PILE-SUPPORTED BRIDGE FOUNDATIONS DESIGNED FOR IMPACT LOADING

Bridge piers designed for impact loading from barges or other vessels represent a large investment of highway dollars in southeastern states, particularly Florida. Recent experimental research on the behavior of groups of piles subjected to large lateral loads has provided insight into the influence of group effects (pile-soil-pile interaction) for such loading conditions. Procedures currenty used in design do not reproduce the observed behavior; thus, improved design techniques are needed. Outlined is a design procedure recommended by the authors that is based on the results of recent well-instrumented, large-scale experiments. Recommendations for modification of p-y curves as a function of row position in a rectangular group arrangement are presented. The procedure is relatively simple and should be easily incorporated into design but should be considered an interim approach because of the limited experimental data that are available on the subject. An example use of the method is provided.