Seismic Design of Reinforced Earth Walls

Seismic design for reinforced earth retaining walls was developed largely on the results obtained from small laboratory scale walls on a shaking table, and is therefore tentative and must await verification from further analytical laboratory and field studies. The laboratory tests showed that the walls responded like a nonlinear damped elastic system to the input vibrations. From measurements of the peak tie forces, an empirical design force envelope was developed which is a function of input acceleration only. It is suggested that the design earth pressures for an actual wall subjected to earthquake loading be based on this design force envelope using a base acceleration determined by response spectra and modal participation factor techniques. Data are also presented of soil-tie friction under static and vibratory loading. The recommendations include data from which the required size and spacing of ties can be determined. Suggested factors of safety are given for tie pull out and tie breaking modes of failure.