PRELIMINARY RESULTS FOR NEESR FULL-SCALE RC COLUMN TESTS UNDER COLLAPSE-CONSISTENT LOADING PROTOCOLS

Direct collapse simulation is a critical tool for understanding the behavior of reinforced concrete (RC) buildings subjected to extreme earthquakes. However, there are major shortcomings in currently available test data for modern RC moment frame columns in order to develop suitable models for the collapse simulation. Most of the currently available test data correspond to smaller scale specimens subjected to deformation levels that are not large enough to capture accurately their degradation and softening behavior. Moreover, there are limited test data available for identical specimens tested under monotonic and cyclic loading protocols. To address this critical need, a set of full-scale reinforced concrete columns was tested at the NEES (Network for Earthquake Engineering Simulation) Multi-Axial Sub-assemblage testing (MAST) facility at the University of Minnesota as part of a U.S. National Science Foundation (NSF) NEES research project. The specimens had cross sectional dimensions that were larger than most if not all columns tested previously under simulated seismic loading. The specimens were subjected to large monotonic and cyclic displacement reversals up to 10% story drift ratio to investigate the behavior at or near collapse conditions. An overview of the load-deformation relations, strength and stiffness deterioration, and the effect of loading protocols are discussed.