| Steel tube concrete arc bridge is a new type of beam and the hybrid system arch Bridges.The system is mainly composed of arch rib, collar beam, derrick structure, etc. Derrick ascollar beam and arch rib of the connection between the components, its stress state is rea-sonable and reliable directly affects the stress performance of the whole bridge, which willdetermine whether the bridge to work safe and reliable. In arc bridge, especially forlong-span Bridges boom tension is not a one-off, derrick cable force need many times ten-sion adjustment, to meet the requirements of the construction design of integrated linearstress and bridge. Arc bridge this internal statically indeterminate, the outside of staticallydeterminate structure, combined with the concrete shrinkage, creep effect makes the stress ofarch bridge is more complicated. Because of the complexity of the structure system, the con-struction of the bridge during the accurate theoretical calculation again also cannot com-pletely replace field monitoring work. Therefore, during the boom tensioning for derrick ca-ble force monitoring, on the basis of monitoring results formulate detailed reasonable ten-sioning scheme is very necessary.On the other hand, in the process of the use of the bridge, due to the boom itself existsrelaxation and stress losses, plus alternating effect of traffic load, derrick cable force changeswith the bridge using. Engineering practice shows that the boom of degradation is a randomand nonlinear process. You could suggest that during the operation of the bridge, the boomof monitoring is also very important. Due to the boom arch bridge effective length is shorter,monitoring during the bridge operation need some necessary data. Based data acquisition isthe most effective means to monitor the quality of derrick through during the boom tension-ing, it also illustrates the derrick tension during the necessity of the construction monitoring.In this paper, taking the construction boom tension control of Zhao Wanghe bridge asthe engineering, mainly carry out the following research work:1、First of all, on the mechanical characteristics of derrick arch bridge are briefly ana- lyzed. From the safety of the construction phase components of the derrick tensioning taskdecomposition, the boom tension in the process of the key technologies are discussed in thispaper.2、According to the design parameters and MIDAS Civil’s theory of finite elementanalysis of the steeve arch model is established. Based on the theory of influence matrix andthe iterative algorithm combining with the finite element analysis model to simulate theboom in the construction process, analyzes the solving process of the derrick force, formu-late the corresponding tension, through the theoretical calculation of the eventual into acompleted bridge of derrick arch bridge meet the design requirements.3、Combining with the vibration of the existing theoretical basis, the method of fre-quency test of principle are introduced, and discusses the application of frequency method tosolve the three theoretical calculation model of cable force. Considered in the practical en-gineering, because of the cable length, bending rigidity, installation of dampers will bringcertain influence to the model, to modify the model or in combination with some of the newalgorithm, to obtain more accurate results, formed a kind of high precision of frequency cal-culation method based on vibration test is carried out.4、Combined with practical engineering, tension scheme, as defined by the cable forcewas tested by frequency method for derrick tension and cable force adjusting the construc-tion phase of the process of real-time monitoring.，and the key section of stress and dis-placement monitoring.Comprehensive analysis of all monitoring results verify the effective-ness of the method in this paper... |
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