劲性骨架对悬臂施工桥梁合龙段影响分析
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摘要
悬臂施工预应力混凝土桥梁一般采用锁定装置对最大悬臂结构进行强制合龙。合龙段作为施工阶段的“终点”,因其受力状态较为复杂,受外界影响因素较多,因此桥梁建成后预应力混凝土主梁合龙段病害屡见不鲜。
随着对大跨径预应力混凝土桥梁尤其是连续刚构桥病害认识的不断深入,国内外学者开展了广泛的研究工作,但未有涉及到劲性骨架类型对合龙段混凝土影响的数值或试验研究的相关报道。本文作为西部交通建设项目《大、中跨径预应力混凝土桥梁检测技术》中的有效预应力评定与桥梁评估的组成部分,定量分析了合龙锁定装置对混凝土截面应力影响的时变规律；基于结构分析程序,以陕西某连续刚构桥(跨径组合：72m+120m+72m)为工程背景,对合龙段混凝土箱梁因内置劲性骨架产生的内力及应力分布变化规律进行了数值仿真分析。
进行了劲性骨架的刚度大小对合龙段箱梁混凝土的应力影响分析,得到了箱梁底板混凝土压应力与箱梁含钢率的关系；选取最常用的内置锁定和外置锁定装置两种劲性骨架来代表两类合龙方式,将桥梁铺装结束作为起点,以运营十年作为终点,比较采用两种合龙方式产生的桥梁内力差异及变化情况,得到了内置劲性骨架对桥梁结构的影响区域。以永久作用下的截面内力为基础,分析大桥服役阶段合龙段箱梁上、下缘混凝土的应力分布,比较了截面正应力的变化情况。经过分析,发现内置劲性骨架吸收预应力现象明显,会导致合龙段箱梁截面混凝土有效应力不足,是合龙段病害产生的重要因素之一。
从设计角度进行分析,结合设计单位对桥梁结构的计算习惯,采用荷载标准值组合作用下的截面内力对合龙段进行应力分析,比较了考虑内置骨架与否给结构带来的风险；考虑劲性骨架刚度影响对大桥超载状况下的跨中截面正应力进行了计算。结果表明,劲性骨架对混凝土底缘正应力影响较大,应在设计及施工监控实践中予以重视。
Locking device is also used to closure the bridge constructed by cantilever method.As the end-point of the construction stage, the defects is of common occurrence because of the complex forced state and external affecting factors on the closure of the large span presstressed concrete bridge.
The extensive research is developed by scholars wordwide with the understanding of defects on the large span prestressed concrete bridge, especially continuous rigid frame bridge, but the experiment or numerical simulation about the influence of the types of stiff skeleton on the concrete of the closure. As a part of the western communition construction technology project--< The Detection Technique on Large and Medium Span PC Bridge>, to get the time-dependent rules of concrete stress which is impacted by the locking device exactly, the research work is developed on the change of internal forces and stress brought by the stiff skeleton basing on the structural analysis program of a continous rigid frame bridge in Shanxi Province (span arrangement:72m+120m+72m).
According to analyze the influence of the skeleton stiffness on closure concrete stress, the relation cures that concrete stress varies with the steel ratio is obtained. The affected area, the differences and changes of internal forces and stress by the stiff skeleton in ten years is caculated in this paper by chosing two types of stiff skeleton as representative based on the engineering example.
The stress distribution of the concrete of the boxgirder located at mid span is studied and the change of the section normal stress is compared by the basis of section internal force which is produced by the permanent action when the bridge is on the using stage. The result shows that the absorption of prestress is obvious because of the inner stiff skeleton, and this phenomenon give cause for the decrease of effective stress and the defects on closure.
From the viewpoint of Designer and combined with the checking habit of design institute, the stress analysis of closure is done to forecast the risk brought by inner stiff skeleton. The result shows that the stiff skeleton has a obvious effect on the normal stress of the bottom concrete. This influence should be claimed attention in design and construction control.
随着对大跨径预应力混凝土桥梁尤其是连续刚构桥病害认识的不断深入,国内外学者开展了广泛的研究工作,但未有涉及到劲性骨架类型对合龙段混凝土影响的数值或试验研究的相关报道。本文作为西部交通建设项目《大、中跨径预应力混凝土桥梁检测技术》中的有效预应力评定与桥梁评估的组成部分,定量分析了合龙锁定装置对混凝土截面应力影响的时变规律；基于结构分析程序,以陕西某连续刚构桥(跨径组合：72m+120m+72m)为工程背景,对合龙段混凝土箱梁因内置劲性骨架产生的内力及应力分布变化规律进行了数值仿真分析。
进行了劲性骨架的刚度大小对合龙段箱梁混凝土的应力影响分析,得到了箱梁底板混凝土压应力与箱梁含钢率的关系；选取最常用的内置锁定和外置锁定装置两种劲性骨架来代表两类合龙方式,将桥梁铺装结束作为起点,以运营十年作为终点,比较采用两种合龙方式产生的桥梁内力差异及变化情况,得到了内置劲性骨架对桥梁结构的影响区域。以永久作用下的截面内力为基础,分析大桥服役阶段合龙段箱梁上、下缘混凝土的应力分布,比较了截面正应力的变化情况。经过分析,发现内置劲性骨架吸收预应力现象明显,会导致合龙段箱梁截面混凝土有效应力不足,是合龙段病害产生的重要因素之一。
从设计角度进行分析,结合设计单位对桥梁结构的计算习惯,采用荷载标准值组合作用下的截面内力对合龙段进行应力分析,比较了考虑内置骨架与否给结构带来的风险；考虑劲性骨架刚度影响对大桥超载状况下的跨中截面正应力进行了计算。结果表明,劲性骨架对混凝土底缘正应力影响较大,应在设计及施工监控实践中予以重视。
Locking device is also used to closure the bridge constructed by cantilever method.As the end-point of the construction stage, the defects is of common occurrence because of the complex forced state and external affecting factors on the closure of the large span presstressed concrete bridge.
The extensive research is developed by scholars wordwide with the understanding of defects on the large span prestressed concrete bridge, especially continuous rigid frame bridge, but the experiment or numerical simulation about the influence of the types of stiff skeleton on the concrete of the closure. As a part of the western communition construction technology project--< The Detection Technique on Large and Medium Span PC Bridge>, to get the time-dependent rules of concrete stress which is impacted by the locking device exactly, the research work is developed on the change of internal forces and stress brought by the stiff skeleton basing on the structural analysis program of a continous rigid frame bridge in Shanxi Province (span arrangement:72m+120m+72m).
According to analyze the influence of the skeleton stiffness on closure concrete stress, the relation cures that concrete stress varies with the steel ratio is obtained. The affected area, the differences and changes of internal forces and stress by the stiff skeleton in ten years is caculated in this paper by chosing two types of stiff skeleton as representative based on the engineering example.
The stress distribution of the concrete of the boxgirder located at mid span is studied and the change of the section normal stress is compared by the basis of section internal force which is produced by the permanent action when the bridge is on the using stage. The result shows that the absorption of prestress is obvious because of the inner stiff skeleton, and this phenomenon give cause for the decrease of effective stress and the defects on closure.
From the viewpoint of Designer and combined with the checking habit of design institute, the stress analysis of closure is done to forecast the risk brought by inner stiff skeleton. The result shows that the stiff skeleton has a obvious effect on the normal stress of the bottom concrete. This influence should be claimed attention in design and construction control.
引文
[1]戴竞,凤懋润.我国预应力混凝土公路桥的发展与现状[J].土木工程学报,1997,30(8)：3-10
[2]王法武.大跨径预应力混凝土梁桥长期挠度控制研究[D].上海：同济大学.2006：1-2
[3]马保林.高墩大跨连续刚构桥[M].北京：人民交通出版社.2001：19
[4]郑一峰.混凝土部分斜拉桥设计理论研究[D].哈尔滨：哈尔滨工业大学.2005：4-12
[5]刘一波.大跨PC箱梁裂缝研究分析[D].西安：长安大学.2006
[6]王法武,石雪飞.大跨径预应力混凝土梁桥长期挠度控制分析[J].上海公路.2006,(01)：29-32
[7]高仙桂,陈希安.大跨度连续刚构主梁下挠及箱梁裂缝成因分析[J].公路与汽运.2007,119(2)：109-111
[8]杨志平,朱桂新,李卫.预应力混凝土连续刚构桥挠度长期观测[J].公路.2004,(8)：285-289
[9]谢峻,王国亮,郑晓华.大跨径预应力混凝土箱梁桥长期下挠问题的研究现状[J].公路交通科技,2007,24(1)：47-50
[10]詹建辉,陈卉.特大跨度连续刚构主梁下挠及箱梁裂缝成因分析[J].中外公路.2005,25(1)：56-58
[11]李俊,李小珍,卫星等.连续刚构桥底板纵向裂纹原因分析[J].公路.2005,(9)：1-5
[12]楼庄鸿.现有大跨径预应力混凝土梁式桥的缺陷[A].中国公路学会桥梁和结构工程学会2003年全国桥梁学术会议论文集[C].北京：人民交通出版社,2003
[13]刘效尧,蔡键,刘晖.桥梁损伤诊断[M].北京：人民交通出版社,2002：33-35
[14]施建振,虞建成,施为民等.连续箱梁桥中跨合龙段劲性骨架优化设计[J].施工技术.2004,33(9)：3-5
[15]朱芳芳,于忠涛.连续刚构桥合龙中劲性钢骨架的施工控制[J]北方交通.2006,9：37-40
[16]张继尧,王昌将.悬臂浇筑预应力混凝土连续梁桥[M].北京：人民交通出版社.2004：33-35
[17]刘吉士,张俊义,陈亚军.桥梁施工百问[M].北京：人民交通出版社.2003
[18]刘建楼.预应力混凝土连续梁0#块与合龙段应力分析[D].西安：长安大学.2005
[19]敬启双.河耳沟特大桥合龙段施工技术[J].铁道建筑.2006,7：1-3
[20]张欣禹,郎宏继,孙庆东等.沈阳市富民桥主桥合龙设计[J].桥梁建设.2004(增)：11-13
[21]刘剑雄,李芳军.重庆大佛寺长江大桥边跨合龙段施工[J].中外公路.2004,24(4)：78-80
[22]周翰斌,钱门友.长联多跨预应力混凝土刚构-连续梁桥的合龙施工[J].交通科技.2004,206(5)：57-60
[23]王治群,左宜军,刘钧泉.刚构连续组合梁桥合龙施工技术[J].湖南交通科技.2005,31(4)：111-113,118
[24]曾波.株洲建宁大桥斜拉桥主梁合龙施工技术与控制[J].湖南交通科技.2006,32(4)：88-91
[25]李永,吴春朝.多跨连续箱梁悬臂浇筑合龙段施工关键技术[J].铁道标准设计.2006,(11)：44-45
[26]李银坤,薛继连.喜旧溪大桥连续刚构梁合龙施工技术[J].铁道标准设计.1999,7：48-52
[27]周辉.高墩大跨连续刚构合龙段施工技术研究[Z].中铁四局集团有限公司黄延高速公路项目经理部
[28]李闻涛.大跨径连续体系梁桥墩顶块空间应力数值分析[D].西安：长安大学.2007
[29]交通部公路科学研究所.公路桥梁承载能力检测评定规程(征求意见稿)[Z].2003
[2]王法武.大跨径预应力混凝土梁桥长期挠度控制研究[D].上海：同济大学.2006：1-2
[3]马保林.高墩大跨连续刚构桥[M].北京：人民交通出版社.2001：19
[4]郑一峰.混凝土部分斜拉桥设计理论研究[D].哈尔滨：哈尔滨工业大学.2005：4-12
[5]刘一波.大跨PC箱梁裂缝研究分析[D].西安：长安大学.2006
[6]王法武,石雪飞.大跨径预应力混凝土梁桥长期挠度控制分析[J].上海公路.2006,(01)：29-32
[7]高仙桂,陈希安.大跨度连续刚构主梁下挠及箱梁裂缝成因分析[J].公路与汽运.2007,119(2)：109-111
[8]杨志平,朱桂新,李卫.预应力混凝土连续刚构桥挠度长期观测[J].公路.2004,(8)：285-289
[9]谢峻,王国亮,郑晓华.大跨径预应力混凝土箱梁桥长期下挠问题的研究现状[J].公路交通科技,2007,24(1)：47-50
[10]詹建辉,陈卉.特大跨度连续刚构主梁下挠及箱梁裂缝成因分析[J].中外公路.2005,25(1)：56-58
[11]李俊,李小珍,卫星等.连续刚构桥底板纵向裂纹原因分析[J].公路.2005,(9)：1-5
[12]楼庄鸿.现有大跨径预应力混凝土梁式桥的缺陷[A].中国公路学会桥梁和结构工程学会2003年全国桥梁学术会议论文集[C].北京：人民交通出版社,2003
[13]刘效尧,蔡键,刘晖.桥梁损伤诊断[M].北京：人民交通出版社,2002：33-35
[14]施建振,虞建成,施为民等.连续箱梁桥中跨合龙段劲性骨架优化设计[J].施工技术.2004,33(9)：3-5
[15]朱芳芳,于忠涛.连续刚构桥合龙中劲性钢骨架的施工控制[J]北方交通.2006,9：37-40
[16]张继尧,王昌将.悬臂浇筑预应力混凝土连续梁桥[M].北京：人民交通出版社.2004：33-35
[17]刘吉士,张俊义,陈亚军.桥梁施工百问[M].北京：人民交通出版社.2003
[18]刘建楼.预应力混凝土连续梁0#块与合龙段应力分析[D].西安：长安大学.2005
[19]敬启双.河耳沟特大桥合龙段施工技术[J].铁道建筑.2006,7：1-3
[20]张欣禹,郎宏继,孙庆东等.沈阳市富民桥主桥合龙设计[J].桥梁建设.2004(增)：11-13
[21]刘剑雄,李芳军.重庆大佛寺长江大桥边跨合龙段施工[J].中外公路.2004,24(4)：78-80
[22]周翰斌,钱门友.长联多跨预应力混凝土刚构-连续梁桥的合龙施工[J].交通科技.2004,206(5)：57-60
[23]王治群,左宜军,刘钧泉.刚构连续组合梁桥合龙施工技术[J].湖南交通科技.2005,31(4)：111-113,118
[24]曾波.株洲建宁大桥斜拉桥主梁合龙施工技术与控制[J].湖南交通科技.2006,32(4)：88-91
[25]李永,吴春朝.多跨连续箱梁悬臂浇筑合龙段施工关键技术[J].铁道标准设计.2006,(11)：44-45
[26]李银坤,薛继连.喜旧溪大桥连续刚构梁合龙施工技术[J].铁道标准设计.1999,7：48-52
[27]周辉.高墩大跨连续刚构合龙段施工技术研究[Z].中铁四局集团有限公司黄延高速公路项目经理部
[28]李闻涛.大跨径连续体系梁桥墩顶块空间应力数值分析[D].西安：长安大学.2007
[29]交通部公路科学研究所.公路桥梁承载能力检测评定规程(征求意见稿)[Z].2003