What is balanced cantilever method in constructing bridges
The balanced cantilever method is found in bridge construction with few spacings varying from 50 to 250m.
The bridge may come in either cast-in-place or precast.
Besides, the elementary method for balanced cantilever construction is to connect the segments in an alternate method at opposite ends of cantilevers which are supported with piers.
This method can be simply adjusted with rough and long span lengths, clogged project sites, rough and water terrain, rail crossings, and ecologically sensitive areas.
The balanced cantilever method is also very useful for making construction of cable-stayed bridges since as soon as parts are arranged, they will be supported with new cable-stays in each production phase.
As a result, no supplementary supports should be provided. Consequently it is both inexpensive and practical method for long cable-stayed bridges.
Process for balanced cantilever method of cast-in-situ bridge Construction:
1. Once the construction of lower infrastructure of the bridge is finished, the construction of bridge is started at each pier. After that, special formwork is arranged and cast-in-situ pier segment is provided. The entire pier segment is then applied as an fabrication platform to support a form traveler for cast-in-place segments.
2. Then, soffit shuttering, shuttering for web & deck shuttering is settled on both sides of pier.
3. After that, concreting is accomplished on both sides of the pier. The segment production rate for form travelers normally remains one segment each 5 days per traveler.
4. Cast-in-situ segments vary from 3m to 5m in length with formwork driving in combination with each segment. Segment construction is sustained unless a joining midpoint is attained where a balanced pair is stopped.
Progression of balanced cantilever method of precast bridge construction :-
1. Initially, the construction is done for foundations and pier shafts of all permanent piers in the primary unit.
2. As soon as the piers are constructed, they are applied as an erection platform for precast segments.
3. Compile and set up lifting frame.
4. Arrange first pair of precast segments.
5. Build wet joints.
6. Cure the wet joints.
7. After that, set up next pair of precast segments. Then, construct and cure joints. This method should go on unless the construction process is finished.
8. At last, detach the lifting frame.