钢玄武岩纤维复合筋混凝土梁受剪承载力试验研究

钢玄武岩纤维复合筋（SFCB）兼具钢筋的延性和玄武岩纤维的防腐性能，并具有显著的二次刚度，但弹性模量低于钢筋。SFCB作为纵向筋时可使混凝土构件的受弯性能具有二次刚度，但构件的受剪承载力会低于钢筋混凝土梁。为深入研究SFCB作为纵筋时混凝土梁的受剪性能，以纵筋筋材种类、构件剪跨比为试验参数，进行梁的四点加载试验。详细分析了不同参数对混凝土梁的破坏形态、裂缝发展、受剪承载力的影响。试验结果表明：SFCB混凝土梁的受剪破坏主要呈现斜压破坏、剪压破坏和非典型剪压破坏3种形态。SFCB混凝土梁的受剪承载力整体低于钢筋混凝土梁、斜裂缝宽度大于钢筋混凝土梁。基于桁架拱模型，推导了SFCB混凝土梁受剪承载力的理论计算公式。与试验承载力对比发现，SFCB混凝土梁受剪承载力理论计算公式具有一定的适用性与安全性。

Experimental study on shear capacity of steel-basalt fiber composite bar(SFCB) reinforced concrete beams

The steel-basalt fiber composite bar (SFCB) has the advantages of the ductility of steel bar and the corrosion resistance of basalt fiber, and has significant secondary stiffness as well. However, SFCB''s elasticity modulus is lower than that of the steel bar. The application of SFCBs as longitudinal reinforcement bars enables the flexural properties of concrete members to present secondary stiffness, but the shear capacity of the members will be reduced, compared with that of steel reinforced concrete beams. In this paper,four-point loading experiment of the beams longitudinal reinforced with SFCBs were carried out, taking the following variables of the specimens into consideration: the type of longitudinal reinforcement, and the shear span ratio. The influences of the above variables on the shear failure modes, the development of diabonal cracks, and shear force capacity of the above concrete beams were analyzed and summarized in detail.The research revealed the following three main results: the failure modes of the SFCB beam were mainly described as diagonal-compression failure,shear-compression failure and atypical shear-compression failure; the shear force capacity of SFCB beams was lower than that of steel reinforced beams; the diagonal cracks of SFCB reinforced beams were wider than those of steel reinforced beams. Based on the truss arch model, the shear force capacity formula of SFCB beams is derived.The calculating results of the formula agree well with the experimental ones with fairly applicability and safety.