How to make highway bridge concrete girders?
Highway Bridge concrete girders could be made by 4 methods: full span prefabrication, segments prefabrication, full span cast-in-place and segment cast-in-place
- Full span girder fabrication in the precast yard
Build precast yards to prefabricate precast girders, after stressing, the girders are transported by girder carrier to rear part of the beam launcher and then are lifted to proper position. Rail girder carrier has small pressure on the bridge deck, but costs much.
Front part of beam launcher for girders carrying and installing could erect precast girders on the abutment, and the rear part could carry girders in the precast yard, so it saves one set gantry crane.
The most widely used tires girder carrier nowadays could go about 15km. to reduce pressure on the bridge deck, the beam launcher goes to next pier by self-balancing method. Full span girder installation is suitable for bridges with a large quantity of precast girders.
- Segment girder prefabrication
After girder segments are prefabricated, tires carrier carrys them to rear part of beam launcher or under the bridge, then the beam launcher lifts them segment by segment and coats glue, and tension them to an entirety. The construction period for a complete span may take 10 days. The construction method is suitable for bridges in the city or across the river.
- Full span cast-in-place girder
Steel pipe supporting in the urban construction has a long assembly time and a large influence on traffic.
In the mountain area, the movable supporting system is widely used. Put mould plate, inner formwork and steel cage on the supporting part, pour concrete once to make full span cast-in-place box girder, begin to produce another girder after 12 days later
- Segment cast-in-place
The traveling formwork is mostly used. Firstly make cast-in-place segment with formwork on the pier, then symmetrically make two pieces of girders to two sides, repeat it until the bridge deck is connected.
The construction method is widely used in railway bridge across highway, has a small influence on ground traffic.
