Sensitivity Analysis Of Reliability Of Reinforced Concrete Beam

The sensitivity analysis of structural reliability can provide the information about the influence of the variation of basic random variables on the failure probability, which would lead to an optimum design for structures. Based on the advanced first order second moment (AFOSM) method for structural reliability analysis, the reliability sensitivity analysis for reinforced concrete beam in the serviceability limit state and strong shear-weak bending design state is performed.The main contents in this paper are outlined as follows:Firstly, considering the serviceability and durability of concrete structures, the sensibility of the reliability for serviceability limit state of reinforced concrete beam is performed, in which the new"Chinese Code for design of Concrete Structures"(GB 50010-2002) is followed. The factors that pose major influence on the reliability of concrete beam for serviceability are obtained.Secondly, according to the"Chinese Code for Seismic Design of Buildings"(GB 50011-2001), the non-time varying and time-varying reliability of reinforced concrete strong-shear-weak-bending beam for earthquake design is calculated, and their sensibility to random variables involved is analyzed. The results show that, in both the time-varying and non-time varying cases, the reliability is very sensible to the shear resistant calculation mode, the effective height of beam cross section, and the concrete tensile strength. The adopted shear-enhanced coefficients in current design code provide insufficient confidence for the strong-shear-weak-bending design, and this coefficient is to be appropriately enlarged.The researches in this paper will provide valuable basis for reliability design of reinforced concrete structure.