Estimation of the structural performance levels and inelastic drift of reinforced concrete frames, considering the variability of the materials of Bogotá

Abstract

The structural engineers calculate the seismic capacity of reinforced concrete frames with the geometry of the structural elementsand with the mechanical properties of the materials. The most important mechanical properties of the concrete and the steel used toestimate this capacity are: elasticity modulus (E) and compressive strength (f `c) of the concrete, yield stress (Fy) and maximumstress of the steel (Fu) and its strains. Based on these facts, results of more than 1,500 concrete compression tests (only fromBogotá), and more than 900 steel tension tests were statistically studied. Then, five stories reinforced concrete buildings weremodeled (finite element analysis – frame elements) and designed according to the Colombian Earthquake Resistant Code (NSR-10) and with two design spectrums of the Bogota microzoning (2010). Using the frame models and generating random numbers ofthe steel and concrete mechanical properties (according to the statistic analyses of the laboratory test) 80,000 pushover analyses of2D frames were performed to obtain the inelastic drift and its probability distribution functions for different damage levels(Montecarlo simulations). According to the results the average drifts limits for a yield damage level, immediate occupancydamage level and life safety damage level are 0,51%, 0,84% and 1,41% respectivel.