【摘要】 为研究植筋锚固在混凝土构件受拉区的受力性能,进行了5根采用植筋技术进行受拉主筋搭接的钢筋混凝土梁受弯试验。其中3根试验梁先静力加载至60%设计荷载,卸载后再加载至破坏,2根试验梁承受2×106次疲劳荷载后再静力加载至破坏。静力试验结果表明,植筋搭接梁在加载再卸载后有较大的残余变形,反映了植筋胶及粘结界面的弹塑性特性。不同搭接长度的植筋搭接梁其抗弯刚度差异不大,但其开裂荷载和极限承载力却有较大差异。将植筋搭接梁的试验结果与块体试件植筋锚固单向拉拔试验的结果比较表明,在相同植筋条件下,梁式试件破坏时钢筋的应力远小于块体试件单向拉拔试件破坏时钢筋的应力。在梁底部纵筋搭接区范围有较多的交叉斜裂缝。这些现象表明基材的应力状态及植筋的混凝土保护层厚度对粘结锚固性能有很大影响。疲劳试验结果表明,在疲劳加载的早期裂缝就基本出齐,从5×105次至2×106次加载过程中裂缝发展不大,也没有新的裂缝产生。在本文的试验条件下,疲劳加载对梁的抗弯刚度和梁的极限承载力影响并不明显。更多还原

【Abstract】 To study the behavior of adhesive reinforcement in tensile area of reinforced concrete element, 5 beams with the tensile reinforcement bars connected by bonded bars were tested under bending load. In which 3 of them were tested to failure under static load after a cycle of static loading up to 60 percent of the design load, the other 2 beams were tested to failure under static load after two million times of fatigue load. Result showed that there is residual deformation after the first cycle of loading and unloading. It reflects the elastic-plastic characteristic of adhesive and the bonding interfaces. There are little differences in bending stiffness for beams with different bonding anchorage length, while there are obvious differences in cracking load and ultimate load. While under the same anchorage conditions, the ultimate tensile stress in adhesive reinforcement of beam is much smaller than the ultimate stress in pull-out test of block specimen. There are a lot of cross cracks in bonding anchorage area at the bottom side of the beam. That means the bonding behavior of adhesive reinforcement is strongly affected by the stress situation of base material and the thickness of concrete cover. The result of fatigue tests showed that most cracks in beams appear during early cycles of loadings. The cracks develop very slowly and there is no new crack found when the fatigue loading cycles change from 5×10~5 to 2×10~6. Under the present testing conditions, the bending stiffness and the ultimate bending capacity of the beam are not much affected by the fatigue load.更多还原