【作者】 文立阁；

【导师】 程永春；

【作者基本信息】 吉林大学 ， 工程力学， 2004， 硕士

【摘要】 随着国民经济的发展，对交通运输能力要求不断提高，原来设计标准较低的桥梁，或者达到服役期限的桥梁，已严重影响了交通运输的发展。提高公路技术标准后, 由于桥梁设计荷载的提高和宽度的增加, 使原有桥梁要么加固、要么重建, 工程量甚为巨大。鉴于投资、材料和工期的缘故, 不可能拆除全部旧桥进行重建, 而采取投资较少、节省材料、工期短的补修和加固措施是解决以上问题的有效方法之一。碳纤维加固技术是二十世纪八十年代开始在国际上研究应用的一种混凝土结构外部补强加固新技术，其应用形式主要是片材和层压板。该项技术最早应用于修复日本阪神地震和美国洛杉机地震等造成的损坏工程，此后美日欧大力研发此项技术，并开始应用于桥梁加固。我国自1997年开始对碳纤维加固混凝土等结构进行研究, 并已在一些工程中得到应用, 但相关技术标准、应用规程及施工指南在国内仍不完善。该方法采用同一方向排列的碳纤维织物, 在常温下用环氧树脂胶粘贴于混凝土结构、钢筋混凝土结构、砌体结构或木结构表面, 利用其紧密粘着于混凝土结构表面, 使二者作为一个新的整体, 共同受力, 从而达到对结构加固补强及改善受力性能的目的, 由于我国地域广泛，南北的地理、温差较大，还没有形成一套统一的有关碳纤维加固桥梁的技术规程，就目前研究方法来看，主要是按结构设计原理的基本思想：把碳纤维折合成受拉钢筋面积，进行计算极限载荷；破坏形式混凝土被压碎,达到极限压应变,通过平面假定,计算碳纤维拉应变,再进行计算极限载荷；通过平面假定，应变协调关系，按设计原理进行计算极限载荷。但并未有在粘贴方式，粘贴的部位纤维层数的变化，宽度的变化，对梁包裹高度等几个方面进行试验和理论分析，以及胶层剪切应力的分<WP=70>布等，只有充分考虑以上方面才能使纤维的力学性能得以充分发挥，本文将在以往的研究基础上，从这几个方面进行了研究工作。在理论计算方面：按照结构设计原理有关理论，把碳纤维视作受拉钢筋，进行了极限载荷计算，运用计算公式（2-25）和（2-26）进行计算，结果列于表2-2、表2-3。本文主要从事的是试验研究，在阅读了大量文献后，设计并制作钢筋混凝土梁，购买碳纤维、粘贴剂等材料。根据所设计的混凝土梁，分别进行理论极限承载能力预测，和有关试验。在试验方面，首先进行了碳纤维与混凝土的粘贴强度的试验，其次进行了不同粘贴方式后，对梁的纯弯曲试验，具体工作如下：简单轴向拉伸试验测定碳纤维粘贴混凝土上的粘贴强度：为了有效测量出二者的粘贴强度，加工了拉伸试件，如图3-1所示，用环氧树脂胶系列把碳纤维布粘贴在混凝土两侧表面上，沿拉伸方向在碳纤维表面上粘贴应变片。试验现象表现为：在荷载作用下，中间出现裂缝后，依靠两侧的碳纤维承担载荷，直至碳纤维剥离，按试验后测量出的应变值计算出粘贴强度，列于表3-8。并测量出沿碳纤维拉伸方向应变分布规律，如图3-6、图3-7。梁底部粘贴包裹式碳纤维的弯曲试验：对梁进行纯弯曲试验。本组试验采用4根梁，1根不粘贴碳纤维的对比梁，1根只在底部受拉区粘贴与梁等宽的碳纤维，另两根两侧碳纤维包裹过来，分别是一层和两层,测量混凝土梁中截面沿高度的应变、碳纤维表面沿长度方向的应变。观测破坏方式，测量屈服载荷、极限载荷、跨中挠度。分别列于表4-8、表4-9。并与试验结果比较，列表于4-11，通过试验结果表明：极限载荷计算值比试验值小。 <WP=71>通过测量中截面应变沿高度的分布规律来看，加固后的梁不再完全符合平截面假设条件。无包裹变厚度粘贴方式试验：如何在梁下部粘贴纤维，才能既达到加固效果又节省资金，这也是个重要问题，因此采用了一层、一层半、二层。观测破坏方式，测量屈服载荷、极限载荷、跨中挠度。分别列于表4-14、表4-15。综上所述，试验过程中所使用的设备在功能和精度等方面均满足工作的要求，所设计和加工的试件均符合相关标准，试验结果对工程实际应用具有参考价值。粘贴二层比粘贴一层半碳纤维试验梁的屈服载荷提高较小,说明合理布置碳纤维的粘贴位置及厚度的有效分布,可以提高加固效率,降低成本。从粘贴位置和方式比较，在试验梁上有一层包裹粘贴碳纤维，再以跨中为中心无包裹粘贴一层半碳纤维的加固方式更为合理，且充分发挥碳纤维的性能，达到安全、经济的效果。理论计算的极限承载能力低于对应的试验值，该理论应用于碳纤维加固梁的计算，已不完全适用，有待于建立更合理的计算模型。更多还原

【Abstract】 With the economic development of all the nations, the ability of traffic transportation has been required to improve. The overdue bridges with lower designing standard have influenced the development of transportation. Owing to the improvement of designing standard and the increase of width and load of the roads, the original bridges are required to be consolidated or rebuilt, therefore the amount of work is very large. Because of the investment, materials and project time, it is impossible to demolish all the old bridges and rebuild them; so one of effective methods to solve the problems above is to adopt the measure of less investment, saving material and shorter project time. The technology of reinforcing carbon fiber began in 1980s. It is a new technology that studies how to use a kind of concrete to consolidate the external structure of the roads. Its applied form is mainly sheet and laminating board. The technology was applied to repair the damage of the earthquake of Hanshin in Japan and Los Angeles in America firstly, henceforth it is developed actively in America、Japan and Europe and applied to reinforced bridges. In 1997, the study of the Carbon fiber reinforced concrete structure began in our country, and has been applied to some projects, but the related technical standard, application rules and construction guide are not perfect.This method adopts the fabric of carbon fiber with the same one side, under normal temperature, with the glue of epoxy resin paste it on the surface of concrete structural, structure of reinforced concrete, build structural and timber structure, and make both be a new whole to load together through pasting it on the concrete structure face. Thereby reach for the purpose of the structure being consolidated and improve the mechanics performance of structure. Owing to the region of my country is extensive, differences in temperature and the geography of south to north are greater, So do not yet form a set of relevant unification technical rules of carbon fiber to consolidate bridge, At the present time, the basic thought of design according to principle of structural design mainly. <WP=73>To calculate ultimate load through converting carbon fiber area into the reinforcing bar area；The destruction forms: concrete is crushed and reaches ultimate press strain. To calculate the tensile strain of carbon fiber through plane assumption to calculate ultimate load；Through plane assumption and strain coordinative relation calculate ultimate load according to principle of structural design.But there is not experiment and academic analysis about the way of pasting, the change of carbon fiber number of layers at pasting location, the change of width, the change of wrap altitude and the distribution of shear stress of the sticky layer. None but those facts are ample considered we can make the mechanics performance of fiber play fully with top surface, this paper will carry out research work on the foundation of the former research from those aspects. Aspect of theoretical and calculation:According to the relevant theory about principle of structural design regard carbon fiber as pull reinforcing bar, we calculate the ultimate load using formula (2-25), (2-26) calculate, as a result list in table 2-2, table 2-3. In this paper we mainly works on experiment research, after reading large numbers of articles we design and make the beam of reinforced concrete, purchase the material of carbon fiber and so on.According to the design beam to forecast the ultimate capability of the beam and some experiments.On experiment, first carry out the pasting strength experiment of carbon fiber and concrete; second carry out the experiment with different way of pasting. The specific work of the flexural experiment of beam is as follow:Menstruate the pasting strength of carbon fiber and concrete through the simple Axial stretch experiment:In order to measure effectively the pasting strength of carbon fiber and concrete , we machined the stretch specimen, Figure 3-1，Which shows that carbon fiber更多还原