预应力高强软钢丝加聚合物砂浆抗弯加固性能试验与理论分析
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摘要
为了给预应力高强软钢丝加聚合物砂浆加固方法的设计计算与施工张拉控制提供依据,首先通过5根钢丝束张拉试验提出了考虑张拉力损失、由施工扭力换算得到的钢丝束初张力设计计算公式;然后完成了2根预应力高强软钢丝加聚合物砂浆加固矩形梁和1根对比梁的抗弯性能试验,研究了加固梁的抗裂性、抗弯承载力、刚度等性能的提升效果,并探明加固梁的破坏模式;同时定义了加固梁的开裂、屈服和抗弯极限等特征状态,利用理论分析推导出加固梁的开裂、屈服、极限弯矩和开裂、屈服刚度等设计计算公式,并将理论计算结果与试验结果进行了对比。研究结果表明:混凝土梁采用预应力高强软钢丝加复合砂浆加固后,钢丝束越多、相同荷载等级下的裂缝宽度越小,说明预应力软钢丝束能较好地抑制原混凝土结构裂缝的产生和发展;与未加固梁相比,加固梁的抗裂性能提升了60.3%~101%,抗弯承载力提高了17.3%~35.8%,跨中挠度减小了10.4%~27.4%,构件的抗裂性、抗弯承载力和刚度均明显提高;钢丝束初张力设计公式、加固梁在开裂、屈服和极限状态时的特征弯矩以及开裂和钢筋屈服时跨中挠度的理论计算方法均与试验结果吻合较好,且偏于保守,能够满足工程应用的精度要求。
In order to provide references for the design and tensioning construction control of a new kind of strengthening method of prestressed high-strength steel wire ropes and polymer mortar,the tensile tests of 5steel wire ropes were carried out.And a designing calculation formula for initial tension considering the loss of tension was firstly proposed according to the conversion of the exerted torque.Then,flexural tests on three reinforced concrete(RC)rectangle beams,that is,two strengthened by the proposed rehabilitation scheme and an un-strengthened beam,were conducted to investigate the failure mode as well as improvements of cracking resistance,bending bearing capacity and stiffness.Meanwhile,the cracking,yielding and ultimate state of strengthened RC beams were defined.The corresponding design formulas were theoretically deduced.Besides,those theoretical computing results were compared with experimental results.The results shows that with the proposed strengthening scheme,the more strands arranged in the beams,the smaller the crack width under the same load can be achieved.It illustrates that prestressed steel wire ropes can well restrain the generation and development of the cracks in the original concrete structure.In comparison with the un-strengthened beam,the cracking resistance of the strengthened RC beams increases by 60.3% to 101% and the bending bearing capacity increases by 17.3% to 35.8%.However,the mid-span deflection declines by10.4%to 27.4%.That is to say,the cracking resistance,the bending bearing capacity and the stiffness of strengthened beams get improved apparently.The design formulas of the initial tension of steel wire ropes,the characteristic moments of strengthened beams in cracking,yielding and ultimate state and theoretical method to compute the mid-span deflection are in good agreement with the experimental results.It is possible to meet the required precision in engineering with conservative estimation.
In order to provide references for the design and tensioning construction control of a new kind of strengthening method of prestressed high-strength steel wire ropes and polymer mortar,the tensile tests of 5steel wire ropes were carried out.And a designing calculation formula for initial tension considering the loss of tension was firstly proposed according to the conversion of the exerted torque.Then,flexural tests on three reinforced concrete(RC)rectangle beams,that is,two strengthened by the proposed rehabilitation scheme and an un-strengthened beam,were conducted to investigate the failure mode as well as improvements of cracking resistance,bending bearing capacity and stiffness.Meanwhile,the cracking,yielding and ultimate state of strengthened RC beams were defined.The corresponding design formulas were theoretically deduced.Besides,those theoretical computing results were compared with experimental results.The results shows that with the proposed strengthening scheme,the more strands arranged in the beams,the smaller the crack width under the same load can be achieved.It illustrates that prestressed steel wire ropes can well restrain the generation and development of the cracks in the original concrete structure.In comparison with the un-strengthened beam,the cracking resistance of the strengthened RC beams increases by 60.3% to 101% and the bending bearing capacity increases by 17.3% to 35.8%.However,the mid-span deflection declines by10.4%to 27.4%.That is to say,the cracking resistance,the bending bearing capacity and the stiffness of strengthened beams get improved apparently.The design formulas of the initial tension of steel wire ropes,the characteristic moments of strengthened beams in cracking,yielding and ultimate state and theoretical method to compute the mid-span deflection are in good agreement with the experimental results.It is possible to meet the required precision in engineering with conservative estimation.
引文
[1]蒙云,卢波.桥梁加固与改造[M].北京:人民交通出版社,2004.MENG Yun,LU Bo.Reinforcement and Reconstruction of Bridge[M].Beijing:China Communications Press,2004.
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[6]黄华,刘伯权,邢国华,等.高强不锈钢绞线网-渗透性聚合砂浆加固的T型梁桥试验[J].中国公路学报,2007,20(4):83-90.HUANG Hua,LIU Bo-quan,XING Guo-hua,et al.Experiment on RC T-type Beam Bridge Strengthened with High Strength Stainless Steel Wire[J].China Journal of Highway and Transport,2007,20(4):83-90.
[7]聂建国,王寒冰,张天申,等.高强不锈钢绞线网-渗透性聚合砂浆抗弯加固的试验研究[J].建筑结构学报,2005,26(2):1-9.NIE Jian-guo,WANG Han-bing,ZHANG Tian-shen,et al.Experimental Study on Flexural Behavior of RC Beams Strengthened with Stainless Steel Wire Mesh and Permeability Polymer Mortar[J].Journal of Building Structures,2005,26(2):1-9.
[8]吴刚,蒋剑彪,吴智深,等.预应力高强钢丝绳抗弯加固钢筋混凝土梁的试验研究[J].土木工程学报,2007,40(12):17-27.WU Gang,JIANG Jian-biao,WU Zhi-shen,et al.Experimental Study on Flexural Strengthening of RC Beams with Prestressed High Strength Steel Wire Ropes[J].China Civil Engineering Journal,2007,40(12):17-27.
[9]吴刚,吴智深,魏洋,等.预应力高强钢丝绳抗弯加固钢筋混凝土梁的理论分析[J].土木工程学报,2007,40(12):28-37.WU Gang,WU Zhi-shen,WEI Yang,et al.Theoretical Analysis on Flexural Strengthening of RC Beams with Prestressed High Strength Steel Wire Ropes[J].China Civil Engineering Journal,2007,40(12):28-37.
[10]张鹏飞,孙全胜.复合砂浆预应力钢丝绳加固实桥的试验分析[J].建筑结构,2014,44(3):67-70.ZHANG Peng-fei,SUN Quan-sheng.Experimental Analysis of the Bridge Strengthening by Composite Mortar Prestressed Steel Cable[J].Building Structure,2014,44(3):67-70.
[11]张鹏飞.复合砂浆预应力钢丝绳抗弯加固的研究[D].哈尔滨:东北林业大学,2014.ZHANG Peng-fei.Research on Flexural Reinforcement by the Composite Mortar Prestressed Steel Wire[D].Harbin:Northeast Forestry University,2014.
[12]GB 50010—2010,混凝土结构设计规范[S].GB 50010—2010,Code for Design of Concrete Structures[S].
[2]张树仁.桥梁加固设计理念剖析与商榷[C]//交通部公路科学研究院.全国既有桥梁加固、改造与评价学术会议论文集.北京:人民交通出版社,2008:3-11.ZHANG Shu-ren.Analysis and Discussion on the Ideas of Bridge Reinforcement Design[C]//Highway Research Institute of Ministry of Communications.The National Conference on Strengthening,Transformation and Evaluation of the Existing Bridges in China.Beijing:China Communications Press,2008:3-11.
[3]任伟,贺拴海,赵小星,等.黏贴钢板加固持荷钢筋混凝土T梁模型试验[J].中国公路学报,2008,21(3):64-68.REN Wei,HE Shuan-hai,ZHAO Xiao-xin,et al.Model Test on Preloaded RC T-beam Strengthened by Bonded Steel Plates[J].China Journal of Highway and Transport,2008,21(3):64-68.
[4]ESMAEELI E,BARROS J A O.Flexural Strengthening of RC Beams Using Hybrid Composite Plate(HCP):Experimental and Analytical Study[J].Composites Part B,2015,79:604-620.
[5]项贻强,姚永丁,胡峰强,等.体外索加固T型刚构桥的静动力性能研究[J].中国公路学报,2004,17(1):39-44.XIANG Yi-qiang,YAO Yong-ding,HU Feng-qiang,et al.Study of Static and Dynamic Behavior of Tshape Rigid Frame Bridge Reinforced by Prestressed External Tendon[J].China Journal of Highway and Transport,2004,17(1):39-44.
[6]黄华,刘伯权,邢国华,等.高强不锈钢绞线网-渗透性聚合砂浆加固的T型梁桥试验[J].中国公路学报,2007,20(4):83-90.HUANG Hua,LIU Bo-quan,XING Guo-hua,et al.Experiment on RC T-type Beam Bridge Strengthened with High Strength Stainless Steel Wire[J].China Journal of Highway and Transport,2007,20(4):83-90.
[7]聂建国,王寒冰,张天申,等.高强不锈钢绞线网-渗透性聚合砂浆抗弯加固的试验研究[J].建筑结构学报,2005,26(2):1-9.NIE Jian-guo,WANG Han-bing,ZHANG Tian-shen,et al.Experimental Study on Flexural Behavior of RC Beams Strengthened with Stainless Steel Wire Mesh and Permeability Polymer Mortar[J].Journal of Building Structures,2005,26(2):1-9.
[8]吴刚,蒋剑彪,吴智深,等.预应力高强钢丝绳抗弯加固钢筋混凝土梁的试验研究[J].土木工程学报,2007,40(12):17-27.WU Gang,JIANG Jian-biao,WU Zhi-shen,et al.Experimental Study on Flexural Strengthening of RC Beams with Prestressed High Strength Steel Wire Ropes[J].China Civil Engineering Journal,2007,40(12):17-27.
[9]吴刚,吴智深,魏洋,等.预应力高强钢丝绳抗弯加固钢筋混凝土梁的理论分析[J].土木工程学报,2007,40(12):28-37.WU Gang,WU Zhi-shen,WEI Yang,et al.Theoretical Analysis on Flexural Strengthening of RC Beams with Prestressed High Strength Steel Wire Ropes[J].China Civil Engineering Journal,2007,40(12):28-37.
[10]张鹏飞,孙全胜.复合砂浆预应力钢丝绳加固实桥的试验分析[J].建筑结构,2014,44(3):67-70.ZHANG Peng-fei,SUN Quan-sheng.Experimental Analysis of the Bridge Strengthening by Composite Mortar Prestressed Steel Cable[J].Building Structure,2014,44(3):67-70.
[11]张鹏飞.复合砂浆预应力钢丝绳抗弯加固的研究[D].哈尔滨:东北林业大学,2014.ZHANG Peng-fei.Research on Flexural Reinforcement by the Composite Mortar Prestressed Steel Wire[D].Harbin:Northeast Forestry University,2014.
[12]GB 50010—2010,混凝土结构设计规范[S].GB 50010—2010,Code for Design of Concrete Structures[S].