【作者】 刘华新；

【导师】 王清湘；

【作者基本信息】 大连理工大学 ， 结构工程， 2010， 博士

【摘要】 碳纤维增强复合材料(CFRP)和玻璃纤维增强复合材料(GFRP)加固修复混凝土结构技术在国内外得到迅速的发展,FRP具有高强、轻质、耐腐蚀、耐疲劳、施工便利、不增加构件尺寸等优点,因此,在混凝土加固工程中得到大量的应用。然而,国内外现有的资料大部分是关于纤维增强复合材料约束混凝土圆柱体性能研究,对于纤维增强复合材料约束混凝土棱柱体受力性能研究相对较少。应用改进稳健设计方法分析影响FRP约束混凝土的几个基本因素,同时通过试验结果加以比较分析指导试验设计。通过16组纤维增强复合材料约束混凝土棱柱体试件的轴心受压试验,研究纤维增强复合材料约束混凝土棱柱体的受力性能,得出应力-应变本构关系曲线；分析纤维增强复合材料用量、粘贴方式、纤维布条带宽度和间距等不同试验参数对约束效果的影响。试验结果表明：不同形式纤维增强复合材料约束混凝土棱柱体的承载力都有一定程度的提高,延性增大,破坏过程与没包裹纤维布的试件相比缓慢。粘贴1-3层碳纤维增强复合材料约束混凝土棱柱体试件,其峰值应力比未约束混凝土棱柱体试件分别提高了15.1%、35.3%、58.3%,不同条带宽度约束的试件抗压强度提高最大的是条带宽度为60mm的试件为13.6%。粘贴1-3层玻璃纤维增强复合材料约束混凝土棱柱体试件,其峰值应力比未约束混凝土棱柱体试件分别提高了14.3%、25.0%、25.9%,不同条带宽度约束的试件抗压强度提高最大的是条带宽度为40mm的试件为14.6%。根据试验结果,推导验证纤维增强复合材料约束混凝土棱柱体的应力-应变模型及参数。对于纤维约束混凝土棱柱体,应力-应变曲线过了峰值应力后,会由于纤维的不同用量而可能出现三种发展趋势：应力缓慢上升、基本保持不变、缓慢下降。纤维约束混凝土棱柱体的应力-应变曲线主要分三个阶段：第一阶段,弹性变形阶段,当轴向压力很小时,应力-应变曲线和普通混凝土的应力-应变曲线基本一样；第二阶段,当轴向压力不断增大,超过未约束混凝土的抗压强度时,棱柱体横向变形加大,纤维的应变发展进一步加快,纤维处于未约束混凝土到约束混凝土的过渡阶段；最后,整个试件随着荷载的继续增加,横向变形不断增大,直至纤维被拉断,试件被压坏。由于纤维增强复合材料与混凝土的温度线膨胀系数的不同,由于温差的作用,在纤维增强复合材料约束混凝土结构中将产生温度应力。应用ANSYS软件分别对在降温温差30℃、40℃、50℃、60℃作用下的碳纤维增强复合材料约束混凝土棱柱体进行了温度应力分析。分析结果表明随着温差的增大,温度应力也随之增大,当降温温差60℃时,最大温度应力达到184Mpa,碳纤维增强复合材料的最大压应力达到-211Mpa。对玻璃纤维和碳纤维增强复合材料约束混凝土进行简单的性价比数据分析比较,阐述了玻璃纤维增强复合材料在我国现阶段应用的实际意义和经济适用性,对无特殊要求的结构修复加固应优先考虑采用玻璃纤维增强复合材料。更多还原

【Abstract】 The technology of CFRP (Carbon Fiber Reinforced Plastic) and GFRP (Glass Fiber Reinforced Plastic)confining concrete structure has been rapidly developed at home and abroad, it has received significant attentions in civil engineering due to their unique properties, such as high strength-to-weight radio, good resistance to corrosion and fatigue, convenient to construction and no additional dimension. However, most information available in our country is on the study of FRP confining concrete cylinder properties, little information on the properties of FRP confining concrete prism is available.The improved robust design method is applied to analyze several important factors of concrete by FRP.the purpose is used base in following test and design.Study the properties of FRP confining concrete column through sixteen groups columns subjected to axial loading, and receive the stress-strain curves; various design parameters, such as amounts of FRP sheets, width of straps and spacing of straps, have been considered. The results are:The axial compressive strength and ductility of concrete prism wrapped by CFRP sheets or CFRP straps have all increased to a certain degree, the process of destruction of concrete prism wrapped by CFRP become slower than common concrete prism. For fully wrapped concrete prism, the axial compressive strength increased 15.1%,35.3%,58.3%, respectively. For separately wrapped concrete prism, the largest increased axial compressive strength is the specimen wrapped by the width of 60 millimeters CRFP straps, is 13.6%. The results are:The axial compressive strength and ductility of concrete prism wrapped by GFRP sheets or GFRP straps have all increased to a certain degree, the process of destruction of concrete prism wrapped by GFRP become slower than common concrete prism. For fully wrapped concrete prism, the axial compressive strength increased 14.3%, 25.0%,25.9%, respectively. For separately wrapped concrete prism, the largest increased axial compressive strength is the specimen wrapped by the width of 40 millimeters GRFP straps, is 14.6%.Based on the test results, deducing and validating the stress-strain relationship model of FRP confined concrete. The results are:For concrete prism wrapped by FRP sheets, after the stress exceeds the peak stress, the stress may ascend slowly with adequate confinement, or it may be almost unchanged with moderate confinement, or it may descend slowly with deficient confinement. The experimental stress-strain diagram has three different stages. Firstly, the initial portion of the stress-strain response of confined concrete follows the path of unconfined concrete. Secondly, after exceeding the unconfined strengthen of concrete, the curve starts to form a transition zone. Finally, the FRP sheets are fully activated and the confining stress provided by the FRP sheets continues to increase with the applied load until failure.Because the temperature-swelling coefficient is different between FRP and concrete, temperature stress is produced when the temperature changes. The temperature stress is emulated by the ANSYS finite element program under the difference temperature of 30℃, 40℃,50℃,60℃. As the difference temperature increases, the temperature stresses increase. Under the difference temperature of 60℃, the largest temperature stress is 184Mpa, the largest compressive stress in CFRP sheets is-211Mpa.Through date to make cost-effectiveness compare GFRP and CFRP, exposition the application of GFRP practical significance and economic applicability on our country in the morden, no special requirements on confining concrete structure, GFRP should be given priority.更多还原