Singapore Punggol Bridge Project

How to operate HZQ59/80 bridge girder launching gantry?

FAQ Jul 12, 2012 No Comments

Installation in the factory

HZQ59/80 bridge girder launching gantry  is of non-standard equipment in worksite, some temporary works should be done in worksite in service process, which is important. Pier cap fixed block and lateral moving plan satisfy demands of the first site. In the later use, construction companies should make corresponding pier cap fixed block and lateral moving plans according to practical situation of bridge and pier caps. It demands the pier cap fixers must be stable and reliable, and piers plan can meet the demand of crossing piers for the bridge girder launcher.

Install the precast girder

1carry girders

Carry precast girder from precast yard to the rear part of the bridge girder launcher by using gantry crane, about 20m interval is controlled, install flexible rails between main girder (7# main girder) and 6# main girder, lifting trolley lifts girder to move forward after finishing handing over precast yard.

 

① Before the precast girder enters the bridge girder launcher, firstly check whether there are obstacles on the complete machine to hinder girders to move forward, and check whether obstacles on top of girders affect feeding girders;

②Before feeding girders, check support at rear support leg and anchor locking device of the bridge girder launcher to avoid too much sink at rear middle support leg part as feeding girders

③There should have someone to take care of the flexible rails, avoid lifting trolley moving not in a straight line. Appoint professional drivers to operate the lifting trolley;

④ after finishing handing over precast girder, lock the sliding rail for gantry crane support leg to avoid moving and tilt of gantry crane support leg as feeding girders

⑤ lifting trolley should move slowly to pass the flexible rails of launcher main girder and gantry crane main girder.

 

2Lift girder and drop girder

①. Try lifting before lifting girders any time. After bundling the girder, make winch brake test 2-3 times, then lift the girder a little, check whether steel wire rope is in order, iron tiles to protect the girder fall off or move, start formal operation after confirmation

②. Lifting winches should act uniformly with an even force. It should be prevented strictly to have a large partial load or violent swing of girder body;

③. Keep the girder in a level in the process of lifting, moving and falling down. If found the girder is inclined with naked eyes, adjust it immediately. In order to drop girder conveniently, a little but not serious tilt is allowed

④. Prevent steel wire rope being disordered or falling off. Various obstacles influencing moving girders must be cleaned

⑤. Arrange specialist to monitor the girder running condition on abutment as moving girders. Especially when the girder is near to be in position, watcher, commander and operating driver on abutment should be cautious and cooperate closely, avoid the girder to collide with support leg. If necessary, abutment watcher can pull the limit switch for safety;

⑥. The girder is suitable to move at a higher position, moving at lower position is likely to cause crash due to violent swing;

⑦. The bridge girder launcher is prohibited to lift girders with over-load

3Install precast girder

① after finishing adjusting the position of the precast girder, lock the lifting trolley to avoid position deviation caused by trolley moving in the construction process

② after connection for precast girder and nearby girder meet the design demand, remove locking between precast girder and sling, gantry crane moves back to the precast yard to carry girders

③ see construction drawing to find concrete steps

 

Note 注:

The sling is special sling for the bridge girder launcher, if it is used to lift other girder sections for other bridge, please check the dimension of sling and the girder section lifting points

 

4Work requirement

① before the bridge girder launcher moves laterally every time, use cushion block to make the middle support leg firm, the corresponding top plate for box girder web plate should be made firm with cushion block (if cushion block for lateral sliding rail of the middle support leg is not in a level with box girder web plate, put flexible cushion block on the top surface of box girder web plate, ensure load transmission)

② after the bridge girder launcher moves laterally to the certain position, lock middle support leg moving system to avoid overturn and displacement. Central line deviation between middle support leg and gantry crane support leg should be not more than 5mm, ensure the gantry crane and main girder to connect smoothly.

 

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