Predicting the collapse potential of structures in earthquakes

This study derived and presented an analytical expression to estimate the collapse potential of a generic class of multi-storey, uniform, moment-resisting steel frames (MRSF). This expression was compared and validated with nonlinear pushover analysis (POA) and Incremental Dynamic Analysis (IDA) for a range of different heights of buildings which were designed according to Eurocodes. Moreover, the factors that influence the collapse potential, such as lateral load patterns, displaced shape and arrangement of plastic hinges formed were also investigated. From this study, two key parameters were introduced, the damage index (DI), %, or adjusted DI, i, and strength parameter, s. The results indicated that the analytical expression produced quite promising results compared to both static and dynamic nonlinear finite element analyses. This analytical expression shows that the design base shear suggested by Eurocode 8 is not a good estimate of the collapse load. Furthermore, from this piece of know ledge, % or i and s are the important parameters that are needed to calibrate and develop an equivalent Single-Degree-of- Freedom (SDOF) system. The SDOF model can be used as a precursor to Multi-Degree-of- Freedom (MDOF) analysis. It can play a useful role in accelerograms records selection because it requires less computational time in determining critical records for MDOF analysis. However, it is difficult to develop the SDOF system and replace the MD OF system because parameters such as elastic viscous damping, ~, and pseudo-yield, x~, are difficult to control. These two parameters are dependant on the type of the structural system and ground motion records. This is because every single earthquake has its own unique characteristics. Moreover, a new intensity measure (IM) called normalised peak ground acceleration (pGA) has been introduced. It produces strong correlation between IM and DM (i.e. inter-storey drift) for all events rather than conventional IM, i.e. PGA and Se (.7;).EThOS - Electronic Theses Online ServiceGBUnited Kingdo