Procedural Assumption Comparison for Old Buildings via Pushover Analysis Including the ASCE 41 Update

The two different procedures of ASCE/SEI 41 Supplement 1 and the EC 8 based Greek Retrofitting Code (GRECO) are compared via pushover analyses for the seismic assessment of RC buildings designed to old codes. In addition, the FEMA 356 procedure is considered in order to evaluate the new provisions of ASCE/SEI 41. Results from two moderate level seismic tests performed on a four-story building are used for comparison. For the first test, all procedures overestimated the experimentally observed limited damage but GRECO was more satisfactory. For the second higher excitation test, all procedures predicted the building's high vulnerability but failed to predict the experimentally observed imminent collapse of a stiff column. In all cases, GRECO gave higher displacements. ASCE/SEI 41 and FEMA 356 predicted better the building's stiffness and gave much higher available plastic hinge rotations for beams when compared to GRECO. Concerning the columns, available plastic hinge rotations at the Life Safety performance level from the ASCE procedure were higher than GRECO, while ASCE values at the collapse prevention performance level were slightly lower than GRECO. Finally, a comparison of the above procedures with nonlinear dynamic analyses of a past earthquake is performed to identify potential pushover analysis concerns.