预应力活性粉末混凝土箱梁抗剪性能试验研究  

Experimental study on shear behavior of prestressed reactive powder concrete box girders

作　　者：郑辉[1] 方志[1] 刘明[1] 

机构地区：[1]湖南大学,湖南长沙410082

出　　处：《土木工程学报》2015年第6期51-63,共13页China Civil Engineering Journal

基　　金：国家自然科学基金(51078134);教育部博士基金(20120161110021)

摘　　要：通过对9片预应力高性能活性粉末混凝土(RPC)薄壁箱梁进行荷载试验,研究配箍率、剪跨比等参数对RPC箱梁抗剪性能的影响,对比分析不同参数下试验梁的破坏形态、荷载-挠度关系、开裂荷载及抗剪承载能力、腹板主压应变角、箍筋应变等的发展规律。试验结果表明:在实验室条件下普通养护的掺入体积掺量为2%钢纤维的RPC试件立方体抗压强度可达110MPa,劈裂强度约为9MPa,弹性模量约为42000MPa;抗剪承载力和临界斜裂缝倾角均随着剪跨比的增大而减小,由腹板平均应变计测试得到的主压应变倾角可以较好地反映斜裂缝倾角的变化规律,RPC中钢纤维的掺入导致试验梁裂缝呈现"细而密"的特征。箱梁受剪时总是一侧腹板首先开裂,但极限状态时,箱梁腹板两侧的斜裂缝间距、倾角、宽度及破坏形态基本一致,说明在进行箱梁腹板斜裂缝开裂荷载计算时需考虑两侧腹板受力不均匀的影响,而抗剪承载力计算时可忽略该影响。结合试验结果及其他文献RPC试验梁,提出RPC抗剪承载力建议公式,计算值与试验值比值平均值为0.901,标准差为0.103,建议公式可较好地预测预应力RPC梁抗剪承载力。The shear behaviors of nine prestressed Reactive Powder Concrete( RPC) thin-wall box girders are investigated and the influence of some parameters,such as the shear-span to depth ratio and the stirrups ratio in bending shear zone,is analyzed. In the experiments,the crack patterns and width,load-deflection relationship,diagonal cracking behaviors,ultimate shear capacity,the average web strain,principal strain direction and stirrup strain are studied. The test results show that under the condition of the general laboratory maintenance,the cube compressive strength,the splitting strength and elastic modulus of the RPC with 2% volume content of steel fiber is about 110 MPa,9MPa and 42000 MPa,respectively. Shear capacity increases with stirrup ratio,which have little effect on the cracking load and the critical angle of inclined cracks; shear capacity and the critical angle of inclined cracks decreases with the shear span ratio. Due to the steel fiber in RPC beams,the cracks of the tested girders become small and dense. The initial inclined cracks always appeared on one of webs of the box girder. Under the ultimate state,the width,spacing and angle of inclined cracks on both webs of box girder were almost same. The characteristic of box girders with thin webs effects should be considered in cracking loading calculation. On the basis of the test results and the results of other researches,a formula of shear capacity is proposed. The mean ratio of the calculated value to the experimental value is0. 901,and the variance is 0. 103,which indicate that the proposed formula is reasonable to predict the shear capacity of PRC girders.

关 键 词：活性粉末混凝土 抗剪性能 箱梁 试验研究 建议公式 

分 类 号：U446[建筑科学—桥梁与隧道工程] U448.35[交通运输工程—道路与铁道工程]