不同界面下梁端直剪型锚栓钢板剪切承载力试验研究

Experimental Study on Shear Capacities of Reinforced Concrete Beams Strengthened by Direct-shear-bolted Side-plates near Beam Ends Under Different Interfacial Conditions

开展梁端直剪型锚栓钢板剪切承载力加固试验研究。试验序列包含1个对比试验段、5个剪切承载力加固试验段。试验参数包括界面条件和钢板高度。结果表明:受力过程中钢板与混凝土之间的黏结界面终会剥离,不同黏结界面不影响剪切承载力;增加钢板高度和配套的直剪型锚栓数量能有效提高混凝土梁的剪切承载力。直剪型锚栓钢板剪切承载力加固存在2种机制,约束机制通过限制斜裂缝宽度提高剪切承载力,而组合受力机制通过钢板将一部分剪力直接传入支座。加固钢板高度较小时以约束机制为主,加固钢板高度较大时,2种加固机制联合发挥作用。

This paper presents a test program of shear capacities of reinforced concrete beam strengthened by direct-shear-bolted side-plates near beam ends.The test program consists of one control shear span and five shear spans strengthened in shear.Test parameters involve interfacial conditions and depth of side-plates.Test results show that all kinds of adhesion interfaces are eventually de-bonded in loading process,without affecting shear capacities whether the adhesion is weak or strong.Shear capacities are effectively improved by increasing the plate depth and the number of corresponding direct-shear bolts.There are two mechanisms in the shear strengthening of direct-shear-bolted side-plates system,i.e.,the constraint mechanism and the composite action mechanism.The constraint mechanism takes effect by constraining the development of diagonal crack width,and in the composite action mechanism the bolted side-plates directly transfer part of the shear force to the support.Steel plates with lower depth are mainly in the constraint mechanism,while steel plates with higher depth work both in the constraint mechanism and composite action mechanism.