Sensitivity Analysis Of Construction Control Parameters Of Simple Branch Transformer Continuous Beam Bridge

In view of the unique advantages of simply supported variable structure continuous beam bridge,this type of bridge has been widely used in highway construction,but there are a lot of diseases in the bridge operation stage.This paper first studies the types of diseases in the operation process of simply supported variable structure continuous beam bridge,and then analyzes the causes of various diseases,and finally selects the prestressed system,construction process and time-varying According to the four kinds of variables,the sensitivity analysis of these four kinds of variables on the bridge structure response is carried out in detail,and the final conclusions are as follows:(1)The influencing factors of variable deviation of prestressed system include positive moment prestressed tension control force,positive moment prestressed pipeline friction coefficient,positive moment pipeline local deviation coefficient,negative moment prestressed tension control force,negative moment prestressed pipeline friction coefficient,negative moment pipeline local deviation coefficient;the influencing factors of time variable deviation in construction process include main beam storage time The influence factors of the deviation of atmospheric environment variables during the construction process mainly include the environmental humidity and closing temperature during the beam storage period;the influence factors of the deviation of concrete mechanical properties variables mainly include the concrete bulk density and concrete elastic modulus.(2)The sensitivity coefficient of positive moment tension control force,negative moment tension control force,main beam storage time,closing temperature and other factors is positive for bridge deflection;the sensitivity coefficient of pipeline friction coefficient,local deviation coefficient,negative moment concrete age,beam storage environment humidity,concrete bulk density,concrete elastic modulus and other factors is negative for bridge deflection as a whole.The sensitivity coefficients of pipeline friction coefficient,negative moment concrete age and humidity of beam storage environment are positive on the whole for the top stress of bridge beam;the positive moment tension control force,negative moment tension control force,main beam storage time,concrete bulk density and concrete elastic modulus are negative on the whole for the bottom stress of bridge beam.The sensitivity coefficients of pipeline friction coefficient,local deviation coefficient,negative moment concrete age,beam storage environment temperature,concrete bulk density,concrete elastic modulus and other factors are positive for the stress at the bottom of bridge beam on the whole;the sensitivity coefficients of positive moment tension control force,negative moment tension control force,main beam storage time and other factors are negative for the stress at the bottom of bridge beam on the whole.(3)Based on the above comparative analysis results of sensitivity coefficient of girder displacement,girder top stress and girder bottom stress,it can be known that the deviation of concrete bulk density,concrete elastic modulus,girder storage environment humidity and positive moment tension control stress has the largest sensitivity coefficient for structural response;the displacement sensitivity coefficient of the above four factors can reach-100-200 The stress sensitivity coefficient at the top of the beam can reach-27-27,and the stress sensitivity coefficient at the bottom of the beam can reach-114-45.(4)Compared with the single factor,the multi factor combination can increase the deviation of 114%-170%,the multi factor analysis can increase the deviation of 125%-200%,and the multi factor analysis can increase the deviation of 125%-200% The results of element analysis can increase the deviation of 125%-165%.(5)The machine learning method of BP neural network can be applied to the establishment of the mathematical model for predicting the structural response of simply supported variable structure continuous girder bridge,and the prediction error can be controlled between-10% and 10%.