How to install boundary beams safely?

It is a challenge to install boundary beams for launching gantry, which matters safe operation and efficient work.

So for successful installing boundary beams, ZZHZ designs the trolley as two layers just like an overhead crane, the down trolley as a frame moves along the main girder longitudinally, and the upper trolley moves along the down trolley frame laterally, which allows the trolley carrys the precast girder to move laterally.

As installing boundary beams, the launching gantry moves laterally to the proper position, then two trolleys lift boundary beam to move laterally to the proper position and put down the beam.

Kindly note the support leg shall not move out of the bridge deck, only the main girder could go out; if necessary, please strengthen the lateral sliding rail for safe operation before the support leg has to move the end of lateral sliding rail which is out of the deck.