INCREMENTAL DYNAMIC ANALYSIS OF COUPLED TALL REINFORCED CONCRETE WALLS SUBJECTED TO FAR-FIELD AND NEAR-FIELD EARTHQU

Near-field (NF) earthquakes, compared to far-field (FF) ones, may result in a variety of responses of the structure. In this research, the behavior of a tall building with coupled reinforced concrete (RC) core-wall, is investigated. Firstly, the structure is designed using the methods in the conventional codes and utilizing the response spectrum analysis procedure. Then, fiber elements and nonlinear shear hinge are used for preparing the nonlinear model of RC shear wall and for coupling beams, respectively. The structure is analyzed using the nonlinear time history analysis at maximum considered earthquake level, implemented for NF and FF record sets and the results are compared. Results show that the base moment demand are identical and the average base shear demand obtained from the NF record is 1.5 times the corresponding demand obtained from the FF record. Also, the inter-story drift ratio demand envelope, curvature, roof drift and stories acceleration are compared. In addition, some important earthquake intensity indices for sets of NF and FF ground motions are studied. Besides, incremental dynamic analysis is used to calculate fragility curves. This analysis demonstrates that the difference between fragility curves from NF and FF earthquakes is significant. Also, with the increase of selected performance limit state, the general difference between the two fragility curves becomes relatively smaller.