Investigation of efficiency of vector-valued intensity measures for displacement-sensitive tall buildings

摘要

The design of tall buildings is different from that of ordinary buildings and performance-based earthquake engineering (PBEE) plays an important role in the design and assessment of tall buildings. Incremental dynamic analysis (IDA) is mainly the method used to analyze tall buildings in the framework of PBEE. Owing to the enormous amount of computation in IDA, seeking an efficient intensity measure (IM) is of vital importance. When an efficient IM is used, the number of seismic records and nonlinear analyses for IDA can be significantly reduced without affecting the accuracy, which is important in IDA especially for tall buildings where elastoplastic time-history analysis requires more time. However, there have been only few studies on IMs for tall buildings. Moreover, although IMs have been extended from the scalar-valued type to the vector-valued type, there are no vector-valued IMs proposed for tall buildings. Thus, in order to provide a systematic investigation on IMs for a specific type of tall structures, this study investigated six vector-valued IMs as well as their scalar types for a displacement-sensitive tall building. The investigated IMs included five acceleration-based IMs with three considering nonlinearity development and two incorporating higher modes effect, as well as one velocity-typed IM. IDA was carried out for the structure under fifteen ground motions and the residual sum of squares (RSS) as well as R-2 values were calculated to compare the efficiency of the IMs. The results indicate that for a displacement-sensitive structure, the peak ground velocity (PGV) is the most efficient scalar-valued IM, while the < S-a(T-1), PGV > is the most efficient vector-valued IM. The vector-valued IMs are more efficient than corresponding scalar-valued IMs. The IMs considering nonlinearity are more efficient than the IMs incorporating higher modes and within a certain range the more refined the considered nonlinearity is, the more efficient the IM becomes.