Research On Compression Performance Of CFRP-steel Composite Plate And Its Application In Reinforcement

Reinforced structural restoration project on CFRP, which is increasingly wide in use, is one of the hot research topics in recent years. For the time being, there have been comparatively mature researches on CFRP reinforcement, as well as concrete structure restoration and masonry structure. However, it is still a long way to go in researching steel structure reinforcement and restoration. This paper does a relatively systematic survey on inner compression performance over CFRP-steel plate.This paper individually designs experimental device and composite slab units so as to test its inner compression performance. The parameters involved in the experiment include different ways of patching, boundary situations, width-to-thickness ratio as well as length-width ratio of the testing units. The paper tested 36 CFRP steel composite slab, and mechanical characteristics combination plates, failure mode, ultimate bearing capacity and load-deflection curve were observed. As shown by the results, limiting bearing capacity increased more obviously with CFRP-steel composite slab made by thinner slabs. And three-legged ones increase more than four-legged ones despite the patching ways and width-to-thickness ratio as well as length-width ratio. The bigger the width-to-thickness ratio was, the more three-legged composite slabs can bear, while length-to-width ratio mattered little in its bearing capacity.Finite element analysis was done towards CFRP-steel composite slabs. Firstly, taken adhesive layer into consideration, a CFRP-steel composite slab model was set up, and the adhesive layer was simulated through migration units. This paper compared the results simulated through finite elements with those got from the experiment concerning limiting bearing capacity, destruction mode, and load-deflection curve. According to the comparison, the finite model established in this paper can correctly simulate the bearing capacity, destruction mode and load-deflection curve of CFRP-steel composite slab, and the model features good reliability and applicability. In this paper, further analysis was done on the effects that finite elements have on CFRP-steel composite plates.At last, combined with the resulted simulated respectively by finite elements and numerical simulation, curves of composite slab transformation capacity and bearing capacity were drawn out. Those curves can approximately show the bearing capacity of three-legged composite slab and the four-legged ones within the common width-to-thickness ratios. Compared with the stability curve of steel plate, limiting bearing capacity of composite slabs is higher. Following the laminated plate theory, this paper deduces formulas concerning the elastic buckling loads of the CFRP-steel composite slabs with four simple legs as well as with three legs and one free leg. Based on the formulas, CFRP matters little in elastic buckling loads of steel plates. And the formulas will be used in unit design for reinforcing the steel structures.