【作者】 黄华；

【导师】 刘伯权；

【作者基本信息】 长安大学 ， 结构工程， 2008， 博士

【摘要】 高强钢绞线网-聚合物砂浆加固技术作为一种新型的加固方法,在工程界的运用正逐步兴起。对该加固技术的加固机理和设计方法进行研究是该技术推广运用的前提和基础。本文围绕河北沧州东关大桥加固工程,经过一系列试验研究,深入分析了高强钢绞线网-聚合物砂浆加固层与混凝土界面之间的粘结破坏机理、高强钢绞线网-聚合物砂浆加固钢筋混凝土梁的抗弯和抗剪性能;确立了从承载力计算、界限配筋率、到剥离强度验算的加固梁计算体系;并通过东关大桥加固前后的静载试验和动力性能分析,验证了计算体系和加固效果。取得的主要成果有以下几个方面。1、通过243个测点的正拉粘结强度试验、24个测点的剪切粘结强度试验、9个界面剥离破坏试验,分析了聚合物砂浆与混凝土之间的粘结性能及影响因素。研究认为抹灰龄期、界面粗糙度、混凝土和砂浆强度、修补方位等是影响粘结性能的主要因素,其显著性水平按此顺序由高到低排列;此外,加固层长度对剥离强度的影响非常显著,存在有效锚固长度的限制;结合试验数据提出了粘结面正拉强度模型、剪切强度模型、加固层剥离强度模型;结合有限元分析,提出并验证了加固层粘结-滑移本构关系;分析了加固层各材料之间的粘结锚固性能,提出高强钢绞线与聚合物砂浆之间的粘结强度计算模型和锚固长度计算公式;最后结合试验提出加固施工中的注意事项。2、依据高强钢绞线网-聚合物砂浆加固钢筋混凝土梁试验研究以及加固材料与混凝土之间的粘结性能试验研究,分析了高强钢绞线网-聚合物砂浆加固钢筋混凝土梁破坏模式,着重对加固层界面剥离破坏受力机理进行了深入研究。从加固界面“粘结破坏区”出发,引出“粘结破坏层”概念,建立基于“粘结破坏层”的抗弯构件端部剥离破坏剪应力和正应力的解析解,提出端部剥离破坏准则以及端部剥离承载力简化计算公式;分析了抗弯加固梁中部剥离破坏机理,建立基于“粘结破坏层”的抗弯加固梁中部剥离破坏承载力计算公式,并建立了相关破坏准则;从“粘结破坏层”角度出发,分析了抗剪加固剥离破坏受力机理,基于抗剪加固试验研究和数值分析结果,建立了剥离承载力计算公式。3、依据本文5根6.6m跨的T形梁抗弯加固试验及其14根梁的抗弯加固数值试验、9根2.5m跨的矩形梁抗剪加固试验及其12根梁的抗剪加固数值试验,分析了混凝土强度、原梁配筋率、原梁配箍率、高强钢绞线用量、二次受力、剪跨比、加固方式等因素对高强钢绞线网-聚合物砂浆加固钢筋混凝土梁受力性能的影响;结合粘结强度和剥离破坏的研究,提出了加固梁抗弯、抗剪承载力计算公式、考虑和不考虑剪切变形影响下的挠度计算公式、最大弯曲裂缝和斜裂缝宽度计算公式、高强钢绞线界限用量计算公式。最终确立了较为完善的加固梁计算体系,并且所有计算结果与相关试验数据吻合良好。4、为考察高强钢绞线网-聚合物砂浆加固东关大桥的受力性能,本文进行了东关大桥加固前后的车辆静载试验;在此基础上,根据已有的交通调查,建立模型车辆库,编制桥梁荷载谱程序VLS,实现了随机车辆荷载谱的构造及有限元程序的加载,为桥梁结构在随机车辆荷载谱作用下的动力分析、疲劳分析提供了一种可行的方法;并利用该方法分析了车辆荷载谱作用下桥梁加固前后的动力性能。结论进一步表明加固梁计算体系是可行的;动力作用下最不利荷载为密集运营状态下的二车道同向偏载作用,该荷载作用下加固桥梁完全满足承载能力的要求;桥梁横向振动普遍较小,中小跨径公路钢筋混凝土桥梁的横向振动可以忽略不计,并且车流方向对桥梁振动的影响不大;与加固前对应状态相比,加固使桥梁最大挠度减小14.97%,一阶频率提高6.94%,桥梁整体刚度和承载力获得较大幅度提高,加固效果明显;与静载试验相比,最不利荷载作用下桥梁动挠度要小于汽车-超20级静载作用下的挠度,加固后的东关大桥能够达到汽车-超20级荷载的要求。更多还原

【Abstract】 A new strengthening technology with high strength stainless steel wire mesh and permeability polymer mortar has been gradually used in the domain to reinforce concrete in recent years. This dissertation regards Dongguan Bridge as engineering background and focuses on the systemic experiments and theoretical analysis on behavior of strengthened RC structures with high strength stainless steel wire mesh and permeability polymer mortar. The main research contents and achievements can be summed up in the following aspects.1. Based on the test of 243 axial tensile adhesive strengths, 24 shear adhesive strengths, and 9 debonding strengths, the bond behavior between polymer mortar and concrete was studied and its influencing factors were analyzed. The main influencing factors include four aspects. The first is plastering age, the second is interface roughness, the next is the strength of concrete and mortar, the last is position of the repaired interface. Their significance level from high to low arranges according to this order. Furthermore, there is an effective length of reinforcing layer, which is extremely remarkable to the bond strength. At the same time, axial tensile adhesive strength models, shear adhesive strength models, bond strength models are proposed. Combined finite element analysis, the bond-slip models are proposed and validated. The bonding anchorage performance of stainless steel wire mesh and polymer mortar was also analyzed, and their bond strength models and the anchorage length models are proposed. At last, the points for attention in reinforcement construction were given.2. Based on the experimental study on strengthening performance of beams with high strength stainless steel wire mesh and permeability polymer mortar and on bond behavior between polymer mortar and concrete, the failure models of strengthened beams were analyzed. The debonding failure mechanism of the reinforcing plate is principally explored. In view of the debonding failure zone, the concept of debonding failure plate is educed. Based on the debonding failure plate, the analytic solutions of shear stress and normal stress are deduced, which is at the end of reinforcing plate of flexural member, and its failure criterions are also proposed. The simplified formulae of debonding strength are deduced at the end of reinforcing plate. Based on the debonding failure plate, the formulae of debonding strength and its failure criterions are also deduced, which failed because of the mid-span bending cracks. At the same time, based on the shear behavior of strengthened beams and finite element analysis, the formulae of shear debonding strength are proposed.3. Based on the experimental study on 14 beams and the finite element analysis on 26 beams, which were strengthened with high strength stainless steel wire mesh and permeability polymer mortar, the influencing factors of reinforcing performance were analyzed, such as concrete strength, reinforcement ratio of the old members, stirrup ratio of the old members, secondary loading, shear span ratio, strengthening modes, the amount of stainless steel wire mesh. Combined the study on bond mechanism and debonding failure, the design formulae of flexural load-carrying capacity, shear load-carrying capacity,flexural stiffness, shear stiffness, maximum crack width, maximum diagonal crack width and the maximal ratio of reinforcement are proposed. And now, the calculation system of strengthened RC beams is founded. Furthermore, the calculation results are in good agreement with the interrelated tests.4. In order to know the strengthening performance of Dongguan Bridge with high strength stainless steel wire mesh and permeability polymer mortar, this dissertation focuses on the static load tests before and after the installation of the strengthening system. Making use of others traffic investigation, the program of VLS, vehicle load spectrum, is written, and stochastic vehicle load spectrums in different traffic conditions are constructed. By using ANSYS, a familiar finite element program, the bridge’s space dynamic response under stochastic vehicle load spectrums is analyzed, which provides a method for analyzing dynamic performance and fatigue performance of highway bridges under stochastic vehicle load spectrums. The results farther show that the calculation system is correct and the strengthened bridge has good dynamic performance and static performance. Under dynamic loads, the most dangerous load is two-lane non-symmetric vehicle load spectrum in uniform direction. The transverse vibration of the medium and small span highway RC bridges is weak, and train flow direction has a weak effect to the bridge’s vibration. Because of strengthening, the bridge’s maximum displacement reduces 14.97%, and its fundamental frequency increases 6.94%. The whole bridge’s stiffness and its carrying capacity are greatly improved, and the strengthening effect is significant. The bridge’s dynamic deflection under vehicle load spectrum is less than its static deflection under the load of China specification of HS-20.更多还原