Quick and accurate prediction of seismic demand of tall buildings is one of the toughest tasks for engineers in civil industry. Nonlinear response time history analysis method (NLRHA) is currently considered as the most accurate and rigorous method, but the computation consumption is exceptionally high. The conventional pushover procedures, in which the building is treated as a single degree of freedom system, are not capable of reasonably estimating seismic demands of mid- to high rise-buildings, due to an over-simplification of the multi-mode effect and the complexity of seismic performance of buildings.

In this study, an efficient, yet accurate, method of analysis, named spectrum-based pushover analysis (SPA) method, is proposed for the quick estimate of seismic demands of ta...[ Read more ]

Quick and accurate prediction of seismic demand of tall buildings is one of the toughest tasks for engineers in civil industry. Nonlinear response time history analysis method (NLRHA) is currently considered as the most accurate and rigorous method, but the computation consumption is exceptionally high. The conventional pushover procedures, in which the building is treated as a single degree of freedom system, are not capable of reasonably estimating seismic demands of mid- to high rise-buildings, due to an over-simplification of the multi-mode effect and the complexity of seismic performance of buildings.

In this study, an efficient, yet accurate, method of analysis, named spectrum-based pushover analysis (SPA) method, is proposed for the quick estimate of seismic demands of tall buildings. In the proposed SPA procedure, the very complex and complicated dynamic coupling effect of different modes of the nonlinear seismic performance of the building is simplified and the consecutive pushover technique is adopted to consider the simplified coupling effect. The SPA procedure is then modified to include the impact of the wall-frame interaction in dual wall frame structures for the fast prediction of the earthquake-induced deformations.

The SPA procedure is further applied for the quick estimate of the tall buildings with singly symmetric building plans, by including the torsional effect. Finally, the SPA is extended to predict the earthquake-induced forces of the structures. Comparison of the seismic demands of tall buildings with different structural types from the NLRHA method, the modal pushover analysis (MPA) method, the consecutive modal pushover analysis (CMP) method and the proposed SPA procedures are conducted. It can be seen from the comparison of the results that the SPA method is capable of predicting the seismic demand of buildings, such as inter-storey drift ratio, hinge plastic rotation, shear force and bending moment accurately and the predictions are very close to those obtained from NLRHA.

The SPA procedures are efficient and effective in estimating the seismic demands of building structures and the computation procedure of SPA procedures is simple. Additonally, the roof displacement calculation procedure is spectrum-based, which is user-friendly to engineers. Owing the impressive advantages of the SPA method, it is believed that the proposed SPA procedure can be one of the best alternatives of the NLRHA method in the fast estimate of seismic demands of tall buildings.