粘砂变形GFRP筋的粘结滑移本构关系  

CONSTITUTIVE RELATIONSHIP OF BOND-SLIP BEHAVIOR OF SAND-COATED DEFORMED GFRP REBARS

作　　者：郑乔文[1] 薛伟辰[1] 

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《工程力学》2008年第9期162-169,共8页Engineering Mechanics

基　　金：国家自然科学基金项目(50008012);交通部西部交通建设科技项目(200631882244);国家"十一五"科技支撑计划重点课题(2006BAJ16B07)

摘　　要：基于18个梁式试验、42个Losberg拉拔试验和6个标准拉拔试验,对工程中应用最普遍的粘砂变形GFRP筋与混凝土之间的粘结滑移本构关系进行了较系统的研究。研究表明:GFRP筋试件的粘结应力-滑移曲线(τ-S曲线)可分为微滑移段、滑移段、下降段和残余段,区分这四段的三个特征点分别为弹性滑移点、峰值滑移点和残余滑移点;与变形钢筋不同,GFRP筋试件τ-S曲线的上升段可分为滑移量较小的微滑移段和滑移量明显增大的滑移段,下降段的粘结应力降幅较小,残余段近似呈正弦曲线;随着直径和粘结长度的增加,GFRP筋试件τ-S曲线上峰值滑移点的滑移量减小,3个特征点的粘结应力也呈降低趋势。基于试验结果,建立了粘砂变形GFRP筋与混凝土之间粘结滑移本构关系的理论模型,并提出了曲线上特征点的粘结应力及其滑移量的计算公式。Based on 18 beam tests, 42 Losberg pullout tests, and 6 standard pullout tests, the constitutive relationship of bond-slip behavior for GFRP rebars in concrete is systematically analyzed. The experimental bond stress-slip （τ-S） curves of sand-coated deformed GFRP rebars in concrete are composed of four segments, i.e. micro-slippage segment, slippage segment, descending segment, and residual segment. The four segments are divided by elastic bond point, peak bond point, and residual bond point, respectively. It has 3 major differences from deformed steel rebars, 1） the ascending segment of τ-S curves of GFRP rebars is subdivided into the micro-slippage segment and the slippage segment; 2） smaller drop of the bond stress occurs in the descending segment; 3） the curve in the residual segment is approximately sinusoid. With the increasing of the embedment length and the diameter of GFRP rebars, the slippage at the peak bond point, as well as the bond stresses at three characteristic points, decrease. This paper also develops the theoretical model for the bond-slip relationship of GFRP rebars in concrete, the theoretical formulae of bond stresses, and the corresponding slippages at the characteristic points in τ-S curves.

关 键 词：结构工程 GFRP筋 粘结试验 梁式试件 拉拔试件 粘结滑移本构关系 理论模型 

分 类 号：TU377.9[建筑科学—结构工程]