EP2403997B1

EP2403997B1 - Precast wall system

Info

Publication number: EP2403997B1
Application number: EP10749396.7A
Authority: EP
Inventors: Thomas L. Rainey
Original assignee: Earth Reinforcement Technologies LLC
Current assignee: Earth Reinforcement Technologies LLC
Priority date: 2009-03-06
Filing date: 2010-03-05
Publication date: 2017-08-16
Anticipated expiration: 2030-03-05
Also published as: CA2758248A1; EP2403997A1; NO2403997T3; CA2758248C; PL2403997T3; ES2647244T3; EP2403997A4; WO2010102213A1; DK2403997T3; PT2403997T

Description

BACKGROUND

Modular earth retaining walls are commonly used for architectural and site development applications. Such walls are subjected to very high pressures exerted by lateral movements of the soil, temperature and shrinkage effects, and seismic loads.
A retaining wall block including of a front face portion, a web portion and a rear portion is known from PCT application WO 2007/117250 A1 . Aligning elements are arranged on the rear portion and on the web portion, extending onto the front face portion. The aligning elements on the rear portion on the one hand and the web portion and the front face portion on the other hand can be connected into a single aligning element. In a stacked configuration, a front surface of the foremost aligning element aligns with a rear surface of the front face portion of the retaining wall block or retaining wall blocks stacked underneath so as to lock the blocks against being shifted against each other due to the pressure of a material held behind the resulting retaining wall. Since the aligning element extends from the web portion onto the front face portion, each subsequent course of retaining wall blocks is set back by the amount of this extension with respect to the course of retaining wall blocks immediately below.
A retaining wall block including a front face portion, a web portion and a rear panel portion is known from US patent application US 2006/0179780 A1 . On the bottom surface of the retaining wall block, there are two aligning elements, one on the front face portion and one on the rear panel portion. In a stacked configuration the front sides of the aligning elements rest against the rear side of the front face portion or the rear panel portion, respectively, of the retaining wall block or retaining wall blocks in the course below, creating a retaining wall with each subsequent course set back with respect to the course below. In an alternative embodiment disclosed in US 2006/0179780 A1 , a retaining wall block without aligning elements is fixed in position with respect to a retaining wall block or retaining wall blocks in a course immediately below by means of a clip. The clips, basically h-shaped or H-shaped, are elements separate from the retaining wall block.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIGS. 1A-1E are views of an exemplary precast wall system modular block in accordance various embodiments of the disclosure;
FIG. 2 is a view of the precast wall system modular block of FIGS. 1A-1E including an exemplary mechanical geogrid connection in accordance various embodiments of the disclosure;
FIGS. 3A-3B are views of an exemplary system of reinforcement of a precast wall system modular block of FIGS. 1A-1E in accordance various embodiments of the disclosure;
FIGS. 4A-4B are views of an exemplary precast wall systems including the precast wall system modular block of FIGS. 1A-1E in accordance various embodiments of the disclosure;
FIG. 5 illustrates the addition of a modular block of FIGS. 1A-1E to an exemplary precast wall system in accordance various embodiments of the disclosure;
FIG. 6A-6B are views of a drainage material installed on a precast wall system modular block of FIGS. 4A-4B and 5 in accordance various embodiments of the disclosure;
FIG. 7 is a cross-sectional view an exemplary precast wall system including a cap unit in accordance various embodiments of the disclosure;
FIG. 8 illustrates the addition of backfill to a modular block of FIGS. 1A-1E to an exemplary precast wall system in accordance various embodiments of the disclosure;
FIG. 9 is a view of the precast wall system modular block of FIGS. 1A-1E including an exemplary soil nail connection in accordance various embodiments of the disclosure;
FIG. 10 is a cross-sectional view an exemplary precast wall system including a traffic barrier in accordance various embodiments of the disclosure;
FIGS. 11A-11B are views of exemplary precast wall system modular blocks including extended web portions in accordance various embodiments of the disclosure;
FIGS. 12A-12C illustrate precast wall system modular blocks including straight, convex and concave front face portions in accordance various embodiments of the disclosure;
FIG. 13 is a cross-sectional view an exemplary precast wall system including the soil nail connection of FIG. 9 in accordance various embodiments of the disclosure; and
FIG. 14 is a cross-sectional view an exemplary precast wall system including the mechanical geogrid connection of FIG. 2 in accordance various embodiments of the disclosure.

DETAILED DESCRIPTION

Disclosed herein are various embodiments of systems related to modular earth retaining wall systems. Reference will now be made in detail to the description of the embodiments as illustrated in the drawings, wherein like reference numbers indicate like parts throughout the several views.
Modular or segmental earth retaining walls commonly comprise courses or tiers of modular units or blocks. The blocks are typically made of concrete. The blocks are typically dry-stacked (i.e., no mortar or grout is used), and often include one or more features adapted to properly locate adjacent blocks and/or courses with respect to one another, and to provide resistance to shear forces from course to course. The weight of the blocks is typically in the range of fifty to several thousand pounds (1 pound = 0.45 kg) per unit. Modular retaining walls commonly are used for architectural and site development applications. Such walls are subjected to high loads exerted by the soil behind the walls. These loads are affected by, among other things, the character of the soil, the presence of water, surcharge loads, and seismic loads. To handle the loads, modular retaining wall systems often comprise one or more layers of soil reinforcement material extending behind the tiers of blocks back into the soil behind the blocks.
Generally speaking, the modular blocks can include blocks of different sizes, shapes, and orientations. With reference to FIGS. 1A-1E, shown is an exemplary embodiment of a modular block 100 including a horizontally oriented rectangular front face portion 103 including a front surface 106, a rear surface 109, a top surface 113, and a bottom surface 116. Other embodiments can include, but are not limited to, vertically oriented rectangular front face portions and/or front face portions of different dimensions. The front face portion 103 may include a front surface 106 that is sculptured or textured as illustrated in FIGS. 1A-1C. The front surface 106 may have a straight 100, convex 1210, or concave 1220 profile as illustrated in FIGS. 12A-12C, respectively. During fabrication, a filler 1206, 1209, 1212 is included in the mold to provide the desired shape. A mold liner 1203 is used to produce the desired texture of the front face portion 103.
In one embodiment, the front face portion 103 of modular block 100 has a height of about 46 cm (18 inches), a width of about 122 cm (48 inches), and a thickness of about 10.2 cm (4 inches). Alternatively, the front face portion 103 of modular block 100 may have a height of about 76 cm (30 inches), a width of about 190 cm (75 inches), and a thickness of about 12.7 cm (5 inches). Other embodiments may have front face portions 103 with other dimensional combinations (height x width) such as, but not limited to, about 46 cm (18 inches) by about 61 cm (24 inches), about 46 cm (18 inches) by about 122 cm (48 inches), about 91 cm (36 inches) by about 61 cm (24 inches), and about 91 cm (36 inches) by about 229 cm (90 inches). In addition, the thickness and front surface texture of the front face may vary between embodiments.
The modular block 100 also includes one or more web portions 123 extending from the rear surface 109 of the front face portion 103. In the embodiment of FIGS. 1A-1E, two web portions 123 extend from the rear surface 109 of the front face portion 103. In other embodiments, a single web portion 123 may extend from the rear surface 109 of the front face portion 103. In one embodiment, the web portion(s) 123 extends from (or beyond) the rear surface 109 a depth of about 36 cm (14 inches). If the thickness of the front face portion 103 is about 10.2 cm (4 inches), the overall depth of the exemplary modular block 100 is about 46 cm (18 inches). In other embodiments (as illustrated in FIGS. 11A-11B), the extension depth of the web portion 123 can vary.
A web portion 123 includes a vertical center portion 126 that extends from the top surface 113 to the bottom surface 116 of the front face portion 103. Protrusions 129 extend from the lower sides of the vertical center portion 126. In the embodiment of FIGS. 1A-1E, the protrusions 129 are substantially triangular. The substantially triangular protrusions 129 may extend rearward along at least a portion of the web portion 123. In the embodiment of FIGS. 1A-1E, the substantially triangular protrusion 129 along the outer surface of the web portion 123 extends the entire length of the web portion 123 and the substantially triangular protrusion 129 along the inner surface of the web portion 123 extends along only a portion of the web portion 123. In the embodiment of FIGS. 1A-1E, the vertical center portion 126 has a thickness of about 7.6 cm (3 inches) and the substantially triangular protrusions 129 extend from the sides of the vertical center portion 126 about 12.7 cm (5 inches). Alternatively, the vertical center portion 126 may have a thickness of about 8.9 cm (3.5 inches) and the substantially triangular protrusions 129 extend from the sides of the vertical center portion 126 about 14.0 cm (5.5) inches.
Web portions 123 may also include one or more lifting and/or attachment holes 133, such as illustrated in the exemplary embodiment of FIGS. 1A-1E. The lifting holes 133 may be positioned in a centroid position to maintain the modular block in a level orientation when raised and during installation. This location of the lifting holes 133 also allows for pivoting of the block.
The modular block 100 may also include a rear panel portion 143 that extends between adjacent web portions 123. In the embodiment of FIGS. 1A-1E, the rear panel portion 143 extends from the top surface to the bottom surface of the web portions 123. In other embodiments, the height of the rear panel portion 143 may be less than the height of the web portions 123. The rear panel portion 143 may include a protrusion that extends toward the rear surface 109 of the front face portion 103 from an inner surface of the rear panel portion 143. The protrusion may be substantially triangular. The rear panel portion 143 may also include an opening 146 that extends through the rear panel portion 143. In the embodiment of FIGS. 1A-1E, the opening 146 is a vertical slot that is approximately centered in the rear panel portion 143.
FIG. 2 provides a view of the precast wall system modular block 100 of FIGS. 1A-1 E including an exemplary mechanical geogrid connection. A polymer geogrid 153 wrapped around the rear panel portion 143 may extend longitudinally into backfill soil to provide additional support to a wall system including the modular block 100. In another embodiment, an anchor bar 906 (FIG. 9) may be attached through the vertical slot 146 of the rear panel portion 143 to provide additional support to the wall system. The corners 149 at the top and/or bottom of the rear panel portion 143 may be curved, rounded, or tapered (as illustrated in FIGS. 1A-1E) to reduce wear of the material of the geogrid 153 when installed. FIG. 14 is a cross-sectional view illustrating a precast wall system 1400 including the geogrid 153 extending into the earth behind the wall system 1400. As depicted, the geogrid 153 wraps around the rear panel portion 143 and extends rearward from both the top and bottom of the rear panel portion 143.
With reference to FIGS. 3A-3B, shown is an exemplary system of reinforcement that can be included in a modular block 100. In the embodiment of FIGS. 3A-3B, the modular block 100 is reinforced with reinforcing rods (or rebar). A plurality of rebar rods 309 (e.g., two or four) are positioned horizontally within the front face portion 103 (e.g., at the top and bottom) as illustrated in FIG. 3A. Additional rebar rods 303 extend through each of the web portions 123 such that the rebar rods 303 hook around at least one of the horizontal rebar rods 309 within the front face portion 103 and extend vertically within the front face portion 103 as illustrated in FIG. 3B. In some embodiments, the rebar rods 303 in the web portions 123 are formed in a C-shape, which extends from the rear of the web portions 123 into the front face portion 103, with the opening of the C-shape within the front face portion 103. In the embodiment of FIGS. 3A-3B, rebar rods extend horizontally through the rear panel portion 143 into the web portions 123. The horizontal rebar rods in the rear panel portion 143 may be extensions of bars 303 or may be separate rebar rods. Vertical rebar rods 306 may be included in the ends of the web portions 123 and/or adjacent to the vertical slot 146 in the rear panel portion 143 to provide additional reinforcing at stress points. In other embodiments, additional rebar rods and/or shapes may be utilized.
With reference to FIGS. 4A-4B, shown are exemplary precast wall systems 410 and 420 in accordance various embodiments of the disclosure. The precast wall systems include a plurality of courses of modular blocks 100. In some embodiments, the precast wall systems may include blocks of different sizes, shapes, and orientations. Each modular block 100 may be configured so as to mate with at least one other modular block 100 when the blocks are stacked atop one another to form a modular retaining wall 400 as illustrated in FIG. 5. This mating restricts relative movement between vertically adjacent modular blocks 100 in at least one horizontal direction and allows adjacent courses of blocks 100 to be aligned with one another. To provide for this mating, the modular blocks 100 can include locking means that secure the blocks 100 together to further increase wall stability.
Referring back to the exemplary embodiment of FIGS. 1A-1E, the locking means may be provided on one or more web portions 109 by aligning elements 136 such as, but not limited to, tabs or nodes that extend from the bottom of the protrusions 129. The aligning elements 136 of FIGS. 1A-1E extend along the bottom of the protrusions 129 from the rear surface 109 of the front face portion 103 towards the rear of the web portion 123 to form an alignment seat 139. The aligning elements 136 may extend rearward along a portion of the substantially triangular protrusion 129 or along the entire length of the substantially triangular protrusion 129. When stacked atop one or more blocks 100, the alignment seat 139 is positioned atop the vertical center portion 126 of a web portion 123 of a block in the lower course. The front of the aligning elements 136 is aligned with the rear surface 109 of the front face portion 103 to allow the modular blocks 100 to be properly located with modular blocks 100 in the lower course and to provide resistance to shear forces from course to course. An aligning element 136 extends along each side of the vertical center portion 126 to align the block 100 and limit lateral movement of the block 100. In one embodiment, the aligning elements 136 are tabs having a height of about 3.8 cm (1.5 inches) and a depth of about 15.2 cm (6 inches). Alternatively, the height may be about 5.0 cm (2 inches). Various tab widths and depths can be provided to allow alignment with the top of a web portion 123 in the lower course. The modular blocks 100 in the bottom course may not include alignment seats 139 (e.g., formed by aligning elements 136) to facilitate leveling.
As illustrated in FIGS. 4B and 6A-6B, drainage materials 430 and 630 may be secured to roll down the rear surface 109 of the front face portion 103 between the web portions 123. Drainage materials 430/630 include, but are not limited to, filter fabric and prefabricated plastic drainage board.
FIG. 7 illustrates an exemplary precast wall system 700 including six courses of blocks 100. In the embodiment of FIG. 7, the depth of the web portions 123 is increased for the lower courses for overall structure stability and to resist soil and surcharge loads. The additional depth, when combined with the triangular protrusions 123, provides added stabilization and support for the wall system. Other groupings may be utilized in other embodiments (e.g., different web depths for each course or groups of three as in FIG. 10).
The web portions 123 of each course extend back into the earth to create a gravity system to resist overturning and sliding of the precast wall system. Stone and/or soil 803 can be deposited between the web portions to provide additional downward force on the web portions 123 of the modular block 100 to resist overturning or sliding. Referring now to the modular block 100 of FIG. 8, the substantially triangular protrusions 129 are obliged at opposing sides of the vertical center portion 126 to create an arch of the stone and/or soil 803 placed between the web portions 123, which creates a downward force on the web portions 123 of the modular block 100 to resist movement of the block 100 from its stationary position, therein creating a stable mass to resist overturning and sliding. In some embodiments, the web portions 123 may be extended beyond the rear panel portion 143, as illustrated in FIGS. 11A-11B, to provide additional stability to the wall system. For example, the web portions 1103 extending rearward beyond the rear panel portion 143 of modular block 1110 of FIG. 11A may extend to a depth of about 152 cm (60 inches) while the web portions 1103 extending rearward beyond the rear panel portion 143 of modular block 1120 of FIG. 11B may extend to a depth of about 244 cm (96 inches).
FIG. 9 illustrates a soil nail connection that may also be utilized to connect a modular block 100 of a precast wall system to a cut face of earth behind the wall system. In the exemplary embodiment of FIG. 9, an anchor bar 906, such as a threaded bar, extends into the modular block 100 through the vertical slot, and is secured by a fastener, e.g., a nut 916, washer 919, and/or plate 909, to a soil nail bar or earth anchor that has been fixed in the cut face of the earth behind the wall system. In other embodiments, the anchor bar 906 may include other securing means such as, but not limited to, a pin and washer combination or a bolt head. In some embodiments, the anchor bar 906 may include a plurality of sections that are coupled together to provide the desired length. FIG. 13 is a cross-sectional view illustrating a precast wall system 1300 including the anchor bar 906 extending into the earth behind the wall system 1300. As depicted, the anchor bar 906 extends rearward from the vertical slot 146 of the rear panel portion 143.
Referring back to the exemplary precast wall system 700 of FIG. 7, the front of the aligning elements 136 are seated against the rear surface 109 of the front face portion 103 to align the front face 106 of a block 100 in an upper course with the front face 106 of a block 100 in a lower course. In some embodiments, interlocking means such as, but not limited to, a rebar rod may be placed in channels or recesses of adjacent blocks 100 to provide additional horizontal alignment and stability.
In the embodiment of FIG. 7, the precast wall system 700 includes a cap unit 703 placed on the top course of modular blocks 100. In one embodiment, the cap unit 703 includes one or more alignment seats on a bottom surface. In other embodiments, the cap unit 703 may not include alignment seats on the bottom surface.
In the embodiment of FIG. 10, one or more modular blocks in the top course of the precast wall system 1000 includes a traffic barrier 1003. In one embodiment, the traffic barrier 1003 is connected to the modular block, e.g., to the web portions 123. Alternatively, the modular block may be fabricated with the traffic barrier 1003 may be integrated into the modular block. For example, the modular block/traffic barrier may be fabricated with reinforcing rods (rebar) 1006 extending through the traffic barrier 1003 into the web portions 123. This allows for the elimination of a typical moment slab for the traffic barrier. The modular block helps to prevent tipping of the traffic barrier 1003 when impacted (e.g., by a moving vehicle).

Claims

A precast retaining wall block (100, 1110, 1120), configured for assembly into a retaining wall (400) including a plurality of stacked rows of at least a plurality of said retaining wall blocks (100, 1110, 1120), said retaining wall block (100, 1110, 1120) comprising:
a front face portion (103) including a front surface (106), a rear surface (109), a top surface (113), and a bottom surface (116); and

at least one web portion (123) extending outwardly from the rear surface (109) of the front face portion (103), the at least one web portion (123) including a vertical center portion (126) extending from the top surface (113) to the bottom surface (116) of the front face portion (103), and characterized by

left and right protrusions (129) extending outwardly from the lower sides of the vertical center portion (126), the left and right protrusions (129) substantially triangular; and

left and right aligning elements (136) extending downwardly from a bottom surface of the left and right protrusions (129), respectively, a front surface of each aligning element (136) aligned with the rear surface (109) of the front face portion (103) and extending rearward along at least a portion of the respective protrusion (129), the left and right aligning elements (136) defining an alignment seat (139) configured to engage a top portion of a web portion (123) of a retaining wall block (100, 1110, 1120) in a lower row of the retaining wall (400).
The precast retaining wall block (100, 1110, 1120) of claim 1, further comprising a rear panel portion (143) extending between the at least one web portion (123) and an adjacent web portion (123) of the retaining wall block (100, 1110, 1120).
The precast retaining wall block (100, 1110, 1120) of claim 2, wherein the at least one web portion (123) and the adjacent web portion (123) extends rearward beyond the rear panel portion (143) of the retaining wall block (100, 1110, 1120).
The precast retaining wall block (100, 1110, 1120) of claim 2, wherein at least a portion of a corner edge of the rear panel portion (143) is curved.
The precast retaining wall block (100, 1110, 1120) of claim 2, further comprising a geogrid (153) material wrapped around a top and a bottom of the rear panel portion (143).
The precast retaining wall block (100, 1110, 1120) of claim 2, wherein the rear panel portion (143) includes a protrusion (129) extending towards the rear surface (109) of the front face portion (103) from an inner surface of the rear panel portion (143), the protrusion (109) substantially triangular.
The precast retaining wall block (100, 1110, 1120) of claim 1, further comprising:
a first reinforcing bar (309) extending within the front face portion (103) between left and right sides of the front face portion (103); and

a second reinforcing bar (303) extending through the at least one web portion (123) into the front face portion (103), the reinforcing bar (303) configured to hook around the first reinforcing bar (309).
A precast retaining wall system (410, 420, 700, 1000, 1300, 1400) comprising:
a first course including a first retaining wall block (100, 1110, 1120) comprising:
a front face portion (103) including a front surface (106), a rear surface (109), a top surface (113), and a bottom surface (116); and

at least one web portion (123) extending outwardly from the rear surface (109) of the front face portion (103) of the first retaining wall block (100, 1110, 1120), the at least one web portion (123) including a vertical center portion (126) extending from the top surface (113) to the bottom surface (116) of the front face portion (103); and

a second course on top of the first course, the second course including a second retaining wall block (100, 1110, 1120) comprising:
a front face portion (103) including a front surface (106), a rear surface (109), a top surface (113), and a bottom surface (116); and

at least one web portion (123) extending outwardly from the rear surface (109) of the front face portion (103) of the second retaining wall block (100, 1110, 1120), the at least one web portion (123) including a vertical center portion (126) extending from the top surface (113) to the bottom surface (116) of the front face portion (103), characterized in that

the at least one web portion (123) of the first retaining wall block (100, 1110, 1120) includes left and right protrusions (129) extending outwardly from the lower sides of the vertical center portion (126), the left and right protrusions (129) of the first retaining wall block (100, 1110, 1120) substantially triangular;

the at least one web portion (123) of the second retaining wall block (100, 1110, 1120) includes left and right protrusions (129) extending outwardly from the lower sides of the vertical center portion (126), the left and right protrusions (129) of the second retaining wall block (100, 1110, 1120) substantially triangular; and

left and right aligning elements (136) extend downwardly from a bottom surface of the left and right protrusions (129) of the second retaining wall block (100, 1110, 1120), respectively, a front surface of each aligning element (136) aligned with the rear surface (109) of the front face portion (103) of the second retaining wall block (100, 1110, 1120) and extending rearward along at least a portion of the respective protrusion (129), the left and right aligning elements (136) defining an alignment seat (139) engaged with a top portion of the at least one web portion (123) of the first retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 8, wherein the first retaining wall block (100, 1110, 1120) further comprises a rear panel portion (143) extending between the at least one web portion (123) and an adjacent web portion (123) of the first retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 9, wherein the at least one web portion (123) and the adjacent web portion (123) of the first retaining wall block (100, 1110, 1120) extends rearward beyond the rear panel portion (143) of the first retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 8, wherein the second retaining wall block (100, 1110, 1120) further comprises a rear panel portion (143) extending between the at least one web portion (123) and an adjacent web portion (123) of the second retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 11, further comprising a geogrid material (153) wrapped around a top and a bottom of the rear panel portion (143) of the second retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 8, wherein the front surface of at least one of the left and right aligning elements (136) is engaged with the rear surface (109) of the front face portion (103) of the first retaining wall block (100, 1110, 1120).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 6, wherein the second retaining wall block (100, 1110, 1120) further comprises a soil nail connection secured in earth material behind the wall system (410, 420, 700, 1000, 1300, 1400).
The precast retaining wall system (410, 420, 700, 1000, 1300, 1400) of claim 6, wherein the second retaining wall block (100, 1110, 1120) further comprises a traffic barrier (1003).