【作者】 闫昕；

【导师】 李惠；

【作者基本信息】 哈尔滨工业大学 ， 防灾减灾工程及防护工程， 2010， 博士

【摘要】 桥梁结构的耐久性损伤是当前世界范围内所面临的一大问题,严重威胁着桥梁的安全运营与使用寿命。纤维复合材料(Fiber reinforced polymer,简称FRP)是一种新型材料,FRP与混凝土复合组成的组合结构可以有效地解决桥梁结构的长期耐久性问题。本文以FRP管约束混凝土为研究对象,并首次提出FRP-钢复合管约束混凝土,系统地研究了它们的轴压力学性能、耐久性性能和抗震性能。同时,采用光纤光栅应变传感器预埋技术,使上述结构具有损伤自监测性能,并建立了基于监测信息的结构损伤评价方法。本文的主要研究内容包括:首先,针对FRP管约束混凝土轴压延性较差的缺点,本文首次提出了FRP-钢复合管约束混凝土。试验研究了FRP管/FRP-钢复合管约束混凝土的轴压力学性能,对影响FRP管结构性能的纤维缠绕方式、局部加强纤维管等进行了研究。提出了评价FRP管/FRP-钢复合管约束混凝土的轴压延性系数计算方法,并对其延性进行了分析。利用大量现有研究成果,回归分析得到了FRP管/FRP-钢复合管约束混凝土核心混凝土的受压本构关系模型下降段系数,并利用该模型较好地模拟了FRP管/FRP-钢复合管约束混凝土的轴压力学性能。其次,研究了FRP管/FRP-钢复合管约束混凝土的耐久性能。研究以对FRP管/FRP-钢复合管约束混凝土耐久性威胁最大的冻融循环为对象,对上述结构进行了56次冻融循环试验,同时量测了试验前后结构的轴压力学性能,对核心混凝土的相对动弹性模量进行了全程测试,并对试验前后试件表面的孔洞与缺陷进行了红外热成像分析。分析了结构的冻融耐久性损伤机理,并以菲克定律为基础模拟分析了溶液在FRP管内的扩散,计算了FRP管内的结冰压。试验研究了纤维混凝土的火灾爆裂性能,提出了FRP管约束混凝土火灾耐久性损伤评估与修复方法。第三,研究了FRP管/FRP-钢复合管约束混凝土的自监测性能。开发了具有自监测性能的FRP管/FRP-钢复合管约束混凝土的制备方法,分别研究了FRP管/FRP-钢复合管约束混凝土的力学性能损伤自监测性能和耐久性损伤自监测性能,提出了基于监测信息的力学性能损伤评价方法和耐久性损伤评价方法。最后,试验研究了FRP管/FRP-钢复合管约束混凝土的抗震性能,并与钢筋混凝土的抗震性能进行了比较分析;建立了适于抗震分析的FRP管/FRP-钢复合管约束混凝土的ABAQUS有限元模型,并利用该模型对上述结构的抗震性能进行了模拟分析。更多还原

【Abstract】 The durability damage of bridge is one of the most concerned problems in allover the world. It is a great threat to the safety and life of bridge. Fiber reinforced polymer (FRP) is a new material, and the composite structure composed by the FRP and concrete can effectively solve the long term durability of bridge. In this thesis, the concrete-filled FRP tube (CFFT) was studied, and the concrete-filled FRP-steel composite tube (CFST) was presented firstly. The compressive properties, durability and earthquake-resistance were studies. The FBG strain sensors were firstly pre-embedded in the FRP tube or the interface of the FRP-steel composite tube. It makes the structure have the ability of self-sensing. Then, the monitoring based damage assessment was presented.The main research in this thesis includes:First, the axial compressive properties of the CFFT were studied experimentally, including the winding mode of fibers and locally-strengthened FRP tube. To improve the axial ductility of CFFT, the concrete-filled FRP-steel composite tube (CFST) was presented firstly. The axial compressive properties of the CFST were studied experimentally. The axial ductility coefficients of the CFFT and CFST were presented, and the ductility of CFFT and CFST was analyzed. The descending coefficient of the compressive stress-strain relationship of the core concrete was analyzed in regression through a large of existing research results. A finite element model of CFFT and CFST was established and the compressive properties of the CFFT were modeled well through the model.Second, the durability of the CFFT and CFST was studied. 56 freeze-thaw cycles were conducted on those specimens. At the same time, the residual mechanical properties of the specimens after the freeze-thaw cycles, the relative dynamic modulus of elasticity of the core concrete with the freeze-thaw cycles, and the infrared thermography analysis on the pores and flaws on the surfaces of the specimens after the freeze-thaw cycles were studied. The damage mechanism of CFFT and CFST during the freeze-thaw cycles was analyzed. The diffusing of solution in the FRP tube was analyzed based on the Fick’s law. The icing pressures in the FRP tube were calculated. The spalling of fiber reinforced concrete was tested, and the assessment and repair of CFFT after fire was presented. Third, the self-sensing of the CFFT and CFST was studied. The preparation of the CFFT and CFST having the self-sensing was introduced. The self-sensing in mechanical properties and durability was studied. Based on the monitoring information, the damage assessment methods on mechanical properties and durability were presented respectively.At last, the earthquake resistance of the CFFT and CFST was studied experimentally, and then compared with the RC structure. The ABAQUS finite element model applicable to earthquake resistance analysis was established on the CFFT and CFST. In using the model, the earthquake resistance of the CFFT and CFST was modeled respectively.更多还原