Refined analysis on transient temperature effect during closing process of cross-sea bridge
In order to study the transient temperature effect during the construction of the cross-sea bridge off the coast,based on Hong Kong-Zhuhai-Macao Bridge-Pipe Bridge Crossing Cliff 13-1 Gas Field,the refined analysis of transient temperature gradient and prediction,as well as structural response were conducted under the conditions of strong solar radiation and atmospheric convection during closing process using the method of combining theoretical research and numerical simulation.Firstly,the partial differential equation of uniform heat flux density on the outer surface of the main girder under the action of solar radiation and atmospheric convection was established,and the equivalent comprehensive temperature at any time of the main girder was obtained by solving the equation.Secondly,the transient temperature gradient of the main girder section was obtained by establishing a numerical analysis model of the heat conduction,and the result was verified in comparison with the measured data.Finally,the temperature effect under transient temperature gradient of the main girder during closing process was calculated,and the corresponding construction control measures were discussed.The research results show that the prediction value of the transient temperature gradient is consistent with the measured value(the maximum deviation is less than 2℃),and the predicted value is slightly larger than the measured value,which makes the structure safer.During the closing process,the temperature gradient of the main girder has obvious non-linear characteristics:the temperature gradient is relatively high within 0.4m from the top surface of the roof,while tending to zero outside 0.4m.The best closing time of the main girder is from 21:00 in the evening of the closing day to 6:00 am of the next day.For the small angles at both ends of the closure segment during the best closing time,Temporary adjustment jacks and temporary counterweights can be adopted to eliminate the small angles at both ends of the final closure.
Hong Kong-Zhuhai-Macao Bridgebridge engineeringtransient temperature effectbridge closingcross-sea bridgerefined analysis
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