Arch and vault shall be built simultaneously from both sides of the arch of the foot to the center of symmetry, when masonry, inverting concentric reducer of arch brick is prohibited; the lock should be driven into the brick arch from the side, if the last rider brick can't be driven from the side, you can process the first 1-2 brick to make the size of the lock and the lock buckle equal, and then drive suitable rider brick from top, and use steel plate to jam-pack the side; dismantling arch tire must be performed after all rider bricks are driven and lock brick arch foot ditch masonry is completed and the final tightening nut for skeleton retractor rear.
