碳纤维拉索及其锚固系统横向受力性能试验研究

发布时间：2018-04-12 12:06

本文选题：CFRP + RPC　；参考：《湖南大学》2015年硕士论文

【摘要】：传统斜拉桥斜拉索及悬索桥吊杆体系一般采用钢绞线或平行钢丝束,随着桥梁跨度的不断增大,拉索或吊杆普遍面临着钢材锈蚀导致的结构耐久性问题和由于钢材材料重度大导致的桥梁结构本身自重产生的应力占承重体系容许应力随着跨度增大呈平方增长、施工工程量大等问题。此外钢材拉索或吊杆建成以后的维护和更换造价高,对现有交通产生较严重影响,这就要求大跨桥梁所使用的材料必须具有超高性能及良好耐久性,以保证处于恶劣环境工作的大跨桥梁拉索或吊杆体系在长期荷载作用下的稳定性和耐久性。碳纤维增强复合材料CFRP(Carbon Fiber Reinforced Polymer/Plastic)以其强度高、重量轻和免锈蚀等优异性能极有希望成为大跨桥梁钢拉索或吊杆的替代品,RPC(Reactive Powder concrete)以其具有的超高抗压强度、高耐久性及高韧性等优良性能极有希望成为拉索或吊杆体系粘结式锚具中传统水泥砂浆等粘结介质的替代品。本文结合国家自然科学基金项目-CFRP拉索及其锚固系统的抗冲击性能研究(NO:51478177),对两端采用以RPC为粘结介质的粘结式锚具的CFRP拉索的横向受力特点进行了试验研究,主要内容包括:(1)对两端采用粘结式锚具的CFRP拉索试件进行纵向静力拉拔和横向静力试验,研究内容包括试件在纵向静力作用下的破坏形式、极限荷载、锚具内应变分布特征及荷载滑移曲线,横向静力荷载作用下的破坏形式、极限横向荷载、最大横向位移、横向荷载-位移曲线、极限状态下锚具内粘结应力分布特征及荷载滑移曲线试验结果表明:在横向静力加载试验中锚具临界锚固长度小于150mm,初张力的施加有利于CFRP拉索的横向受力性能。(2)利用湖南大学高性能落锤冲击试验机,对两端带粘结式锚具的CFRP拉索试件进行横向低速冲击试验研究,主要研究了为碳纤维拉索及其锚固系统在横向冲击荷载作用下的筋材及其锚固系统的破坏形态,横向冲击荷载—位移曲线,极限索力及索力增量,滑移特点,探讨了不同锚固长度、不同冲击能量及防护等参数对试件抗冲击性能的影响,分析了CFRP棒材在冲击荷载作用下的吸能能力。试验结果表明:冲击能量增大50%,横向剪断角增加0.2?;承受初始冲击荷载作用试件的初始滑移阀值仅为45.92k N-50.56k N;横向冲击荷载作用下的CFRP拉索的临界锚固长度小于150mm。(3)在CFRP拉索横向静动力试验结果的基础上,对两种不同荷载作用下试件的破坏模式,极限横向荷载,极限纵向索力及索力增量,滑移特点等展开对比分析。
[Abstract]:Traditional cable-stayed bridge cable and suspension bridge suspension system generally use steel strand or parallel steel wire bundle, with the continuous increase of the span of the bridge,Cable or suspension generally faces the durability problem caused by steel corrosion and the stress caused by self-weight of bridge structure due to heavy steel material. The allowable stress of load-bearing system increases square with the increase of span.Large amount of construction projects and other problems.In addition, the high cost of maintenance and replacement of steel cables or suspenders after they have been completed has a serious impact on the existing traffic, which requires that the materials used in long-span bridges must have super-high performance and good durability.In order to ensure the stability and durability of long span bridge cable or suspension system under long term load.Carbon fiber reinforced composites (CFRP(Carbon Fiber Reinforced Polymer / Plastics), with excellent properties such as high strength, light weight and rust-free, are expected to be a substitute for steel cables or suspenders for long-span bridges.The excellent properties such as high durability and high toughness are expected to be a substitute for the traditional cement mortar in the bond anchors of cable or suspension system.In this paper, based on the research on the impact resistance of -CFRP cable and its anchoring system under the National Natural Science Foundation project, no: 51478177, the transverse force characteristics of CFRP cable with bonded anchor with RPC as bonding medium at both ends are studied experimentally.The main contents include: (1) Longitudinal static drawing and transverse static test of CFRP cable specimens with bonded anchors at both ends. The research contents include the failure form and ultimate load of the specimens under longitudinal static force.The characteristics of strain distribution and load-slip curve in Anchorage, failure form under transverse static load, ultimate transverse load, maximum transverse displacement, transverse load-displacement curve,The experimental results of bond stress distribution and load-slip curve in the ultimate state show that the critical Anchorage length is less than 150mm in the transverse static loading test, and the initial tension is favorable to the transverse behavior of the CFRP cable.Using the high performance drop hammer impact testing machine of Hunan University,The transverse low speed impact test of CFRP cable specimens with bonded anchors at both ends is carried out. The failure patterns of steel bars and anchoring systems for carbon fiber cables and their anchoring systems under transverse impact loads are mainly studied.The transverse impact load-displacement curve, ultimate cable force and cable force increment, slip characteristics are discussed. The effects of different anchoring lengths, different impact energy and protection on the impact resistance of the specimens are discussed.The energy absorption capacity of CFRP bar under impact load is analyzed.The experimental results show that the impact energy increases by 50 and the transverse shear angle increases by 0.2, the initial slip threshold of the specimen subjected to initial impact load is only 45.92k N-50.56kN, and the critical anchoring length of CFRP cable under transverse impact load is less than 150mm.Based on the results of lateral static and dynamic tests for CFRP cables,The failure mode, ultimate transverse load, ultimate longitudinal cable force and the increment of cable force, and the characteristics of slip of the specimen under two different loads are compared and analyzed.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446.1

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