Shear capacity of the toe

The critical section for shear capacity in the toe is at a distance d from the interface of the toe and the stem, where d 19.5. Because the length of the toe is short, moment capacity is not checked. Vtoe 4293 lbs - 413 lbs 3880 lbs Kear -2- fe b-d Vs > 1.3-(Vu - Vc) 0.85 2 4000 psi 12-19.5 L3-(Vu - -Vc) 13-(6596 lbs - 25,159 lbs) Use 11 9 c-c As 2.08 in2 per ft of wall Figure A-5a shows the steel reinforcing detailing, determined previously (note development lengths need to be checked),...

Stage Sizing of the Cantilever Retaining Wall

As stated previously, the first design stage consists of sizing the cantilever wall such that global stability requirements are satisfied (i.e., sliding, overturning, and bearing capacity), in general accordance with EM 1110-2-2502 (HQUSACE 1989). The structural wedge of the proposed wall and backfill is shown in Figure A-1, as well as the backfill and foundation material properties. To assess the global stability of the wall, the external forces and corresponding points of action acting on the...

Interface elements

Interface elements were used to model the interaction between the concrete retaining wall and the soil. However, FLAC does not allow interface elements to be used at the intersection of branching structures (e.g., the intersection of the stem and base of the cantilever wall). Of the several attempts by the authors to circumvent this limitation in FLAC, the simplest and best approach found is illustrated in Figure 3-6. As shown in this figure, three very short beam elements, oriented in the...

Notation Sign Convention and Earth Pressure Expressions

Passive Soil Wedge

The notation shown in Figure B-1 is used throughout this report. All the variables shown in this figure are presented in their positive orientation. Additionally, expressions for the classical Mononobe-Okabe active and passive dynamic earth pressures are presented (e.g., Ebeling and Morrison 1992, Chapter 4),1 as well as expressions for the slope of the corresponding failure planes. 1 References cited in this appendix are included in the References section at the end of the main text. Figure...

Total resultant forces and points of action

Backfill Flac

The horizontal acceleration ah and the corresponding dimensionless horizontal inertial coefficient kh at approximately the middle of the backfill portion of the structural wedge were computed during the FLAC analyses, as shown in Figure 4-3. Appendix B gives the appropriate sign convention related to ah and kh. In this figure, the potential active and passive failure planes are shown for illustration only. The kh time-history shown in this figure is that to which reference is made during the...

Stage Structural Design of Concrete Cantilever Retaining Wall

Concrete Heel Design

As stated in the introduction to this appendix, the second stage of the wall design entails the structural design of the concrete wall, to include the dimensioning of the concrete base slab the toe and heel elements and stem, and the detailing of the reinforcing steel. All reinforced-concrete hydraulic structures must satisfy both strength and serviceability requirements. In the strength design method, this is accomplished by multiplying the service loads by appropriate load factors and by a...

Research into the Seismic Response of a Cantilever Retaining Wall

Cantilever Wall Design

The seismic loads acting on the structural wedge of a cantilever retaining wall are illustrated in Figure 1-3. The structural wedge consists of the concrete wall and the backfill above the base of the wall i.e., the backfill to the left of a vertical section through the heel of the cantilever wall . The resultant force of the static and dynamic stresses acting on the vertical section through the heel i.e., heel section is designated as PaE, heel, and the normal and shear base reactions are N'...

Background

Formal consideration of the permanent seismic wall displacement in the seismic design process for Corps-type retaining structures is given in Ebeling and Morrison 1992 . The key aspect of this engineering approach is that simplified procedures for computing the seismically induced earth loads on retaining structures are dependent upon the amount of permanent wall displacement that is expected to occur for each specified design earthquake. The Corps uses two design earthquakes as stipulated in...