大吨位FRP复合材料拉索整体式锚固理论分析
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摘要
针对大吨位纤维增强聚合物(FRP)复合材料拉索锚固问题,基于前期提出的一种适用于多根、大直径的FRP复合材料拉索整体式变刚度锚固方法(简称大吨位锚固),利用应力-应变关系分析了FRP复合材料拉索加载端应力集中产生的本质原因,推导了FRP复合材料拉索与荷载传递介质协同工作的界面摩擦系数关系式。基于功能原理,推导了大吨位锚固体系的锚固力计算公式,并基于锚固力计算公式进行了参数分析。理论推导结果表明:等刚度荷载传递介质会引起FRP复合材料拉索加载端应力集中,变刚度荷载传递介质的大吨位锚固方法可以有效避免FRP复合材料拉索"切口效应"。推导的界面摩擦系数关系式能够作为FRP复合材料拉索与荷载传递介质是否同步跟进的判断依据。参数分析表明:增加锚固长度和锥角(保持加载端厚度不变)有利于设计较小尺寸大吨位锚固体系,而增加锥角(保持自由端厚度不变)和同时改变加载端与自由端厚度不利于设计较小尺寸大吨位锚固体系。
In view of the anchor problem of large-tonnage fiber reinforced polymer(FRP)composites cable,basing on previous proposed integral variable stiffness anchor method suitable for multi root and large-diameter FRP composite cables(large-tonnage anchor for short),the essential reason of stress concentration at the loading end of FRP composite cable was analyzed based on the relationship between stress and strain,and the interfacial friction coefficient relationship of cooperative work between the FRP composites and load transfer component was deduced.Based on the principle of work and power,the calculation formula of anchor force for large-tonnage anchor was derived,and the parameter analysis was carried out based on the calculation formula of anchor force.The theoretical derivation results show that the stress concentration at the loading end of FRP composite cable can be caused by load transfer component with equal stiffness,and the large-tonnage anchor basing on load transfer component with variable stiffness can effectively avoids the cut effect of FRP composite cable.The derived interfacial friction coefficient relationship can be used as the basis for judge whether FRP composite cable and load transfer component follow up synchronously.The parameter analysis shows that increasing the anchor length and the cone angle(keeping the thickness of loading end unchanged)is advantageous to design small size and large-tonnage anchor system,while increasing the cone angle(keeping the thickness of free end unchanged)and the thickness of the loading end and the free end simultaneously is disadvantageous to design small size and large-tonnage anchor system.
In view of the anchor problem of large-tonnage fiber reinforced polymer(FRP)composites cable,basing on previous proposed integral variable stiffness anchor method suitable for multi root and large-diameter FRP composite cables(large-tonnage anchor for short),the essential reason of stress concentration at the loading end of FRP composite cable was analyzed based on the relationship between stress and strain,and the interfacial friction coefficient relationship of cooperative work between the FRP composites and load transfer component was deduced.Based on the principle of work and power,the calculation formula of anchor force for large-tonnage anchor was derived,and the parameter analysis was carried out based on the calculation formula of anchor force.The theoretical derivation results show that the stress concentration at the loading end of FRP composite cable can be caused by load transfer component with equal stiffness,and the large-tonnage anchor basing on load transfer component with variable stiffness can effectively avoids the cut effect of FRP composite cable.The derived interfacial friction coefficient relationship can be used as the basis for judge whether FRP composite cable and load transfer component follow up synchronously.The parameter analysis shows that increasing the anchor length and the cone angle(keeping the thickness of loading end unchanged)is advantageous to design small size and large-tonnage anchor system,while increasing the cone angle(keeping the thickness of free end unchanged)and the thickness of the loading end and the free end simultaneously is disadvantageous to design small size and large-tonnage anchor system.
引文
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[13]NANNI A,BAKIS C E,O’NEIL E F,et al.Performance of FRP tendon-anchor systems for prestressed concrete structures[J].PCI Journal,1996,41(1):34-44.
[14]Al-MAYAH A,SOUDKI K,PLUMTREE A.Novel anchor system for CFRP rod:Finite-element and mathematical models[J].Journal of Composites for Construction,2007,11(5):469-476.
[15]FAVA G,CARVELLI V,PISANI M A.Mechanical behaviour modelling of a new anchor system for large diameter GFRP bars[J].Compos Part B:Engineering,2012,43(3):1397-404.
[16]WANG X,XU P C,WU Z S,et al.A novel anchor method for multi-tendon FRP cable:Concept and FE study[J].Composite Structures,2015,120:552-564.
[17]WANG X,XU P C,WU Z S,et al.A novel anchor method for multi-tendon FRP cables manufacturing and experimental study[J].Journal of Composites for Construction,2015,19(6):04015010.
[18]LIU Y,ZWINGMANN B,SCHLAICH M.Carbon fiber reinforced polymer for cable structures:A review[J].Polymers,2015,7(10):2078-2099.
[19]WANG L C,ZHANG J Y,XU J,et al.Anchorage systems of CFRP cables in cable structures:A review[J].Construction and Building Materials,2018,160:82-99.
[20]MEIER U,FARSHAD M.Connecting high-performance carbon-fibre-reinforced polymer cables of suspension and cable-stayed bridges through the use of gradient materials[J].Journal of Computer-Aided Materials Design,1996,3(1-3):379-384.
[21]BURGOYNE C J.Parafil ropes for prestressing applications[J].Fiber-Reinforced-Plastic(FRP)Reinforcement for Concrete Structures,1993,42:333-354.
[22]CARVELLI V,FAVA G,PISANI M A.Anchor system for tension testing of large diameter GFRP bars[J].Journal of Composites for Construction,2009,13(5):344-349.
[23]TAHA M,SHRIVE N G.New concrete anchors for carbon fiber-reinforced polymer post-tensioning tendons Part 2:State-of-the-art review/design[J].ACI Structural Journal,2003,100(1):86-95.
[24]WANG X,WANG Z H,WU Z S,et al.Shear behavior of basalt fiber reinforced polymer(FRP)and hybrid FRP rods as shear resistance members[J].Construction and Building Materials,2014,73:781-789.
[25]SHI J Z,WANG X,WU Z S,et al.Effects of radial stress at anchor zone on tensile properties of basalt fiber-reinforced polymer tendons[J].Journal of Reinforced Plastics and Composites,2015,34(23):1937-1949.
[2]朱虹,董志强,吴刚,等.FRP筋混凝土梁的刚度试验研究和理论计算[J].土木工程学报,2015,48(11):44-53.ZHU H,DONG Z Q,WU G,et al.Experimental study and theoretical calculation on the flexural stiffness of concrete beams reinforced with FRP bars[J].China Civil Engineering Journal,2015,48(11):44-53(in Chinese).
[3]李趁趁,王英来,赵军,等.高温后FRP筋纵向拉伸性能[J].建筑材料学报,2014,17(6):1076-1081.LI C C,WANG Y L,ZHAO J,et al.Longitudinal tensile properties of FRP bars after high temperature[J].Journal of Building Materials,2014,17(6):1076-1081(in Chinese).
[4]PATRICK X W Z.Long-term properties and transfer length of fiber-reinforced polymers[J].Journal of Composites for Construction,2003,7(1):10-19.
[5]SAADATMANESH H,TANNOUS F E.Relaxation,creep,and fatigue behavior of carbon fiber reinforced plastic tendons[J].ACI Materials Journal,1999,96(2):143-153.
[6]WANG X,SHI J Z,WU Z S,et al.Fatigue behavior of basalt fiber-reinforced polymer tendons for prestressing applications[J].Journal of Composites for Construction,2015,20(3):0000649.
[7]SHI J Z,ZHU H,WU Z S,et al.Bond behavior between basalt fiber-reinforced polymer sheet and concrete substrate under the coupled effects of freeze-thaw cycling and sustained load[J].Journal of Composites for Construction,2013,17(4):530-542.
[8]WANG X,SHI J Z,LIU J,et al.Creep behavior of basalt fiber reinforced polymer tendons for prestressing application[J].Materials and Design,2014,59(7):558-564.
[9]WANG X,WU Z S.Modal damping evaluation of hybrid FRP cable with smart dampers for long-span cable-stayed bridges[J].Composite Structures,2011,93(4):1231-1238.
[10]WANG X,WU Z S,WU G,et al.Enhancement of basalt FRP by hybridization for long-span cable-stayed bridge[J].Composite Part B:Engineering,2013,44(1):184-192
[11]WANG X,WU Z S.Evaluation of FRP and hybrid FRP cables for super long-span cable-stayed bridges[J].Composite Structures,2010,92(10):2582-2590.
[12]SHI J Z,WANG X,WU Z S,et al.Effects of radial stress at anchor zone on tensile properties of basalt fiber-reinforced polymer tendons[J].Journal of Reinforced Plastics and Composites,2015,34(23):1937-1949.
[13]NANNI A,BAKIS C E,O’NEIL E F,et al.Performance of FRP tendon-anchor systems for prestressed concrete structures[J].PCI Journal,1996,41(1):34-44.
[14]Al-MAYAH A,SOUDKI K,PLUMTREE A.Novel anchor system for CFRP rod:Finite-element and mathematical models[J].Journal of Composites for Construction,2007,11(5):469-476.
[15]FAVA G,CARVELLI V,PISANI M A.Mechanical behaviour modelling of a new anchor system for large diameter GFRP bars[J].Compos Part B:Engineering,2012,43(3):1397-404.
[16]WANG X,XU P C,WU Z S,et al.A novel anchor method for multi-tendon FRP cable:Concept and FE study[J].Composite Structures,2015,120:552-564.
[17]WANG X,XU P C,WU Z S,et al.A novel anchor method for multi-tendon FRP cables manufacturing and experimental study[J].Journal of Composites for Construction,2015,19(6):04015010.
[18]LIU Y,ZWINGMANN B,SCHLAICH M.Carbon fiber reinforced polymer for cable structures:A review[J].Polymers,2015,7(10):2078-2099.
[19]WANG L C,ZHANG J Y,XU J,et al.Anchorage systems of CFRP cables in cable structures:A review[J].Construction and Building Materials,2018,160:82-99.
[20]MEIER U,FARSHAD M.Connecting high-performance carbon-fibre-reinforced polymer cables of suspension and cable-stayed bridges through the use of gradient materials[J].Journal of Computer-Aided Materials Design,1996,3(1-3):379-384.
[21]BURGOYNE C J.Parafil ropes for prestressing applications[J].Fiber-Reinforced-Plastic(FRP)Reinforcement for Concrete Structures,1993,42:333-354.
[22]CARVELLI V,FAVA G,PISANI M A.Anchor system for tension testing of large diameter GFRP bars[J].Journal of Composites for Construction,2009,13(5):344-349.
[23]TAHA M,SHRIVE N G.New concrete anchors for carbon fiber-reinforced polymer post-tensioning tendons Part 2:State-of-the-art review/design[J].ACI Structural Journal,2003,100(1):86-95.
[24]WANG X,WANG Z H,WU Z S,et al.Shear behavior of basalt fiber reinforced polymer(FRP)and hybrid FRP rods as shear resistance members[J].Construction and Building Materials,2014,73:781-789.
[25]SHI J Z,WANG X,WU Z S,et al.Effects of radial stress at anchor zone on tensile properties of basalt fiber-reinforced polymer tendons[J].Journal of Reinforced Plastics and Composites,2015,34(23):1937-1949.