What are steps for launching gantry to cross piers?
Walking type launching gantry is a special bridge construction equipment for highway construction. With step by step, it crosses piers to prepare for gider installation. Below steps for crossing piers for your reference:
launching gantry
Step 1:
After installation, check the operating condition of the complete machine. If everything is ok, level the main girder as well as drive girder carrier with precast girder to rear part of launching gantry to prepare for crossing piers.
Step 2:
Hydro-cylinders in front support and rear bracket jack main girder to a certain height, then put pin roll into drivepipe. Middle support moves forward 30m by its suspension institution. Put down middle support and transverse sliding rail to lay a solid foundation.
Step 3:
Hydro-cylinders in front support and rear bracket bear loads to get pin roll out, the whole machine drop down. Main girder stands on roller wheel of middle support and rear bracket, front and rear trolley moves near to middle support. Then start roller mechanism of middle support and rear bracket to make main girder move forward 10m, front trolley and rear trolley move backward 10m at the same time.
Step 4:
Rear support leg jacks main girder to certain position, cylinder in rear bracket draws back to make main girder suspend in the air, then main girder moves forward 15m with its own suspension institution (without power). Then keep rear bracket in a level and plug in pin roll. Take back cylinder of rear support leg to make it suspend
Step 5:
Start roller mechanism of middle support leg and rear bracket, make main girder move forward 10m
Step 6:
Two trolleys continue to move backward to rear part of main girder, and girder carrier puts precast girder in certain place, front trolley lifts one end of girder as counterweight and fixes it
Step 7:
Start roller mechanism of middle support and rear bracket to make main girder move forward 10m, then front support is jacked onto front abutment to meet demand of installing girder. Check operating condition of the complete machine to prepare for installing girders
