Analysis of the bearing capacity test results of aluminum foil cloth:
First batch of specimens, main reinforcement 3 φ 10 reinforcement ratio ρ= 0.58<1.4 ρ MB, the failure mode of the specimens is fiber reinforcement fracture, while the concrete has not reached compressive strength. At this point, changing the shear span ratio has little effect on initial cracking and ultimate load; Shear span ratio λ From 0.67 to 1, the initial crack load decreased by 6.0%, and the ultimate load increased by 8.8%; The initial crack load and ultimate load coefficient of the same type of fiber reinforced and reinforced concrete beams are close to 1, indicating that the bearing capacity of the two types of beams is similar; The main reinforcement is 5 φ The initial crack load and ultimate load of two rows of GFRP beams with 10 are 65% and 63% of the bearing capacity of similar reinforced beams, respectively. It can be seen that the arrangement of GFRP bars in two rows cannot fully utilize the load-bearing reinforcement like in reinforced beams; Mainly because the GFRP reinforcement of aluminum foil cloth lacks ductility, when the first row of GFRP reinforcement fractures, it loses its bearing capacity. Due to inertia, the internal force of the second layer of aluminum foil cloth GFRP reinforcement suddenly increases, reaching tensile strength and subsequently fractures. However, the reinforced beams arranged in two rows can transfer the "internal force" in a timely manner during the bearing process, so that both layers of steel bars can effectively "share" the external load, thus having a higher bearing capacity.
The second batch of specimens had a high reinforcement ratio, and the failure mode of the samples was concrete crushing failure. According to Figures 6-14 and Tables 6-6, it can be seen that the initial crack load coefficients of the bearing capacity of GFRP reinforced beams without stirrups and similar reinforced beams are both smaller than the bearing capacity limit coefficient. It can be seen that the initial crack bearing capacity of aluminum foil GFRP reinforced beams is less than that of similar reinforced beams, about 60% of it. But the ultimate bearing capacity coefficient is close to 1, because the second batch of tests were all concrete crushing failure, and the reinforcement material in the tensile zone did not fracture, so the bearing capacity of similar GFRP reinforced beams and reinforced beams is very close.
Comprehensive analysis of the results of two experiments (3) φ 10g was the first batch of test samples, and it was found that the initial crack coefficient and ultimate bearing capacity coefficient of GFRP reinforced beams with hoop reinforcement were equal to those of similar reinforced beams.
Aluminum foil test equipment and measurement content:
The load equipment is a 5000kN pressure testing machine, and the testing device is shown in Figure 6-2. The layout of measurement points and measurement content are shown in Figures 6-3 to 6-7, and the main measurement content is as follows.
① The tensile and compressive strains of pure bending concrete, as well as the main reinforcement strains, and the diagonal section strains of bending and shear sections are completed through resistance strain gauges attached to them.
② Install 5 displacement meters at the supports at both ends of the beam, under the two loading points, and at the mid span to test the deflection values at each point.
③ Observe the occurrence and development of cracks in aluminum foil cloth, measure the crack width under each level of load, depict the development of existing cracks, and search for new cracks.
④ The ultimate load of the component.