Research And Application Of Online Monitoring System For Bridge Construction Support

As a temporary structure of highway standard,Bailey beam is currently widely used in bridge construction because of its advantages such as simple structural system,clear force transmission path,large carrying capacity,convenient assembly,and little influence of site.Due to the complex construction conditions,on-site high-altitude operations,and improper use,destabilizing safety accidents have occurred from time to time,which not only seriously endangered the personal safety of construction personnel,but also brought huge economic losses and bad social impacts to all parties of the project.In order to effectively prevent the risk of collapse of the temporary support structure during construction and minimize the loss of casualties and property,on the basis of existing research,this article established a set of online support monitoring system to achieve remote online monitoring,feedback and The function of early warning,online real-time monitoring of the typical section deflection and stress of the support structure during the construction process,to protect the construction safety.This article takes the construction support of Jing xiong high-speed rail corridor Zhuo high-speed bridge as the engineering background,combined with the online monitoring system of bridge support structure,analyzes the safety of the support structure during the bridge construction process.The main analysis contents and results are as follows:(1)The online monitoring system uses wireless sensing technology,combined with GPRS communication technology to achieve data transmission and short message alarm.By comparing the monitoring data with the early warning value,it provides a reference basis for safety early warning.(2)Through the Midas / Civil software,the stress analysis of the support structure is carried out,and the stability of the support structure is checked.It can be seen from the analysis that the first three buckling coefficients of the stent system meet the relevant requirements,which is consistent with the foregoing force analysis results,indicating that the stability of the stent structure meets the relevant specifications.(3)Comparing and analyzing the field measured data of Jingxiong high-speed rail corridor Zhuo high-speed bridge construction support with the theoretical value of the model The values are relatively close,less than the warning value and the design specification limit of 15 mm,and the deflection meets the requirements.The maximum pressure value of stress at the measuring point during the pouring of 27 # pier is-103.8 MPa.The measured stress value of each monitoring point is less than the early warning value and the standard value,and the strength and stability of the steel pipe column meet the requirements.It shows that the support structure has sufficient safety during the concrete pouring stage.(4)After the prestressed steel bar is tensioned,the deflection and stress values of the measuring points show a decreasing trend,and the farther away from the position of the pier,the greater the influence.The values of some measuring points increase slightly.The tension and the beam itself have a certain bearing effect,and the actual change of the measuring point is basically consistent with the change trend of the theoretical calculation result.(5)Based on the monitoring results of the high-speed prestressed concrete continuous beam construction support of Jingxiong high-speed rail corridor,a load identification model of BP neural network was established to predict the stress status of the subsequent support system.The results show that the expected load value and the identified load value have a good agreement,indicating the correctness of the dynamic de-identification method,which shows that the neural network de-identification model established in this paper has good applicability in the bridge support structure of this project.