Abstract:  The authors investigate how concrete voids located at the base of steelshelled concrete angle connectors affect their shear performance and propose an effective repair method for these voids. Focusing on the angle steel connectors in the immersed tunnel of the Shenzhen－Zhongshan link, eight fullscale test specimens are designed. Shear performance tests and finite element simulations are conducted with varying parameters such as void shape, void repair, and concrete strength. The findings reveal that: (1) In ordinary concrete specimens, crush damage primarily occurs within the angle′s internal concrete, with the damage mode being minimally influenced by the void form and repair. (2) Concrete voids significantly reduce the shear bearing capacity and stiffness of angle steel connectors, with reductions of up to 32.8% and 76.9%, respectively, in specimens with a triangular prism void. (3) While void repair enhances the shear load capacity and stiffness of the connectors, the improvement is limited due to the challenges in achieving cohesive bonding between the repair material and the void interface. (4) Substituting ordinary concrete with ultrahigh performance concrete (UHPC) without repairing the void increases the shear bearing capacity of the specimen by 77% compared to those without voids. However, the shear stiffness is decreased by 8.9% compared to specimens with voids. (5) Despite UHPC′s superior mechanical properties, it cannot effectively increase the shear stiffness due to significant deformation in the angle steel connectors caused by the voids. (6) Finite element analysis indicates that improving the mechanical properties of the repair material does not significantly enhance the shear bearing capacity postvoid repair in triangular prismshaped voids.

Key words: steelshell concrete, void repair, angle steel connectors, mechanical property, triangular prism void, immersed tunnel, launch specimen, ultrahigh performance concrete, finite element simulation