Time-Invariant Reliability Analysis of RC T-Beam Bridge Girder—Limit State of Strength in Flexure

The purpose of structural design is to fix the dimensions of a structural member, to safely withstand the loads anticipated during its life cycle and to serve the intended purpose satisfactorily throughout its service life in the environment it is built for. The main aim of the present work is to determine the probability of satisfactory performance of flanged reinforced concrete beams in limit state of strength in flexure. For this purpose, two methods, namely simulation approach and analytical approach, have been made use of. For the study purpose, standard T-beam bridge cross sections for different spans as recommended by MORTH have been made use of. The typical load combinations as specified in IRC: 6-2017 are considered. Also, the special vehicle load which was introduced in the recent code IRC: 6-2017 is also considered to check the performance of bridge beams against limit state of strength in flexure. The various basic random variables are assumed to be statistically independent normal and non-normal random variables. The moment of resistance is found to follow normal distribution, external moment found to follow Type-1 distribution, and the safety margin is found to follow lognormal distribution. The reliability index value tends to decrease with an increase in span.