Safety Assessment And Early Warning Of Large-span Cable-stayed Bridge Based On Limit Analysis

Long span cable-stayed bridge is of a key of transportation system, thusplaying an important role in national economy. Cable-stayed bridges feature heavyinvestment, long design life and fragile in harsh environment. Therefore, it is ofgreat significance to take appropriate technical measures to evaluate its performanceto ensure safety, serviceability and durability.Safety assessment and early warning of large-span cable-stayed bridges areinvestigated in this thesis by considering the two design limit states and push-overlimit analysisi. The research is exemplified by application of the method to theNingbo Xiangshangang bridge. Detailed reseaches are summarized follows.Firstly, an initial finite element model of Xiangshangang Bridge is establishedusing the ABAQUS in accordance with the design and construction data. Then themodel is modified using the bridge loading test data in order to better predict itsbehavior.Secondly, the displacement influence surfaces of traffic load are calculatedbased on the revised finite element model, and the most unfavorable load positionsare obtained. The responses of the bridge corresponding to the serviceability limitstate and load-capacity ultimate state. are calculated The reponse of the bridge towerfrom elastic to collapse state is calculated under the combination of wind load,vehicle load and seismic action by using the concept of pushover analysis.Finaly, a three-level safety warning system of cable-stayed bridge is establishedby setting the response of bridge structure in serviceability limit state, load-capacityultimate state and pushover analysis limit state as the warning thresholds for eachlevel.