施工缝力学特性及对RC柱抗震性能影响分析
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摘要
对带缝试件和整浇试件进行了静力试验和拟静力试验研究施工缝的力学性能。结果表明施工缝对混凝土的受压性能几乎没有影响,对混凝土的受拉和受剪性能影响较大;施工缝处混凝土的抗拉强度只有母体抗拉强度的一半,拉力主要由穿过接缝面的钢筋承担;纯剪切状态下,施工缝处混凝土的抗剪强度约为母体混凝土的40%;带缝构件的抗剪承载力主要取决于轴向荷载作用和穿过缝面的纵向钢筋的销栓作用。钢筋混凝土结构中的施工缝可能会造成应力集中,把破坏区域限制在很小的范围内,对构件的抗震性能形成不利因素;但同时也有可能通过缝面摩擦力消耗地震能量,此时反而会对抗震性能有益。具体哪种情况占主导地位,取决于接缝面法向和切向应力的相对大小。
Static tests and pseudo-static tests were conducted to investigate the mechanical properties of construction joint of jointed specimens and integral casting specimens.Tests results show that construction joint has little effect on the compressive force characteristics and has great influence on tensile and shear properties of concrete.The tensile strength of jointed concrete is about half of the parent concrete and it could be neglected in the numerical analysis.And the tensile force of joint is born mainly by lengthways reinforcements passing through the joint.In pure shear condition,the shearing capacity is about 40 percents of that with integral concrete in the construction joint.The shear capacity of jointed specimens depends on the compressive forces and the dowelling action of the main reinforcement passing through the joint.Construction joints of reinforced concrete structures may cause stress concentration,which will strict the damage area in a small range and adverse factors will be formed for seismic performance.Which kind of specific situation is dominant depends on the relative size of normal stress and shear stress of joint surface.
Static tests and pseudo-static tests were conducted to investigate the mechanical properties of construction joint of jointed specimens and integral casting specimens.Tests results show that construction joint has little effect on the compressive force characteristics and has great influence on tensile and shear properties of concrete.The tensile strength of jointed concrete is about half of the parent concrete and it could be neglected in the numerical analysis.And the tensile force of joint is born mainly by lengthways reinforcements passing through the joint.In pure shear condition,the shearing capacity is about 40 percents of that with integral concrete in the construction joint.The shear capacity of jointed specimens depends on the compressive forces and the dowelling action of the main reinforcement passing through the joint.Construction joints of reinforced concrete structures may cause stress concentration,which will strict the damage area in a small range and adverse factors will be formed for seismic performance.Which kind of specific situation is dominant depends on the relative size of normal stress and shear stress of joint surface.
引文
[1]李英民,刘立平.汶川地震建筑震害与思考[M].重庆:重庆大学出版社,2008.
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[7]LPEZ-BTIZ O.Behavior of reinforced concrete framestructures with construction joints under lateral loads[J].Magazine of Concrete Research,1998,50(2):133-145.
[8]于婧,李英民,夏洪流.施工缝对框架柱抗震性能影响的试验研究[J].土木工程学报,2011,44(S1):81-86.
[9]李英民,于婧,夏洪流.施工缝模型及在钢筋混凝土柱非线性分析中的应用[J].土木建筑与环境工程,2011,33(5):1-6.
[2]WATERS T.A study of the tensile strength of concreteacross construction joints[J].Magazine of ConcreteResearch,1954,6(18):151-153.
[3]GB50011—2010建筑抗震设计规范[S].北京:中国建筑工业出版社,2010.
[4]宋玉普,魏春明.混凝土施工缝接缝面劈拉强度试验研究[J].混凝土,2006(6):22-25.
[5]MONKS W L.Treatment of construction joints[J].Concrete,1974,8(2):28-30.
[6]ISAO U,YOSHIDA N,MORISHITA S.Evaluation ofmechanical properties of construction joint between newand old concrete under combined tensile and shearstresses[J].Journal of the Society of Materials Science,1998,47(1):73-88.
[7]LPEZ-BTIZ O.Behavior of reinforced concrete framestructures with construction joints under lateral loads[J].Magazine of Concrete Research,1998,50(2):133-145.
[8]于婧,李英民,夏洪流.施工缝对框架柱抗震性能影响的试验研究[J].土木工程学报,2011,44(S1):81-86.
[9]李英民,于婧,夏洪流.施工缝模型及在钢筋混凝土柱非线性分析中的应用[J].土木建筑与环境工程,2011,33(5):1-6.
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