Studi Kasus Analisis Kerusakan Abutmen Jembatan Sungai Bahalang Kalimantan Tengah

  • Gawit Hidayat Lambung Mangkurat University


Bahalang Bridge is a Class B truss bridge crossing the Bahalang River in Ampah (Central Kalimantan). It
was built to connect roads for coal transportation. The bridge structure has a problem, namely an abutment failure in its
east-side abutment. There has been a 30-degree rotation that the back side of abutment has moved about 2 meters
downward and slipped from its place about 1 meter to the river. The purpose of this study is to study the behavior of the
soil layers around the abutment and to find out the main cause of failure. The analysis is based on approximate
calculation using Plaxis and Xstabl computer packages. Two options of calculation are considered. In the first option a
water level of29.5 m is used. Xstabl shows an SFmin of 0.764 and Plaxis shows a total displacement of 64.5 m. In the
second one the water level of the river is assummed to be 27.4 m. Xstabl shows an SFmin of 0.807 and Plaxis shows a
total displacement of 4.15 m. The results suggest that the collapse already took place during the backfill activity on the
east-side approach road. During that process the backfill material consisting of sand was laid too rapidly by direct
dumping from truck and spreading by excavator.s. The total displacement is 6.45 m. The pile bending moments aer
found to be above the allowable value, that is 57.81 kNm in front of the piles, and 63.90 kNm on the back. It can be
concluded that the failure is due to excessive displacement that has. the potential to damage the piles.