Flexural performance and crack width prediction of steel-UHTCC composite bridge decks with wet joints

Abstract

Composite bridge deck (CBD) structure has been widely used in recent decades, particularly in long-span bridges. The application of ultra-high toughness cementitious composite (UHTCC) in composite bridge deck (CBD) structures has garnered attention due to its exceptional resistance to tensile cracking and strain hardening. However, their widespread adoption necessitates a thorough understanding of crack resistance, especially in the presence of wet joints between cast regions. This study investigates the flexural performance and crack width prediction method of steel-UHTCC/concrete CBDs with wet joints using a combined experimental and theoretical approach. Six specimens with UHTCC wet joints and either UHTCC or concrete precast layers were designed and tested under hogging moment. The analysis focused on failure modes, load-deflection responses, and crack development while considering the wet joints. All specimens exhibited interfacial slip between the UHTCC/concrete layer and the steel beam. A novel theoretical model was developed to predict crack width in steel-UHTCC/concrete CBDs with wet joints. This model incorporates established crack theories for fiber-reinforced concrete while explicitly accounting for the strain-hardening behavior of UHTCC. Furthermore, this model provides a detailed bending analysis of steel-UHTCC CBDs considering the interface slip phenomenon, to derive various mechanical parameters for crack width prediction.