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Numerical study of seismic behavior of reinforced soil bridge abutments located on soft clays of Southwest Iran

This paper investigates the seismic response of several reinforced soil abutments of railway overpass bridges constructed in southwest of Iran. Due to high seismicity and soft to medium stiff clayey deposits in the region, evaluating the stability and deformation behavior of these abutments against prob-able earthquakes were significant. The reinforcing elements are uniaxial extruded geogrids and reinforced soil is composed of granular material.
A 2-D, explicit finite difference scheme is used to perform the dynamic analyses of a single-span rein-forced soil abutment with a wrap-around facing, making use of hysteretic damping feature of the numeri-cal model. The seismic response of an instrumented reduced-scale reinforced soil retaining wall tested on a shaking table is used for numerical modeling verification purposes. The comparisons between predicted results from the numerical model and the measurements of the physical model have shown good agree-ment.
Parametric studies are performed to investigate the effects of system parameters on the abutment seismic behavior. The results show that characteristics of foundation and reinforced soil, stiffness and length of geogrids and also input acceleration amplitudes are having significant impact on the maximum horizontal displacement and maximum vertical displacement of bridge deck footing. The overall response of the re-inforced soil abutment subjected to seismic excitations is evaluated and discussed.