U.S. patent number 3,922,864 [Application Number 05/445,233] was granted by the patent office on 1975-12-02 for stringer for retaining wall construction.
This patent grant is currently assigned to Hilfiker Pipe Co.. Invention is credited to William K. Hilfiker.
United States Patent |
3,922,864 |
Hilfiker |
December 2, 1975 |
Stringer for retaining wall construction
Abstract
A stringer constructed of cast reinforced concrete. The stringer
includes an elongate body having two spaced-apart stacking pads
thereon. The stacking pads are arranged so that the pads of an
upper stringer which is superposed on a lower stringer engage the
pads of the lower stringer and retain the two stringers against
substantial relative movement. Each stringer has two openings
therein for engaging a stretcher rod, the opposite end of which is
anchored to a deadman, or the like. Because the pads of adjacent
stringers engage one another, only alternate rows of stringers are
secured to stretchers.
Inventors: |
Hilfiker; William K. (Eureka,
CA) |
Assignee: |
Hilfiker Pipe Co. (Eureka,
CA)
|
Family
ID: |
23768093 |
Appl.
No.: |
05/445,233 |
Filed: |
February 25, 1974 |
Current U.S.
Class: |
405/262; D25/58;
405/286; D25/113 |
Current CPC
Class: |
E02D
29/02 (20130101); E02D 29/025 (20130101); E02D
29/0233 (20130101) |
Current International
Class: |
E02D
29/02 (20060101); E02D 017/00 () |
Field of
Search: |
;61/47,39,35,49,37
;52/588,592 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Shapiro; Jacob
Attorney, Agent or Firm: Naylor, Neal & Uilkema
Claims
What is claimed is:
1. A stringer for a retaining wall comprising an elongate body
having first and second spaced-apart stacking pads thereon, each
said pad having an upper and a lower bearing surface thereon, one
of said bearing surfaces having a concavity and the other said
bearing surface having a convexity complemental to said concavity
so that superposed stringers engage one another by engagement of
the concavity and convexity in respective said bearing surfaces,
said pads having a vertical extent exceeding the vertical extent of
said bodies so that a space is defined between the bodies of
adjacent stringers when vertically stacked with the pads thereon in
engagement with one another.
2. A stringer, according to claim 1, wherein said concavity and
convexity are symmetrically spaced on opposite sides of a vertical
midplane through said stringer so that oppositely oriented
superposed stringers engage one another.
3. A stringer, according to claim 1, wherein said upper and lower
pad surfaces are identical, each said bearing surface having a
concavity and convexity complemental to said concavity, said
concavity and convexity being disposed on a plane normal to the
central longitudinal axis of the body and symmetrical of said axis
so that oppositely oriented superposed stringers engage one another
by engagement of the concavity and convexity in the lower bearing
surface of the upper stringer with the respective convexity and
concavity in the upper bearing surface of the lower stringer.
4. A stringer, according to claim 3, wherein said concavity and
convexity are defined by a rabbet formed by two congruent
horizontal surfaces at vertically spaced-apart levels, there being
a substantially vertical surface extending between said horizontal
surfaces, said vertical surface being in a vertical plane that
extends through the central longitudinal axis of said body.
5. A stringer, according to claim 1, wherein said concavity and
convexity are of complemental V-shape, the apices of said V-shapes
residing in the vertical midplane of said stringer.
6. A stringer, according to claim 1, wherein said pads are disposed
on opposite sides of the longitudinal midpoint of said body.
7. A stringer, according to claim 6, wherein said pads are disposed
symmetrically of the longitudinal midpoint of said body.
8. A stringer, according to claim 7, wherein the distance between
respective said pads and the midpoint of said body is at least as
great as the distance from respective said pads to respective
longitudinal extremities of said body.
9. A stringer, according to claim 1, wherein each said pad defines
an opening therethrough for receiving a stretcher therethrough,
said opening being substantially parallel to and midway between
said upper and lower bearing surfaces.
10. A stringer, according to claim 1, wherein said body has upper
and lower surfaces that define outward diverging surfaces to
promote water run-off from the retaining wall.
11. A stringer, according to claim 1, wherein said body and said
pads are constructed of concrete including reinforcing steel
therein.
12. A wall for retaining an earthen mass comprising a plurality of
identical stringers each having an elongate body and at least two
stacking pads disposed in spaced apart relation along said body,
each said pad having an upper and lower bearing surface, said
surfaces defining complemental concavities and convexities so that
the upper bearing surface of the pad of a lower stringer engages
the lower bearing surface of the pad of an upper stringer
superposed on the lower stringer to resist relative movement in a
direction normal to the longitudinal axes of the stringers, said
plurality of stringers being arranged in stacked relation with the
pad bearing surfaces of vertically adjacent stringers interengaged
and said pads having a vertical extent exceeding the vertical
extent of said bodies so as to define a space between the bodies of
adjacent vertically stacked stringers, and means for securing
alternate horizontal rows of stringers to the earthen mass.
13. A retaining wall, according to claim 12, wherein said securing
means comprises at least one tension member having a first end
fixed to said stringer and a second end remote from said first end,
and a deadman fixed to said second end, said deadman being buried
in the earthen mass.
Description
FIELD OF THE INVENTION
This invention relates to a stringer for use with a plurality of
identical stringers to construct an earth retaining wall of the
type retained in place by attachment to buried "deadman"
members.
Known retaining walls require substantial cutting and fitting on
the job and/or a plurality of different shaped parts which must be
fit together in a precise way on the job (e.g., see U.S. Pat. No.
3,631,682).
SUMMARY OF THE INVENTION
The present invention provides a stringer so configured that a
plurality of identically shaped stringers can be assembled in
interlocking relationship to form a retaining wall. Because the
stringers interlock with one another, the size of each individual
stringer can be maintained relatively small so as to facilitate
shipment of the stringers and manipulation of the same on the
construction site. Because each stringer is a lower stringer will
engage the same because the lower surface of the pad of production
and inventorying are achieved.
A stringer according to the present invention includes an elongate
body having two stacking pads extending therefrom. The stacking
pads have upper and lower surfaces. The upper and lower surfaces
are formed so as to be complemental with one another. Thus, an
upper stringer when stacked on the pad of the upper stringer is
complemental to the upper surface of the pad in the lower
stringer.
A feature and advantage of a stringer of the type referred to above
is that only alternate rows of stringers need be anchored to
deadman members or the like.
One specific form of the invention affords the advantage of
versatility in that the stringers can be constructed in vertically
aligned tiers or, in the alternative, can be constructed in
staggered relationship. The advantage of the former assembly
technique is that relative movement between different parts of the
retaining wall is afforded, a desirable condition in certain
environments. An advantage of the latter construction configuration
is that relative movement between elements of the retaining wall is
avoided, a condition desirable in other environments.
The foregoing, together with other objects, features and
advantages, will be more apparent after referring to the following
specification and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fragment of a retaining wall
constructed with stringers of the present invention.
FIG. 2 is a perspective view of a single stringer constructed
according to the present invention.
FIG. 3 is a cross-sectional view of a stringer according to the
invention showing a deadman member and stretcher for retaining the
stringer in place.
FIG. 4 is a front elevation view of a stringer according to the
present invention showing a satisfactory arrangement of reinforcing
steel bars therein.
FIG. 5 is a perspective view of an alternate mode of assembling
stringers according to the present invention into a retaining
wall.
FIG. 6 is a cross-sectional view of an alternate form of stringer
embodying the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring more particularly to the drawings, reference numeral 12
indicates a satisfactory form of stringer constructed according to
the present invention. The stringer is formed by an elongate body
14 of generally hexagonal shape and preferably formed of concrete
reinforced with steel reinforcing bars. Integral with body 14 at
locations spaced apart along the longitudinal axis of the body are
stacking pads 16 and 18. The stacking pads have upper and lower
bearing surfaces 20 and 22 which are complemental with one another.
In the embodiment shown in FIGS. 1-5, surfaces 20 and 22 are
identical to one another.
Bearing surfaces 20 and 22, as seen most clearly in FIG. 3, each
include a concavity 24 and a convexity 26 which is complemental to
the concavity. By "complemental" is meant that the convexity of a
lower stringer engages the concavity in a stringer superposed on
the lower stringer while the convexity of the upper stringer enters
the concavity of the lower stringer. To assure alignment between
stringers stacked as described next, both the concavity and
convexity are disposed symmetrically of a centrally disposed
longitudinal vertical plane of the body, such plane being indicated
at 28 in FIG. 3.
One satisfactory form for the bearing surfaces 20 and 22 is a
rabbet formed by congruent horizontal surfaces 30 and 32 which are
vertically spaced apart from one another and between which extends
a vertical surface portion 34 that lies in plane 28.
Each pad 16, 18 is provided with an opening 36 therethrough for
affording engagement of one end of a stretcher rod 38, the opposite
end of which is engaged with a deadman member 40. Opening 36 is
substantially parallel with upper and lower bearing surfaces 20 and
22 and resides midway between the upper and lower bearing surfaces.
Threaded flanges 42 or the like are fixed to opposite ends of
stretcher rod 38 to retain the ends of the stretcher to stringer 12
and deadman member 40.
In the embodiment of the invention shown in FIGS. 1-4, pads 16 and
18 are disposed symmetrically of the midpoint line 44 of body 14.
Additionally, the centerline of the pads, such as the centerline 46
of pad 16, is spaced from the midpoint 44 of the stringer by a
distance A; the longitudinal extremity 48 of stringer 12 is spaced
from pad centerline 46 by a distance B. Because the portion of body
14 outward of the pads is loaded as a caternary when the stringer
is installed in the retaining wall, it is desirable that dimension
B be less than dimension A, and such is the case with the
embodiment of the invention shown in FIGS. 1 - 4.
For reinforcing the concrete material of which stringer 12 is
constructed, there is embedded in the stringer a plurality of
longitudinally extending steel reinforcing rods 50 which are
circumscribed adjacent the pads by saddles 52 formed of similar
material. Finally, there is a plurality of U-shaped vertical bars
54 which reinforce the vertical extremities of pads 16 and 18.
Thus, the stringer has sufficient strength to retain the earth
placed behind it and to support all stringers placed above it.
In constructing a wall employing stringers according to the present
invention, the earth behind the site of the retaining wall is
removed to a degree sufficient that deadman 40 can be installed
behind the theoretical slip circle or slip line indicated at 56 in
FIG. 1. In the retaining wall shown in FIG. 1, the lowermost row of
stringers identified as 12' are disposed at an appropriate height
and are arranged with the concavities 24 facing the front, i.e.,
facing the exposed surface of the retaining wall. Superposed on
stringers 12' is a second row of stringers 12" which are oriented
so that their convexities face the front in order that such
convexities engage the concavities in stringers 12'. Because of the
substantial surface area of contact between lower pad surfaces 22
of stringers 12" with the upper pad surfaces 20 of stringers 12',
the upper row of stringers remains in place during installation of
stretchers 38 and deadman 40. Flanges 42, preferably threadably
engaged with the forward end of stretcher 38, can be installed
loosely and not finally tightened until backfilling has covered the
installed elements. It will be noted that in the embodiment of FIG.
1 the abutting extremities of stringers 12', indicated at 58, are
in vertical alignment with the abutting extremities of stringers
12" indicated at 60. This aligned relationship continues throughout
the vertical extent of the wall in order that one row of stringers
can move relative to adjacent rows in order to compensate for
seismic phenomena or unequal settling behind the retaining wall.
Forces on the lower row of stringers 12' tending to push such
stringers forward are resisted by the complemental interengagement
of the pads and, more specifically, by engagement between
respective vertical surfaces 34 of the respective superposed
stringers.
A third row of stringers indicated at 12'" is installed in vertical
alignment with stringers 12". Stringers 12'" are oriented as are
stringers 12' in order to afford inter-engagement between the
respective pad-bearing surfaces. Forces tending to push stringers
12'" outward are resisted because the convexities and concavities
of the respective bearing surfaces engage one another. Installation
of succeeding rows of stringers proceeds as described above and as
shown in FIG. 1 with alternate stringers being secured to deadmen
40 by stretchers 38. Only those stringers in which convexities 26
face forward need be secured to deadmen since all intermediate
stringers are retained by the improved pad configuration of the
invention. All stringers, however, can be secured to deadmen if
conditions require. As construction and backfilling proceed,
flanges 42 can be tightened in sequence so that the vertical
position of the retaining wall is maintained.
In order to afford drainage of the earth behind the retaining wall,
it is preferred that the upper and lower extremities of body 14 be
spaced vertically inward by an interval from the bearing surfaces
of the pads 16 and 18 to define a slit between adjacent stringers,
such interval being indicated in FIG. 2 at 62 and the slit being
indicated in FIG. 1 at 64. It is further preferable that the upper
and lower surfaces of body 14 be sloped to define outward diverging
surfaces, indicated at 66 and 68 in FIG. 2, to inhibit entry of
rain water into the earth behind the retaining wall from the
exposed surface of the retaining wall.
The stringer of the present invention can also be constructed in
order to provide a retaining wall that is substantially interlocked
against relative movement between laterally spaced elements. With
reference to FIG. 5, the stringers there shown and identified by
reference numeral 12a are substantially identical in details of
construction to stringer 12 shown in FIG. 2. Because of such
identity in construction, the individual parts of the stringer 12a
will not be further defined. The principal critical relationship in
the stringer of FIG. 5 is the spacing of pads 16a and 18a with
respect to the midpoint and extremities of body 14a of stringer
12a. The midpoint line of stringer 12a is indicated by reference
character 44a of FIG. 5. Pads 16a and 18a are symmetrical of the
midpoint line 44a and are spaced therefrom by a distance C. The
opposite longitudinal extremities of stringer 12a, one of which is
indicated by reference character 48a in FIG. 5, are spaced from the
respective pads by a distance equal to D. In the embodiment of FIG.
5, the dimension D is equal to or slightly less than C so that when
the stringers 12a are installed in staggered relation, there is a
space 70 between the longitudinal extremities of adjacent stringers
in the same row. In one stretcher designed according to FIG. 5,
dimension D is less than dimension C by one-quarter inch, thereby
forming a gap 70 which has a horizontal dimension of one-half
inch.
Installation of a wall employing the stringer of FIG. 5 proceeds
more or less in the manner described above in conjunction with FIG.
1 except that vertically adjacent stringers are staggered from one
another. More specifically, a stringer 12a is installed in
alignment with other stringers (e.g., 12a ") and the next row of
stringers indicated at 12a' are placed thereupon in staggered
relation and oppositely oriented. In other words, because lower
stringer 12a is secured by stretchers 38a, stringer 12a is oriented
so that convexities 26 face forward, and stringers 12a' are
oriented so that concavities 24 face forward for engagement with
the convexities of the lower stringer. It will be noted that pad
18a of stringer 12a' engages pad 16a of stringer 12a and that pad
16a of stringer 12a' engages pad 18a of stringer 12a. Accordingly,
the two stringers 12a' are interlocked with one another even though
a space exists at gap 70. Next, a row of stringers, one of which is
indicated at 12a", is superposed on stringers 12a' and is oriented
the same as stringer 12a so that the respective bearing surfaces of
the uppermost stringer engage with the bearing surfaces of the
central row of stringers. Stringer 12a" is anchored to deadmen (not
shown) by stretchers 38a and construction proceeds as described
above in conjunction with FIG. 1. The retaining wall of FIG. 5 is
somewhat more rigid than the retaining wall of FIG. 1, a
characteristic that may well be desirable in certain environments.
It will be noted that the stringers of FIG. 5 can be installed
either as shown in that figure or as shown in FIG. 1, a feature
which demonstrates the versatility of stringers constructed
according to the invention.
As shown in FIG. 6, a stringer 72 has an elongate generally
hexagonal body 74 that is identical to body 14 in the embodiments
described hereinabove. Stringer 72 has two pads disposed along body
74 in the spatial relationship described above, one such pad being
indicated at 76. The pad has an upper surface 80 and a lower
surface 82 that is complemental with the upper surface. Upper
surface 80 is formed by two surfaces 84 and 86 that converge to a
centrally disposed apex 87 to define a V-shaped concavity. Lower
surface 82 is formed by two surfaces 88 and 90 that diverge to a
centrally disposed apex 91 to define a V-shaped convexity. The
angle of convergence of surfaces 84 and 86 is equal to the angle of
divergence of surfaces 88 and 90 so that surface 82 of an upper
stringer 72 complementally engages a surface 80 of a lower stringer
on which the upper stringer is superposed. Such complemental
engagement precludes relative movement between superposed stringers
in a direction normal to the longitudinal axes of the
stringers.
An interval 96 can be provided between surfaces 80 and 82 and the
upper and lower extremities of body 74 to provide a slit (such as
identified at 64 in the embodiment of FIG. 1) for drainage.
Moreover, pad 76 has an opening 94 therethrough for receiving a
stretcher, such as indicated at 38 in FIGS. 1 and 3. The embodiment
of FIG. 6 thus affords the advantage to which reference has been
made hereinabove.
Thus, it will be seen that the present invention provides a
retaining wall stringer that reduces construction and inventory
costs, which is versatile in its mode of installation, and which
affords expeditious erection because only alternate rows of
stringers need be anchored. Because the pads on the stringers are
provided with complemental interlocking bearing surfaces, relative
movement between superposed stringers is highly unlikely.
Although three embodiments of the invention have been shown and
described, it will be obvious that other adaptations and
modifications can be made without departing from the true spirit
and scope of the invention.
* * * * *