U.S. patent application number 10/752998 was filed with the patent office on 2004-09-16 for protective wall panel assembly.
Invention is credited to Hanks, Jeffrey Alan.
Application Number | 20040177568 10/752998 |
Document ID | / |
Family ID | 32771939 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040177568 |
Kind Code |
A1 |
Hanks, Jeffrey Alan |
September 16, 2004 |
Protective wall panel assembly
Abstract
An assembly of wall panels particularly suitable for protection
against wind blown debris or an explosion includes a bent strap
connecting an air gap between adjacent wall panels with the bent
strap capable of flexing due to a sudden external force.
Inventors: |
Hanks, Jeffrey Alan;
(Midlothian, VA) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
32771939 |
Appl. No.: |
10/752998 |
Filed: |
January 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60441535 |
Jan 21, 2003 |
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Current U.S.
Class: |
52/79.1 |
Current CPC
Class: |
E04H 9/14 20130101; E04B
2001/6195 20130101; E04B 1/6116 20130101; Y02A 50/00 20180101 |
Class at
Publication: |
052/079.1 |
International
Class: |
E04H 001/00; E04H
014/00 |
Claims
What is claimed:
1. An assembly of wall panels comprising; (a) at least two wall
panels positioned in a non-planer orientation to one another
wherein an air gap is present between two adjacent wall panels; (b)
at least one bent strap spanning the air gap between two adjacent
wall panels wherein the bent strap is rigidly connected to adjacent
wall panels and wherein the strap is capable of flexing due to a
force on a wall panel.
2. The assembly of claim 1 with individual straps connecting inner
and outer surfaces of adjustment wall panels.
3. The assembly of claim 1 with one wall panel connecting to two
wall panels with individual straps.
4. The assembly of claim 1 where the strap comprises a band.
5. The assembly of claim 1 wherein the straps comprises a
plate.
6. The assembly of claim 1 wherein the strap comprises metal.
7. The assembly of claim 6 wherein the strap comprises steel.
8. The assembly of claim 6 wherein the strap comprises
aluminum.
9. The assembly of claim 1 wherein the strap comprises a
composite.
10. The assembly of claim 1 wherein wall panels are positioned at
an angle between 30 and 120 degrees on to another.
11. The assembly of claim 1 wherein with a gap of at least 0.125
inches (3 mm) between adjoining wall panels.
12. The assembly of claim 1 wherein a single metal strap is
used.
13. The assembly of claim 1 wherein a double metal strap is
used.
14. The assembly of claim 1 wherein the straps are between 0.075
inches (0.19 mm) and 0.150 inches (3.8 mm).
15. The assembly of claim 1 wherein one wall panel comprises in
order: (a) a layer of material having a density not greater than
0.10 grams per cubic centimeter, (b) a layer of a fabric containing
fibers bonded with a resin, (c) a layer of structural sheathing.
wherein the fabric layer will deflect in a range from 5.0 to 17.5
centimeters when impacted by a 33 kilogram (15 pound) projectile at
a speed of 161 kilometers (100 miles) per hour in accordance with
ASTM test procedure E1886-97 with said composite mounted on a rigid
frame.
16. The assembly of claim 1 wherein the strap is capable of flexing
due to an external force from wind blown debris or an explosive
blast.
17. The assembly of claim 16 wherein the stap is capable of flexing
due to debris at a wind speed of 100 miles per hour.
Description
TECHNICAL FIELD
[0001] The invention relates to a method for the assembly of
protective wall panels using a bent strap-joint to provide improved
resistance to impact loads such as generated by severe storm events
and explosive blasts.
BACKGROUND OF THE INVENTION
[0002] Storm and blast shelters are necessary to provide a safe
haven for civilian protection against severe storm events in
regions prone to tornado or hurricane activity and military
protection from explosive blast events. Protective wall and
building designs are known in the art and take on various forms.
Wall designs proposed for severe storm events are detailed in
various reports developed for, or by, the Federal Emergency
Management Agency (FEMA). Various wall designs for blast resistant
shelters are detailed in patent art.
[0003] In Taking Shelter from the Storm (FEMA Publication 320) and
Design and Construction Guidance for Community Shelters--(FEMA
Publication 361) design for construction of walls and buildings to
resist tornado generated wind loads and debris impact are
described. Wind impact resistant walls of other designs are
detailed in a report dated May 31, 2000 by Clemson University
submitted to the Federal Emergency Management Agency entitled
"Enhanced Protection for Severe Wind Storms. While these designs do
not meet Tornado Impact criteria, they do provide enhanced
protection from less severe storms.
[0004] U.S. Pat. No. 3,994,105, U.S. Pat. No. 4,143,501, U.S. Pat.
No. 4,566,237, U.S. Pat. No. 4,691,483, U.S. Pat. No. 4,748,790 and
U.S. Pat. No. 4,937,125 each detail some of the various forms for
blast and bullet resistant walls and buildings.
[0005] Many of these engineered wall systems provide the capability
to produce modular wall systems that are subsequently assembled in
the field for use. When such modular approaches are used, a simple
field joint that enables easy assembly provides for structural load
transfer and yet provides impact resistance is desirable.
[0006] It is well known in the art that if some flexibility can be
engineered in the direction of impact, that such flexibility will
improve overall impact resistance. The various wall designs in the
art that have such flexibility must be joined together in a manner
that does not restrain the movement of these wall systems,
especially near the point of attachment. This is most critical near
joints where walls abut one another at corners or other non-planer
joints where one wall can substantially restrain the movement of
the other.
[0007] A substantial need exists for a method for the assembly of
protective wall systems for wind and blast resistance that provides
improved flexibility between wall segments. A particular need
exists for a joint between non-planer wall segments that is easily
assembled in the field and provides improved flexibility.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to an assembly of wall
panels particularly suitable for protection against wind blown
debris or an explosive blast comprising;
[0009] (a) at least two wall panels positioned in a non-planer
orientation to one another wherein an air gap is present between
two adjacent wall panels;
[0010] (b) at least one bent strap spanning the air gap between two
adjacent wall panels wherein the bent strap is rigidly connected to
adjacent wall panels and wherein the strap is capable of flexing
due to an external force on a wall panel such as from an impact
resulting from wind blown debris or an explosive blast.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic of a shelter system of Example 1.
[0012] FIG. 2 is a schematic of wall positions connected by
strapping of Example 1.
DETAILED DESCRIPTION OF THE INVENTION
[0013] In the present invention it is necessary to employ at least
one wall panel capable of withstanding a force generated from a
sudden impact such as wind blown debris of from an explosion. The
types of wall panels are varied and can be formed from a metal such
as steel, from wood or from a composite of several different
materials. Although typically there will be wall damage due to an
impact, the purpose of the wall is to maintain its integrity such
as to protect a person within a room of a building. Although only
one impact resistant wall panel can be employed to protect against
an external force, it is desirable for greater protection to employ
two adjacent wall panels to have impact resistance.
[0014] The protection from a wall panel will depend on its
construction. The greater the ability to withstand force will in
turn offer a greater protection. An example of a test procedure to
determine impact resistance is ASTM procedure E 1886-97.
Illustratively a 33 kilogram (15 pound) 2.times.4 lumber projectile
is employed to impact a wall. The ability of the wall to withstand
a projectile speed is a measure of determining its resistance. A
desirable resistance is an at an impact speed of 161 kilometers
(100 miles) an hour. Less resistance would be at failure at impact
speeds above 80 or 90 miles an hour.
[0015] In similar fashion to determining resistance in accordance
to ASTM procedure E 1886-97 test procedures to obtain a desired
resistance to a force generated from an explosion can be used to
determine the type of wall panel to be employed.
[0016] For windblown debris a suitable wall constructions are
described in U.S. patent application 09/977,648 filed 15 Oct. 2001
and 10/308,492 filed 3 Dec. 2002 incorporated by reference herein.
An example of a construction is a composite comprising in
order:
[0017] (a) a layer of material having a density not greater that
0.10 grams per cubic centimeter,
[0018] (b) a layer of a fabric containing fibers bonder with a
resin and
[0019] (c) a layer of structural sheathing.
[0020] A necessary portion of the construction of the wall assembly
is the use of a strap to connect adjacent wall panels. As employed
herein the term strap means a band or plate for holding an object
in a fixed position. Although the strap may be of metal
construction, such as steel or aluminum, other materials are
suitable such as plastic or a composite of different materials.
[0021] The strap is rigidly connected to adjacent wall panels and
holds the panels in place. However, the strap is capable of flexing
due to a force on a wall panel. It is directly understood that the
amount of flex of the strap will be determined by its end use.
Illustratively, a need for a greater resistance to an impact will
determine a greater resistance to flex. Also the amount of stap
flex will be determined by the number of straps connecting adjacent
wall panel. The greater number of straps, the lesser is a need for
resistance to flexing.
[0022] For purposes of illustration both single and double straps
are suitable. An example of a suitable thickness for a metal strap
is from 0.06 inches (1.5 mm) to 0.375 inches (9.5 mm) such as 0.075
inches (0.19 mm) to 0.150 inches (3.8 mm).
[0023] Although a strap may be employed on only an inner or outer
wall portion, preferably individual straps are present to connect
adjacent wall panels on inner and outer walls. As employed the term
inner means portions of wall which face one another, such as walls
that form the interior of a room. The term outer means portions of
a wall which do not face one another, such as walls that form the
exterion of a room. The strap or straps connect walls in a
non-planer orientation, i.e. the wall are at an angle to one
another. For purpose of illustration most walls are joined at an
angle of 90 degrees. An example of two walls joining one another is
an angle within a range from 30 to 120 degrees. Also generally
there will be an air gap between adjacent wall since if the wall
touch there may be an inability for the strap to flex properly upon
a sudden impact. A typical air gap is considered to be at least 3
mm (0.125 inches). In a preferred construction a wall capable of
withstanding a sudden impact is joined to two adjacent wall with
straps on both on inner and outer wall surfaces connecting adjacent
walls.
[0024] In the above disclosure the combination of a wall assembly
with use of straps has been describe in relationship to resistance
and protection of a sudden impact such as from wind blown debris
and an explosion. However it is within the scope of the present
invention that a wall assembly need not possess such resistance.
Therefore, wall panels can be employed with such resistance to an
excess sudden impact. In turn the staps would have the ability to
flex under a minimum amount of force upon one of the wall
panels.
[0025] To further illustrate the present invention the following
example is provided.
EXAMPLE 1
[0026] A shelter system shown in FIG. 1 with external dimensions of
115 inches long by 64 inches wide by 94 high was assembled from
engineered wall and roof panels designed to protect occupants from
windborne debris generated by tornadic winds. Five wall panels and
a modular door unit, each 48-in wide by 88-in high were used. Two
ceiling panels that were 48-in wide by 48-in long were used for the
roof. Panels were produced using, in order, 1 layer of 3/4-in
plywood, followed by a 5-1/2 inch thick steel reinforced expanded
polystyrene core with a density of 1 lb/cu-ft (0.016 gm/cc),
followed by a laminated fabric made from 3 layers of a 13 oz/sq-yd
aramid cloth that was bonded together with a polyethylene
co-polymer resin, followed by one 1 layer of 1/2-in plywood. Steel
reinforcement within the core, was done with 24-gauge 2.times.4
common metal framing studs on 16-inch centers that were laid flat
on each face of the panel. Reinforcement was added during the
foaming process as described in U.S. Pat. No. 4,241,555. The layers
of material were joined together by fastening with power driven
knurled nails driven on each face of the panel, around the
perimeter on 3-in centers and along the field studs on 6-in
centers.
[0027] The panels were assembled as shown in FIG. 2, using two, 11
gauge (0.12-inch thick) sheet metal brackets that were bent in two
places with 45.degree. angles to create the 90.degree. corner
connections required to assemble the rectangular shelter. The 1/2
plywood face was oriented outwardly. Three, 3/8-in diameter bolts
were used to fasten the edges of each panel to the metal strap
connector. A space of 3/8-in was present between the corners of any
adjacent panels that were connected.
[0028] The shelter was impacted in several locations with a 15-lb
2.times.4 (inches) timber projectile traveling at 100 mph, to
access ability to meet the "Windborne Missile Impact Resistance on
Shelter Wall and Ceiling" provisions of the National Performance
Criteria for Tornado Shelters, First Addition, FEMA, May 28, 1999.
Cannon set-up and firing was done in accordance with ASTM E
1886-97.
[0029] All projectiles fired at the shelter were stopped from
passing through it, as required by the FEMA provisions, and the
projectile was rebounded back. High speed photography taken during
the event showed the joints to flex inwardly upon impact, helping
to absorb a portion of the energy from the projectile. The plywood
layer on the backside showed only very minor cracking around the
impact point. The shelter assembly was deemed compliant with the
provisions of the National Performance Criteria for Tornado
Shelters.
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