【作者】 乔文靖；

【导师】 宋一凡；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2014， 博士

【摘要】 圬工拱桥采用复合拱圈加固后，能够提高加固结构的整体性、耐久性、强度、刚度和承载力，同时，这种加固方法因其施工方便、造价低廉等优点，在我国应用前景广阔。但是，就圬工拱桥加固理论而言，国内外就此开展的理论研究很少。因此研究复合拱圈加固圬工拱桥的加固技术，具有十分重要的理论意义和实际工程应用价值。本文以某实施复合拱圈技术加固的圬工拱桥为工程背景，采用理论分析、数值模拟及模型试验相结合的方法，研究了加固后的拱段。针对加固拱段的受力特点，系统研究了理论分析方法、承载能力、破坏形态、应力-应变曲线、复合拱圈统一偏心受压本构关系和加固后正截面极限承载力计算方法。最后，将所研究的主要内容应用于复合拱圈加固石拱桥的设计示例中，促进了研究成果在工程实践中的应用。主要研究成果如下：1、设计制作了9个典型的加固柱和2个未加固的对比柱，并进行阶段试验设计。制定完整试验计划，明确测试内容和试验目的，确定受压破坏的静力试验加载方案。上述工作是加固试验完成的前提条件，直接关系到整个试验的成败，为复合拱圈加固圬工拱桥提供分析基础和计算依据。2、在试验室2000kN千斤顶上进行了11个模型的试验，加载过程中，观察各试件的破坏过程，采集了各试件的承载力、荷载-应变曲线。对影响试件极限承载力的各种因素，包括受压区高度、原拱圈裂缝高度、加固层宽度和初应力一一作了分析。发现各试件在测试截面处的荷载-应变曲线的整体测试值与局部测试值基本接近，验证了试验数据的准确性。通过对试验数据分析，加载初期时砌体和混凝土复合拱圈截面应变分布情况不满足平截面假定，随着荷载的不断增大，复合拱圈截面应力重分布，砌体和混凝土层协调变形、共同受力，加载至0.9Pu时截面应变分布仍近似满足平截面假定。因此可近似认为复合拱圈截面的变形满足平截面假定。3、根据复合拱圈满足平截面假定的条件，基于4种常用的不同混凝土本构关系和1种常用的砌体本构关系，分别推导了4种复合材料的本构关系。将这4种复合材料本构关系应用于试件的有限元仿真模型中，比较有限元数值和实测数值，结果表明，采用混凝土Rüsch二次抛物线加水平直线模式推导出的复合材料本构关系的极限承载力有限元数值接近实测数值。以该复合材料本构关系模型为研究对象，分析应力-应变云图：发现理论破坏过程与实际破坏过程相近；对比理论荷载-应变数值和曲线与实际荷载-应变数值和曲线的，可以看出，砌体和混凝土偏压构件的荷载-应变曲线理论值和实际值能较好地吻合。说明混凝土采用Rüsch二次抛物线加水平直线模式推导出的复合材料本构关系还是比较符合实际情况的。从而，为复合拱圈加固圬工拱桥数值分析提供了准确的简化方法。4、考虑加固前原拱圈的初应力，砌体、混凝土和钢筋的本构关系，针对加固前圬工主拱圈是否出现横向裂缝，以混凝土肋式截面加固圬工拱桥为例，推导了复合拱圈加固圬工拱桥的正截面极限承载力计算公式。采用适于工程师使用的mapple软件，可以快速计算所求截面极限承载力。算例表明，公式计算值与试验实测值相比，误差在9%以内，为该推导公式在工程实际应用中提供可靠的理论支撑，说明本文所推导的公式还是比较符合工程实际应用。因为推导的公式对于大、小偏心受压构件均适合，所以该公式具有较高的适用性。5、基于平截面假定，复合材料本构关系和推导的复合拱圈加固圬工拱桥极限承载力公式，详细提出从截面设计到截面复核的加固设计流程。通过一个较为全面的复合拱圈加固圬工拱桥的设计示例，证明了本文推导的复合材料本构关系和极限承载力计算公式可以安全可靠的应用于复合拱圈加固圬工拱桥的正截面极限承载力计算中，把理论分析和工程实践完整的结合起来，促进了研究成果更好的推广应用于工程实践。综上所述，文中具有的创新点为：1、基于试验数据分析，验证了加固截面加载至破坏的平截面假定。加载初期由于砌体和混凝土的变形不同步，所以截面应变分布情况并不满足平截面假定。随着加载的不断增大，组合截面应力重分布，砌体和混凝土层协调变形、共同受力，加载至0.9Pu时截面应变分布近似满足平截面假定，因此可近似认为复合截面的变形满足平截面假定。2、根据复合拱圈满足平截面的假定条件，基于4种常用的不同混凝土本构关系和1种常用的砌体本构关系，分别推导了4种复合材料的本构关系。将这4种复合材料本构关系应用于试件的有限元仿真模型中，通过有限元数值与相应的模型试验实测数值的对比，分析得出混凝土采用Rüsch二次抛物线加水平直线模式的复合材料本构关系计算的承载力与实际试验值接近。将该复合材料的本构关系应用于工程实例的有限元分析中，在精简有限元模型和简化计算工作量同时，仍能准确地计算极限承载力。3、基于加固结构初应力和加固材料非线性，针对加固前圬工主拱圈是否出现横向裂缝，推导出的正截面极限承载力公式，并用试验进行验证。结果表明，公式计算值与试验实测值误差在9%以内，可以准确快速计算各截面极限承载力。再将该极限承载力公式应用于工程实例中，公式计算值与有限元计算值相近，说明推导公式能安全可靠应用于工程实践中。更多还原

【Abstract】 Masonry arch bridge reinforced by composite arch circle can increase the integrity,durability, strength, stiffness and bearing capacity of the reinforcment structure, meanwhile,this reinforcement method has the advantage of convenient construction and low cost, so ithas a broad application prospect in our country. However, for reinforcement theory of amasonry arch bridge, its theoretical study is seldom carried out so far both at home and abroad.So the study on this reinforcement technology as for masonry arch bridge is ofgreat theoretical significance and engineering applications’value.In the engineering background of a some masonry arch bridge reinforced by compositearch circle method, this paper gives a research on reinforced arch segment by combination oftheoretical analysis, numerical simulation and model test. According to the stresscharacteristics of a reinforced arch segment, the research is carried out for the theoreticalanalysis method, bearing capacity, failure mode, stress-strain curve, eccentric compressionconstitutive relation of composite arch circle and the formulas of reinforcement normalsection bearing capacity. Finally, main contents in our study are applied to a design exampleof masonry arch bridge reinforced by composite arch circle, which promotes the applicationof research results to engineering practice. The principal results are as follows:1. Nine typical reinforced columns and two columns without reinforcement have beendesigned, produced and carried out periodical experimental design. The complete test plan hasbeen made, the test content and test purpose has been definited, and the static test loadingscheme of uniaxial compressive failure has been determined. The above work is theprecondition of fulfilment of strengthening test, which is directly related to the success orfailure of whole experiment, and provides the analysis foundation and calculation for masonryarch bridge reinforced by composite arch circle.2. Eleven speciments has been tested by2000kN jack in the testing laboratory. Duringthe test, the failure process of specimens were observed, the bearing capacity and load-straincurves of these were collected. The analysis of various factors which have influence onultimate bearing capacity of specimens has been carried out, such as the depth of compression,the fracture height of original arch ring, the width of reinforcing layer and the initial stress. It has been found that the whole test values of the load-strain curves are almost close to thepartial test values at the test section of each specimens, thus the accuracy of experimental datais verified. According to measurement data, the analysis shows that the section’s straindistribution of masonry and concrete is failed to meet plane section assumption at an initialstages of loading. Along with increase of loading, the composite section stress will beredistributed, the masonry and concrete will be coordination deformed and costressing. Whenloading is up to0.9Pu, the strain distribution of section will be approximately to meet planesection assumption. Therefore, the deformation of a composite section is able to approximatlymeet plane section assumption.3. According to assumed conditions that a composite arch circle meets the plane sectionassumption, four kinds of the composite material constitutive relations are deducedrespectively by four different kinds of concrete’s constitutive relation and one kind ofmasonry’s constitutive relation. The four kinds of the composite material constitutive relationsare used for finite element simulation model of specimens, the finite element numerical andthe measured value are compaMPared, the result shows that the finite element numerical ofultimate bearing capacity is close to the measured value by using the composites materialconstitutive relations of the concrete Rüsch model of quadratic parabola plus horizontal line.The distribution of stress and strain are analyzed by taking that the composite materialconstitutive relations as a research object, it is found that theoretical failure process is close tothe practical failure process, numerical and curves of theoretical load-strain is derived, incompaMParison with numerical vale and curves of practical load-strain, we can see thattheoretical value by load-strain curves of masonry and concrete under eccentric compressionLoading agree with practical value. It shows that the composite material constitutive relationsof the concrete Rüsch model of quadratic parabola plus horizontal line is compaMParativelycomformable to actual conditions, thus providing a simplified way to numerical analysis ofmasonry arch bridge reinforced by composite arch circle.4. In considerations of the initial stress of unreinforced original arch ring and theconstitutive relations between masonry, concrete and steel, according to judgement whetherthe masonry arch bridge has horizontal crack or not, the formulas of normal section flexuralload-bearing capacity of masonry arch bridge reinforced by composite arch circle are deduced with a masonry arched bridge reinforced ribbed section as example. The bearingcapacity of every section can be calculated fastly by means of a mapple software which iseasy to be adopted by engineers. A numerical example shows that an error between calculatedvalues by fomula measured values by test is within9%. This provides a theoretical support forpractical engineering application of that derivation formulas, and shows that the derivationformulas are coMParatively comformable to practical engineering application. The derivationformulas are suitable to big and small excursion compressive members, so that these formulasare of high suitability.5. This paper in detail puts forward a reinforcement design process from section designto section check on the basis of a plane section assumption, composite material constitutiverelation and formulas of normal section flexural load-bearing capacity of masonry arch bridgereinforced by composite arch circle. It is proved that the deductive composite materialconstitutive relation and formulas of normal section flexural load-bearing capacity in thepaper can be safely applied to the calculation of normal section flexural load-bearing capacityof a masonry arch bridge reinforced by composite arch circle through a complete designexample of masonry arch bridge reinforced by composite arch circle. The combination oftheoretical analysis with project practice can help the promotion of the result to theengineering project.In a word, three innovative points of this paper are summed up:1. Plane section assumption of reinforced section from loading to failure is certified onthe basis of analysis of experimental data. Section’s strain distribution isn’t able to meet planesection assumption in initial stages of loading due to deformation asynchrony of masonry andconcrete. Along with the increase of loading, the composite section stress will be redistributed,masonry and concrete will be coordinately deformed and costressing. While loading is up to0.9Pu, the strain distribution of section is able to approximatly meet plane section assumption.Therefore, it can be seen that the deformation of composite section is able to approximatlymeet the plane section assumption.2. According to the assumed conditions that a composite arch circle meet the planesection assumption, four kinds of the composites material constitutive relations are deducedrespectively by four different kinds of concrete’s constitutive relation and one kind of masonry’s constitutive relation. When the four kinds of the composites material constitutiverelations are used for finite element simulation model of specimens, and the finite elementnumerical value is compared with the measured value, the result shows that the finite elementnumerical of ultimate bearing capacity is close to the measured value by using the compositesmaterial constitutive relations of the concrete Rüsch model of quadratic parabola plushorizontal line. If this composite material constitutive relation is applied to finite elementanalysis on engineering example, ultimate bearing capacity can be accurately calculatedconsidering both simplify finite element model and calculation work.3. In combination of the initial stress of reinforcement structure with the reinforcedmaterials nonlinear, and based on an judgement whether the masonry arch bridge withoutreinforcement has horizontal crack or not, the formulas of normal section flexuralload-bearing capacity are deduced and verified by test. The result shows that an error betweencalculated values by fomula and measured values is within9%, load-bearing capacity of everysection is accurate and can be rapid calculated. When the formulas of normal section flexuralload-bearing capacity are applied to engineering example, finite element calculation is thesame as that of formulas, the result shows that derivation formulas is coMParativelycomformable to practical engineering application.更多还原