NONLINEAR SIMULATIONS TO EVALUATE THE CODE-BASED RESPONSE MODIFICATION FACTOR FOR SEISMIC DESIGN OF SLAB-ON-PILE STRUCTURE

Abstract

Slab on Pile (SOP) structure using concrete spun pile (CSP) is frequently constructed for highway or railway infrastructures in Indonesia. However, some previous studies showed that spun piles have low energy dissipation and ductility. Therefore, spun pile application as bridge piers, particularly in high seismic locations such as Indonesia, needs additional consideration. The response modification factor (R) in the SOP elastic seismic design needs to be carefully considered since this parameter reflects the ability of the structure to dissipate energy through inelastic behavior. The work discussed in this paper primarily concerns the evaluation of the R-value based on the Indonesia seismic bridge design code, SNI 2833-2016, which is applied to SOP seismic design. The study provided an alternative reference for engineers in the seismic design of a SOP structure. Preliminary elastic design of SOP structures demonstrated that the number of piles and structural flexibility is significantly affected by the R-values consideration. In addition, the pinching hysteresis captured from the nonlinear dynamic analysis results emphasized the limited capability of an SOP structure in dissipating energy under seismic excitation. Moreover, the spun pile concrete material, especially in the pile-to-pile head connection, was observed to have an earlier failure. This study strongly suggested using an R-value of 1.5 to achieve a high seismic performance SOP structure with little need for aftershock retrofitting, even though this would necessitate much more spun piles. However, some further research could be conducted to develop the high seismic performance but economical design of SOP structures.