Research On The Damage Reason And Reinforcement Of Concrete Trussed Combination Archbridge

The trussed combination arch bridge originated by our country in the 1980's is such a new type . Compared with traditional truss bridge , it is cost less , simple and long-span , so it had developed rapidly in the past 20 years . But many cracks have been found at the intersections of the main trusses almost in all of these bridges , and some bridges even have been demolished , so it is necessary and exigent to investigate the damage reason of this kind of bridge . Especially in recent years more and more trussed combination arch bridges bring to enter the lines of dangerous bridges , the majority of traffics have been controlled , which limited the development of local transport . Clearly , such a timely manner to the critically dangerous trussed combination arch bridge maintenance has been reinforcement of no delay now . However , the current bridge strengthening and maintenance methods of trussed combination arch bridge have played very limited role in most cases . And efective research results in trussed combination arch bridge reinforcement are very few .It is put out that reforcements on the combination action of the bottom-chord members are efective when the trussed combination arch bridges are repairing . And it is proved that it is correct by using plane and solid finite element model .First , based on the first design and construction drawing , using Dr.Bridge plane finite element analysis software , establish plane finite element model of Yuancun bridge in Guizhou province to simulate the construction process as well as MIDAS/FEA , and through static analysis under constant load , the live load and load combinations , the author reaches the result that the main reasons why diseases and deficiencies appear in trussed combination arch bridge are the type of the bridge system itself birth defects . As a result of excessive pursuit of technical indicators for the economy , it can cause many cases of partial bridge collapse , component strength can not meet the requirements of design , safety reserves will be low and structure durability will be poor . It also point out that plane finite element model can not describle the true sitiation of bridge when it is designed .Second , put out the reinforcement methods of trussed combination arch bridge . Combining the result of analyse and the main diseases and deficiencies causes of trussed combination arch bridge , this paper put forward method reinforcement ideas that reforcement on the combination action of the bottom-chord members and changing them into arch constrction are efective . As a result of this method , the construction will bear more eaqually , and can support the higher grade load .At last , the author analyze its static and dynamic performances for a practice example . Using MIDAS/FEA , stablishe volid finite element model before and after reinforcement and analyze its static and dynamic performances . Also , the vibration frequency bands reinforcement than before , and the whole bridge has increased stiffness , reinforced significantly , and improved dynamic performance . And it is proved once again that the consolidation that trussed combination arch bridge reinforced by this method is feasible .