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The following design example is provided with the permission of the Reinforced Earth Company. Typical calculations are shown, including the determination of allowablereinforcement tension for galvanized steel reinforcing strips. Figure 8.40 shows a cut­away view of a typical Reinforced Earth retaining wall. Refer to Fig. 8.41 for illustration of calculation steps. Geometry Height of wall […]

The durability of polymeric reinforcements is influenced by time, temperature, mechanical damage, stress levels, microbiological attack, and changes in the molecular structure due to radiation or chemical exposure. The effects of aging and of chemical and biological exposure are highly dependent on material composition, including resin type, grade, and additives; manufacturing process; and final product […]

Where metallic reinforcement is used, the life of the structure will depend on the corro­sion resistance of the reinforcement. Practically all the metallic reinforcements used in construction of embankments and walls, whether they are strips, bar mats, or wire mesh, are made of galvanized steel. Epoxy coating can be used for additional corrosion protection, but […]

There are instances when one MSE wall is built on top of another. In certain instances, these walls can be considered to be two independent structures, each requiring its own internal design and external stability. The global stability of the slope must be suffi­ciently stable so as not to undermine the stability of the entire […]

Figure 8.32 shows the general design equations given by AASHTO for MSE walls with a horizontal backslope and a traffic surcharge. Included is the calculation of safety factors for overturning and sliding, and the maximum base pressure. Inclusion of a traffic sur­charge is required only in those instances where traffic loadings will actually surcharge the […]

Well-graded, free-draining granular material is usually specified for permanent-placed soil reinforced walls. Lower-quality materials are sometimes used in reinforced embank­ment slopes. Experience with cohesive backfills is limited. However, low strength, creep properties, and poor drainage characteristics make their use undesirable. Some current research is focused on the use of cohesive soil backfills. The following gradation […]

MSE walls should be dimensioned as required by AASHTO. The soil reinforcement length must be at least 70 percent of the wall height, as measured from the leveling pad, but not less than 8 ft (2.4 m) for both strip and grid type reinforcement. AASHTO requires the reinforcement length to be uniform throughout the entire […]

The types of facing elements used in the different reinforced soil systems control their aesthetics, since they are the only visible parts of the completed structure. A wide range of finishes and colors can be provided in the facing. In addition, the facing provides protection against backfill sloughing and erosion, and provides drainage paths. The […]

8.5.1 Types of MSE Walls Mechanically stabilized earth (MSE) walls are made up of several elements—specifically, the reinforcement of a soil mass through the use of steel strips, steel or polymeric grids, or geotextile sheets, capable of withstanding tensile forces, and a facing material. Figure 8.25 depicts different types of geosynthetic reinforced walls. The walls […]

A typical cantilever retaining wall is illustrated by the insert sketch in Fig. 8.21. This rigid-type wall can be constructed with or without a base shear key (see Fig. 8.20) depending on an analysis for resistance to sliding, as discussed later. The specifications of the owner will govern the selection and use of backfill materials […]