and
250 can be moving coil velocity sensors, piezoelectric velocity
sensors, or the like, or any combination thereof. In still other
embodiments, sensors 240 and 250 can be displacement sensors that
output data proportional to positional displacement. For example,
sensors 240 and 250 can be capacitive displacement sensors,
eddy-current displacement sensors, or the like, or any combination
thereof. In still other embodiments, sensors 240 and 250 can
include a combination of accelerometers, velocity sensors, and
displacement sensors.
[0092] As will be appreciated by those of ordinary skill in the
art, data output from sensors 240 and 250 can be processed,
transformed, or the like. For example, displacement data output
from a displacement sensor can be differentiated to provide
velocity data, and differentiated a second time to provide
acceleration data. Velocity data output from a velocity sensor can
be differentiated to provide acceleration data. Similarly,
acceleration data output from an accelerometer can be integrated to
provide velocity data, and integrated a second time to provide
displacement data. Velocity data output from a velocity sensor can
be integrated to provide displacement data. The skilled artisan
will appreciate that the processing or transforming of data can be
achieved with a combination of hardware and/or software.
[0093] Data from sensors 240 and 250 can be transmitted to a
receiver 270. For example, FIG. 7A is a simplified block diagram
illustrating sensors 240 and 250 in communication with a receiver
270 according to some embodiments. The output of sensors 240 and
250 can include analog signals, digital signals, pulse-width
modulated (PWM) signals, and other types of signals. Data generated
by sensors 240 and 250 (i.e., sensor data) can relate to time,
voltage, acceleration, velocity, displacement, and other
information. Sensor data can be transmitted from sensors 240 and
250 to receiver 270 via wired or wireless connections 242 and 252,
respectively. For example, in some embodiments, sensor data can be
transmitted to receiver 270 via coaxial transmission lines (e.g.,
as illustrated in FIGS. 2-5). Other types of wired connections may
also be used as will be apparent to those of skill in the art. In
other embodiments, sensor data can be transmitted from sensors 240
and 250 to receiver 270 via a suitable wireless technology such as,
for example, a radio frequency (RF) technology, near field
communication (NFC), Bluetooth, Bluetooth Low Energy, IEEE 802.11x
(i.e., Wi-Fi), Zigbee, Z-Wave, Infrared (IR), cellular, and other
types of wireless technologies as will be apparent to those of
skill in the art. Communication of sensor data from sensors 240 and
250 to receiver 270 can also comprise a combination of both wired
and/or wireless connections.
[0094] In some embodiments, such as that illustrated in FIG. 7B,
receiver 270 can be in communication with an external system 290.
In some embodiments, external system 290 can comprise a computing
device such as a tablet, smartphone, laptop computer, desktop
computer, or the like. For example, receiver 270 can be a data
acquisition device (DAQ) and external system 290 can be a computer.
In some embodiments, external system 290 can be a network, such as
a private network, the Internet, or the like. It should be noted
that external system 290 need not be a single system. Rather,
external system 290 can comprise a combination of computing
devices, networks, servers, the Internet, or the like.
Communication medium 292 can comprise a wired or wireless
connection. For example, in some embodiments, communication medium
292 can be a wired connection, such as a coaxial transmission line,
USB cable, Ethernet cable, and other types of wired connections as
will be apparent to those of skill in the art. In other
embodiments, communication medium 292 can be a suitable wireless
technology such as, for example, a radio frequency (RF) technology,
near field communication (NFC), Bluetooth, Bluetooth Low Energy,
IEEE 802.11x (i.e., Wi-Fi), Zigbee, Z-Wave, Infrared (IR),
cellular, and other types of wireless technologies as will be
apparent to those of skill in the art. In the case of external
system 290 comprising multiple systems or devices, communication
media 292 can comprise a combination of both wired and/or wireless
connections using any of the aforementioned technologies. Further,
external system 290 need not be located near receiver 270. Indeed,
receiver 270 can be located on a work site while external system
290 can be located elsewhere, such as an office or laboratory.
[0095] Receiver 270 can include hardware, firmware, and/or software
that generally enables a user to interact with the system, to
receive data from sensors 240 and 250, to process the data, to
analyze the data, to store the data, and/or to transmit the data to
external system 290. FIG. 7C is a block diagram illustrating an
example receiver 270 according to some embodiments. The receiver
270, which is communicatively coupled to sensors 240 and 250 via
communication media 242 and 252, respectively, can receive sensor
data from sensors 240 and 250 via an input/output (I/O) module 271.
The I/O module 271 can send the data to processor module 272.
[0096] Processor module 272 can be coupled to one or more memory
devices 273. The one or more memory devices 273 can store data,
such as data received from sensors 240 and 250, data received from
a user, and data received from an external system 290. The one or
more memory devices 273 can also store software 274 (i.e.,
computer-executable instructions). Processor module 272 can process
data, wherein the processing can include, for example, amplifying,
converting from analog to digital or digital to analog,
conditioning, filtering, and/or transforming the data. Processor
module 272 can also serve as a central control unit of receiver
270. For example, software 274 can comprise operating system
software, firmware, and other system software for controlling
receiver 270 and its components. Software 274 can further include
data processing software, application software, or the like, as
discussed in more detail below.
[0097] Receiver 270 can include a user interface 280 that comprises
input and output components configured to allow a user to interact
with receiver 270. For example, user interface 280 can include a
keyboard 281, mouse 282, trackpad 283, touch-sensitive screen 284,
one or more buttons 285, display 286, speaker 287, one or more LED
indicators 288, and microphone 289. Processor module 272 can
control user interface 280 and its components. For example,
processor module 272 can receive data and commands from input
components through I/O module 271 and provide data and commands to
output components through I/O module 271. Processor module 272 can
execute software 274 stored in the one or more memory devices 273
to cause a graphical user interface (GUI) to be displayed on
display 286. The GUI can provide the user with an intuitive and
user-friendly means for interacting with the system, including to
provide output to the user such as prompts, messages,
notifications, warnings, alarms, or the like.
[0098] The components of the user interface 280 include controls to
allow a user to interact with the receiver 270. For example, the
keyboard 281, mouse 282, and trackpad 283 can allow input from the
user. The touch-sensitive screen 284 can enable a user to interact
with the GUI, for example, by inputting information, making
selections, or the like. The one or more buttons 285 can provide
for quick and easy selection of options or modes, such as by
toggling functions on/off. The display 286 can be any type of
display, such as an LCD, LED, OLED, or the like. The display 286
can provide the user with visual output. The speaker 287 can
provide the user with audible output, such as by alerting the user
of notifications, warnings, alarms, or the like. The one or more
LED indicators 288 can provide the user with visual indications.
For example, one LED indication might represent whether there is
sufficient battery power, or whether the receiver is receiving
power from an external source. Another LED indication might inform
the user whether the receiver 270 is in an active state and
measuring data received from sensors 240 and 250. The microphone
289 can provide a user with the capability to control receiver 270
by voice. Although not illustrated, the user interface 280 can
include other components, such as a vibrating module to provide a
user with tactile signals or alerts, a backlight to facilitate
viewing the display in low light conditions, or the like.
[0099] As further illustrated in FIG. 7C, receiver 270 can include
communication module 275, which can comprise components, such as
transceivers, drivers, antennas, and the like, to enable
communication with various types of devices and systems. For
example, communication module 275 can include Ethernet ports, USB
ports, and ports for communicating over RS-232, RS-422, RS-485, and
other protocols. Communication module 275 can further include
antennas and other components typically used for wireless
communication, such analog frontend circuitry, A/D converters,
amplifiers, filters, and the like. Communication module 275 can
enable communication with an external system 290. For example, an
external system 290 may send commands or data to, or receive
commands or data from, receiver 270. Communication module 275 may
also enable receiver 270 to receive software updates. Thus,
communication module 275 is a two-way communication module that
enables receiver 270 to communicate with an external system 290 or
other devices.
[0100] As further illustrated in FIG. 7C, receiver 270 can include
a power supply 276, which can include rechargeable or disposable
batteries. Power supply 276 may also include circuitry to receive
power from an external source and to supply the necessary power to
receiver 270, such as through an AC adapter. In some embodiments,
the external source can be a computer that supplies power to
receiver 270 over a USB cable.
[0101] Receiver 270 can support various other functions. For
example, in some embodiments, receiver 270 can include the ability
to record and playback data events received from sensors 240 and
250, while also permitting for real-time display of the events. In
some embodiments, receiver 270 can include the ability to tag
events as they occur. For example, receiver 270 can include one or
more buttons 285 that enables a user to insert a marker onto data
in real-time. In some embodiments, receiver 270 can permit remote
control and monitoring. For example, receiver 270 can be
communicatively coupled to an external system 290 to enable the
external system 290 to view data events in real time and to control
receiver 270.
[0102] It should be noted that FIG. 7C is a block diagram and not a
strict architectural diagram. Thus, FIG. 7C generally illustrates
the components in receiver 270, some of which may be combined and
some of which may be separated. For example, some or all of the
functionality of the I/O module 271 might be combined with some or
all of the functionality of the communication module 275 and vice
versa. As another example, communication module 275 may comprise
several individual modules, some of which may communicate with
sensors 240 and 250 via wired or wireless connections, while others
may communicate with external system 290 via a wired or wireless
connection. As yet another example, processor module 272 may
comprise several components, such as discrete processing elements
for amplifying, converting, conditioning, filtering, and
transforming data, and a microprocessor and/or microcontroller for
controlling receiver 270 (in addition to performing other
functions, such as further processing data). Further, the blocks
illustrated in FIG. 7C are communicatively coupled in an
appropriate manner as would be appreciated by one of ordinary skill
in the art. For example, the components can be communicatively
coupled with a bus. Thus, commands, data, and other information
received from the I/O module 271 and communication module 275 could
be transmitted to processor module 272 for processing, storing, and
or other action. Similarly, processor 272 could transmit commands,
data, and other information to I/O module 271 and communication
module 272, as appropriate, to be further communicated to other
components, such as sensors 240 and 250, external system 290, and
user interface 280 and its components.
[0103] Software 274 on receiver 270 can be programmed to perform a
variety of functions. For example, as explained above, software 274
can comprise instructions that, when executed by processor module
272, cause processor module 272 to generate a graphical user
interface (GUI) on display 286. The GUI can allow a user to
interact with the system. Software 274 can further comprise
instructions that, when executed by processor module 272, cause
processor module 272 to receive data from sensors, process the
data, and analyze the data to determine whether the data is usable
or suitable for calculating a thickness of a buried concrete
structure. Software 274 can further comprise instructions that,
when executed by processor module 272, cause processor module 272
to analyze data received from sensors and calculate the thickness
of a buried concrete structure.
[0104] It should be noted that software 274 described herein is not
limited to residing on, or being executed by, receiver 270.
Instead, some or all of the software may reside on or be executed
by external system 290. As one non-limiting example, software 274
on receiver 270 may receive data from a sensor resulting from the
sensor being excited by a dispersive wave. Software 274 on receiver
270 can process the sensor data and provide feedback as to whether
the sensor data is usable or suitable to calculate a thickness of a
buried concrete structure. After a positive determination is made
for necessary data, the data can be analyzed in real time to
determine the thickness of the buried concrete structure.
Alternatively, the data can be stored and analyzed at a later time.
As another alternative, the sensor data can be communicated to
external system 290, which can include software that analyzes the
sensor data (in real time or at a later time) to determine a
thickness of the buried concrete structure. Thus, the inventions
disclosed herein contemplate a distributed architecture in which
sensor data can be procured and analyzed on site, off site, or a
combination of both.
[0105] Returning to FIG. 2, the general operation of the system 200
for estimating the thickness T of buried concrete 102 is now
provided. As disclosed herein, dry parallel seismic (dry PS)
testing is a nondestructive method for determining the thickness of
structural foundations (e.g., thin concrete) that are below-grade
(e.g., buried). Following an impact to the buried concrete portion
or pad generating one or more waves, resulting signals are
collected as one or more data sets at one or more (e.g.,
incremental) depths. In conventional methods, after a data set is
collected, it is necessary to have a signal analyst review the data
set manually before it could be determined conclusive enough to
make a prediction about the thickness of concrete. Requiring a
signal analyst to manually validate data, such as during a
so-called call-off process, poses a variety of problems, including
communication when field operators and signal analysts are located
in different time zones. The need therefore exists for system and
methods to avoid operator signal analysis and data evaluation.
[0106] Due to the inaccessibility of the surface of the buried
concrete portion, dry PS testing is used to determine thickness of
buried structural foundations. The dry PS test employs a rod that
is driven into the ground such that the rod comes into contact with
the buried concrete portion (e.g., a top surface of the foundation
pad). The rod is oriented perpendicular to a plane corresponding to
a horizontal surface of the buried concrete portion. An impulse is
generated by exciting an exposed portion (e.g., a top) of the rod,
such as by employing a striking instrument (e.g., a handheld
hammer, a mechanical force mechanism, etc.). The excitation
generates one or more waves that travel downward through the rod
and then through the concrete or other materials of the buried
concrete portion.
[0107] Some energy from the excitation is transmitted through the
concrete/soil boundary, which radiates outward into the surrounding
soil. One or more sensors can be arranged within a conduit, tube,
pipe or other physical channel. In some examples, the sensor(s) are
oriented relative to the buried concrete portion (e.g., parallel to
a vertical edge of the concrete of the structural foundation) to
detect arrival of the waves radiating outwardly from the buried
concrete portion. The sensor(s) generate signals associated with
the waves, which can be transmitted to a receiver 270 (e.g., via a
wired or wireless transmission channel) as explained above.
[0108] For example, as shown in FIG. 2, sensor S.sub.1 240 is
located in channel 232 at a distance approximately above the top
surface of buried concrete 102, a dispersive wave is generated and
transmitted down rod 260 to trigger sensor S.sub.2 250, which
represents time T.sub.0. A dispersive wave can be generated, for
example, by striking the top of rod 260. A dispersive wave can be
generated by other means, such as with an impact device. The
dispersive wave continues down rod 260 and is transmitted to buried
concrete 102. At least a portion of the dispersive wave is emanated
from the buried concrete 102, transmitted through the Earth 108,
and is received by hollow tube 230. The dispersive wave is
transmitted from hollow tube 230 to casing 210, which is in contact
with hollow tube 230. The wave is then transmitted to sensor
S.sub.1 240, which is in contact with casing 210. The time when the
dispersive wave triggers sensor S.sub.1 240 can represent time
T.sub.1. Sensor S.sub.1 240 can then be incrementally lowered to
various positions within channel 232, which is illustrated in FIG.
8. At each incremental position, the above process can be repeated
until sensor S.sub.1 240 is beneath the bottom of buried concrete
102. The time elapsed from T.sub.0 to T.sub.1 for each incremental
position can be correlated with the location of sensor S.sub.1 240
when each wave was generated to estimate the thickness of buried
concrete 102.
[0109] For example, FIG. 9A is a graph diagram illustrating an
example plot for estimating the thickness of buried concrete 102.
In FIG. 9A, time is plotted on the horizontal axis in microseconds
and the vertical position of sensor S.sub.1 240 is plotted on the
vertical axis in inches. In this example, sensors S.sub.1 and
S.sub.2 comprised accelerometers A.sub.1 240 and A.sub.2 250. In
the example graph of FIG. 9A, the arrival times of the dispersive
waves at accelerometer A.sub.2 250 (when accelerometer A.sub.2 250
is triggered at time T.sub.0) are represented by time=0 for each
waveform. The approximate arrival times of the dispersive waves at
accelerometer A.sub.1 240 (when accelerometer A.sub.1 240 is
triggered at time T.sub.1) are represented graphically as the point
at which each waveform transitions from an approximate steady state
to a non-zero amplitude. In this example, 23 measurements were made
(illustrated by the 23 waveforms) beginning with accelerometer
A.sub.1 240 placed at -37 inches, which represents the approximate
depth of accelerometer A.sub.1 240 below the surface of the ground
106. That depth may have been chosen, for example, by first
determining the approximate depth of the surface of the buried
concrete, then placing accelerometer A.sub.1 240 a short distance
above that depth. Each of the 22 subsequent measurements were made
by incrementally lowering accelerometer A.sub.1 240 by
approximately 2 inches. Thus, there are 23 values for T.sub.0 (all
of which are time=0) and 23 values for T.sub.1, each corresponding
to a different vertical position for accelerometer A.sub.1 240.
[0110] FIG. 9B is a graph diagram illustrating how the thickness of
buried concrete 102 can be estimated based on at least the times of
arrival of the dispersive waves at accelerometer A.sub.1 240. The
arrival times for the dispersive waves at accelerometer A.sub.1 240
that are substantially equal may be grouped. This is illustrated by
vertical line 902 in the example graph of FIG. 9B. The non-vertical
lines 904 and 906 in the example graph of FIG. 9B illustrate
arrival times that increase and/or decrease with depth, indicating
a spatial relationship between the time it takes the dispersive
wave to reach accelerometer A.sub.1 240 and the location of
accelerometer A.sub.1 240. In the example graph of FIG. 9B, 12
arrival times at accelerometer A.sub.1 240 are grouped (illustrated
by the 12 waveforms between the non-vertical lines 904 and 906).
Because each of these 12 arrival times corresponds to a 2-inch
incremental vertical displacement of accelerometer A.sub.1 240, it
can be estimated that the thickness of buried concrete 102 is
approximately 24 inches.
[0111] Several items are noted here. First, although the
explanation above and FIG. 8 illustrates sensor S.sub.1 240
beginning above buried concrete 102 and being incrementally
lowered, the invention is not limited in this fashion. For example,
sensor S.sub.1 240 can begin beneath buried concrete 102 and
incrementally raised. As another example, sensor S.sub.1 240 can be
placed at any position within channel 232 that is above, below, or
approximately equal to, the depth of buried concrete 102. The
thickness of the buried concrete 102 can still be estimated because
there will be a group of waveforms having substantially equal times
of arrival at sensor S.sub.1 240, and each waveform corresponds to
a vertical position (which can be known, for example, with a scale
labeled on connection 242 (if connection 242 is a wired connection)
or on conduit 220). Thus, the order in which sensor S.sub.1 240 is
placed in different vertical positions is not a limitation of the
invention.
[0112] Second, the example graphs of FIGS. 9A and 9B illustrate
ideal conditions in that the vertical placement of accelerometer
A.sub.1 240 was at approximately distance D.sub.1 each time a
measurement was made. In practice, these ideal conditions may not
always occur or be possible to achieve. For example, hollow tube
230 may be driven at a slight angle relative to a vertical edge of
the buried concrete 102. As a result, some measurements may be
taken at distance D.sub.1 while other measurements may deviate from
distance D.sub.1. Nevertheless, the thickness of buried concrete
102 can still be estimated because the times of arrival at
accelerometer A.sub.1 240 should have a definable trend. That is, a
group of waveforms should still exhibit approximately equal arrival
times with some constant delay factor, whereas the waveforms
corresponding to vertical placements for accelerometer A.sub.1 240
that are above or below buried concrete 102 should deviate by a
degree greater than the delay factor. As a result, vertical line
902 illustrated in FIG. 9B may be angled.
[0113] Third, although the invention described above utilized one
sensor that is incrementally displaced below the surface of the
ground for each measurement, multiple sensors can be used. For
example, similar results can be achieved by serially bundling
multiple sensors, such as accelerometers, in a vertical orientation
at known distances and incrementally moving the bundle. As one
example, two sensors can be bundled 2 inches apart in a vertical
direction. In this way, when one dispersive wave is generated, it
will trigger two sensors (not including sensor S.sub.2 250, which
is triggered at time T.sub.0), thereby cutting the amount of
measurements in half. As another example, 12 sensors can be bundled
1 inch apart in a vertical direction. Thus, from one dispersive
wave, it may be possible to determine 12 times of arrival that
correspond to 12 inches. Thus, the invention is not limited to
using any particular number of sensors.
[0114] FIG. 3 is a schematic diagram illustrating an alternative
example setup of a system 300 for estimating the thickness of
buried concrete 102. The primary differences between systems 200
and 300 concern where sensor S.sub.2 250 can be located and how a
dispersive wave is generated. As illustrated in FIG. 3, sensor
S.sub.2 250 can be removably coupled to exposed concrete 104
instead of to rod 260. Sensor S.sub.2 250 can be removably coupled
to exposed concrete 104 using, for example, wax. Other means of
removably coupling sensor S.sub.2 250 to exposed concrete 104 can
be used. For example, adhesives such as tape or glue can be used.
Additionally, a dispersive wave can be generated in system 300 by
exciting exposed concrete 104 instead of rod 260. Besides these
noted differences, the remainder of the general operation of system
300 is the same as the general operation of system 200. Therefore,
it will be appreciated that the other details explained in
connection with system 200 illustrated in FIG. 2 apply to system
300 illustrated in FIG. 3 and are therefore not repeated.
[0115] FIG. 4 is a schematic diagram illustrating an alternative
example setup of a system 400 for estimating the thickness of
buried concrete 102. The primary differences between systems 200
and 400 concern how sensor S.sub.1 240 can be placed at different
vertical positions in the Earth 108. As illustrated in FIG. 4,
sensor S.sub.1 240 can be placed at different vertical positions by
driving casing 210 directly into the Earth 108, for example, by
striking conduit 220. This is an alternative to a casing slidably
engaging a hollow tube as explained above in connection with FIG.
2.
[0116] FIG. 10 is a perspective view illustrating an example casing
210 and conduit 220 that can be used in system 400. Casing 210 can
include a pointed tip 212 to help facilitate driving casing 210
into the Earth 108. Casing 210 can further include a stem 219
having male threads configured to engage conduit 220. Casing 210
can further include a cavity 213 (shown in phantom in FIG. 10) that
is dimensioned to securably house sensor S.sub.1 240 (not
shown).
[0117] Conduit 220 can include a female threaded portion 222 (shown
in phantom in FIG. 10) configured to engage the stem 219 of casing
210. Conduit 220 can further include a slot 224 through which a
transmission line 242 (not shown) can be routed. Slot 224 can help
protect transmission line 242 from being damaged when casing 210 is
driven into the Earth 108. Conduit 220 can further include a stem
226 having male threads configured to engage a cap 228, which cap
228 can include a female threaded portion 229 (shown in phantom in
FIG. 10). Cap 228 can be secured to conduit 220 so that conduit 220
may be struck to drive casing 210 into the Earth 108. As previously
explained, conduit 220 can comprise one piece of a desired length,
or can comprise multiple sections that engage one another, for
example, using male/female interfaces (not shown), to extend
conduit 220 to a desired length. A longitudinal channel 214 (shown
in phantom in FIG. 10) can extend from cavity 213, through stem
219, and through conduit 220 to accommodate routing transmission
line 242 (not shown).
[0118] Casing 210 can comprise one piece or multiple pieces. For
example, as illustrated in FIG. 11A, casing 210 can comprise a tip
portion 210a and stem portion 210b. Sensor S.sub.1 240 (not shown)
can be secured in cavity 213 with transmission line 242 (not shown)
routed through longitudinal channel 214. Tip portion 210a can then
be permanently joined to stem portion 210b, for example, by
welding, to form casing 210 that is effectively one piece as
illustrated in FIG. 11B. Alternatively, and preferably, as
illustrated in FIG. 12A, casing 210 can comprise a primary assembly
210c and a removable portion 210d. Sensor S.sub.1 240 (not shown)
can be secured in cavity 213 with a transmission line 242 (not
shown) routed through longitudinal channel 214. Primary assembly
210c can then be joined with removable portion 210d as illustrated
in FIG. 12B and held together when conduit 220 engages stem 219. It
will be appreciated that other configurations are possible for
securing sensor S.sub.1 240 in casing 210 and that the example
embodiments shown in FIGS. 11A-12B are for illustration purposes
only.
[0119] Besides driving casing 210 directly into the Earth 108
instead of using hollow tube 230, the remainder of the general
operation of system 400 is the same as the general operation of
system 200. Therefore, it will be appreciated that the other
details explained in connection with system 200 illustrated in FIG.
2 apply to system 400 illustrated in FIG. 4 and are therefore not
repeated.
[0120] FIG. 5 is a schematic diagram illustrating an alternative
example setup of a system 500 for estimating the thickness of
buried concrete 102. As illustrated, sensor S.sub.2 250 can be
removably coupled to exposed concrete 104 and a dispersive wave
generated by exciting exposed concrete 104 as explained in
connection with system 300 of FIG. 3. Also as illustrated, sensor
S.sub.1 240 can be placed at different vertical positions by
driving casing 210 directly into the Earth 108, for example, by
impacting conduit 220 as explained in connection with system 400 of
FIG. 4. Thus, the other details and general operation of the system
500 is the same as the other details and general operation of the
previous systems and are therefore not repeated.
[0121] FIG. 13 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete. The method of FIG. 13
will be described with reference to system 200 shown in FIG. 2, but
is not so limited. In other examples, additional or alternative
systems or components can be used to perform the method of FIG. 13,
including, for example, systems 300, 400, or 500. Additionally, for
illustration purposes and convenience, sensors S.sub.1 and S.sub.2
comprise accelerometers A.sub.1 240 and A.sub.2 250 in the example
methods provided below. As noted elsewhere in this disclosure,
sensors S.sub.1 and S.sub.2 can be other types of sensors.
[0122] Upon starting at step 1302, a first accelerometer A.sub.1
240 is placed at a vertical position below the surface of the
ground 106 at step 1304. Accelerometer A.sub.1 240 can be placed
approximately at a first distance D.sub.1 from a vertical edge of
buried concrete 102. At step 1306, a dispersive wave is generated
in buried concrete 102. At step 1308, the time of arrival of the
dispersive wave at accelerometer A.sub.1 240 is measured. It is
possible that, at step 1308, the time of arrival of the dispersive
wave cannot accurately be determined. For example, the dispersive
wave generated at step 1306 may contain anomalies, for example, due
to interference from nearby sources. Other factors can cause
difficulty in determining a time of arrival. Therefore, at step
1310, it is determined whether the dispersive wave should be
regenerated at the same vertical position for accelerometer A.sub.1
240. If the wave should be regenerated, steps 1306 and 1308 can be
repeated.
[0123] If the wave does not have to be regenerated, it is
determined at step 1312 whether additional data is needed. For
example, the accuracy of estimating the thickness of buried
concrete 102 may be related to the incremental positions at which
accelerometer A.sub.1 240 is placed. Preferably, accelerometer
A.sub.1 240 is moved incrementally at distances of one inch and
include measurements taken when accelerometer A.sub.1 240 is
slightly above the surface of buried concrete 102, slightly below
the bottom of buried concrete 102, and in between the top and
bottom. Thus, if it determined at step 1312 that additional data is
needed, accelerometer A.sub.1 240 can be moved to another vertical
position below the surface of the ground at step 1314. Ideally,
accelerometer A.sub.1 240 is moved to another vertical position
that is approximately at distance D.sub.1 from the vertical edge of
buried concrete. Steps 1306 through 1312 can then be repeated for
the new vertical position. When it is determined at step 1312 that
additional data is not needed, at step 1316, the thickness of
buried concrete 102 can be estimated based on at least the times of
arrival of the dispersive waves at accelerometer A.sub.1 240. The
method ends at step 1318.
[0124] FIG. 14 is a flow diagram illustrating an example method for
placing accelerometer A.sub.1 240 at a plurality of vertical
positions below the surface of the ground 106. The method of FIG.
14 can be used, for example, in connection with method 1300 of FIG.
13.
[0125] Upon starting at step 1402, a depth of the top of the buried
concrete 102 can be determined relative to the surface of the
ground 106 at step 1404. For example, a rod can be driven into the
Earth 108 in the vicinity of where buried concrete 102 is expected
to be located. At step 1406, a hollow tube 230 having a channel 232
can be placed substantially parallel to a vertical edge of the
buried concrete 102. The hollow tube 230 can be placed such that it
extends beyond an estimated bottom of the buried concrete,
preferably, approximately 2 feet beyond the estimated bottom. At
step 1408, accelerometer A.sub.1 240 can be placed into the channel
232 and in (direct or indirect) contact with hollow tube 230 (e.g.,
by being placed directly in hollow tube 230 or by being encased in
casing 210, which can be in contact with hollow tube 230). At step
1410, accelerometer A.sub.1 240 can be moved to incremental
vertical positions within channel 232. The method ends at step
1412.
[0126] FIG. 15 is a flow diagram illustrating an example method for
generating a dispersive wave in the buried concrete 102. The method
of FIG. 15 can be used, for example, in connection with method 1300
of FIG. 13.
[0127] Upon starting at step 1502, a rod 260 can be placed into
contact with the buried concrete 102 at a second distance D.sub.2
from a vertical edge of buried concrete 102 (step 1504).
Preferably, D.sub.2 is within the range of 1.5 to 3 feet. At step
1506, a dispersive wave can be generated by exciting the top of rod
260. This should cause a dispersive wave to travel down rod 260 and
to be transmitted to buried concrete 102. The method ends at step
1508.
[0128] FIG. 16 is a flow diagram illustrating an example method for
determining a time of arrival of the dispersive wave at
accelerometer A.sub.1 240. The method of FIG. 16 can be used, for
example, in connection with method 1500 of FIG. 15.
[0129] Upon starting at step 1602, a second accelerometer A.sub.2
250 can be removably coupled to rod 260 at step 1604. Accelerometer
A.sub.2 250 can be removably coupled to rod 260, for example, with
a magnet. Preferably, accelerometer A.sub.2 250 is removably
coupled approximately 6 inches from the top of rod 260. However,
other distances for removably coupling accelerometer A.sub.2 250 to
rod 260 can be used and are contemplated herein. At step 1606, the
time elapsed for a dispersive wave to travel from accelerometer
A.sub.2 250 to accelerometer A.sub.1 240 can be determined. For
example, when the method of FIG. 16 is used in connection with the
method of FIG. 15, a dispersive wave can be generated by exciting
the top of rod 260. When the dispersive wave reaches accelerometer
A.sub.2 250, it can be used as a reference for measuring the time
it takes the wave to reach accelerometer A.sub.1 240. For example,
the time of arrival at accelerometer A.sub.2 250 can be considered
time T.sub.0 and the time of arrival at accelerometer A.sub.1 240
can be considered time T.sub.1. Thus, the elapsed time from
accelerometer A.sub.2 250 to accelerometer A.sub.1 240 can be
determined by subtracting T.sub.1 from T.sub.0. The method ends at
step 1608.
[0130] FIG. 17 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete 102. The method of FIG.
17 can be used, for example, in connection with method 1300 of FIG.
13.
[0131] Upon starting at step 1702, each time of arrival of the
dispersive wave at accelerometer A.sub.1 240 can be correlated with
each vertical position of accelerometer A.sub.1 240 when the time
of arrival was determined (step 1704). This can be achieved, for
example, using a graph similar to the graphs illustrated in FIGS.
9A and 9B. At step 1706, the times of arrival that are
substantially equal can be grouped as explained above in connection
with FIG. 9B. At step 1708, the thickness of buried concrete 102
can be estimated based on vertical positions of accelerometer
A.sub.1 240 that correspond to the times grouped in step 1706. The
method ends at step 1710.
[0132] FIG. 18 is a flow diagram illustrating an example method for
estimating the thickness of buried concrete. The method of FIG. 18
will be described with reference to system 200 shown in FIG. 2, but
is not so limited. In other examples, additional or alternative
systems or components can be used to perform the method of FIG.
18.
[0133] Upon starting at step 1802, a hollow tube 230 having a
channel 232 can be placed into the ground substantially parallel to
a vertical edge of the buried concrete 102 at a distance D.sub.1
from the vertical edge (step 1804). The hollow tube 230 can be
placed such that it extends beyond an estimated bottom of the
buried concrete, preferably, approximately 2 feet beyond the
estimated bottom. At step 1806, a rod 260 can be driven through the
Earth 108 and into contact with buried concrete 102 at a distance
D.sub.2. Preferably, distance D.sub.2 is within the range of 1.5 to
3 feet. At step 1808, a first accelerometer A.sub.1 240 can be
placed into the channel 232 and in (direct or indirect) contact
with hollow tube 230 (e.g., by being placed directly in hollow tube
230 or by being encased in casing 210, which can be in contact with
hollow tube 230). At step 1810, a second accelerometer A.sub.2 250
can be removably coupled to rod 260. Accelerometer A.sub.2 250 can
be removably coupled to rod 260, for example, with a magnet.
Preferably, accelerometer A.sub.2 250 is removably coupled
approximately 6 inches from the top of rod 260. However, other
distances for removably coupling accelerometer A.sub.2 250 to rod
260 can be used and are contemplated herein.
[0134] At step 1812, accelerometer A.sub.1 240 can be placed at a
first vertical position within channel 232. At step 1814, a
dispersive wave can be generated by exciting rod 260. At step 1816,
the time elapsed for a dispersive wave to travel from accelerometer
A.sub.2 250 to accelerometer A.sub.1 240 can be determined. For
example, when the dispersive wave is generated by impacting the top
of rod 260 in step 1814, the dispersive wave should travel down rod
260 and trigger accelerometer A.sub.2 250, which can be used as a
reference for measuring the time it takes the wave to reach
accelerometer A.sub.1 240. For example, the time of arrival at
accelerometer A.sub.2 250 can be considered time T.sub.0 and the
time of arrival at accelerometer A.sub.1 240 can be considered time
T.sub.1. Thus, the elapsed time from accelerometer A.sub.2 250 to
accelerometer A.sub.1 240 can be determined by subtracting T.sub.1
from T.sub.0.
[0135] It is possible that, at step 1816, the time of arrival of
the dispersive wave cannot be accurately determined. For example,
the dispersive wave generated at step 1814 may contain anomalies,
for example, due to interference from nearby sources. Other factors
can cause difficulty in determining a time of arrival. Therefore,
at step 1820, it is determined whether the dispersive wave should
be regenerated at the same vertical position for accelerometer
A.sub.1 240. If the wave should be regenerated, steps 1814 and 1816
can be repeated.
[0136] If the wave does not have to be regenerated, it is
determined at step 1822 whether additional data is needed as
explained above in connection with step 1312 of FIG. 13. If
additional data is needed, accelerometer A.sub.1 240 can be moved
to another vertical position below the surface of the ground 106 at
step 1824. Steps 1814 through 1822 can then be repeated for the new
vertical position.
[0137] When it is determined at step 1822 that additional data is
not needed, at step 1826, the time elapsed for the dispersive wave
to travel from accelerometer A.sub.2 250 to accelerometer A.sub.1
240 can be correlated with each vertical position of accelerometer
A.sub.1 240 when the elapsed times were determined. At step 1828,
the elapsed times that are substantially equal can be grouped. At
step 1830, the thickness of buried concrete 102 can be estimated
based on vertical positions of accelerometer A.sub.1 240 that
correspond to the elapsed times that were grouped in step 1828. The
method ends at step 1832.
[0138] FIG. 19 is a flow diagram illustrating an example method for
placing the first accelerometer A.sub.1 240 at a plurality of
vertical positions within channel 232. The method of FIG. 19 can be
used, for example, in connection with method 1800 of FIG. 18.
[0139] Upon starting at step 1902, accelerometer A.sub.1 240 can be
placed at a first vertical position within channel 232 that is
approximately above the top of the buried concrete 102 (step 1904).
At step 1906, accelerometer A.sub.1 240 can be incrementally
lowered in channel 232 to a plurality of positions until
accelerometer A.sub.1 240 is below an estimated bottom of the
buried concrete. For example, accelerometer A.sub.1 240 can be
lowered in channel 232 in increments of one inch. The method ends
at step 1908.
[0140] Although the inventive methods, including the methods of
FIGS. 13-19, are described in terms of vertically displacing a
first sensor S.sub.1 240 (in the examples, an accelerometer), as
previously explained, the inventive methods are not limited to
using one sensor, but rather can employ one or more first sensors.
For example, the inventive methods can use two first accelerometers
bundled together. As another example, the inventive methods can use
four velocity sensors bundled together. As yet another example, the
inventive methods can use 3 accelerometers and 3 displacement
sensors bundled together.
[0141] FIGS. 20-24 illustrate graph diagrams of example plots for
alternative or additional systems and methods of estimating the
thickness of buried concrete 102. In each example, sensors S.sub.1
and S.sub.2 comprise accelerometers A.sub.1 240 and A.sub.2 250 for
convenience and ease of explanation. As explained elsewhere in this
disclosure, sensors S.sub.1 and S.sub.2 can be other types of
sensors. The figures plot time on the horizontal axis
(microseconds) and the vertical position of accelerometer A.sub.1
240 on the vertical axis (in inches). In the example graph of FIGS.
20-24, the arrival times of the dispersive waves at accelerometer
A.sub.2 250 (when accelerometer A.sub.2 250 is triggered at time
T.sub.0) are represented by time=0 for each waveform. The
approximate arrival times of the dispersive waves at accelerometer
A.sub.1 240 (when accelerometer A.sub.1 240 is triggered at time
T.sub.1) are represented graphically as the point at which each
waveform transitions from an approximate steady state to a non-zero
amplitude. In this example, 29 measurements were made (illustrated
by the 29 waveforms) beginning with accelerometer A.sub.1 240
placed at -36 inches, which represents the approximate depth of
accelerometer A.sub.1 240 below the surface of the ground 106. That
depth may have been chosen, for example, by first determining the
approximate depth of the surface of the buried concrete, then
placing accelerometer A.sub.1 240 a short distance above that
depth. Each of the subsequent measurements were made by
incrementally lowering accelerometer A.sub.1 240 by approximately 2
inches. Thus, initial values for each signal are T.sub.0 (all of
which are time=0) and values for T.sub.1 each correspond to a
different vertical position for accelerometer A.sub.1 240. Based on
the data sets, a depth-time plot is generated.
[0142] In disclosed examples, systems and methods are provided
which include a post-processing routine employing software and/or
hardware to immediately determine whether the data collected with
the dry PS systems and methods is conclusive or inconclusive
without the need for an operator to analyze signals and/or to
validate data collection. For example, the systems and methods
receive signals from an impact to the concrete. In some examples,
the sensor(s) may detect the waves at one or more depths relative
to the surface of the ground and/or the buried concrete portion.
For instance, the sensor(s) can be moved (e.g., incrementally,
continuously, to predetermined depths, etc.) between detection
events.
[0143] Thus, data based on the signals generated by the sensor in
response to detection of the waves can then be plotted to generate
a depth vs. time plot, as shown in FIG. 20. The signals are
analyzed to provide data used to identify an inflection point at
which the arrival time of the waves (e.g., based on the data sets)
starts to shift (e.g., beyond a threshold level). Having generated
the depth vs. time plot, the receiver 270 (or external system 290)
can perform an analysis to identify an inflection point at which
the arrival time of the waves starts to shift beyond a threshold
level, as shown in FIG. 23.
[0144] From the inflection point, two or more best fit lines are
drawn above and/or below the inflection point along the depth vs.
time graph of wave arrival times, as shown in FIG. 22. For example,
two or more best fit lines are drawn above and/or below the
inflection point along a graph of wave arrival times. An
intersection point between two or more of the best fit lines is
used to calculate or estimate a depth of the bottom of the buried
concrete portion, as shown in FIGS. 24A and 24B. With calculated or
estimated depths of the top and bottom of the buried concrete
portion, the thickness of the buried concrete pad can be
calculated. In some examples, the receiver 270 (or external system
290) additionally or alternatively calculates the value represented
by the intersection point without plotting the values of depth and
time in a graph.
[0145] In disclosed examples, the systems and methods employ one or
more quality checks to the signal and/or data sets to ensure the
information received from sensors S.sub.1 240 and S.sub.2 250 will
provide conclusive results. For instance, an individual check
function is performed on each signal (e.g., as the wave is detected
and/or when the data is transmitted to the receiver 270 (or
external system 290)) to determine signal quality. One or more
characteristics of the signal can be compared against one or more
signal quality threshold values and, if the characteristics satisfy
the one or more thresholds, the receiver 270 (or external system
290) determines the signal quality is sufficient to generate a
conclusive result about the thickness of the buried concrete
structure.
[0146] As shown in FIGS. 21A and 21B, the arrival time of the wave
at each depth (e.g., a detection event) can be defined by a time
stamp of a negative peak 2102 immediately preceding a first
positive peak 2104 that exceeds a threshold prominence (e.g., an
amplitude, slope, absolute value, etc.). These times stamps are
used in calculating, determining, or otherwise estimating an
inflection point and/or the best-fit lines.
[0147] In some examples, a single time stamp is used to determine
arrival time, whereas in other examples multiple time stamps are
identified during a detection event. For instance, multiple time
stamps may come from positive peaks, negative peaks, or a
combination of both.
[0148] As shown in FIG. 23, analysis of the data sets and/or the
arrival times identifies an inflection depth, which is a depth at
which the arrival times increase most rapidly with depth. This
depth corresponds to the calculated, determined, estimated and/or
plotted inflection point in the data, which is used to calculate or
estimate the depth of the buried concrete portion.
[0149] The inflection depth can be identified through analysis of
one or more groupings of signals. For example, one or more groups
of signals collected over a number of sampling events during a
depth measurement operation are identified, starting from signals
detected at a shallow depth (e.g., least negative), to signals
detected at a greater depth. Multiple signals may be detected
between the two, as the sensor is moved within the channel (e.g.,
at predetermined increments). In some examples, a first group may
contain a first number of signals, and a second group may contain a
second number of signals, which may or may not overlap. In some
examples, the first group would include signals from a first depth
(e.g., corresponding to a top surface of the pad foundation) to a
second depth (e.g., a predetermined depth below the top surface).
The second group of signals would include signals from a third
depth between the first and second depths to a fourth depth greater
than the second depth. A third group of signals would include
signals from a fifth depth between the third and fourth depths to a
sixth depth greater than the fourth depth, and so on.
[0150] In an example, the number of signals in each group does not
vary throughout data collection. In some examples, the number of
signals in each group can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30
or more, less, or any intermediate number of signals. In some
examples, the number of signals in each group can vary. In some
examples, seven signals per group may be used. For example, in a
data set with 36 signals, the first group of signals (e.g., at the
shallowest depth) includes signals from a depth between 1-7 units
(e.g., inches, centimeters, meters, etc.), the second group
includes signals from depths between 2-8 units, the third group
includes signals from depths between 3-9 units, and so on, until
the last group includes signals between depths 30-36. For each
group of signals a corresponding slope is calculated based on the
arrival times of the dispersive waves, as disclosed herein.
[0151] Once the signals are grouped and/or analyzed, a best-fit
line 2106 can be calculated for the wave-arrival time stamps for
each of the groups of signals, as shown in FIG. 22. Analysis of the
line slope identifies a drop, which corresponds to an increase in
depth. As the wave arrival times increase with depth, a drop of the
slope beyond a threshold amount indicates that the sensor has
reached a depth below the bottom of the buried concrete portion.
Therefore, the location of the greatest decrease in the slope(s) of
the lines is identified as corresponding to the inflection depth or
point, as shown in FIG. 23. In some examples, identification of a
first drop in the slope beyond a threshold amount may be used to
identify the inflection point in addition to or in the alternative
of identification of a maximum drop in the slope. In some examples,
the depth at which the maximum error or residual of each line
occurs is used to identify the inflection point.
[0152] In an example employing multiple time stamps for each
signal, two or more methods or techniques may be used to calculate
an inflection depth. For instance, an algorithm may be used to fit
best-fit lines to all possible combinations of time stamps within
the group, using just one time stamp from each signal. The best-fit
line with the lowest residual would be chosen as the line to use
for each group. In some examples, all time stamps, their associated
amplitudes, and the known depth of the buried concrete portion may
be used in a training dataset for a machine-learning model that
will predict buried concrete portion thickness.
[0153] Once the inflection depth is determined, first best-fit line
2106A and second best-fit lines 2106B--one above and one below the
inflection point--are calculated, estimated, or otherwise
determined for a predetermined number of points above and below the
inflection depth, as shown in FIGS. 24A and 24B. One or more of the
best-fit lines may include the inflection-depth point, or may start
some number of points above and/or below the inflection-depth
point.
[0154] FIG. 24B illustrates a detail view 2402 of FIG. 24A. Within
view 2402, an intersection point 2108 of the first and second
best-fit lines is calculated, and the depth-coordinate of this
intersection is determined as the depth of the bottom of the buried
concrete portion. In this example, the first signal was recorded
with the sensor at a depth equal to the top surface of the buried
concrete portion. Thus, the depth corresponding to the intersection
point 2108 is the buried concrete portion thickness.
[0155] In some examples, one or more sensors (e.g., the first
sensor S.sub.1) can monitor for dispersive waves at a variety of
depths. For instance, an inflection depth can be determined for a
top surface of the buried concrete based on arrival times of
dispersive waves. First and second best-fit lines can be
determined, and the intersection point calculated or estimated, the
value of the intersection point corresponding to a value of the
depth of the top surface of the buried concrete. Therefore, the top
surface of the buried concrete may be determined in a manner
similar to the disclosed examples of determining a depth
corresponding to the bottom surface of the buried concrete, in
addition to or in the alternative of determining the depth of the
top surface physically.
[0156] Accordingly, the thickness of buried concrete can be
determined in different ways. For example, the depth of the top
surface of the buried concrete may be determined physically (e.g.,
by driving a rod to the top surface and measuring the distance
driven), the depth of the bottom surface determined by identifying
an inflection depth and the intersection of two best-fit lines, and
the thickness of the buried concrete calculated as the distance
from the measured depth of the top surface to the intersection of
the best-fit lines. As another example, the depth of the top
surface of the buried concrete can be determined by identifying a
top surface inflection depth and a top surface intersection of two
best-fit lines, the depth of the bottom surface determined by
identifying a bottom surface inflection depth and a bottom surface
intersection of two best-fit lines, and the thickness of the buried
concrete calculated as the distance from the top surface
intersection to the bottom surface intersection. Further, it will
be appreciated that a rough estimate of the thickness of the buried
concrete can be determined as the distance between the top surface
inflection depth and the bottom surface inflection depth (or the
measured depth of the top surface to the bottom surface inflection
depth).
[0157] In some examples, one or more concrete pads may be arranged
below ground, such as a series of layers forming the foundation
and/or surrounding features (e.g., bedrock, soil, structural
features of the building, etc.).
[0158] In some examples, one or more layers of the buried
foundation may be constructed of the same material. In some
examples, one or more layers of the buried foundation are
constructed of different materials, which may be identified
separately based on different arrival times, wave characteristics,
etc. Accordingly, the disclosed systems may be configured to
identify an interface between layers, and therefore identify depths
of the interfaces and/or individual layers.
[0159] In some disclosed examples, the systems and methods
incorporate one or more filtering and/or checks to ensure the
collected signals and/or data will yield a conclusive depth
measurement. Some of the filtering and/or checks can be performed
on individual signals collected from the sensors. Other filtering
and/or checks can be performed on the overall signals and/or data
collected.
[0160] For instance, a pre-trigger noise check function can check
each signal in the overall analysis for large amplitudes in the
first 600 pings of the signal. A different number of pings may also
be used and are contemplated herein. The overall pre-trigger noise
check function can include applying a Short Kernel Method (SKM)
filter to the raw signals before checking for fluctuations. Also,
if the pre-trigger noise exceeds a maximum allowable threshold, the
signal is kept but the wave arrival time(s) of that signal is not
used in the overall analysis. This check function is mainly for use
on legacy data that has noisier signals and may be used a backup
check on future data where individual check functions may eliminate
this problem.
[0161] A depth determination is considered valid once the overall
analysis is determined to be conclusive. One or more criteria are
applied to the data and/or analysis to determine conclusiveness. A
non-limiting list of possible inconclusive events include a high
number of missing wave-arrival point; lack of a clear inflection
point; a low number of points to generate best-fit lines; plotted
points fail to generate a qualifying best-fit line; lack of a clear
difference in slope between best-fit lines; or a system failure, as
shown in FIG. 27.
[0162] Although rare, if a crash occurs in the software or hardware
associated with the depth measurement, the results may be rendered
inconclusive. A crash may include acquisition of poor signal
quality and/or data sets, which would also be considered
unacceptable.
[0163] As explained elsewhere in this disclosure, sensors S.sub.1
240 and S.sub.2 250 are used to collect impact signals, and are
operably connected to receiver 270. The receiver 270 may be
connected to or incorporated within an external system 290 (e.g., a
remote computer, a portable or hand-held device such as a tablet or
smartphone, etc.) via a communications channel (e.g., wireless
transmission, wired connection, universal serial bus (USB), etc.)
and receives the impact signals traveling from the buried concrete
portion. The data collection, transmission, and/or analysis process
is controlled by one or more software instructions and/or
algorithms, and in some examples, a dry PS post-processing routine
is included.
[0164] For instance, the post-processing routine can include two or
more parts, such as the individual signal checks and an overall
signal analysis.
[0165] The individual signal checks make sure that each signal is
of sufficient quality or fidelity to be analyzed via the overall
signal analysis. In some examples, the results from the individual
signal checks are provided or otherwise presented to an operator as
data is collected. For example, a display or alert can be presented
to the operator with receiver 270 to indicate that the signal has
failed to satisfy one or more thresholds, and indicate another
sampling event and/or detection event is required to proceed with
analysis.
[0166] In some examples, the overall signal analysis takes some or
all signals from the entire data set into account. As a result,
data and/or signal validation via a manual call-off process may not
require a signal analyst (e.g., a human reviewer or administrator).
The overall signal analysis determines whether the data set is
conclusive or not. If the data is determined to be conclusive, the
systems and methods disclosed herein proceeds to calculate or
estimate the depth at the bottom of the buried concrete portion. If
the data is determined to be inconclusive, however, the operator
may be required to perform a new sampling event and collect new
data sets.
[0167] FIG. 25 is a flow diagram illustrating an example method for
estimating the thickness of a buried concrete portion (e.g.,
foundation pad). The method of FIG. 25 will be described with
reference to system 200 shown in FIG. 2, but is not so limited. In
other examples, additional or alternative systems or components can
be used to perform the method of FIG. 25. Additionally, for
illustration purposes and convenience, sensors S.sub.1 and S.sub.2
comprise accelerometers A.sub.1 240 and A.sub.2 250 in the example
methods provided below. As noted elsewhere in this disclosure,
sensors S.sub.1 and S.sub.2 can be other types of sensors.
[0168] Upon starting at step 2502, a hollow tube 230 having a
channel 232 can be placed into the ground substantially parallel to
a vertical edge of the buried concrete 102 at a distance D.sub.1
from the vertical edge (step 2504). The hollow tube 230 can be
placed such that it extends beyond an estimated bottom of the
buried concrete pad (e.g., approximately 2 feet beyond the
estimated bottom). At step 2506, a rod 260 can be driven through
the Earth 108 and into contact with buried concrete pad 102 at a
distance D.sub.2. In some examples, distance D.sub.2 is within the
range of 1.5 to 3 feet, although other ranges can be used depending
on the application. At step 2508, a first accelerometer A.sub.1 240
can be placed into the channel 232 and in (direct or indirect)
contact with hollow tube 230 (e.g., by being placed directly in
hollow tube 230, or by being encased in casing 210, which can be in
contact with hollow tube 230). In additional or alternative
examples, a second accelerometer A.sub.2 250 can be removably
coupled to rod 260. Accelerometer A.sub.2 250 can be removably
coupled to rod 260, for example, with a magnet or other fastener.
In some examples, accelerometer A.sub.2 250 is removably coupled
approximately 6 inches from the top of rod 260. However, other
distances for removably coupling accelerometer A.sub.2 250 to rod
260 can be used and are contemplated herein.
[0169] At step 2510, accelerometer A.sub.1 240 can be placed at a
first vertical position within channel 232. At step 2512, a
dispersive wave can be generated by impacting rod 260. At step
2514, the time elapsed for a dispersive wave to travel from the
approximately horizontal distance D.sub.1 from the concrete pad to
accelerometer A.sub.1 240 can be determined. For example, when the
dispersive wave is generated by impacting the top of rod 260 in
step 2512, the dispersive wave should travel down rod 260 and
trigger accelerometer A.sub.2 250, which can be used as a reference
for measuring the time it takes the wave to reach accelerometer
A.sub.1 240. For example, the time of arrival at accelerometer
A.sub.2 250 can be considered time T.sub.0 and the time of arrival
at accelerometer A.sub.1 240 can be considered time T.sub.1. Thus,
the elapsed time from accelerometer A.sub.2 250 to accelerometer
A.sub.1 240 can be determined by subtracting T.sub.1 from
T.sub.0.
[0170] At step 2516, one or more filters and/or function checks may
be applied to the signals and/or data sets to determine whether the
signals and/or data sets are of sufficient quality to calculate or
estimate a conclusive depth measurement. For instance, it is
possible that, at step 2516, the time of arrival of the dispersive
wave cannot be accurately determined. For example, the dispersive
wave generated at step 2514 may contain anomalies, for example, due
to interference from nearby sources. Other factors can cause
difficulty in determining a time of arrival. The process of
filtering and/or determining the quality of a received signal
and/or data set is described in greater detail in FIG. 26.
[0171] If the data does not satisfy the applied criteria or meet
the required data quality thresholds, the method can return to step
2512 to repeat the impact and again detect the signals and/or data
from the impact. Therefore, at step 2518, it is determined whether
the dispersive wave should be regenerated at the same vertical
position for accelerometer A.sub.1 240. If the wave should be
regenerated, steps 2514 and 2516 can be repeated.
[0172] If the signals and data are sufficient to provide a
conclusive depth calculation, the wave does not have to be
regenerated, it is determined at step 2518 whether additional data
is needed. In particular, if additional data is needed, at optional
step 2520 accelerometer A.sub.1 240 can be moved to another
vertical position below the surface of the ground 106. The method
then returns to step 2512, such that steps 2512 through 2518 can
then be repeated for the new vertical position.
[0173] When it is determined at step 2518 that additional data is
not needed, at step 2522, the time elapsed for the dispersive wave
to travel from accelerometer A.sub.2 250 to accelerometer A.sub.1
240 can be correlated with each vertical position of accelerometer
A.sub.1 240 when the elapsed times were determined. At step 2524,
the data corresponding to each dispersive wave can be analyzed, as
provided in greater detail in FIG. 27. At step 2526, the thickness
of buried concrete 102 can be estimated based on data collected by
the accelerometer A.sub.1 at the one or more vertical positions an
corresponding elapsed times for each wave. The method ends at step
2528.
[0174] FIG. 26 is a flow diagram illustrating an example method for
applying filters and/or threshold values to the signals and/or data
sets. The method of FIG. 26 will be described with reference to
system 200 shown in FIG. 2, but is not so limited. In other
examples, additional or alternative systems or components can be
used to perform the method of FIG. 26. In practice, the method of
FIG. 26 may be implemented with a combination of hardware and
software, such as hardware and software in receiver 270 and/or
external system 290.
[0175] Continuing from block 2516 of FIG. 25, step 2602 initiates
one or more filter and/or check routines on the signals and/or data
(e.g., received at the receiver 270 (or external system 290)). For
example, the signals and/or data may be subjected to filtering
(e.g., for one or more signal characteristics) and/or one or more
criteria thresholds to determine whether the signals and/or data
are of sufficient quality to provide a conclusive result. For
example, all waves detected by the accelerometer(s) are subjected
to one or more of a pre-trigger noise check function and/or a dead
gauge check function.
[0176] As provided in step 2604, a pre-trigger signal check can be
performed on all incoming signals. An example pre-trigger noise
check function analyzes raw signal characteristics for fluctuations
that exceed one or more thresholds (e.g., positive or negative)
within a predetermined sampling period (e.g., within a given time,
a threshold number (600) of pings, etc.).
[0177] In some examples, a dead gauge check can be performed on
incoming signals in step 2606. For instance, the signals can be
subjected to a dead-gauge check function check to determine whether
the signal(s) have a sufficient amplitude (e.g., as compared to one
or more threshold amplitudes) to provide a conclusive result.
[0178] In some examples, an overall analysis can be performed on
incoming signals and/or data sets in step 2608. Accordingly,
additional or alternative filtering can be performed to reduce or
eliminate noise in the signal and/or reduce or eliminate values
outside a predetermined range or threshold. For instance, one or
more of the detected signals is filtered using a Short Kernel
Method (SKM) filter, which removes frequencies greater than one or
more threshold filter frequencies. The filter frequency, which is
typically in the range of 500 to 1000 Hz, may be hard-coded in an
algorithm implementing the pad thickness, or the range may be
adjustable (e.g., determined by an algorithm based on one or more
conditions, selected by an operator, etc.).
[0179] In step 2610, the system can determine whether the signals
and/or data that have been subjected to analysis satisfy the
applied criteria and/or thresholds. If not, the data is deemed
inconclusive in step 2612, and the sampling event may be repeated
(such as returning to step 2512 of FIG. 25). If the data does
satisfy the applied criteria and/or thresholds, the method proceeds
to step 2614, where the system determines whether a sufficient
number of signals have been accepted. For example, a smaller number
of signals may have satisfied the thresholds than is needed to
conclusively calculate or estimate the depth measurement. If the
number of signals is insufficient, the data is deemed inconclusive
in step 2616, and the sampling event may be repeated (such as
returning to step 2512 of FIG. 25). If the number of signals is
sufficient, the data is deemed conclusive, and the method may
proceed to step 2518 of FIG. 25 to determine whether additional
data is needed.
[0180] As disclosed herein, if a signal (or data set) fails one of
these functions, the signal may be ignored and/or the particular
detection event (e.g., at the particular depth) may be repeated
until the signal(s) and/or data satisfy all required conditions. If
a large enough number of the signals and/or data sets fail these
functions (e.g., beyond a threshold amount), the entire sampling
event may need to be repeated.
[0181] FIG. 27 is a flow diagram illustrating an example method for
analyzing data corresponding to each dispersive wave. The method of
FIG. 27 will be described with reference to system 200 shown in
FIG. 2, but is not so limited. In other examples, additional or
alternative systems or components can be used to perform the method
of FIG. 27. In practice, the method of FIG. 27 may be implemented
with a combination of hardware and software, such as hardware and
software in receiver 270 and/or external system 290.
[0182] Continuing from block 2524 of FIG. 25, step 2702 analyzes
the signals to determine one or more peaks (e.g., a positive and/or
negative peak) corresponding to each depth where a sampling event
occurred. At step 2704, the method compares the peaks to one or
more threshold values to determine whether the signal
characteristics are sufficient to provide a conclusive result.
[0183] In some examples, after filtering and/or function checks, a
number of wave-arrival points may be eliminated. As a result, a
number of wave-arrival-time time stamps for those signals is
missing. For instance, if a number of adjacent points exceed a
threshold value, or if a proportion of a given group of adjacent
signals' arrival-time points are missing, the results may be
rendered inconclusive.
[0184] If not, the data is deemed inconclusive in step 2706, and
the sampling event may be repeated (such as returning to step 2512
of FIG. 25). If the number and/or quality of the peaks are
sufficient, the data is deemed conclusive, and the method may
proceed to step 2708 to identify an inflection depth. If the
magnitude of the greatest negative-change in slope of the group
best-fit lines does not exceed a minimum threshold value, there is
no clear inflection point, and the results may be rendered
inconclusive.
[0185] In step 2710, one or more best-fit lines can be determined
(e.g., by drawing a best fit line on a plotted graph, and/or
calculating based on peak values). For example, a first best-fit
line can be determined on a first side (e.g., corresponding to
shallower depths than the inflection depth) of a point on the
plotted graph corresponding to the inflection depth (e.g., the
inflection point), and a second best-fit line can be determined on
a second side (e.g., corresponding to deeper depths than the
inflection depth) of the point corresponding to the inflection
depth. The first and second best-fit lines are fit to wave-arrival
points immediately above and immediately below the inflection
point. If a number of points missing in these areas exceeds a
threshold number, there are not enough points to accurately
calculate the best-fit lines, and the results may be rendered
inconclusive.
[0186] Once the best-fit lines are determined, the lines are
compared with one or more threshold values in step 2712. For
example, if plots of peaks do not result in a line sufficient to
provide a conclusive result (e.g., insufficient number of peaks,
variations between adjacent peaks exceed a threshold amount), the
data is deemed inconclusive in step 2714, and the sampling event
may be repeated (such as returning to step 2512 of FIG. 25).
[0187] If the plotted points fail to generate a qualifying best-fit
line on one or both of the first and second best-fit lines, the
results may be rendered inconclusive.
[0188] If the best-fit lines do satisfy the applied thresholds, the
method proceeds to step 2716 to determine first and second slopes
corresponding to the first and second best-fit lines, respectively.
At step 2718, the first and second slopes are compared to a
threshold amount. If the difference between the slopes does not
exceed a threshold amount, the data is deemed inconclusive in step
2720, and the sampling event may be repeated (such as returning to
step 2512 of FIG. 25).
[0189] Once plotted, the slopes of the first and second best-fit
lines may be too close (e.g., their slopes do not differ greater
than a threshold amount). As the depth-coordinate of the
intersection point is sensitive to the location of each line, even
slight adjustments of the slope of one or both lines would produce
a large change in the predicted depth. Therefore, if the difference
between the slopes does not exceed a threshold amount, the slopes
are considered too close, and the results may be rendered
inconclusive.
[0190] If the slope does exceed the threshold amount, the method
proceeds to step 2722 to calculate or estimate an intersection
point between the first and second best-fit lines. At step 2724,
the depth of the buried concrete 102 (e.g., a bottom surface) is
calculated or estimated based on the intersection point. The
process then proceeds to step 2526 of FIG. 25 to estimate the
thickness of buried concrete 102.
[0191] Any number of peaks (positive and/or negative) may be
utilized in determining one or more slopes of one or more of the
best-fit lines (or group lines). In some examples, best-fit lines
may be replaced with an entirely different system and/or method of
calculating or estimating buried concrete portion depth.
[0192] In some examples, the systems and/or methods are executed on
a predetermined routine (e.g., algorithms and/or instructions
stored on a memory device) and/or circuit pathways (e.g., hardware
or firmware, printed circuit boards, etc.). In some examples, one
or more routines are informed and/or implemented via
machine-learning techniques to calculate or estimate the buried
concrete portion depth. For instance, a machine-learning model may
be trained using a library of datasets consisting of known buried
concrete portion depths, numerous peaks (e.g., time stamps and/or
amplitudes) corresponding to each signal, and/or the signals
themselves. This model (or application) may utilize best-fit lines
from the post-processing routine, time-stamps and/or amplitudes of
peaks extracted from each signal or data set, or a combination of
one or more features.
[0193] While particular embodiments have been shown and described,
it will be apparent to those skilled in the art that various
changes and modifications in form and details may be made therein
without departing from the spirit and scope of this disclosure and
are intended to form a part of the invention as defined by the
following claims, which are to be interpreted in the broadest sense
allowable by law. Further, the sequence of steps for the example
methods described or illustrated herein are not to be construed as
necessarily requiring their performance in the particular order
described or illustrated unless specifically identified as
requiring so or clearly identified through context. Moreover, the
example methods may omit one or more steps described or
illustrated, or may include additional steps in addition to those
described or illustrated. Thus, one of ordinary skill in the art,
using the disclosures provided herein, will appreciate that various
steps of the example methods can be omitted, rearranged, combined,
and/or adapted in various ways without departing from the spirit
and scope of the inventions. Additionally, while the disclosed
systems and methods have been explained in terms of measuring
dispersive waves in concrete, it is contemplated that the systems
and methods can be applied to other dispersive media.
* * * * *