Abrupt cable loss is a critical extreme event for cable-supported bridges, which can happen under intentional attack scenario or deterioration of cables. Slender long-span bridges may have simultaneous presence of a large number of vehicles or significant wind along with sudden breakage of cables. Most cable-loss events occur suddenly without much warning when service loads like traffic and wind may be present. Such combined extreme and service loads have not been considered in the existing cable-loss analyses. The current load resistant factor design (LRFD) specification do not consider simultaneous loading. The proposed research is to develop a reliability-based dynamic analysis method for slender long-span cable-supported bridges under combined extreme (cable breakage) and service loads such as traffic and/or wind. Analytical method development along with validation with wind tunnel testing is part of the project.
The project will pursue research in response, safety and reliability of cable supported long-span bridges in case of a sudden loss of one or more cables. The cable loss causes dynamic loads on the bridge which can have catastrophic consequences since cable-stayed bridges depend on cables as the main supporting element. A variety of scenario of cable failure and moving traffic on the bridge will be developed to encompass realistic situations. Non-linear analytical simulation will be developed for limit state situation which will be validated with scale model experiment in wind tunnel (normal moving traffic and wind are part of scenario loading). The ultimate goal of the project is to provide consistent reliability to long-span cable supported bridges under various realistic load and accident conditions. Results of the project will be disseminated through publications as well as will be made available to standard writing bodies.
