| A pseudo random vibration approach for seismic analysis of structures is presented to suggest a possible alternative to the conventional approaches such as the time history analysis, the response spectrum method, and the random vibration approach.;The shortcomings of the above three approaches motivated the author to search for an alternative simple procedure to obtain the statistical response of structures to seismic excitation, that can be used by practicing engineers. The Smart 1 Array recorded in Taiwan is adopted to study the response spectrum and its related topics. Ensemble Peak, Mean, and RMS response spectra are generated in addition to cross spectrum, and principal spectrum. Of these spectra, the RMS response spectrum is especially important and is the basis of the pseudo random vibration approach. As related topics, the peak factors, probability distribution, crossing rate, and properties of the response spectrum are also discussed.;Finally, two example problems are introduced to illustrate the difference between the conventional and the random vibration approaches. These two examples also show that the pseudo random vibration approach is quite compatible to the random vibration approach.;The time history analysis is the most exact approach, but is usually regarded as a time-consuming and expensive approach. The response spectrum method is the most popular and simplest procedure so far, however it is an over simplified method that ignores all other factors affecting the total response of the structure. The random vibration approach, on the other hand, is suitable to deal with the uncertainty of stochastic processes such as earthquake ground motions, ocean waves, and strong winds in terms of statistical descriptions. Unfortunately, it is conceptually difficult, so that it has gained neither recognition nor popularity among the practicing engineers. |
