In The Arch Bridge Suspender Load Behavior And Safety Study

Suspenders, the key components of half through or through arch bridge connecting the arch rib and the deck, transfer the load from the deck to the arch rib for the arch bridge's spanning function. Because of the constraint in science and technology and of the development level of industry today, there is yet no definite and uniform criterion in suspender's and anchorage's design, manufacture, fixing, protection, service, maintenance, health diagnosis, remove and repair, ascertaining service life and predicting remain life, etc. It is mainly depended on designer's estimation in the course of suspender design, fixing, maintenance and remove and repair, so it is happened frequently that bridge demolishment and accident owing to the suspender failure. Therefore, in this paper, the suspender's load behavior and safety design are studied particularly on the basis of other researches and the study and design of LaSa LiuWu bridge, and the answers are put forward and applied in designFirstly, the suspender's static and dynamical properties are analyzed and calculated under the dead load or live load in this paper, and the conclusions are made as follows: 1. Reticulate suspender's mechanical properties are better than inclined and parallel suspender's. 2. Internal force of the suspender varies nonlinearly with the rigidity of itself, the arch rib and the deck. 3. The safety factor had better greater than 2.39. 4. Current impact factor is lower.Secondly, this paper discusses the fatigue of suspender in detail, explaining that fatigue failure is the main reason of the demolishment of the suspender, proving that the bend stress of the suspender's anchorage caused by the wind, rain, and so on is 15% of its internal stress caused by the dead load, putting forward the method and the formula of the suspender's fatigue design and remain life estimate , andillustrating the measure of the suspender's protection in its service life, health monitoring and remove and repair.Finally, according to the principle of damage-safety, the suspenders of LaSa LiuWu bridge are designed, and their fatigue life calculated.