| Along with the development of transportation in our country, concrete filled arch bridge has strong competitive power in some areas such as mountains,islands.In general, concrete filled arch bridge is rememberd as the preferred bridge not only for its beauty,strong bearing capacity,good stress condition,economical cost,but also for it can play an important role in exerting compressive property of concret.Because of the transformation of the system and nonlinear factors in construction process,the traditional analysis method is no longer applicable, nonlinear factors has play an important role in bridge design and construction. To ensure the bridge linetype comply with the design requirement and internal force is dominated in permissible range,we must control the bridge in the process of construction.So far,there are a lot of scholars has done many research work on the arch bridge, mainly concentrated on the stability of the arch bridge,but they study less in nonlinear factors influence the stress of the arch bridge.This paper take zhangjiawan arch bridge,which is located in the highway from Yichang to Padang,Yichang city,Hubei province as an engineering example.According to the construction process of zhangjiawan arch bridge,we analyse the arch bridge by using the finite element analysis software Midas/civil,emphasize on the mechanical behavior of the arch bridge for the shrinkage and creep and P-δ effect in large-span arch bridge.The main achievements are as following:(1) Calculating the settlement and stress of the full framing and the settlement and stress of the arch bridge in each construction process, which is in accordance with the field measure results.it provide the theoretical basic for the mould elevation of the arch bridge.(2) The shrinkage and creep of concret has great influence on deflection and stress of the main arch ring in the process of construction.To ensure the linetype and stress of the brigdge comply with the value of design,we have to consider the shrinkage and creep of concret in structure calculating.In each construction stage of zhangjiawan arch bridge,the deflection and stress of the main arch ring has no much change wheather you considering P-δ effect or not.(3) At the time being,there is no unified mathematical calculation model which can describe the rhythms of the shrinkage and creep of concret,A large number of dates in the formula come from the laboratory which is based on the plain concret.In this paper,we calculate the deflection and stress of the main arch ring under the gravity by using different model of shrinkage and creep,compare with the field measured date,we found that the field measured date is very close to the model of shrinkage and creep in Japan.In the process of calculating the concret filled arch bridge,we had better adopt the model of shrinkage and creep in Japan imitate the shrinkage and creep of concret.(4) Calculating the secondary stress on the main arch ring caused by the shrinkage and creep of concret in fold time to eliminate the influence of shrinkage and creep as far as possible,it turned out that the secondary stress caused by the shrinkage and creep are very close between folded immediately and one month later.(5) Through analyzing the change of the elastic molulus of concret and the shrinkage and creep influence the stress of the main arch ring after the bridege completed,it turned out that the elastic molulus of concret has less impact on the deflection and stress of the main arch ring,the shrinkage and creep has great influence on the deflection and stress of the main arch ring. We can not ignor the shrinkage and creep of concret after the bridge completed years in the process of construction.(6) Generally,we do not consider the steel bar in the concret in the process of bridge calculation.In this paper,we calculate the deflection and stress of the main arch ring due to the presence of the steel bar,it turned out that the steel bar has some inhibitory effect and we can not ignore the constrain of steel bar in structure calculation. |
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