Technology Research On The Prefabrication And Marine Transport For 70m Prestressed Concrete Box Girder

Combining with the construction experiences of Hangzhou Bay Bridge , through the test study of various behaviors of marine structure concrete and analytical study of measurements of temperature gradients and stress in the actual girder made up of the concrete, a kind of early time tensioning workmanship when concrete strength is still low is put forward. With the workmanship for tensioning the partial prestressing strands, the possible cracks due to temperature stress in the large size thin-walled box girder can be controlled, and the problem of cracks in the marine structure concrete easily caused by the low water/binder ratio of, and multiple compositions and considerable adding amount of admixtures in the concrete is thus resolved, so it soluted some questions of box girder's quality and Integrity.Through the research technology of manufacture Integrity and erect of 70m, proposed a plan about long and big bridge in environment of sea. Through the research and innovation made for workmanship, schemes and construction equipment for casting concrete of 2,200-t large volume box girder, an amount of 830 m~3 concrete to be cast at one time without stop is realized, and the workmanship and construction method for casting large volume and large tonnage girder have thus been developed and perfected.Through the research of workmanship for integral lifting and setting of large size interior formwork and reinforcement skeleton, the construction efficiency and quality have been greatly improved and gradually, the workmanship has been developed into a fixed construction method.The 17-m span vibrating bridge for deck concrete construction is developed. With the developed vibrating bridge, the evenness of the deck can be ensured, the occurrence of cracks in the deck can be effectively avoided, and the common quality problem in the deck concrete construction is thus eliminated.