Reliability-based linear analysis of low-rise RC frames under earthquake excitation

Determination of seismic reliability of low-rise moment resisting frame RC buildings has been done using probabilistic analysis in this paper. The effect of the number of stories on the safety level of the structures has also been investigated. Reliability-based analyzes were performed using the Monte Carlo simulation technique. The Latin hypercube technique has also been used to reduce the number of simulation samples and to place the responses in the failure region. Conventional low-rise residential buildings with three bays and 2, 3, and 4 stories have been studied. The considered buildings are regular in plan and height. The site is deemed to be a high relative seismic hazard. The time response analyzed has been done by finite element software. The linear elastic behavior of materials is considered in structural analysis. The horizontal component of the Varzaghan earthquake with the peak ground acceleration of 0.4 g was utilized for seismic loading. The engineering parameter of maximum inter-story drift is assigned as the limit state of the reliability problem. Epistemic uncertainty of geometric parameters, gravitational loads, bare frame own-weight, and mechanical properties of concrete materials are considered. Bay length, story height, beam and column cross-sections dimensions, dead load, live load, modulus of elasticity, the density of concrete, and Poisson ratio are utilized as random variables. The coefficient of variation for live load is considered 40% and for the rest of the random variables is 20%. The results showed that the reliability of the studied buildings is over 90%. Also, with increasing the height of the building, the reliability decreases by about 3.5% per story. Sensitivity analysis results showed that the columns dimension in the lower stories and the frame spans, have notable effects on the inter-story drift. Also, gravitational loads (dead and live loads) and bare-frame own-weight have a minor impact on the inter-story drift