Research On The Optimal Layout Of Real-time Monitoring Sensors For Long Spancable-stayed Bridges With Two Towers

Our country is a big country of bridge construction.Bridge engineering is an important lifeline engineering in our country,especially long-span bridge engineering.The force of long-span bridge structure is complex,so people pay more attention to the safety of huge structure.For early warning and prevention of accident of bridge structure,it is necessary to establish a real-time monitoring system of bridge.The key problem of the real time monitoring system of large bridge is the layout of the sensor.It determines the effectiveness and economy of the monitoring system,and it is the most important evaluation index of the monitoring system.As engineering background,the Twin Towers long-span cable-stayed bridge is based on Huaian Minjiang bridge(the main spain:the flat steel box girder,side span:concrete box girder)and Quebec Pu Bridge(with concrete rectangular beam structure),espicially the layout of the sensor.According to the characteristics of its structure and behavior,the real time monitoring system of long-span cable-stayed bridge is studied.The main research contents are as follows:1.According to the design data of bridge structure and the dynamic and static load test data,Huaian bridge and Quipu Bridge initial finite element model is established and is modified to meet the actual structure.By using the theory of finite element analysis and calculation of the design load and structural mechanics performance,the stress condition and stress characteristics are fully understood,for the optimization of the real-time monitoring sensor for the bridge.Theoretical spectra of static and dynamic characteristics of structures are established.2.On the basis of static and dynamic load test,the load test report is analyzed and summarized.The most unfavorable section and vulnerable parts of the bridge are obtained.Then standard spectrum of bridge structure under the action of standard design load are established.3.Combined with the previous theoretical analysis,and long-span cable-stayed bridge sensor layout method at home and abroad,Huaian Minjiang bridge and Lupu Bridge Quebec real-time monitoring system is preliminarily layed out.Through the analysis of the load effect of finite element model and load tests,thc most unfavorable section to the bridge is calculated.On the basis of theory of "spectrum","the standard spectrum" as well as the sensor placement optimization theory of the number,type and location of sensors can be utilized to optimize the design.Finally,the optimal layout of two bridges is obtained.4.Based on the previous research results,the real-time monitoring system is applied to the two bridges.Through the bridge real-time monitoring system to collect the response signal of the bridge,the structure of random response of the random spectrum is established".Combined with the theoretical spectrum,"standard spectrum"and "random spectrum",the mathematical statistics of the bridge are analyzed.The"three-spectrum analysis" is compared,in order to improve our understanding of large-scale complex structures,and to provide theoretical basis and database for the follow-up real-time monitoring system.At the same time,it is also an effective verification of the optimal layout scheme.