固化期间缓黏结预应力梁力学性能试验
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摘要
为了探明固化期间缓黏结预应力混凝土梁的力学性能,制作了4根缓黏结预应力混凝土梁,每根梁直线布置3根缓黏结预应力钢筋,进行试验梁的抗弯承载力测试。通过邵氏硬度计测得试验梁缓黏结剂的硬度,用以反映缓凝材料在加载试验时的固化性质;然后把试验梁分4批进行三分点两点同步单调静力加载试验;最后通过监测梁挠度、关键截面混凝土的应变变化、预应力钢筋张拉端和锚固端的压力变化、裂缝分布等指标,明确缓黏结预应力钢筋与混凝土之间的传力机理以及混凝土梁的抗弯承载能力。结果表明:缓黏结剂的固化度对预应力混凝土梁的开裂荷载影响较小,对最大承载力影响较大,利用现有的预应力混凝土计算理论计算得到的开裂荷载与试验结果吻合较好,但最大承载力的理论计算结果相对保守;随着缓黏结剂逐渐固化,预应力混凝土梁的极限承载力随之增加,当缓黏结剂的邵氏硬度(D型)达到80时,缓黏结预应力钢筋与混凝土具有良好的共同工作状态,梁纯弯段部分的裂缝开展均匀,数量较多,其承载力及延性也最大。
To investigate the mechanical behavior of retard-bonded pre-stressed concrete(RBPC)beam during curing period,four RBPC beams which had arranged three straight retard-bonded pre-stressed tendons in each beam were made and bending resistance capacity tests of these RBPC beams were carried out.The hardness of retard-bonded adhesive in each beam was measured by the Shore durometer to reflect the curing property of the retard-bonded material in loading experiment.These RBPC beams were divided into four groups for monotonic static loading experiment at the one third point and the two thirds point at the same time.Finally,to explore clearly the force transfer mechanism between retard-bonded pre-stressed tendons and concrete and bearing capacity of these RBPC beams,the force-deflection curve,the concrete strain change of key-sections,the pressure change at the tensile end and the anchoring end of pre-stressed tendon,the cracks distribution and other parameters were measured.The result shows that the curing degree of retard-bonded adhesive has little impact on the cracking load of pre-stressed concrete beam,however,it has great impact on the maximum bearing capacity;based on the existedcalculating theory of the PC structure,the calculated cracking load has good agreement with experimental result,but the theoretically calculated maximum bearing capacity is conservative comparatively;with the increase of curing degree,the maximum bearing capacity of RBPC beam also increases.When the Shore hardness(D type)of retard-bonded adhesive reaches 80,the retard-bonded pre-stressed tendons and concrete work synergistically well.Large amount of cracks in the bending segment are distributed uniformly,where its bearing capacity and ductility are also the largest.
To investigate the mechanical behavior of retard-bonded pre-stressed concrete(RBPC)beam during curing period,four RBPC beams which had arranged three straight retard-bonded pre-stressed tendons in each beam were made and bending resistance capacity tests of these RBPC beams were carried out.The hardness of retard-bonded adhesive in each beam was measured by the Shore durometer to reflect the curing property of the retard-bonded material in loading experiment.These RBPC beams were divided into four groups for monotonic static loading experiment at the one third point and the two thirds point at the same time.Finally,to explore clearly the force transfer mechanism between retard-bonded pre-stressed tendons and concrete and bearing capacity of these RBPC beams,the force-deflection curve,the concrete strain change of key-sections,the pressure change at the tensile end and the anchoring end of pre-stressed tendon,the cracks distribution and other parameters were measured.The result shows that the curing degree of retard-bonded adhesive has little impact on the cracking load of pre-stressed concrete beam,however,it has great impact on the maximum bearing capacity;based on the existedcalculating theory of the PC structure,the calculated cracking load has good agreement with experimental result,but the theoretically calculated maximum bearing capacity is conservative comparatively;with the increase of curing degree,the maximum bearing capacity of RBPC beam also increases.When the Shore hardness(D type)of retard-bonded adhesive reaches 80,the retard-bonded pre-stressed tendons and concrete work synergistically well.Large amount of cracks in the bending segment are distributed uniformly,where its bearing capacity and ductility are also the largest.
引文
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[13]赵霄,金凌志.缓粘结预应力混凝土连续梁预应力损失计算及摩阻力研究[J].井冈山大学学报:自然科学版,2011,32(6):99-103.ZHAO Xiao,JIN Ling-zhi.Research of the Calculation to Prestress Loss and the Stretching Friction of Retard-bonded Prestressed Concrete Continuous Beams[J].Journal of Jinggangshan University:Natural Science,2011,32(6):99-103.
[14]吴转琴,尚仁杰,洪光,等.缓粘结预应力钢绞线与混凝土粘结性能试验研究[J].建筑结构,2013,43(2):68-70.WU Zhuan-qin,SHANG Ren-jie,HONG Guang,et al.Experimental Study on Cohesive Property Between Retard-bonded Prestressing Steel Strand and Concrete[J].Building Structure,2013,43(2):68-70.
[15]JTG D62—2012,公路钢筋混凝土及预应力混凝土桥涵设计规范[S].JTG D62—2012,Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridge and Culverts[S].
[2]曹国辉,胡佳星,张锴,等.缓粘结预应力混凝土梁极限承载力试验[J].公路交通科技,2013,30(6):49-55.CAO Guo-hui,HU Jia-xing,ZHANG Kai,et al.Ultimate Bearing Capacity Test of Retard-bonded Prestressed Concrete Beams[J].Journal of Highway and Transportation Research and Development,2013,30(6):49-55.
[3]赵建昌,王起才,李永和.超效缓凝砂浆与缓粘结预应力混凝土构件试验研究[J].土木工程学报,2003,36(8):57-62.ZHAO Jian-chang,WANG Qi-cai,LI Yong-he.Experimental Research on Super-retard-setting Mortar and Retard-bonded Prestressed Concrete Beams[J].China Civil Engineering Journal,2003,36(8):57-62.
[4]尚仁杰,张强,周建锋,等.缓粘结预应力混凝土梁受弯试验研究[J].工业建筑,2008,38(11):24-27.SHANG Ren-jie,ZHANG Qiang,ZHOU Jian-feng,et al.Experimental Study on Retard-bonded Prestressed Concrete Beams in Bending[J].Industrial Construction,2008,38(11):24-27.
[5]熊学玉,沈土富,刘华良.缓粘结预应力技术探讨[J].建筑施工,2004,26(1):52-53,65.XIONG Xue-yu,SHEN Tu-fu,LIU Hua-liang.Discussion on Retard-bonded Prestressed Technique[J].Building Construction,2004,26(1):52-53,65.
[6]张建玲,宋玉普,王志刚.缓粘结预应力筋的试验研究[J].施工技术,2007,36(3):21-23.ZHANG Jian-ling,SONG Yu-pu,WANG Zhi-gang.Experimental Study on Retard-bonded Prestressed Tendons[J].Construction Technology,2007,36(3):21-23.
[7]吴转琴,曾昭波,尚仁杰,等.缓粘结预应力钢绞线摩擦系数试验研究[J].工业建筑,2008,38(11):20-23.WU Zhuan-qin,ZENG Zhao-bo,SHANG Ren-jie,et al.Experimental Study on Friction Coefficient of Retard-bonded Prestressing Strand[J].Industrial Construction,2008,38(11):20-23.
[8]张建玲,宋玉普.缓粘结混合配筋预应力混凝土梁裂缝宽度的试验研究[J].土木工程学报,2008,41(2):54-59.ZHANG Jian-ling,SONG Yu-pu.Experimental Research on Crack Width of Retard-bonded Partially Prestressed Concrete Beams with Mixed Reinforcement[J].China Civil Engineering Journal,2008,41(2):54-59.
[9]周先雁,冯新.缓粘结部分预应力混凝土T梁裂缝宽度的试验研究[J].公路交通科技,2011,28(1):56-61.ZHOU Xian-yan,FENG Xin.Experimental Research on Crack Width of Retard-bonded Partially Prestressed Concrete T-beams[J].Journal of Highway and Transportation Research and Development,2011,28(1):56-61.
[10]Japan Road Association.Specification for Highway Bridges PartⅢ:Concrete Bridge[M].Tokyo:Maruzen Co.,Ltd,2012.
[11]赵建昌,李永和,王起才.新型缓粘结预应力体系试验研究[J].建筑结构学报,2005,26(2):52-59.ZHAO Jian-chang,LI Yong-he,WANG Qi-cai.Experimental Research on a New Type of Bond-retarded Prestressed System[J].Journal of Building Structures,2005,26(2):52-59.
[12]熊小林,李金根,李一心.缓粘结预应力筋摩阻损失的试验研究[J].建筑技术,2008,39(12):943-946.XIONG Xiao-lin,LI Jin-gen,LI Yi-xin.Experimental Study on Frictional Resistance of Bond-retarded Prestressed Bars[J].Architecture Technology,2008,39(12):943-946.
[13]赵霄,金凌志.缓粘结预应力混凝土连续梁预应力损失计算及摩阻力研究[J].井冈山大学学报:自然科学版,2011,32(6):99-103.ZHAO Xiao,JIN Ling-zhi.Research of the Calculation to Prestress Loss and the Stretching Friction of Retard-bonded Prestressed Concrete Continuous Beams[J].Journal of Jinggangshan University:Natural Science,2011,32(6):99-103.
[14]吴转琴,尚仁杰,洪光,等.缓粘结预应力钢绞线与混凝土粘结性能试验研究[J].建筑结构,2013,43(2):68-70.WU Zhuan-qin,SHANG Ren-jie,HONG Guang,et al.Experimental Study on Cohesive Property Between Retard-bonded Prestressing Steel Strand and Concrete[J].Building Structure,2013,43(2):68-70.
[15]JTG D62—2012,公路钢筋混凝土及预应力混凝土桥涵设计规范[S].JTG D62—2012,Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridge and Culverts[S].