Study on the appropriate nominal strength of Wet Joints of Precast Box Girder Structures

Abstract

The wet joint of the precast segmental box girder system, which are used to connect the gaps between bridge girders along their span is typically constructed with an ultimate compressive strength of the concrete equal to that of factory-produced girder segments, without additional reinforcement. However, some construction projects have experienced failures at these joints, leading to the collapse of entire spans. This study examines the behavior of wet joints by producing simple beam test specimens incorporating wet joint segments. The experiments were designed to replicate the behavior of precast segmental box girder bridge systems, with variations in the ultimate compressive strength of the concrete in order to verify the appropriate nominal concrete strength of wet joints. The Experimental results are expected to give guidelines to specify the ultimate strength of concrete in the design standard for precast segmental box girder systems in the future. Moreover, the study compares ordinary concrete with low-carbon concrete, which offers distinct advantages, such as rapid strength development and reduced carbon dioxide emissions, contributing to the mitigation of global warming. This aligns with Thailand’s commitment to achieving net-zero greenhouse gas emissions by 2065.