SGFRP筋与混凝土的粘结滑移本构关系

Bond-slip constitutive relationship of SGFRP rebars embedded in concrete

为了提高玻璃纤维增强聚合物(GFRP)筋的弹性模量,采用钢绞线替代部分玻璃纤维生产钢绞线-玻璃纤维增强聚合物(SGFRP)筋。拉伸试验表明:肋间距增大有助于玻璃纤维拉伸性能的发挥;随着钢绞线体积率的增大,弹性模量显著提高,但抗拉强度变化不明显。通过36个拉拔试件,研究了直径、钢绞线体积率和混凝土的强度等因素对粘结应力-滑移本构关系的影响。结果表明:SGFRP筋的粘结破坏形态、粘结滑移曲线与普通GFRP筋类似,但其弹性模量大,相同的粘结应力作用下,产生的拉应变和径向变形较小,受到的机械咬合力较大、粘结应力更高。根据试验结果提出了SGFRP筋与混凝土的粘结滑移的本构关系,并给出参数取值建议。

In order to improve the elastic modulus of glass fiber reinforced polymer(GFRP)bar,the steel strands were used to replace some glass fibers for the manufacture of steel strand-glass fiber reinforced polymer(SGFRP)rebars.The tensile tests show that larger rib spacing is benefit for tensile property of glass fiber.With the increase of steel strand volume ratio,the elastic modulus was improved obviously while the tensile strength was no significant changes.Furthermore,a total of 36 pull-out specimens were conducted to investigate the effects of rebar diameter,steel strand volume ratio and concrete strength on the bond-slip constitutive relationship of SGFRP rebars embedded in concrete.The results show that the failure form and bond-slip curve are similar to common GFRP rebars.Nevertheless,the SGFRP rebar was achieved higher mechanical interaction and adhesive force with concrete,thanks to the higher elastic modulus,lower tensile strain and radial deformation.Finally,a bond-slip constitutive relationship and its parameter values of SGFRP rebars embedded in concrete were proposed.