Construction Technology On Integral Span Box Girder Fabrication And Erection

Wuhu Yangtze River Bridge was a key project of country's "The Ninth Five-Year Plan", and the last highway and railway combined bridge that built on the Yangtze River in the 20th century. It was with more technical requirment, strict acceptance criterion and great difficulties of construction. This project had an important position in Chinese bridge construction history.The construction of 40m partial prestressed concrete box girder that we have undertaken, was one of the 19 new technologies applied in Wuhu Yangtze River Bridge. In the situation that there was no precedent of construction, we have carried on several technological innovations through analysis and research, adopted the disposable monolithic manner to carry out the site prefabricating 40m box girder for the first time at home. Through examining, each index reached the designing requirement, and has obtained a lot of technological break-throughs and experience succeeding.Technological achievement:1 .On construction method, at home, we adopted disposable integral span pouring 40m partial prestressed concrete railway box girder for the first time, to make box girder with good integrity and aesthetic effect, and passed the static test successfully.2. On formwork design, at home, for the first time we adopted monolithic slip outer formwork, not only made girder body flat and smooth without seam, having guaranteed appearance quality, but also made outer formwork removed and installed convenient, fast, economized a large amount of artificial and machinery. The interior formwork adopted the triangle adjustable truss structure, has already helped the construction of pouring baseplate concrete and convenient to remove, too. That made it possible on the monolithic technology.3. Layout of girder fields was rational in economy, we synthetically applied such as jetting powder piles and spread shallow foundation manners on foundation treatment, etc. And solved the difficult problem for prefabrication of large tonnage box girder and moving sideways on soft soil ground.4.Found out one set of concrete pouring technology that was effectual, andsolved technological difficult problem, such as frost boil of baseplate, and interior formwork floating, and bubble on concrete surface, etc. And succeed in compounding out the pump sending concrete of C60 with the general silicon 525# cement.5.We adopted sliding plate and slipway to move girder body sideways without large tonnage gantry crane, and adopted windlass to drag girder, which was simple and convenient and economy.6.Accomplished the design of large tonnage load walking gantry crane by oneself.V.Have utilized war preparedness apparatus, such as six-four type military girder, etc. Succeeded in assembling 300t bridge girders erection equipment, and opened up wider world for fully utilizing war preparedness apparatus, and have used frequency conversion and adjusted speed technology to reduce the impact force of transporting, hoisting and erecting girders greatly.The above technological achievements have obtained the good economic benefits and social benefit, and offered a lot of new train of thought and good experience on the site prefabricating and erecting long and large tonnage box girder for our country in the future.