Transverse mechanical performance of precast segmental box beam with corrugated steel webs

Abstract As composite box-beam bridges with corrugated steel webs (CSWs) evolve toward larger spans, multi-chamber configurations, and wider cantilevers, understanding deck transverse force transfer becomes critical. This study compares the transverse mechanical behavior of continuous precast and cast-in-place (CIP) CSW box beams through static testing of two variable cross-section specimens. Results reveal that construction methods minimally affect stiffness, strain distribution, and deformation during the elastic phase. Post-cracking behavior diverges significantly, with distinct differences in crack patterns, failure modes, and deformation characteristics. Integral beams developed dense, fine cracks at mid-support and mid-span regions, while precast specimens showed localized cracking near loading segments and middle support joints. The precast beam exhibited 25% faster crack width growth and 35% greater deflection rates post-cracking compared to the CIP specimen. Failure modes differed fundamentally: CIP beams failed through shear cracking in concrete slabs at mid-span, whereas precast beams failed via joint opening at critical connections. Transverse strain distribution patterns remained similar across both specimens, though precast sections demonstrated 12-15% faster transverse strain development. Beyond 1180kN loading, transverse strain differences exceeded 10%, with precast beams sustaining higher tensile (14.3%) and compressive (11.8%) strains than CIP counterparts at equivalent loads.These findings highlight that while both systems show comparable elastic performance, precast construction significantly influences post-cracking behavior through altered damage progression paths and accelerated strain development. The study provides critical insights for optimizing joint design and crack control in prefabricated CSW bridges, particularly regarding load redistribution mechanisms at serviceability and ultimate limit states. Practical implications include recommendations for modified reinforcement detailing at precast joints and enhanced monitoring of transverse strain concentrations in segmental assemblies.