Reliability Estimation of Reinforced Tied-arch Bridge Based on Time-dependent Reliability Theory

In order to estimate the reliability of tied-arch bridge structure before strengthening and after strengthening as well to provide a basis for strengthening strategy and evaluation of strengthening effect,the suitable estimation method was studied.Adopting three-stage working mode and combining with current standards,the failure judgment criterion of RC tied-arch bridge was given.Based on time-dependent reliability theory,real bridge test and random sample analysis,Monte Carlo method was used to analyze and predict the reliability and working states of Boluo bridge(a reinforced concrete uniform sectional half-through tied-arch bridge) before and after strengthening.The results show that(1) the reliability of Boluo Bridge before strengthening is less than target reliability,the structure worked with damage;(2) the reliability of the bridge can meet the standard requirement and the structure is in safe work state after strengthening its arch ribs,bridge decks and foundation.The calculation example shows that the adopted method is effective.