Health Monitoring Of Steel Sheds At Olympic Stadium In Baotou City

The steel shed of Baotou Olympic Stadium is in a variety of environments,with complex forces and high risk of damage and damage.Therefore,it is of great practical significance to carry out health monitoring and diagnosis.The main research work and conclusions are summarized in the following aspects:(1)The functions of monitoring in the engineering structure health monitoring system were studied.The use and advantages of sensing elements commonly used in engineering practice,such as force balance acceleration sensors,are briefly introduced,and the working principle is deeply studied.Preliminary research on the working principle of measuring instruments commonly used in engineering practice,such as total station.(2)For judging the safety performance of the operation phase,we judge the stiffness of the structure from a macro perspective.This paper determines the stiffness of the structure by the vibration characteristics of the overall structure of the stadium steel canopy.In order to ensure that the measured sample data is valid,we use three different sampling frequencies of 200 Hz,500 Hz,and 1000 Hz to ensure the sufficiency of the sample data,and then use the method of de-averaging and eliminating the trend term to make the offset The sample data returns to normal,and the visual inspection method is used to screen out the sample data with stable signal state and less glitch impact to ensure the sample is valid.Finally,the processed sample data and the unprocessed sample data are autocorrelated and The Fourier transform obtains the power spectral density function,finds the resonant frequency of the structure,and compares the measured structural resonant frequency with the structural natural frequency obtained by the finite element software SAP2000 model.The measured resonant frequency is inherent in the structure.The frequency is low,that is,the rigidity of the overall structure of the stadium steel shed is degraded,and the frequency and stiffness degradation degree of the east shed is large,but it is still within an acceptable range.There is no problem with the frequency and stiffness of the western shed beingdegraded within a safe range.(3)In view of the judgment of the structural vibration characteristics in the overall direction,the local variation of the steel structure of the stadium is judged by the displacement of the nodes in a period of time.The results show that the overall structure of the western shed steel structure is basically uniformly deformed with the change of temperature.The structural body is still within the online elastic range.In comparison,the overall height of the east shed is not uniform,and the local nodes have lost part of the binding force.(4)Due to the influence of temperature,the steel structures in the east and west hoods all have the rotation of the arch structure under the cooling state,and the main arch shows a downward trend;the east,fifth,and west 3 of the measuring points are the most obvious.The peripheral support system is loosened under the action of multi-directional complex stress state,so that all three parts have a torsion condition.From the perspective of the degree of corrosion of the steel members and the change of the joint displacement,the east shed is more damaged than the western shed structure.Finally,the research work done in this paper is summarized,and some conclusions with reference value are obtained.And pointed out the problems to be further explored.