ALTERNATIVE DESIGN OF A STEEL TRUSS BRIDGE USING THE TROUGH BALTIMORE TRUSS FOR AN OVERPASS IN KABUPATEN TANGERANG

Abstract

Bridges are essential transportation infrastructures that connect regions and support both economic and social activities. According to SE.MEN PUPR No.07/SE/M/2015, steel truss bridges have an economical span of 40–200 meters, making them suitable for existing conditions. In selecting a bridge structure, strength, aesthetics, cost efficiency, and user comfort must be considered. This study compares the work volume and cost estimation (RAB) between an existing bridge and a redesigned alternative on the overpass crossing the Tangerang–Merak Toll Road. The research applies qualitative analysis through a case study of the existing bridge, redesigned as an alternative design, supported by literature review and previous studies. Two bridge types are compared: a Steel Box Girder 1-Cell bridge for the existing structure and a redesigned steel truss bridge using the Trough Baltimore Truss system. The redesign process covers both the superstructure and substructure (abutments and foundations) using structural analysis software. The redesigned structure applies steel elements including Top Chord H428x407x20x35, Bottom Chord H428x40x20x35, Diagonal H400x408x21x21, Bracing H248x249x8x13, Cross Girder H428x407x20x35, Stringer H350x350x12x19, and End Portal H400x400x13x21, supported by bored pile foundations with 1 m diameter and 30 m depth, pile caps of 10.5 × 6 × 1 m, and abutments of 10.5 × 1.5 × 4.1 m. The results show that the steel usage volume for the existing bridge is 37,623.20 kg, while the redesigned bridge requires 45,324.60 kg, indicating that the Steel Box Girder 1-Cell structure is 15.79% more efficient.