SIMULATION FOR BEHAVIOR OF LENGTH TO HEIGHT RATIO L/H≤1.5 COMPOSITELY REINFORCED COUPLING BEAMS

On the basis of mechanics characteristic analysis of compositely reinforced coupling beams (CRCB) in reinforced concrete coupled shear walls under the experiment of a low frequency cyclic loading sequence and some rationalized hypothesis, the paper presented a statically indeterminate strut-tie model applied to the behavior simulation of CRCBs with the span to depth ratio L/h≤1.5. This model is comprised of a main diagonal strut-tie model which includes a diagonal concrete strut, a diagonal reinforcement strut and a diagonal reinforcement tie, and a rhombic truss model which includes two bars of rhombic reinforcement ties and a secondary concrete strut. The paper gave a definite equation between the deformation of two kind concrete diagonal struts and displacement of the coupling beams, then the struts and ties’ geometric equations and deformation compatibility equations were set up according to the deformation of members. Furthermore, the relationship between the members’ forces and deformations were obtained by the free bodies of the members. The total equilibrium equations at the end section of the beams were established eventually. The result Comparison between iterative calculation of the total 31equations and experiment shows that the model can better reflect the whole process that from crack to failure behavior of CRCBs with the span to depth ratio L/h≤1.5.