How much should be the concrete strength of the main structure of the steel support to carry out the construction
When the support is removed, it is necessary to avoid the excessive pre stress release and cause the local deformation and cracking of the structure.
The concrete strength of the side wall of the main structure needs to reach 75% of the design strength
Support system of the special support for the following points: (1) the support of the switch must be in accordance with the principle of first support after the demolition
