There is a general problem of structural reinforcement: the stress of the newly added part will lag slightly. In order to make the new and old structure to bear force together, should first remove the original structure load before the reinforcement. It is a better way to reapply it after reinforcement.

How do you remove the load?

1.Complete and accurate unloading can be used reverse loading unloading jack; 

2.Simple unloading can be removed only live load, and avoid the construction load.