Numerical analysis of reinforced concrete shear keys in immersion joints

Abstract

Immersion joints are susceptible to be damaged first under various loadings due ito their smaller stiffhess compared to the adjacent tunnel elements. The induced Ideformations and the forces in the joint are transferred by shear keys. If failure occurs in the i shear keys, excessive defbrmations may lead to severe leakage. This paper presents threedimensional numerical analysis results for RC shear keys by using the concrete damaged plasticity (CDP) model. Two types of shear keys, HSK1 and HSK2 with different numbers 0f tenons respectively, are considered, as well as a cyclic loading protocol. The tensile damages of the shear keys are obtained. The numerical results indicate that the damages occur firstly at the bottom of the tenons, close to the clamped edge. Then, the damages develop along the direction to both the middle bottom of the tenon and the middle top of the shear keys. The bottom cracks are more diffxcult to be observed than the top cracks and cross the key. By comparing the experimental results, the obtained tensile damages are in accordance with the observed tensile cracks