Bridge Jacking is also called structure lifting operation. Further, which means each component of the bridge structure gets repaired individually or gets replaced. It is to check the integrity of the bridge structure.
Bridges support the live load. Bridge shoring adds support to the structure of the bridge.
Jacking and shoring both are necessary for different situations like repair or replacement of the bridge. Under the professional engineering firm, these operations take place.
Importance of Bridge Jacking:
To relieve the load of the whole bridge structure bridge jacking is necessary, as it is a high tonnage hydraulic cylinder. We need hydraulic systems for the replacement of stressing cables, bearings, and beams and replacing trusses. Jacking is such a thing that is used even after the completion of the bridge. All the old structure gets removed, and the new structure gets the place. Rigging is also needed during the process of inspection. High tonnage hydraulic cylinder is to ensure the safety of the bridges is one of the important things.
Jacking at the beam seat and under the bottom flange:
Jacking from this location can also reduce the need for additional temporary supports.
Following are some of the factors:
- Jacking is done at the place the height of the bearing assembly can accommodate the jacking cylinder in its collapsed state with shims. The designer has to consider the grade of the bridge while determining the height for jacking.
- One has to evaluate the jacking location to ensure that the intended operation gets completed with jacking or not. There must be adequate space for the manipulation of bearing,
- The designer must provide an adequate offset from the edge of the soleplate to the edge of the seat.
Jacking-up construction design:
It is a project in which the researchers use direct entire jacking methods whose main basis is the middle piers and the side piers which are the basements. Jack is installed between the pier and the girder. And after that, the goal of the elevation of the bridge deck is achieved. The main benefit of this method is that it does not change the force system of the bridge. For the extraordinary modification, the project of jacking is cutted into the piers.
- The space between the bottom of the girder and old middle piers is less than the length which is smaller than 400 mm. The different construction steps are controlled.
- To reduce the support area of the piers after the cut, there must be more than four jacks on the side piers and eight jacks on the middle piers.
- The main target is to monitor results with the mechanical characteristics.
- To ensure the jack construction quality and safety, all modifications with mechanical analysis can consult the reference.
For the adjustment of the jacking, parameter jacking is operated manually. Every group of the jack is equipped with the stroke scale. If you want tro know something extra click here.
Some of the points are as follows:
1. For the counter-force base this method of jacking is used. Synchronize the jacking control system and carry out the synchronization of jacking up one use jacking.
2. The platform or the cushion cap of the bridge describes the counter-force base and the bridge superstructure. It also describes the hydraulic jack between the platform cap and the bent cap or between the cushion cap and the bent cap.
3. The cushion cap of the bridge is pouring into a mold thick pillar beam around the post of the bridge. The described hydraulic jack is arranged between the cushion cap and the thick pillar beam.
4. The upper and lower position of the bridge describes that it is poured into a mold of a thick pillar beam which describes that the counterforce basis is the thick pillar beam between the two thick pillar beams post.
5. The lower position of the plate-girder is at the post of the bridge. It is poured into a mold, the thick pillar beam, which describes the counter-force basis. The hydraulic jack is arranged between the shoulder pole girder and the thick pillar beam.
6. The described bridge bent cap implants bar steel Z bracket, and describes the counter-force basis. Hydraulic jack is between the zee bar steel Z bracket and the cap.
7. After described post cuts off, the post truncation surface cutter gets tapered.
8. Hydraulic jack is installed by downloading the direction, and it keeps the hydraulic jack axis. And the hydraulic jack’s bottom is lined with a steel cushion block.
9. Bridge floor is equipped with attractive stopping which means that it is made of steel angle. During jacking the bolt tightens up the plate-girder.
The jacking of the bridge repairs the bridge or replaces the bridge. Bridge jacking is necessary as it gives support due to its high tonnage hydraulic cylinder. Such a lifting operation is required to guarantee the integrity of the bridge. Jacking adds temporary support to the structure of the bridge.