Assessment of Scour-Induced Damage and Service Life Prediction of a River Bridge Based on Bridge Management System

Abstract

This study assesses the condition of the Sungai Salak Bridge (Sungai Taib Village, Kotabaru Regency) using a visual inspection approach based on the Indonesian Bridge Management System (BMS) procedure. The objective is to identify damage levels at the element and system levels and to provide maintenance-oriented recommendations for a riverine bridge affected by erosion, landslide, and settlement processes. Field observations and BMS scoring indicate that several critical elements have reached severe deterioration, particularly the protective works (retaining structures), arch-related components, railings, and bridge accessories, while the deck system and several crossing elements remain visually intact. The BMS evaluation yields an average condition value of NK = 3, classifying the bridge as damaged, with an equivalent service age estimate of approximately 41 years. Visual evidence suggests that scour-induced erosion and embankment instability have contributed to progressive loss of protection and displacement of structural components, including lateral movement of box culvert units. Based on technical screening, the bridge requires corrective maintenance focused on rehabilitation rather than routine maintenance alone. Priority actions include restoring retaining/protective structures, replacing damaged railings, and reinstating traffic safety facilities (lighting, signs, and markings). The findings demonstrate that combining BMS-based condition ratings with riverine hazard interpretation supports more reliable rehabilitation planning and improved operational safety for flood- and scour-prone bridges.