@article {bnh-5207, title = {Final report on fragility curves for retrofitted URM buildings in Australia}, year = {2018}, month = {12/2018}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

As reported in the previous project report {\textquotedblleft}Fragility Curves for URM Buildings{\textquotedblright}\ (Derakhshan and Griffith, 2018), fragility curves are an important tool for estimating the economic loss due to earthquakes. As a follow-up to that work,\ this report presents fragility curves for URM buildings that have been seismically\ strengthened. With this additional information, it will be possible to estimate the\ reduced damage due to seismic retrofit for cost-benefit analyses for a range of\ earthquake scenarios in order to ensure cost-effective seismic strengthening\ policy.

With this in mind, the remainder of this report should be treated as an addendum\ to the previous project report (Derakhshan and Griffith, 2018), hereafter referred\ to as the August 2018 report.

In the present report, we describe the methodology used to produce empirically-based\ fragility\ curves\ for\ seismically\ strengthened\ URM\ buildings\ on\ the\ basis\ of\ performance\ reported\ for\ 78\ heritage-listed\ buildings\ in\ Christchurch\ during\ the\ 2010\ and\ 2011\ earthquake\ sequence.\ 

Empirical fragility curves for the global damage of strengthened buildings have\ been derived using the simplifying assumption that the PGA to cause a\  particular\ probability of a given damage state in a strengthened building can be obtained\ as a scalar multiple of the probability to cause the same damage state in the\ unstrengthened building. On the basis of this assumption, PGA scaling multipliers\ are calibrated which can be used to apply a rightward shift to the\ unstrengthened building curves (from the August 2018 report) to produce the\ corresponding curves for strengthened buildings. These multipliers were\ calibrated using the Christchurch earthquake damage data for two levels of\ retrofit. It was found that a multiplier of 1.4 produces good agreement for\ buildings with full retrofit, and a multiplier of 1.1 for buildings with partial or\ incomplete retrofit. It is recommended that for buildings strengthened only for\ improved out-of-plane wall resistance by means of bracing/ties only, a multiplier\ of 1.0 should be used.\ 

}, issn = {441}, author = {Jaroslav Vaculik and Michael Griffith} }