Research on the Key Construction Techniques of Precast Assembly for New Type Steel-Concrete Composite Girder Bridge

The precast assembly technology of steel-concrete composite girder bridge is a new type of construction technology, in which piers, caps, steel girders and concrete decks are prefabricated in factories and then transported to the construction site for assembling rapidly.At present, there are many researches on the precast assembly of the main girder of steel-concrete composite girder bridge, but few comprehensive analysis researches on the precast assembly of piers, caps and main girders. Therefore, it is of great significance to research the key construction techniques of the full precast assembly of the main structure of the bridge.
Taking the first multi-girder steel-concrete composite girder bridge in China as an example, this paper researches the key construction techniques of piers, caps and steel-concrete composite girders, such as fabrication, transportation and assembly.Through summarizing the construction experience, the standardized construction technology of the main structure for the steel-concrete composite bridge is determined. Construction technology of steel-concrete composite girders:temporary supports erection,girders hoisting on-site, precise adjustment and positioning for composite girders, construction for the top concrete of bridge deck, grouting construction for anchor bolt holes of permanent bearing, welding for composite girders, girders falling to permanent bearing and concrete construction for beams on pier.Construction technology of piers:surface cleaning for cushion caps, installation for baffle plate of grouting, turning over and hoisting for piers, alignment for piers, precise adjustment for piers, grouting on top of cushion caps, fine adjustment for piers and sleeve grouting. Construction technology of caps:temporary supports installation, installation for baffle plate of grouting, caps installation, grouting on top of piers, cap beam fine adjustment for caps and sleeve grouting, construction for wet-joint, prestressing construction. The conclusions are as follows, the main girder of the bridge is composed of 11 I-shaped steel girders and precast concrete slabs, which reduces the weight of the bridge structure and solves the transportation problem,and it is an optimum design for the structure of steel-concrete composite girders.Standardized temporary support structure, hoisting scheme and construction procedure have been developed in construction of piers, caps and steel-concrete girders, which improves the management level of construction site and promotes the refinement of management.Grouting sleeve connections are adopted between piers,cushion caps and cap beams, and standardized construction technology has been developed, then key technical problems in precast assembly construction have been solved. The main structure of the bridge adopts precast assembly technology, which changes the traditional construction technology and produces good social benefits, which is the inevitable trend of bridge development.