双腹板工字型GFRP腰梁机械连接力学性能试验研究

为深入研究双腹板工字型GFRP腰梁机械连接节点的力学性能,基于无连接和有机械连接2种类型GFRP腰梁的静载试验,分析双腹板工字型GFRP腰梁在三分点对称加荷下的受力特征,明确2种类型腰梁的极限状态和破坏形式。结果表明,GFRP腰梁采用双腹板工字型截面型式,截面的最大应力为183 MPa,是GFRP腰梁纵向抗拉强度的62%,纵向抗压强度的73%(容许压缩承载力的205%),可以使GFRP材料强度得到充分发挥,腰梁稳定性能良好；GFRP腰梁容易出现局部破坏,首先在翼缘板处发生局部失稳,随即引起腹板产生屈曲破坏,翼缘和腹板连接处出现面层剥离和鼓起,腰梁连接处增设的缀板和螺栓可有效的抑制该局部破坏变形；采用螺栓机械连接并在连接处增设同材质缀板,可降低螺栓钻孔对梁体本身截面的削弱作用,使GFRP腰梁的刚度和极限承载能力分别提高17.9%和44.9%,是GFRP腰梁的合理连接方式。研究成果可为GFRP腰梁的推广应用提供参考和借鉴。

Mechanical properties test of double web I-beam GFRP girders with mechanical connection

In order to study the mechanical properties of mechanically connected nodes of double-web I-beam GFRP girders, based on static load tests of two types of GFRP girders without and with mechanical connections, the force characteristics of double-web I-beam GFRP girders under symmetric loading at three points are analyzed, and the limit states and damage forms of the two types of girders are clarified. The results show that the GFRP waist beam adopts double web I-beam cross-section type, and the maximum stress of the cross-section is 183 MPa, which is 62% of the longitudinal tensile strength and 73% of the longitudinal compressive strength of the GFRP waist beam (205% of the allowable compressive load capacity), which can make the GFRP material strength fully developed and the waist beam has good stability performance; GFRP waist beam is prone to local damage, firstly, local instability occurs at the flange plate, which then causes buckling damage to the web, surface peeling and bulging at the connection of flange and web, and the additional splice plate and bolts at the connection of waist beam can effectively suppress the local damage deformation; Adopting bolt mechanical connection and adding the same material splice plate at the connection can reduce the weakening effect of bolt drilling on the cross-section of the beam itself, so that the stiffness and ultimate bearing capacity of GFRP waist beam can be increased by 17.9% and 44.9% respectively, which is a reasonable connection method for GFRP waist beam. The research results can provide reference and reference for the promotion and application of GFRP girders.