Comparison of real vs artificial accelerogram on local ground response analyses

Student: Mohammad Towhidur Rahman Bhuiyan
Supervisors: Dr Carlo G. Lai, Dr Mirko Corigliano, Dr Claudio Strobbia

ABSTRACT

The seismic input used for dynamic analysis of structures is often represented in the form of either an acceleration or a displacement response spectrum. However in geotechnical earthquake engineering, the solution of a problem like site response analysis requires the seismic excitation to be specified as acceleration time-history. According to EC8, time-histories could be spectrum compatible Real acceleration time-history or Artificial acceleration time-history. This work illustrates a comparative parametric study concerned with 1D site response analysis using both real and artificial accelerograms.

1D equivalent-linear site response analysis (using SHAKE2000 [Ordonez, 2000]) were carried out using 7-real & 7-aritificial EC8 spectrum-compatible acceleration time-histories. The results of the analyses with both artificial and real accelerograms were compared in terms of site-transfer function, acceleration response spectrum and several strong motion parameters.

The results of the analyses using real accelerograms provides realistic soil deposit behavior which capture the variability in the response while artificial accelerograms may lead to an unreliable estimation of the variability of the seismic demand and for some strong motion parameters it gives lower bound estimation compared with real accelerograms. Combined with fact of rapid increasing availability of Real accelerograms, it is recommended to use Real accelerograms in dynamic analysis.

You may download a digital version of this MSc dissertation here.