Structural Damage Allocation from Sequential Earthquakes: Fid-Bau Portal

Structural Damage Allocation from Sequential Earthquakes

Arya, B. / Jain, A. / Simsir, C. C. / Reyes, D. G. / Rahmani, M.

This paper presents a practical approach to estimate the contribution of individual earthquakes in a seismic sequence to the overall damage sustained by a structure. In this approach, a single degree of freedom (SDOF) model of the structure with a nonlinear capacity curve is subjected to a sequence of ground acceleration time histories. Structural response of this model is then used to develop a measure of contribution of each earthquake to the overall structural damage. The capacity curve is developed using the procedure outlined in FEMA’s methodology for estimating potential losses from earthquakes (HAZUS-MH) and ASCE 41-13. The SDOF model accounts for both stiffness and strength cyclic degradation as well as second order effects in the structure’s response during strong ground motions. New Zealand’s Canterbury earthquake sequence of 2010–2011 is used as the base excitation for a case study. Ground motions from the recording stations closest to the subject building are combined to produce a single sequential event in the same order as they occurred. A comparison of dissipated energies at the end of each earthquake event yields the relative contribution of each of the earthquakes to the total energy dissipated by the structure during the entire earthquake sequence. The amount of dissipated energy in the structure directly correlates to the damage sustained by various building components as earthquake energy is dissipated through the cyclic inelastic actions of the structure. This analysis can assist forensic investigation by providing information on the damage state of the building after prior events for which an inspection was not performed or there is little or no documentation of damage. In addition, it can serve owners as well as the insurance industry to resolve disputes over insurance claims.