Modeling of pre-cast concrete hybrid connections by considering the residual deformations

Abstract

This paper presents an alternative section analysis and hysteretic modeling for the response of pre-cast concrete hybrid connections which have different level of mild steel contributions to the connection flexural capacity. Well-known classical reinforced concrete section analysis approaches cannot be directly applied to the pre-cast concrete hybrid connections due to the strain incompatibility between the concrete section, and the partially bonded mild steel, and the un-bonded pre-stressing tendons. In the proposed section analysis, initially the moment-rotation behavior of the hybrid connection is modeled by providing a new de-bonding length formulation for the mild steel. Later, a hysteretic response model is proposed by considering the residual displacements measured during the hybrid connection subassembly tests. The general trends and the energy dissipation predictions of the proposed model are compared with the previously published reversed cyclic test results. It is observed that the proposed moment-rotation envelope model and the cyclic response behavior model both exhibit satisfactory agreement with the previously published test results. Key words: Precast concrete, post-tensioning, hybrid connections, moment-rotation envelope, de-bonding length, residual deformations, hysteretic modeling.