Passive Earth Pressure Tests on an Integral Bridge Abutment

Passive loading tests were conducted on a rigid concrete retaining wall to study the effect of wingwall orientation on lateral earth pressure development. Loads were applied at the top of the wall to produce a rotational wall movement. Six tests were conducted (three of which are described herein), two with the wingwalls oriented parallel (0°) to the main wall, and two with the wingwalls oriented at an angle of 45° to the main wall, and two with the wingwalls oriented at an angle of 90° to the main wall. Based on these tests the distribution of passive earth pressure at the centerline of the main wall for different wall displacements and the displacement of the wingwalls for different wall orientations were determined. Results from these tests indicate that passive earth pressures show a triangular distribution, reaching a maximum passive condition in the upper 1/3 portion of the wall after which they decrease to near zero at the base of the wall. This maximum value of earth pressure is dependent on wingwall orientation for the same relative wall movement