DEPARTMENT OF THE ARMY ETL 1110-2-352 CECW-ED U.S. Army Corps of Engineers

velopment of these pressures through soil-structure interaction by simulating the staged construction that occurs. The computer program SOILSTRUCT can model the nonlinear stressstrain behavior of the soil, and allow for relative movement between the soil and the structure by incorporating interface elements in the mesh. (2) Soil-structure interaction analyses are also especially useful for analyzing retaining structures founded on either soils or compressible rock foundations. Differential settlements within the foundation affect the magnitude of the shear force that the backfill exerts on the wall. The SSI analysis procedure has been successfully used for a wide variety of problems, including the Port Allen and Old River locks (Clough and Duncan 1969) and, more recently, the lock at Red River Lock and Dam No. 1 (Ebeling et al. 1993). (3) A soil-structure interaction analysis is recommended for those structures for which the simplified procedure is not applicable (Section 5a) or for t