BFRP-钢板复合加固钢筋混凝土梁的抗弯性能研究

Flexural property of RC beams strengthened with BFRP-steel plates

纤维增强复合材料加固技术与钢板加固技术已广泛应用于对钢筋混凝土梁的加固,但无论采用哪一种加固方式,均有其局限性。为了弥补单一材料的不足,获得更好的加固效果,本研究选用钢板与天然玄武岩纤维增强复合材料(BFRP),采用单独加固与同时粘贴复合材料和钢板的复合加固方式,通过四点弯曲试验,研究钢板厚度、BFRP层数、钢板与BFRP的复合方式对钢筋混凝土梁的抗弯性能的影响。通过对比各试验梁的开裂荷载、极限荷载、跨中挠度、应变和破坏形式等,发现:与未加固梁相比,增加BFRP层数、钢板厚度以及采用复合加固的形式能有效地提高试验梁的承载力和构件刚度,但构件延性降低。其中,同时粘贴2层BFRP和2 mm钢板的复合加固方式最有效。该研究对探索天然纤维复合材料在工程加固领域的应用具有一定的理论指导意义。

Fiber reinforced polymer composites and steel plates have been widely used in the reinforcement of RC beams. However,there are limitations whichever type of materials is employed. In order to obtain a better strengthening effect and to compensate for the weakness of each type of materials,steel plates and natural basalt fiber reinforced polymer(BFRP) composites are employed in this study. Both single type of materials(BFRP or steel) and two types of materials(BFRP-steel combination) are used. The effects of the thickness of steel plate,the number of BFRP layers,and the combination method on the flexural resistance of RC beams are investigated via four-point bending test. By comparing the cracking force,ultimate force,mid-span deflection,strain and failure mode of each test beam,it is found that increasing the number of BFRP layers,or the thickness of the steel plate or using BFRP-steel combination material system can effectively improve the load bearing capacity and the stiffness of the test beam,but the ductility of the beam is reduced. Among all the test beams,the one with the combination of 2-layer BFRP and 2 mm steel plate has the best strengthening effect. This work has guiding significance for exploring the applications of natural-fiber-based composites in the field of structure reinforcement.