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Summary Reinforced concrete (RC) dual systems are composed of RC moment‐resisting frames (MRFs) and RC shear walls, where MRFs are barely designed to handle gravity loads. Investigations have demonstrated that shear walls exert negative effects on the upper part of MRFs. In this paper, the interaction of shear walls and MRFs is inspected using endurance time (ET) method. ET is a dynamic time history‐based pushover procedure in which structures are exposed to a set of predefined intensifying ET acceleration functions. In this method, seismic performance of the considered structure is assessed based on earthquake return periods; during which, required predefined seismic performance objectives are fulfilled. In this study, several buildings with RC dual systems were designed based on the conventional codes. Next, their nonlinear duplicates were generated for the application of the ET analysis. It was revealed that shear wall elements impose considerable rotational demands—exceeding the criteria established by ASCE41‐13—on the beams and columns, especially those located on the upper parts of the buildings. This paper puts forth and reviews certain methods to cushion the negative effects brought about by RC shear walls, along with a detailed discussion on their merits and demerits.

This paper presents a particle swarm optimizer for production of endurance time excitation functions (ETEFs). These excitations are intensifying acceleration time histories that are used as input motions in endurance time (ET) method. The accuracy of the ET methods heavily depends on the accuracy of ET excitations. Unconstrained nonlinear optimization is employed to simulate these excitations. Particle swarm optimization (PSO) method as an evolutionary algorithm is examined in this paper to achieve a more accurate ETEF, where optimal parameters of the PSO are first determined using a parametric study on the involved variables. The proposed method is verified and compared with the trust‐region‐reflective method as a classical optimization method and imperialist competitive algorithm as a recently developed evolutionary method. Results show that the proposed method leads to more accurate ET excitations.

This study proposes a response-based parameter for strong motion duration which is computed for structures and is the total time they are nonlinear during an earthquake. Correlation between structural response and duration for structures, subjected to a set of spectrum matched ground motions, is employed to examine the efficiency of the proposed method. The spectral matching procedure ensures that the influence of amplitude and frequency content of motions on structural response variability is significantly removed. Four concrete building type systems are studied and correlation coefficients of structural response with the proposed duration definition are examined. Comparison of the proposed method with other existing definitions-the recordbased and response-based metrics-shows about 15-20% improvement in the correlation values.

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