The purpose of this paper is to propose an innovative and efficient shear connection for large underground reinforced concrete storage tanks constructed by diaphragm walls and inverted lining or large-scale open caisson method where an extra-deep diaphragm wall is employed to prevent the inflow of ground water during construction. This connection has been introduced because of its potential advantages for both economy and safety. A general nonlinear finite element model to analyze the proposed shear connection is presented. To account for the varied material properties the analytical model is divided into concrete and steel elements. Two-dimensional isoparametric eight nodes quadrilateral plane stress elements having two degrees of freedom at each node are used to idealize both concrete and steel parts. The interface between concrete and steel elements is represented by special six nodes quadratic line gap elements having both normal and shear stiffness. The steel material is modeled using an elasto-perfectly plastic model with a Von Mises yield criterion. The concrete behavior under compression is modeled using an elasto-plastic model with a Drucker-Prager yield criterion and associated plasticity. The concrete in tension is modeled using a smeared cracking model with tension cut-off, tension softening and variable shear retention. The analytical results are compared well with the calculated ones using the principles of static and material properties. Furthermore, the simplified design equations for the proposed shear connections according to ECP’01 are given |
