Collapse fragility curves of RC frames with varying design parameters

Abstract

The inelastic behavior of reinforced concrete structures subjected to a number of strong motion excitations of escalated Intensity Measure (IM) and monitoring of characteristic Engineering Demand Parameters (EDPs) of the structure for all these different instances is presented. This provides the necessary data to estimate the overall performance of a structure at a particular site of specified seismic hazard within the framework of Incremental Dynamic Analysis (IDA). In this, generation of data regarding capacity and demand evolves following a lognormal distribution while the corresponding cumulative distribution function is used to define the corresponding fragility curves. This analysis facilitates further the deduction of statistically sound estimates of the measured parameters. The hysteretic inelastic response of reinforced concrete members, i.e. beams and columns designed on the basis of Eurocodes is of primal importance. The Bouc-Wen model, as implemented in “Plastique” code, with parameters established based on existing experimental data, is considered implementing the IDA procedure. Through this modeling, a series of plane frames of different number of spans and stories designed in a similar manner is investigated. Also, the effect of some general design code provisions on collapse capacity of these frames, such as stiffness distribution along height and strong column-weak beam design principle are examined. Numerical results are presented and their corresponding fragility curves are derived. Interesting features are revealed, regarding the effect of alternative designs on collapse capacity, which often deviate from collapse predictions made using the static pushover analysis.