The Research On Sensors Optimal Placement For Long-Span Steel Truss Railway Cable-Stayed Bridges

The safe operation of large span bridges has close contact with the country's transportation, economic development, military and even people's lives and property safety, large span bridge health monitoring technology research and development have become an important field.In this paper, the design of operational monitoring systems for Han jiatuo Yangtze River Bridge (a large span railway steel truss cable stayed bridge) as background,I researched the framework of the operati,onal monitoring system,and successfully solved the problem of optimal placement of sensors using improved genetic algorithm in the design of the hardware system. I completed the following major areas:(1) First, the mathematical model of optimal sensor placement and its constraints were analyzed,I used the dual structure of genetic code considering the fixed number of sensors, correspondingly selection operator, crossover operator and mutation operator were improved, the convergence of improved genetic algorithms was ensured and the efficiency was improved with the introduction of the probability of adaptive crossover and the probability of adaptive mutation.(2) For different components (monitoring objects) and different sensors (monitoring purposes), Four fitness function were designed based on Modal Strain Energy criteria and MAC criteria, the two criteria was compared and analysised.(3) I have done the optimal sensor placement for the main components of Han jiatuo Yangtze River Bridge, summarized the characteristics of results, discussed the factors of results, verified and necessarily changed the results using the static and dynamic characteristics of Han jiatuo Yangtze River Bridge finite element model.(4) The the general framework of operational monitoring systems and hardware systems were designed, and the state warning of structure was introduced.