The topchord components of beam string structure are fabricated in factory and assembled on site.
该张弦梁上弦构件在工厂分段制作，现场拼装。
2
Concrete was poured in separately from mid-span of arch slab to the supports and then from the supports to the topchord of the arch chord so as to balance the pouring load.
Then the structural accident of total section drive-through type crack is caused in arch frame topchord, which is induced by hoisting and detection using pulley arbitrarily.