Design And Safety Warning Study Of High-Formwork Monitoring System Based On Construction Process

With the rapid development of China’s comprehensive strength and social economy,advanced construction techniques and new building materials are emerging,and the number of cast-in-place concrete structures with large space,large span and high headroom is increasing.As a new technology,high-supported formwork has the advantages of large bearing capacity,fast erection speed and high applicability,and has been widely used in the field of construction engineering.However,due to the high height,large span,numerous rods and complex and variable forces of the high supporting frame,there is a risk of tilting or collapse during the construction process,which is extremely dangerous.The traditional manual monitoring method cannot provide comprehensive,accurate and uninterrupted monitoring for each rod of the high support formwork,and cannot discover the potential risks and make safety warning in time,which makes the high support formwork collapse accidents happen from time to time.In order to effectively improve the problems in the monitoring of high supporting formwork and minimize the probability of accidents,there is a great need to establish a high supporting formwork monitoring system to provide real-time,accurate and comprehensive monitoring and safety warning for high supporting formwork during the whole construction process to ensure the smooth progress of construction.Therefore,in response to the above problems,this paper takes a rail transit phase I high formwork project as the application background and conducts a study on the design of high formwork monitoring system and safety early warning based on the whole process of construction,and mainly researches the following contents:(1)Study the overall design of the high supporting mold monitoring system.According to the characteristics of the high supporting mold,the design principles of the high supporting mold monitoring system are determined,the common monitoring items in the high supporting mold monitoring are summarized,the monitoring purpose of each monitoring item is analyzed,and the importance classification is made.The composition of the high-supported mold monitoring system and the functions of each subsystem are introduced.The principles of sensor selection and deployment are summarized,and the advantages and disadvantages of common sensors in different monitoring items are analyzed.Finally,the above research is applied to the design of the high-supported mold monitoring system with the example of actual project,and the monitoring equipment is determined and the software platform of the monitoring system is built.(2)The finite element simulation of the whole process of high support form construction and the optimization of sensor placement are studied.The finite element analysis software MIDAS/Civil was used to establish the finite element model of the key areas of the high support formwork,and the buckling analysis of the high support formwork frame under the wet weight condition after concrete casting and the force and displacement analysis during the whole process of concrete casting were carried out respectively,and then the vulnerable position and the most unfavorable position were obtained.The accuracy of the finite element calculation results was verified by developing the software for calculating the bearing capacity of the uprights under the beams.According to the analysis results of the model,the initial deployment plan of the sensor was determined.On this basis,the deployment scheme was optimized by analyzing the correlation between the measured data of the deployed sensors.The optimized sensor deployment criteria were proposed,and the importance of each measurement point was summarized to provide criteria and basis for the subsequent sensor deployment.(3)The identification and repair methods of distorted monitoring data of high support mode are studied.By analyzing the monitoring data in a certain area of the high support mode,the common types of distortion data in high support mode monitoring are summarized,including single-point distortion,continuous distortion and missing distortion,and the characteristics and expressions of the three types of distortion data are analyzed.The characteristics of the three types of distortion data are analyzed,and the identification methods and repair methods are studied respectively.Finally,the identification and repair methods are verified based on the measured data collected in a region.The results show that the above methods can effectively identify and repair the distorted data.(4)The safety early warning of the whole process of high-supported formwork construction is studied.The characteristics of the safety warning system are introduced,and the method of setting the warning thresholds is proposed in combination with the characteristics of high-supported formwork,and the warning method of phased and graded warning is adopted,and different levels of safety warnings are made before and during the concrete casting process according to the state of the structure,respectively,and the warning process is developed.On this basis,the method of setting statistical value,correlation,theoretical value of finite element simulation,code limit value and design value of material compressive strength as the warning threshold is proposed,and the above warning method is applied to the warning of the whole process of construction in the key area of high support formwork.The results show that the above method can be well applied to the safety warning of high supporting formwork.