NONLINEAR ANALYSIS MODEL AND NUMERICAL SIMULATION OF COUPLED WALL SYSTEMS

Coupled wall systems, compared with shear walls without openings, have more complex nonlinear behavior due to the existence of coupling beams. The Modified Force-Based Fiber Element (MFBFE), whose flexibility matrix is improved, is served as the nonlinear analysis elements of both wall piers and coupling beams. A hysteretic shear model (DCBHShear) for diagonal reinforced coupling beams was proposed. The envelope curve based on tri-linear model included the cracking, yielding and ultimate points. Changes of both unloading and reloading branches were governed by shear deformation ductility and stiffness reduction factor. Pinching coefficient controlled the effect of pinching. The codes of MFBFE and proposed DCBHShear, as well as another hysteretic shear model (SWShear) for shear wall without opening and the uniaxial materials named Steel02 and Concrete02, have been implemented in OpenSees to simulate two four-story specimens of coupled walls constructed at approximately a one-third scale. Analytical results including initial stiffness, maximum shear force and energy dissipation compared to corresponding experimental findings show a good level of agreement.