On the modal incremental dynamic analysis

Abstract

In this article a new technique for the dynamic response of structures is investigated. This applied procedure can predict the approximate seismic performance of the structures and it is fast, inexpensive and results are reasonably acceptable. In fact, this novel method logically combines two different techniques, ‘incremental dynamic analysis (IDA)’ and ‘modal pushover analysis (MPA)’, presented by other researchers. This method will take advantage of both methodical ideas such as equivalent single degree of freedom of multi-degree structures and the implementation of different scaled level of an earthquake record to the provided equivalent SDF structure. Using this procedure, simple approximate curves that present a realistic linear and non-linear seismic behaviour of the structure due to the applied scaled level of earthquakes can easily be extracted. In this investigation, several four-, eight- and 12-storey structures are specified as the example models and are dynamically analysed. Next, three different scaled earthquakes, El Centro, Northridge and San Fernando, are applied to each example problem. The results of the presented technique, modal incremental dynamic analysis (MIDA), are then compared with the IDA method. Comparison of the results reveals good accuracy in building seismic demands evaluation. Finally, it is also shown that the MIDA method is simple enough to be carried out on most personal computers and the authors believe this technique will serve design engineers working in real design conditions. Copyright © 2005 John Wiley & Sons, Ltd.