预应力钢筒混凝土管体外预应力加固试验研究
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摘要
预应力钢筒混凝土管(PCCP)断丝后,管芯混凝土在荷载作用下会发生开裂,影响PCCP的承载能力。目前针对PCCP断丝管的加固有多种方法。其中利用钢绞线施加体外预应力加固PCCP断丝管的方法能够主动补偿由于断丝导致的预应力损失,同时做到整个管线减压不停水。本文通过PCCP加载-断丝-管体管芯混凝土开裂-减压-施加体外预应力-加载到设计荷载的全过程原型试验,研究了PCCP体外预应力加固效果。并针对试验过程中各阶段PCCP管体的力学特性和变形特点进行分析。试验结果表明,通过钢绞线对PCCP断丝管施加体外预应力进行加固,管体裂缝闭合,承载能力恢复至设计内压0.9 MPa,钢绞线仍处于弹性阶段,管体水密性良好,加固效果明显。
Prestressed concrete cylinder pipe(PCCP) with broken wires suffers from longitudinal cracks in core concrete considering the continuous loads. Compared with other reinforcement methods applied in the field of PCCP, the reinforcement with external prestressed strands is able to actively compensate the prestress loss caused by broken prestressing wires and also unnecessary to dewater the pipes during construction. To assess the reinforcement effect of PCCP with external prestressed strands, a prototype test of PCCP including compression-breaking wires-decompression-tensioning-compression was conducted. The analysis of mechanical characteristics and deformation characteristics of PCCP at various stages in the test process has been analyzed. When the internal water pressure gradually increased to the design pressure of 0.9 MPa to verify the reinforcement effect of the PCCP with external prestressed steel strands, the strain of the core concrete changed slightly and the width of cracks in the outer core concrete was maintained at 0.1 mm. The visible cracks of the reinforced PCCP were constrained and closed at some degree. The strengthened pipe was capable to sustain the design internal water pressure and the water tightness property was in a good state. The reinforcement effect of PCCP with external prestressed steel strands is evident.
Prestressed concrete cylinder pipe(PCCP) with broken wires suffers from longitudinal cracks in core concrete considering the continuous loads. Compared with other reinforcement methods applied in the field of PCCP, the reinforcement with external prestressed strands is able to actively compensate the prestress loss caused by broken prestressing wires and also unnecessary to dewater the pipes during construction. To assess the reinforcement effect of PCCP with external prestressed strands, a prototype test of PCCP including compression-breaking wires-decompression-tensioning-compression was conducted. The analysis of mechanical characteristics and deformation characteristics of PCCP at various stages in the test process has been analyzed. When the internal water pressure gradually increased to the design pressure of 0.9 MPa to verify the reinforcement effect of the PCCP with external prestressed steel strands, the strain of the core concrete changed slightly and the width of cracks in the outer core concrete was maintained at 0.1 mm. The visible cracks of the reinforced PCCP were constrained and closed at some degree. The strengthened pipe was capable to sustain the design internal water pressure and the water tightness property was in a good state. The reinforcement effect of PCCP with external prestressed steel strands is evident.
引文
[1] GE S Q,SINHA S. Failure analysis,condition assessment technologies,and performance prediction of prestressed-concrete cylinder pipe:state-of-the-art literature review[J]. Journal of Performance of Constructed Facilities,2014,28(3):618-628.
[2] ROLLER J J. PCCP risk management-State of the art and strategy optimization[J]. American Water Works Association,2013,105(7):387-394.
[3] GE S Q,SINHA S. Effect of mortar coating’s bond quality on the structural integrity of prestressed concrete cylinder pipe with broken wires[J]. Journal of Materials Science Research,2015,4(3):59-75.
[4] BALL R T,MOORE W G,SMITH D L,et al. Prestressed concrete cylinder pipe rehabilitation repair and replacement:large diameter success stories[J]. Florida Water Resources Journal,2012,12:4-10.
[5] RAHMAN S,SMITH G,MIELKE R,et al. Rehabilitation of Large Diameter PCCP:Relining and Sliplining with Steel Pipe[C]//Pipelines 2012:Innovations in Design,Construction,Operations,and Maintenance-Doing More with Less,2012.
[6] KENNY M K,RAHMAN S. San Diego County Water Authority Aqueduct Protection Program since 1992:Evolution in Design and Construction of Steel Cylinder Relining of PCCP[C]//Pipelines 2014:From Underground to the Forefront of Innovation and Sustainability,2014.
[7] ZARGHAMEE M S,ENGINDENIZ M. CFRP Renewal of PCCP-An Overview[C]//Pipelines 2014:From Underground to the Forefront of Innovation and Sustainability,2014.
[8] ZARGHAMEE M S,MCREYNOLDS M,SLEEPER B,et al. Retrofit of CFRP Installation to Meet Current Design Standard[C]//Pipelines 2013:Pipelines and Trenchless Construction and Renewals—A Global Perspective,2013.
[9]窦铁生,程冰清,胡赫,等. CFRP修复PCCP的内水压试验[J].混凝土与水泥制品,2017(12):35-40.
[10]窦铁生,程冰清,胡赫,等.预应力钢筒混凝土管结构变形规律的原型试验研究Ⅱ:外压[J].水利学报,2018,49(2):207-215.
[11]窦铁生,程冰清,胡赫,等.预应力钢筒混凝土管结构变形规律的原型试验研究Ⅰ:内压[J].水利学报,2017,48(12):1438-1446.
[12] ELNAKHAT H,RAYMOND R. Repair of PCCP by Post Tensioning[C]//Pipelines 2006:Serviceto the Owner,2006.
[13] ANSI/AWWA C304,Standard for Design of Prestressed Concrete Cylinder Pipe[S]. American Water Works Association,America,2014.
[14] GB/T 19685-2017,预应力钢筒混凝土管[S].北京:中国标准出版社,2017.
[15] GB/T 5224-2015,预应力混凝土用钢绞线[S].北京:中国标准出版社,2015.
[16] OJDROVIC R,LABONTE G. Inspection,Failure Risk Analysis,and Repair of Cooling-Water Lines in One Outage[C]//Pipelines 2008:Pipeline Asset Management:Maximizing Performance of our Pipeline Infrastructure,2008.
[17]马哲. CFRP预应力筋在预制节段拼装桥梁中的应用研究[J].交通科学与工程,2017,33(3):50-55.
[18]叶增.体外预应力和碳纤维联合加固混凝土连续梁研究[D].长春:吉林建筑工程学院,2012.
[19] SL 702-2015,预应力钢筒混凝土管道技术规范[S].北京:中国水利水电出版社,2015.
[2] ROLLER J J. PCCP risk management-State of the art and strategy optimization[J]. American Water Works Association,2013,105(7):387-394.
[3] GE S Q,SINHA S. Effect of mortar coating’s bond quality on the structural integrity of prestressed concrete cylinder pipe with broken wires[J]. Journal of Materials Science Research,2015,4(3):59-75.
[4] BALL R T,MOORE W G,SMITH D L,et al. Prestressed concrete cylinder pipe rehabilitation repair and replacement:large diameter success stories[J]. Florida Water Resources Journal,2012,12:4-10.
[5] RAHMAN S,SMITH G,MIELKE R,et al. Rehabilitation of Large Diameter PCCP:Relining and Sliplining with Steel Pipe[C]//Pipelines 2012:Innovations in Design,Construction,Operations,and Maintenance-Doing More with Less,2012.
[6] KENNY M K,RAHMAN S. San Diego County Water Authority Aqueduct Protection Program since 1992:Evolution in Design and Construction of Steel Cylinder Relining of PCCP[C]//Pipelines 2014:From Underground to the Forefront of Innovation and Sustainability,2014.
[7] ZARGHAMEE M S,ENGINDENIZ M. CFRP Renewal of PCCP-An Overview[C]//Pipelines 2014:From Underground to the Forefront of Innovation and Sustainability,2014.
[8] ZARGHAMEE M S,MCREYNOLDS M,SLEEPER B,et al. Retrofit of CFRP Installation to Meet Current Design Standard[C]//Pipelines 2013:Pipelines and Trenchless Construction and Renewals—A Global Perspective,2013.
[9]窦铁生,程冰清,胡赫,等. CFRP修复PCCP的内水压试验[J].混凝土与水泥制品,2017(12):35-40.
[10]窦铁生,程冰清,胡赫,等.预应力钢筒混凝土管结构变形规律的原型试验研究Ⅱ:外压[J].水利学报,2018,49(2):207-215.
[11]窦铁生,程冰清,胡赫,等.预应力钢筒混凝土管结构变形规律的原型试验研究Ⅰ:内压[J].水利学报,2017,48(12):1438-1446.
[12] ELNAKHAT H,RAYMOND R. Repair of PCCP by Post Tensioning[C]//Pipelines 2006:Serviceto the Owner,2006.
[13] ANSI/AWWA C304,Standard for Design of Prestressed Concrete Cylinder Pipe[S]. American Water Works Association,America,2014.
[14] GB/T 19685-2017,预应力钢筒混凝土管[S].北京:中国标准出版社,2017.
[15] GB/T 5224-2015,预应力混凝土用钢绞线[S].北京:中国标准出版社,2015.
[16] OJDROVIC R,LABONTE G. Inspection,Failure Risk Analysis,and Repair of Cooling-Water Lines in One Outage[C]//Pipelines 2008:Pipeline Asset Management:Maximizing Performance of our Pipeline Infrastructure,2008.
[17]马哲. CFRP预应力筋在预制节段拼装桥梁中的应用研究[J].交通科学与工程,2017,33(3):50-55.
[18]叶增.体外预应力和碳纤维联合加固混凝土连续梁研究[D].长春:吉林建筑工程学院,2012.
[19] SL 702-2015,预应力钢筒混凝土管道技术规范[S].北京:中国水利水电出版社,2015.
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