KINERJA PILAR JEMBATAN SUNGAI PACONGKANG SULAWESI SELATAN DENGAN PUSHOVER ANALYSIS

Abstract

The Pacongkang River Bridge in South Sulawesi represents a key infrastructure asset designed using the response modification factor (R) as specified in SNI 2833:2016. However, AASHTO GSID 2014 limits the R value for substructures to a maximum of 1.5, necessitating an evaluation of the appropriateness of the R value adopted in the bridge design. In addition, the site’s proximity to the Walanae Fault raises concerns about the potential effects of Soil-Structure Interaction (SSI) on the dynamic response of the pier and foundation. This study aims to assess the conformity between the actual and design R values, evaluate the seismic performance level of the pier, and verify whether the structural system adheres to the Strong Foundation–Weak Pier concept. The research adopts a pushover analysis within the framework of Performance-Based Seismic Design (PBSD). The numerical modeling was carried out using Midas Civil software under two conditions: a model excluding SSI and a model incorporating SSI through nonlinear springs derived from p–y curve analysis using LPILE. Seismic input parameters were obtained from a Deterministic Seismic Hazard Analysis (DSHA) of the Walanae Fault. The results show that the actual R values for the pier column are 1.64 (longitudinal) and 0.95 (transversal), while those for the bored pile are 1.58 and 1.56, respectively. Based on FEMA 440 and NCHRP 440 criteria, all structural elements are classified as Fully Operational with drift ratios below 1%. The formation of plastic hinges at the pier base further indicates that the structural system satisfies the Strong Foundation–Weak Pier principle.