Research On Calculation Method Of Extension Value Of Prestress Tension In Continuous Box Girder Bridge

Nowadays, the development condition of the prestressed technique of bridgeengineering is: the function of prestressed material and construction technique is moreand more developed, prestressed structure design is also more economic and reasonable.The number of continuous prestressed girder bridge more than half around the world,fully embodies the continuous prestressed girder bridge is an important bridge type ofmodern. Prestressed tension process is an important factor to affect the continuousprestressed concrete beam bridge.This article describes the history of the prestressed beam bridge. At the same time,deducing and analyzing the formula of the loss of pre-stress from 《Code for Design ofHighway Reinforced Concrete and Prestressed Concrete Bridge and Culverts》JTGD62-2004according to surface problem, researching the applicability, weakness and thereasons of error, then discussing the formula of the loss of pre-stress according to spaceproblem and deducing the formula of the prestressed friction factor:^、k.Thisresearch based on Chongqing Rongqiao Road Helix bridge,Chongqing Jiahua JialingRiver bridge (Jiahua bridge), Chongqing Shiban Slope Yangtse Rive bridge these threeactual projects, partly explaining the experiment method of the friction factor ofprestressed plastic corrugated pipe and gathering and analyzing the data from theexperiment, then working out the friction factor of prestressed plastic corrugated pipe:/i、k. Finally，a new Prestressed Steel elongation calculation methods, the complexityof the curve decomposition, paragraph by paragraph through the Excel spreadsheet, andthen aggregated to the total elongation values. Compared the theoretical value ofelongation to the actual value of elongation of a steel beam bridge Chongqing Xiaoquanbridge and Xiamen Zhongzhou bridge engineering，indicating that this method isreliable and effective, can provide for the future project engineering experience.Multi-span continuous beam bridge strand arrangement to calculate the theoreticalvalue of elongation of the tension in the space curve, the ifrst space curve split themulti-plane circular curve, respectively, to calculate the vertical and horizontal angle ofeach curve to calculatethe average power of each strand, and then re-computing each oftensile value. Finally, the elongation value of each accumulation is a steel beam tensileValue，this method is reliable and eiffcient after instance validation...