| At present, due to the design of the lower grade or a variety of diseases affected byvarious kind of factor, tens of thousands of highway bridges built before the1980s in Chinahas got a lower bearing capacity and couldn’t satisfy the needs of the transportation. Toincrease the carrying capacity for the purpose of maintenance and reinforcement of thesebridges’ structures is becoming increasingly imminent. Therefore, the bridge’s maintenance,reinforcement and reconstruction technique research has become an important direction in thebridge engineering. With the development of material, new types of practical reinforcementand reconstruction techniques appear constantly. By using two materials of steel and concrete,and dealing with a reasonable structure interface, the steel and concrete compositereinforcement technique has become a new practical technology which can obviously increasethe bearing capacity and the structural rigidity of bridge. Therefore, it has important theorysignificance and practical value to carry out a study of the steel-concrete compositestrengthening concrete bridge.This paper mainly aims at the key technical problems of the steel plate-concretecombined strengthening concrete bridge’s method and the project’s application. Through themodel beam experiments, theory and numerical simulation analysis and the application of areal bridge, it carries out a systematic study of the mechanical properties of steel-concretecomposite strengthening beam as well as puts forward the corresponding theoreticalcalculation formula. By the use of improving the calculation method of compositesteel-concrete strengthening technique and combined with the project, it proposes thepractical way of structure’s connection. And with the steel plate-concrete compositereinforcement and pasting steel plate method, it completes the reinforcement design of twobridges. Based on bridge loading test, it makes a comparison between the two results affectedby the two kinds of reinforcement methods, and finally confirms the effect of compositestrengthening concrete bridge through one year’s service. This paper provides a support forthe technology of steel plate-concrete composite reinforcement in the application of bridges’reinforcement project.The research results include the following items:This paper, carries out the studies and numerical analysis of the composite steel-concretereinforced T shape beams, observes the experimental beams’ phenomenon and the destroyforms of the different stages from first loading to the ultimate loading, and it carries out adetailed analysis of bending capacity, deformation and strain results during the experiment.The test results indicate that: the steel and concrete composite reinforcement can enhance theultimate bending capacity of the concrete-T beams approximately2times; The influence ofthe bar spacing and original beam deflection’s damage on the ultimate bending capacity of theconcrete-T beams is only about4%; The bigger bar spacing, the greater relative longitudinalslipping of the new and old concrete’s interface. Based on the finite element software Ansys,it carries on analysis of mechanical behavior of the combination of reinforced concrete Tshape beams with the plasticity method, and compares with the test results. The caparisonindicates that the error of ultimate bending capacity between the numerical calculation results and the test results of the concrete-T beams’ is no more than9%. Finally it derives theoreticalultimate bending capacity formula of the steel and concrete composite strengthening concreteT beams for the first time.This paper, makes a study and numerical analysis of shear performance of the steel andconcrete composite T RC beams. With the shear capacity test for the typical damage ofconcrete RC T beams with composite strengthening, it obtains the constructional element’sshear damage features and ultimate bending capacity, and reveals the shear and pressuredamage mechanism of RC T beams with the steel-concrete composite strengthening method.At the same time, the paper establishes finite element model of reinforced concrete T beams,the calculation agrees well with experimental results when considering the material nonlinearcharacteristic. And then it proposes the shear capacity calculation formula of T beams withthe composite strengthening method, and the calculation results and test’s results of the shearcapacity matches well.This paper,applies the steel-concrete composite strengthening technology to thedamaged continuous box beam concrete bridge and the hollow slab bridges’ reinforcementexposing to fire; The reinforcement design proposes for the first time two connectingstructural measures, which could ensure the original structure and the new concrete workingtogether, then the structural safety, durability, performance can be reliable.This paper puts both the steel-concrete strengthening technique and pasting steel platetechnique into usage of superstructure reinforcement of bridge engineering, and carries out ananalysis and contrast between the superstructure mechanical behaviors after the two differentway’s reinforcement, both the girder’s strain theoretical calculation value and measured datawith composite reinforcement are significantly less than with the steel-reinforced results, theeffect of the composite reinforcement is superior to the steel reinforcement method’s, and allthe coefficients of strain under using composite reinforcement girder’s are less than1andhave a relatively uniform distribution. The results show that using the compositereinforcement method can ensure that the new and old structures can work well. Theperformance and the beam’s rigidity by using composite reinforcement method are superior topasting steel plate reinforcement method.The results of this paper have been put into the standards of Shaanxi province-"thedesign and construction technical regulations of steel-concrete composite strengtheningconcrete bridge", it can also give reference for other steel-concrete composite strengtheningconcrete bridges. |
PDF Full Text Request