| Prestressed concrete continuous beam bridge has been widely used because of its structural performance, advantages and mature construction technology. With the further promotion of the country’s economic development in the coastal areas, the construction of concrete bridges under the marine environment in cold areas has entered a new stage. Based on the 2# prestressed concrete continuous beam bridge in the Nachao River, Caofeidian, The time-varying performance test of concrete under natural environment is carried out, and the performance analysis of prestressed concrete continuous beam in construction stage and completion stage based on the test modified prediction model of concrete time-dependent performance are also completed.Firstly, the concrete time-varying properties test under natural environment and its present research situation are introduced. And the project research situation as well as the background of the supportted project is also introduced.Secondly,Based on the natural environment of the bridge, the time-dependent property of concrete is tested and the test results are preliminarily analyzed. The analysis results show that the test modified prediction model of concrete time-dependent characteristics can reflect the development rule of concrete time-varying performance better.Then, based on modified model for concrete predicting time-dependent properties of test result analysis and according to the actual situation of the construction of Nachao River 2# continuous beam, the finite element model is established. The analysis of the stress and deformation of the bridge structure, the analysis of the effective prestress and the loss of prestress in the stage of completion of the bridge are carried out. Analysis results show that the bridge in the construction stage, closure segment bridge overall stress level can meet the requirements of specification. The maximum deflection of the middle section is about 3 cm after the concrete of the 9# block is poured, and after the prestressing force is applied, the lower deflection is obviously reduced, within the allowable range of the specification. The bridge long-term effective prestress of the operational phase can meet the requirements of specification, 30 years prestress loss of bridge is about 17.3%-21.9%%, mainly caused by prestress loss for shrinkage and creep damage in operation phase. The stress of the most unfavorable section position which may be subjected to tension of the bridge is enough.After 100 years of operation, the deformation of the bridge meets the requirements of the code and the overall stress and deformation performance of the bridge is good.Finally, the Nachao River 2# bridge deformation and stress monitoring method is briefly introduced in this paper, and calculation results of test modified model based on concrete time-varying performance test under the natural environment and the measured value are compared, found that the calculation results of the model with the overall situation of the bridge is stable, safe and reliable results. |
