Experimental study on the flexural behavior of profile steel-steel fiber#br#
reinforced concrete composite beams
Wu Kai1,2 Xu Chao1,3 Cao Pingzhou1 Lin Shiqi1 Chen Feng1
1. Hohai University, Nanjing 210024, China; 2. National University of Singapore, Singapore 117576, Singapore;
3. Tongling University, Tongling 244000, China
To solve the construction problems that the profile steel may interfere with steel reinforcement and concrete pouring is difficult, an innovative method is proposed, in which the steel reinforcement cage is completely or partially replaced by steel fiber to form the profile steel-steel fiber reinforced concrete composite beam. The tests on the flexural performance of 12 profile steel-steel fiber reinforced concrete composite beams and 1 specimen without steel fibers and reinforcement cage were carried out, and the influences of steel fiber content, profile steel ratio, application of stirrups and setting of main reinforcement on the flexural behavior of the specimens were investigated. Increasing the content of steel fiber can improve the bearing capacity of specimens to some extent, which is closely related to the profile steel ratio. That is, the greater the profile steel ratio is, the more prominent the influence of the steel fiber shall be. The longitudinal reinforcement can greatly enhance the bearing capacity of the specimen, and the application of steel fiber and stirrups can further enhance the effect of the longitudinal reinforcement. The test results show that when the amount of steel used is similar, the profile steel-steel fiber reinforced concrete composite beam without reinforcement can not only settle the construction difficulties of the profile steel concrete structure, but also greatly improve the ductility performance. By reducing the thickness of the concrete cover and improving the profile steel ratio, the good flexural behavior of the profile steel flange can be fully developed, compensating the effect of unequipping with main reinforcement on the bearing capacity, and at the same time, by increasing the amount of steel fiber, the degradation problem of bonding performance of the steel and concrete interface due to the decrease of the concrete cover can be solved. For beam specimen with steel fiber, the damage development of specimen with higher amount of steel fiber is faster than that with less amount of steel fiber, and with the increase of the amount of steel fiber, the damage degree of peak load is more and more significant. The more the amount of steel fiber is, the better the damage resistance of the specimen under the peak load shall be, and the ultimate bearing capacity can still be remained even in the severe damage state.