Construction and Quality Control of Steel Structure Installation of Suspension Bridge

Construction

The bridge structure is a plate-welded box-type combination, with nine partitions inside, connected by ten webs and upper and lower flange plates. It consists of eleven sections and three pieces, which are connected by high-strength bolts and welding. The height of the box section is 0.600m. The suspension at both ends of the bridge deck to the center of the bridge is controlled by the suspension tower sling. The total weight is about 350t. Bridge welding steel plate adopts Q235B, bridge deck and bottom steel sheet use 24mm, and web and partition steel sheet use 20mm. Two anticorrosive primers and two topcoats. The total thickness is not greater than 210um.

Steel Construction Install

  • Ready for Work

The first thing is to make the material get ready for the project. Including ready for the steel members, the material for welding and more.

  • Steel Structure members Check Out

Before the installing of steel construction must check out the steel members. Such as the deformation of steel construction members, the precision of production, hole location and etc. If the deformation and defects are out of the request of steel structure members, then you must clean them.

  • The ready of high strength bolt

We must ready all specification high strength bolt of the bridge drawing request. And we need to check out the certificate, the report of torque coefficient and more.

  • About the welding material

Before the welding for steel structure members, we need to check out the types, specifications, properties of welding material. All those things must meet the requirement of bridge design and country stand.

  • Hoisting

Usually, the car can not get in there because of the water in the river. And according to this, what we need to do. First of all, we need to drain away water. Drain the water within the parallel area of the projected area of the bridge and within 3m of the outer width. After air drying, backfill and smooth, then crush. The height is 1m upwards from the bottom of the original river bed to make the ground endurance reach 30t bearing capacity, to naturally drain rainwater in time, and pour scaffolding concrete foundation according to the divided construction section.

And the soil bearing capacity of the road of transport must bigger than 60t. At the same time, the distance between the center of the crane road and the center of the bridge deck cannot be greater than 6m, and the road can meet the vehicle (15m long) rotation.

The hoisting adopts special spreader. During lifting, it must be ensured that the bridge section is kept level.

The crane moves to directly above the lifting box beam, and the lifting hook is lowered. According to the position of the crane hook, the positioning rope is retracted and the hook is hung. After inspection, after meeting the requirements of safe lifting, start the crane to slowly lift the steel bridge and observe whether the steel box girder is horizontal, so as to adjust the operating speed of the crane at any time, so that the lifting point is evenly stressed. After the steel bridge body is hoisted to the design position, the bolts connecting the foundation and the bridge body or the temporary connecting bolts of the two adjacent steel box beams are finally loosened. At this time, a section of steel bridge body hoisting task is completed. Move the crane to the next lifting position, repeat the operation, and lift the bridge body in sequence according to the designed lifting sequence. Until the whole bridge is hoisted. Before welding, the whole bridge should be adjusted again, and the suspension points of the rigging should be adjusted according to the layout of the drawing, and the welding should be carried out without error. Each stage adjustment needs to be fine-tuned with a jack.

In summary, during the installation and construction of the steel structure of the suspension bridge, the construction personnel must take effective measures to the problems that often occur in the project during the construction process to minimize the occurrence of undesirable conditions. At the same time, strengthen quality control during the construction process.