Study On Suspender Replacement Of Tied-arch Bridges

The tied-arch bridges have been developing very fast for the recent 20 years in our country, especially the concrete-filled steel tubular arch bridges. The bridge has become an important bridge type. Through the bridge has been developed very lately, it develops very fast in our country. Because designers have considerd little of the suspender deplacement. there appear many problems during service period. Recently, there are many suspenders in the need of repair, and some have to be replaced in some bridges. Therefore, it is very important and instant to further the research of the suspender disrepair and replacement, which is just the content of this paper.The paper summarizes the development, the type, the bearing characteristic of tied-arch bridges as well as the study status of the suspender replacement. The reason and mechanism of the suspender damage are generalized. As a part of the suspender replacement, suspender-force test is very important to assure that the suspenders are replaced successfully. It is an effective method to compute the suspender force that the two-terminal constraints of one suspender are conversed to be Equivalent hinged constraints. The method illustrates that the constraints of suspender is neither hinged nor fixed. In fact, the constraint form of suspender is very special because it is between the hinged constraint and the fixed constraint. At present, temporary suspender method is applied mostly in the engineering. The design and check of the temporary suspender is supplied in the paper. How to remove an old suspender and how to install a new one is simulated with the finite element theory and software. The applicable method of the suspender replacement is applied as well as the optimum project, which is applid to the Yeqingdou bridge. At last, the replacement construction and monitoring is very important, which is the assurance of the successful replacement. Some constructing and monitoring points and principles are suggested for the replacement. At the same time, there are some evaluating criteria and some methods of adjusting suspender force.The temporary suspender method is very effective and useful in engineering. As time goes on, there are more and more tied-arch bridges which need replace suspenders. The outcome of the paper can guide and apply to the similar engineering, which has great practical significance.