型钢-钢纤维混凝土组合梁抗弯性能试验研究

为解决型钢混凝土结构中型钢与钢筋相互干扰、混凝土浇筑困难等施工难题，将型钢混凝土梁中的钢筋笼完全或部分替换成钢纤维，形成型钢–钢纤维混凝土组合梁。完成12个型钢钢纤维混凝土组合梁和1个未添加钢纤维、未设置钢筋笼对比试件的抗弯性能试验。主要研究钢纤维掺量、型钢配钢率、箍筋设置和主筋设置对抗弯性能的影响。增加钢纤维用量能够在一定程度上提高承载力，其影响程度与型钢配钢率有重要的相关性，型钢配钢率越大，钢纤维的影响越突出。纵筋的设置能够大幅提升承载力，箍筋和钢纤维能够使纵筋对承载力的增强效果更为突出。试验结果表明：在相似用钢量的情况下，无配筋的型钢钢纤维混凝土组合梁不但能够解决型钢混凝土结构的施工困难，而且能够大幅提升延性性能，但由于未配置纵筋，正截面抗弯能力有所削弱；减小保护层厚度，提高型钢配钢率，能够充分发挥型钢翼缘良好的抗弯能力，弥补未设置主筋对承载力的影响，同时增加钢纤维用量，解决因保护层减小而导致的钢与混凝土界面黏结性能变差的问题；在设置钢纤维的情况下，钢纤维掺量较多试件的损伤发展快于掺量较少的试件，并且随着钢纤维掺量的增加，峰值荷载的损伤度越来越大；钢纤维用量越多，试件在峰值荷载状态下的耐损伤性能越好，即使在较严重的损伤状态下也依然能够保持极限承载能力。

Experimental study on the flexural behavior of profile steel-steel fiber#br#reinforced concrete composite beams

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.