Shear Deformation and Sliding-Based Fiber Beam-Column Model for Seismic Analysis of Reinforced Concrete Coupling Beams

Conventional RC coupling beams have been widely used as key energy-dissipation components in frame-core tube structural systems for high-rise buildings. A model with sufficient efficiency, accuracy, and practicality is urgently needed for the seismic analysis of high-rise structures. According to test results, both the shear deformation and shear sliding mechanisms are critical to assessing the seismic performance of coupling beams. However, available shear models for beams and columns cannot give satisfactory results in modeling both mechanisms in finite-element analysis (FEA). To address this problem, this study takes into account the section shear force-shear strain and shear sliding laws in the traditional displacement-based fiber beam-column element, which is implemented into a general FEA package. A new section shear force-shear strain law, which can consider the pinching effect, strength and stiffness deterioration, shear capacity degradation, and arbitrary complex loading path is first proposed. In addition, a new section shear force-shear sliding strain law is developed to model the special shear sliding phenomenon. Then, shear sliding and shear compression limit formulas are given to determine different failure modes. Two beam-column elements, named the shear element and sliding element, are finally developed and combined to model the coupling beam. To verify the proposed model, 47 test specimens are collected and summarized. The formulas for the shear strength, cracked shear stiffness, and shear displacement limit are proposed and verified. Then, the model is applied to 16 test specimens. It is indicated that the model has sufficient accuracy, high efficiency, and convenient modeling procedure, which offers a reliable and powerful tool for seismic analysis of conventional RC coupling beams and high-rise structures. (c) 2016 American Society of Civil Engineers.