Temperature Effect Analysis Of Long Span Suspension Bridge Based On Monitoring Data

As an important part of the modern large-span bridge structure,health monitoring system can provide corresponding analysis data for various responses evaluate of the bridge structure.However,bridge health monitoring data have always contained a variety of factors,especially for the temperature effect in the long span bridge,temperature will change during the four seasons and one day,and the temperature difference will cause the large deformation,temperature stress and additional stress in the bridge structure,sometimes the temperature effect is more than the vehicle load in the daily operation,it will cause great influence on the structures.The innovation of this paper lies on the analysis of the temperature effect of the long-span suspension bridge based on the health monitored data and probability theory,the local time-varying reliability of the suspension bridge is analyzed considering about the temperature effect.The main research content are as follows:(1)The long-term temperature variation characteristics of the steel box girder of long-span suspension bridges are quantitatively studied based on one year’s temperature statistics.Based on one year’s temperature monitoring data of Jiangyin bridge in 2013 and statistics such as the probability and statistics analysis,parameter estimation,hypothesis testing,the probability analysis model of the temperature of the steel box girder panel and the probability statistical model of the transverse temperature difference are calculated.And on the basis of the results,the daily temperature value and the transverse temperature difference value are also calculated.(2)The components of the monitored strain data is analyzed,and the temperature induced strain and vehicle load strain are separated based on the results.Based on the two kinds of strain sensor monitoring data in 2006 and 2013 of the Jiangyin bridge,the measured strain sensor measuring principle is demonstrated from the stress calculation and longitudinal girder displacement calculation,the temperature induced strain and the vehicle load strain are isolated,which are the the two main random variables in the reliability analysis.The long-term and short-term correlations between the longitudinal strain and temperature of the main girder are also analyzed.(3)The correlation between the temperature and the structural response of the steel box girder is analyzed,and the abnormal state evaluation method of the bridge structure is proposed.Based on the long monitored data of the optical fiber sensor and the longitudinal displacement sensor in the expansion joints,the correlation mathematical model between the temperature and temperature difference and longitudinal static strain of the box girder and the correlation mathematical model between the average temperature and longitudinal displacement of the beam is established,the temperature effect on the longitudinal displacement of the girder suspension bridge is eliminated,and the abnormal state evaluation method of the bridge structure is proposed.At the same time,the correlation between temperature field and girder deflection is qualitatively analyzed.(4)The 3D finite element model of the Jiangyin bridge is established,and the temperature field is analyzed in the established 3D finite element model.The content and loading scheme of dynamic and static load test of Jiangyin bridge is introduced,the correctness of the finite element model is verified by the monitoring data of static load test,and the temperature field of steel box girder of the suspension bridge is analyzed in the established 3D finite element model.(5)Based on one year’s long-term monitoring data,the local time-varying reliability index of long-span steel box girder suspension bridge is calculated quantitatively considering the temperature effect.The temperature induced strain and vehicle load induced strain is isolated in the monitored strain data.And the temperature induced strain and vehicle load strain is simulated by the probability density function,which are the the two main random variables in the reliability analysis,the bearing capacity limit state equation is established.Every one month is taken as a calculation cycle,the time-varying reliability index of steel box girder of long span suspension bridge is calculated in a year.