'required strengthening' is correct and usable in written English.
You can use it when referring to the need for something to be reinforced or strengthened with more effort. For example: The infrastructure of the country needs to be improved and requires strengthening.
Success in Colombia required strengthening the capacity and integrity of the country's policing, prosecutorial and judicial institutions.
It is time for final preparations: honing the extreme fitness required, strengthening the bonds that will matter most in the lung-burning torture of a gold medal game.
A need for experimental test results with low value of concrete strength to mimic the local old-age structures condition that required strengthening in local countries.
The short, eleven minute, bombardment by the French did little damage, but alerted the Ottomans that their defences there required strengthening.
To respond to the ongoing HIV epidemic among MSM, the Zhejiang Provincial CDC has required strengthening the HIV testing programme among MSM, and promoting the use of RHT to increase the testing coverage in this group.
In the meanwhile, functionality of the basement, after required strengthening, was also determined to be slightly impaired due to the revised loading conditions.
Here, again, strengthening Europe requires strengthening the alliance.
Retrofit of existing steel buildings often requires strengthening of the connection regions.
Cutting new openings weakens the overall response of such elements, so they usually require strengthening.
Taylor says that club owner Pozzo and head coach Jokanovic have to assess quickly where the squad requires strengthening.
Middlesbrough require strengthening in midfield, after releasing Julio Arca, Nicky Bailey and Kieron Dyer at the end of last season.
