Evaluation of filler material behavior in pre-bored pile foundation system due to slow cyclic lateral loading in sandy soil

Maintenance of a bridge structure is still the main issue in Indonesia due to the high cost of maintaining the elastomeric bearing especially in the remote area. Integral abutment bridges are becoming popular because the elastomeric bearings are eliminated, which can reduce the maintenance costs. Pre-bored pile foundation system is a typical foundation for integral bridge abutment to supports lateral displacement due to thermal expansion of the girder bridge. Pre-bored pile foundation system can be used to increase the pile flexibility using a pre-bored hole that filled with elastic materials such as bentonite slurry, loose sand or gravel. Some of the integral abutment bridges foundation design has proposed, but the previous studies only focus on the structural system, the soil characteristic behavior and soil response due to this system are still rarely explained. Therefore, it is necessary to examine the effects of cyclic loads on the filler material inside the pre-bored ring. The soil behavior for ground soil and filler material due to cyclic lateral loading were performed using macro-scale testing. In this paper, a series of two-way lateral cyclic loading tests were performed to evaluate the effect of slow cyclic lateral loading on the filler material behavior of the pre-bored pile foundation system. The experimental setup is explained in details, and the results are presented in the form of normalized bending moment and maximum lateral capacity charts against the number of cycles. Moreover, the densification effect of the filler material inside the pre-bored system due to the cyclic loading was evaluated.