Some issues regarding the models of the mass and damping matrices in nonlinear seismic analysis of moment resisting steel frames

摘要: Abstract Software users concerning seismic analysis of buildings usually use the concentrated mass (ML) matrix and Rayleigh damping (C). Similarly, initial stiffness (KO) first two modes are commonly used to calculate C. In addition, it is believed that forces small so there no significant errors if model used. The evaluation accuracy these practices for case steel constitutes main objective this research. To aim responses three models, representing low-, mid- high-rise considered. If ML used, shears bending moments in columns underestimated by up 31% 65%, respectively. shears, drifts, beams 27%, 50%, 55%, respectively, while axial loads underestimation can be 78%. 350% 325%, Damping represent a considerable fraction (0.47) plastic beams. KO C, 80%. results study give rise state consistent should structural modelling system under consideration. mode one superior, tangent formulate matrix.