Beam strengthening

According to the enlarged test result of R-GHHT 2011-0054 "Rebound Method Testing Concrete Compressive Strength Report" issued by Foshan Nanhai District Construction Quality Inspection Station on April 08, 2011, the presumed value of concrete compressive strength of the two-story beam is 28.3 Mpa, which does not meet the requirements of the original construction drawing design.

After checking, it is shown that the ultimate bearing capacity state and normal service limit state of the original beam meet the requirements of the code, and the layer beam has no safety problems and can continue to use. For the previous "Drilling Core Method Test Concrete Strength Report," the strength of the two-story 5-6_B beam is estimated to be 19 Mpa, after a large area of expanded test results show that it is an individual phenomenon. Because the span of the span beam is small, the original section and reinforcement can meet the requirements of the code even if it is checked according to the concrete strength estimation of 19 Mpa.

In order to meet the durability requirements of concrete, it is decided to reinforce the RC beam with FRP wrap(fiber reinforced polymer wrap).

Externally bonded fiber reinforced polymer(FRP) wrap is to apply carbon fiber fabric to the tensile area of the strengthened member, so that it can work with the strengthened section to improve the bearing capacity of the member. In addition to the similar advantages of sticking steel plates, it also has the advantages of corrosion resistance, moisture resistance, almost no increase in structural deadweight, durability, low maintenance costs, etc. It is suitable for various mechanical properties of concrete structural components and general structures.