What is the difference between Time History and Response Spectrum?
calculates the response of a structure subjected to earthquake excitation at every instant of time (hence the name Time History). Various seismic data are
necessary to carry out the seismic analysis i.e. acceleration, velocity,
displacement data, etc., which can be easily procured from seismograph data’s
analysis for any particular earthquake. It is an important technique for
structural seismic analysis especially when the evaluated the structural response
This method is derived from time history analysis. A designer is not often bothered about the structure’s response at every instance of time, a maximum response is enough information to design an adequately strong structure. In this method graph between maximum spectral acceleration and various time periods of the structure is prepared for some ground acceleration and structures response at every instance of time is not calculated. The response spectrum method is the linear dynamic analysis method. This method involves the calculation of only the maximum values of displacements and member forces in each mode of vibration. This method uses smooth design spectra that are the average of several earthquake motions. The different earthquakes will have different response spectra but for ease of structural engineer IS 1893:2002 has given a general-purpose response spectrum which is derived by considering a few big earthquakes from the past.