港口工程高桩码头结构性能退化研究

发布时间：2018-07-23 19:18

【摘要】：处于严酷海洋环境中的港口工程结构,直接或间接都受到波浪、风、水流还有氯盐侵蚀作用,结构性能退化问题尤为严重。开展港口工程高桩码头结构性能退化的研究,掌握其退化规律,对结构性能从定性到定量的分析,不仅与结构的安全性密切相关,而且有助于已有结构的性能评定,选择正确的结构修复处理方法和定期维护方案,确保结构的正常工作,具有重要的现实意义和经济价值。首先,本文开展了典型港口工程钢筋混凝土结构性能退化状况的现场调研,对其影响因素进行了总结和分析,进行了海洋环境下高桩码头结构性能退化主要影响因素识别。确定了在结构型式上,高桩梁板式码头结构为主要研究对象,在退化形式上,钢筋锈蚀引起的构件安全性和适用性退化、氯离子侵蚀引起的耐久性退化和桩基水平承载性能引起的整体结构性能退化为高桩码头结构的主要退化形式,为进一步研究高桩结构性能退化规律提供了依据和方向。其次,开展了不同应力状态下不同锈蚀程度的钢筋混凝土梁电解液加速腐蚀试验,研究了持续应力状态下钢筋锈蚀对混凝土构件的影响,并开展了锈蚀钢筋混凝土构件的结构力学性能试验,对不同锈蚀率的试验梁的破坏形态、裂缝开展状况、截面应变等进行了测试和分析。建立了不均匀锈蚀情况下,基于锈胀裂缝宽度并考虑相邻测点相互影响的钢筋最大锈蚀率计算模型,将外观可视、易测的锈胀裂缝宽度与钢筋锈蚀率定量地联系起来,可以实现从外观检测到结构性能退化预测的定量计算。给出了基于钢筋锈蚀率的钢筋混凝土梁抗弯承载力、抗弯刚度和构件延性退化计算方法,并提出了锈蚀率梁危险截面位置预测和结构性能退化评估流程,为港口工程高桩码头结构提供更加科学合理的设计和维护依据。再次,选取高桩码头中广泛使用的后张法预应力混凝土大直径管桩和先张法预应力高强混凝土管桩作为基础结构代表研究其耐久性的退化规律。通过开展室内试验研究桩基础的混凝土本体的耐久性,获得耐久性退化的初始边界条件;通过对服役1~17年的大管桩和PHC管桩的现场调研和桩身钻孔取样,结合室内化学试验,测试分析了不同取样深度下桩身混凝土的氯离子含量,得到了不同环境和服役时间对管桩氯离子扩散系数和腐蚀参数等耐久性指标的影响,在大量现场取样数据统计分析的基础上,建立了大管桩和PHC管桩耐久性退化模型。最后,在大量高桩码头桩基试桩资料的基础上,分析了大位移情况下桩基水平受力过程中桩身的刚度退化和桩周土体抗力退化规律,拟合确定了适合于不同土质条件的土体抗力系数与桩基在泥面处水平位移的指数退化关系,为在不同水平荷载作用下合理选取土体抗力系数供了可靠的理论计算依据。本文研究成果丰富和完善了港口工程高桩码头结构性能退化的内容和方法,也为港口工程结构全寿命设计从理论研究推进到应用方法研究奠定了基础,同时也可为港口工程结构提供设计、施工、检测和维护方法等方面的指导。
[Abstract]:The port engineering structure in the harsh marine environment is directly or indirectly affected by the erosion of waves, wind, water and chlorine, and the degradation of structure and performance is particularly serious. It is closely related to the property, and helps to evaluate the performance of the existing structures, select the correct structural repair methods and regular maintenance schemes, and ensure the normal work of the structure. It is of great practical significance and economic value. First, the field investigation of the performance degradation of the reinforced concrete structure in the typical port engineering is carried out in this paper. The factors are summarized and analyzed, and the main factors that affect the structural performance degradation of High Pile Wharf under marine environment are identified. In the structure type, the structure of the high pile beam and plate wharf is the main research object. In the degenerate form, the safety and applicability of the member caused by the corrosion of the steel bar and the durability of the chloride ion erosion caused by the corrosion of the steel. The overall structural performance caused by the horizontal bearing performance of the pile and the pile foundation is degenerated to the main degenerate form of the high pile wharf structure, which provides the basis and direction for further research on the law of the performance degradation of high pile structures. Secondly, the accelerated corrosion test of the electrolyte of reinforced concrete beams with different corrosion degrees in different stress states is carried out, and the continuation of the corrosion test is carried out. The effect of steel corrosion on the concrete members under stress state, and the structural mechanical properties test of corroded reinforced concrete members are carried out. The failure forms of the test beams with different corrosion rates, the conditions of crack development, and the strain of the cross section are tested and analyzed. The width of the crack expansion cracks is established and the phase is considered under the condition of uneven corrosion. The calculation model of the maximum corrosion rate of steel bar affected by adjacent sites, which can be seen in appearance, is connected with the corrosion rate of the steel bar, and the quantitative calculation of the prediction of structural performance degradation from appearance detection can be realized. The bending bearing capacity, flexural rigidity and components of steel reinforced concrete beams based on the corrosion rate of steel bars are given. In order to provide more scientific and reasonable design and maintenance basis for the structure of the port engineering high pile wharf, the post tensioned post tensioned concrete large diameter pipe pile and the pretensioned prestressing force are selected. The strong concrete pipe pile as the foundation structure represents the degradation law of its durability. Through the indoor test, the durability of the concrete body of the pile foundation is studied, and the initial boundary conditions for the durability degradation are obtained. Through the field investigation of the large pipe pile and the PHC pipe pile in the service 1~17 years, the sampling of the pile bore hole and the indoor chemical test, The chlorine ion content of pile concrete under different sampling depth was tested and analyzed. The effect of different environment and service time on the durability index of chloride diffusion coefficient and corrosion parameter of pipe pile was obtained. On the basis of a large number of field sampling data, the durability degradation model of large pipe pile and PHC pipe pile was established. On the basis of pile foundation pile test data of high pile wharf, the stiffness degradation of pile body and the law of soil resistance degradation in pile foundation under large displacement are analyzed. The relationship between soil resistance coefficient and horizontal displacement of pile foundation at the mud surface is determined by fitting for different soil conditions. The results of this study enrich and improve the content and method of the structural performance degradation of the port engineering high pile wharf. It also lays a foundation for the whole life design of the port engineering structure from the theoretical research to the application method, and can also be a port engineering structure. Provide guidance on design, construction, testing and maintenance methods.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U656.113

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