Aftershock Collapse Vulnerability Assessment of An Older Reinforced Concrete Frame


Abstract eng:
Buildings located in seismically-active regions may experience ground shaking from multiple earthquakes, such as mainshock-aftershock sequences. In mainshock-aftershock sequences, the seismic events generally occur in close succession, leaving insufficient time for repair or retrofit between the events. In such cases, seismic performance of a building during an aftershock may depend on the level of damage sustained by the building in mainshock. This study evaluates the aftershock collapse vulnerability of a non-ductile reinforced concrete moment frame building designed according to the 1967 Uniform Building Code. This type of reinforced concrete moment frames is relatively weak, and susceptible to shear and axial column failure (among other failure modes) due to inadequate reinforcement detailing and lack of capacity design requirements. Here, the reinforced concrete frame is modeled in two dimensions with zero-length springs on top of columns capable of capturing shear and axial failure modes. Incremental dynamic analysis on nonlinear analytical building models is used to generate damage and collapse fragility curves for intact and mainshock damaged buildings. The results show that the structure’s ability to withstand collapse and further damage are decreased as the extent of damage after the mainshock increases. This trend is similar to what has been observed for ductile RC frames. However, a modern ductile RC frame can undergo higher levels of damage before its aftershock collapse capacity is seriously compromised. In addition, the drop in collapse capacity, as a function of mainshock damage, is more precipitous for the non-ductile RC frame building.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 1576.:
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