Performance of Skewed Abutments from Large-Scale Testing

Abstract

A series of large-scale passive force-deflection tests were performed on a model abutment to investigate the effect of skew angle on performance. Tests were conducted at skew angles of 0°, 15° and 30° with a backwall that was 3.35 m wide and a backfill that was 0.9 m deep and 6.7 m wide. Test results indicate that the passive force decreases significantly as the abutment skew angle increases to 30° relative to non-skewed walls. These results confirm observations from previous lab- scale tests and large-scale field tests where the abutment width to height ratio was about one-half of that in this series of tests. The results also indicate that the reduced passive force can be accounted for using a simple adjustment factor that is a function of skew angle. The initial stiffness of the passive force-deflection curves was relatively unaffected by skew angle. In addition, the displacement required to develop the peak passive force was about 3% of the wall height regardless of skew angle. Transverse shear resistance developed with displacements less than 2 mm.