Then the structural accident of total section drive-through type crack is caused in arch frame top chord, which is induced by hoisting and detection using pulley arbitrarily.

Concrete was poured in separately from mid-span of arch slab to the supports and then from the supports to the top chord of the arch chord so as to balance the pouring load.

Based on the error theory, we strictly deduce where is the optimum measuring point and when the standard error of arch-height and that of chord - length are both defined in this paper.