Effectiveness of CFRP reinforcement for cracked brick walls

It is very effective to reinforce the cracked brick walls with CFRP sheets. The ultimate load of cracked wall strengthened with CFRP is significantly higher than that of unreinforced wall.

The technology of Strengthening Masonry Structure with CFRP has the advantages of high strength, high efficiency, convenient construction, good durability, no increase of weight and volume, wide application and so on. It has a broad application prospect in China. In this paper, the related research on the reinforcement and repair of the cracked brick masonry structure with CFRP is carried out. The test proves that the method can easily and effectively solve the problems of building wall cracks in the buildings that have plagued the society at present.

Test situation

Design and manufacture of 11 specimen

The height width ratio of the specimen is 1: 114, the wall thickness is 240mm, width 1400mm, and height 1000mm. When the specimen is made, the wall is made of MU10 brick and M10 cement mortar, and the upper and lower beams are C30 concrete. The vertical compressive stress is 0 2MPa = 11, and the specimen size is shown in Figure 1.

CFRP reinforcement for cracked brick walls

Reinforcement scheme for test parts

he specimen Wall 22 was cracked. First, the positive load is applied to the wall. When the loading to the cracking load (212kN), the brick wall suddenly cracks (the corresponding cracking displacement is 21 0mm) and forms a slanting crack quickly. As shown in Figure 2, the crack is about 01 25mm at the width of the crack. At this point, some cracks are closed and the width of the crack is about 011. Mm.

Strengthening by carbon fiber reinfroced polymer(CFRP). Double side sticking carbon fiber fabric , the width is 300mm, "X" shape, both upper and lower ends are anchored.

CFRP reinforcement for cracked brick walls

Test result

Wall	f1(Mpa)	f2(Mpa)	Loading direction	Cracking load		Ultimate load		Dehiscence displacemen		Maximum tensile stress of CFRP
Wall	f1(Mpa)	f2(Mpa)	Loading direction	Experimental value	Increase the degree value	Experimental value	Increase the degree value	Experimental value	Increase the degree value
Wall 21	11164	16189	Average	224	-	224	-	3107	-
Wall 22	11164	16189	Positive	-	-	276	2312	810	16016	4323	1519
Wall 22	11164	16189	Negative	368	6413	368	6413	1114	27113	3392	545

Conclusion

In this paper, it is proved that carbon fiber sheet is very effective in strengthening and repairing cracked brick walls. The ultimate load of the cracked wall reinforced by CFRP is obviously higher than that of the unreinforced wall, and the deformation ability of the reinforced wall is obviously improved, and the cracking displacement of the reinforced wall is significantly increased.
The carbon fiber cloth can improve the stress state of the wall through the pull rod mechanism in the truss model, so as to improve the shear capacity of the component.