NEESR-SG: Self-Centering Damage-Free Seismic-Resistant Steel Frame Systems SC-MRF Hybrid Simulation for Aftershock
October 31, 2008
This simulation represents an aftershock following an earthquake that produced the median-level maximum considered earthquake (i.e., MCE, with 2% probability of exceedance in 50 years) response. The input ground motion is the SJTE315 record from the 1989 Loma Prieta event, scaled by -2.234. The response to the aftershock will be equivalent to the median-level design basis earthquake (DBE) response. No significant yielding is expected in the beams and columns and no other damage is expected. The maximum story drift will be approximately 2.9 % radians. The prior median-level MCE simulation caused minor yielding in the columns at the base of the first story and in the 3^rd floor beams, more extensive yielding of the roof beams, small reductions in the post-tensioning forces, and small residual drift.
The 4-story, 2-bay self-centering (SC) moment-resisting frame (MRF) test structure is based on a prototype structure designed for a site in Van Nuys, California. The test structure has been subjected to numerous previous laboratory tests, including several median-level frequently occurring earthquake (i.e., FOE, with 50% probability of exceedance in 50 years) hybrid simulations, two low-level DBE hybrid simulations, one median-level DBE hybrid simulation, one high-level DBE hybrid simulation, one high-level DBE/median MCE hybrid simulation, and one median-level MCE hybrid simulation. From these previous laboratory tests, the SC-MRF test structure has no significant residual drift, minor yielding in the columns at the base of the first story, and small reductions in post-tensioning forces from the DBE-level simulations, as well as the damage identified above from the MCE-level simulation.