Small And Medium Span Stone Arch Bridge Bearing Capacity Reliability Study

Most of stone bridges on the highways in my country were built before 1970s. And because of its low design carrying capacity, some damages are appearing now, such as arch leaking, mortar weathering and arch springing cracking. As the development of traffic, a large number of low grade highways are reconstructed ot extended, which makes the safety problem become more important.Based on the collapse tests of actual and model stone bridges in home and foreign countries, the author of the paper researches the limit states of stone bridges and determines four-hinge collapse model and the method of determining plastic hinges. This method can give convenience to the calculation of reliability. Based on the stress-strain relationship, tests, no tensile stress of masonry and assuming resistance submit gauss distribution, the resistance equations and its statistic parameters are obtained. At last, based on JC method, the reliability of cross sections can be calculated, and based on incremental load to research the main fail model, the arch system fail probability is obtained.