Measurement And Analysis Of Stress In Suspenders For Danyang Canal Bridge In Jiangsu Province

The tied arch bridge is a kind of bridge without horizontal forces, in which tie-rods are mainly for the outward-directed horizontal forces and arch ribs are mainly for compression and carriageway beams are bearing bending moment. The outside of the tied arch bridge is a statically determinate structure and the inside of it is a high-order indeterminate structure. Any stress change in a suspender would have effect on the whole structure.In recent years, there are some collapse cases because of the suspender failure in the tied arch bridge. So it's quite necessary to do some research concerning the stress change in suspenders during the construction stage as well as serviceability state.Danyang Canal Bridge in Jiangsu province is a tied arch bridge, its suspender consists of two parts, one is the stay cable, and the other is the steel tube which is used for protecting the stay cable. The stay cable is made from bunched steel wires. There isn't any filling material between the steel tube and the stay cable. In this bridge, the steel tube is not only for protection of the stay cable, but also acts as a part of the suspender, which carries some forces during the construction stage as well as serviceability state. In this paper, the stresses of the stay cable and the steel tube are measured and numerically analysed at different construction stages and under loading test when the bridge construction is finished.It's indicated that the stay cable and the steel tube work together during the construction stages as well as loading test when the bridge construction is finished. The measured stresses in the stay cable and the steel tube are less than the calculated ones during the construction. At the final stage of the construction, the stresses in all of the suspenders are close to each other. During the loading test, the stress increments in suspenders are quite limit and within 30MPa in the different loading patterns. But the force increments in the steel tube are as large as 5 times comparing to the force increments in the stay cable. It shows that, in daily use of the bridge, the suspender is not easily broken by the stress increment, and it should enhance the durability of the suspender.In addition, based on the "Code of Maintenance of Highway Bridges and Culvers " and analysed by the Analytic Hierarchy Process, the weight factors for the super structure of the tied arch bridge are obtained.