Monitoring Research Of Formwork Support Frame On Random Defect Method

With the development of engineering construction technology,the monitoring system of support frame is gradually popularized in engineering.The axial force and deformation of the support frame can be monitored by Support frame monitoring in real time,early warning is given to avoid the abnormal situation of the support frame,the safety of personnel and property in the construction can be ensured.In order to solve the problem that random defects are not considered in the past research of support frame,this paper puts forward a support frame model based on random defects method,and makes a nonlinear analysis based on it to study the accuracy of using standard and other early warning value determination methods,and further studies the parametric modeling method of support frame.Finally,the field measurement of the high formwork is carried out.The specific research contents are as follows:1.Based on the analysis of the flaw sensitivity of the support frame,the sensitivity of the fastener type full hall support frame to the random flaw is studied.The results show that the flaw of the member is the main flaw that affects the ultimate load of the support frame.The wall thickness,outer diameter and initial bending are selected as random initial defects,and the support frame model based on random defect method is established.The reliability of the model is proved by comparing the analysis results with the test results.2.The random defect method model in the first chapter is used to study the accuracy of two methods to determine the early warning value.The results show that the early warning value of horizontal displacement and the determination method of monitoring points are not accurate.By using the finite element software and the consistent defect method,the early-warning value of axial force and monitoring point position of the support frame can be well studied.However,the early-warning value of horizontal displacement needs to be multiplied by the random distribution influence coefficient of displacement defect to be modified,and the conservative value of the coefficient is 0.75.In the monitoring of the support frame,when the axial force early warning value is the limit bearing capacity of the support frame specified in the specification,the monitoring system can early warn the damage of the support frame caused by human negligence;when the finite element method is used to study the axial force early warning value with the perfect structure model,the value of the early warning value should not be higher than 60% of the calculated ultimate load.3.In view of the difficulty of ANSYS software modeling,the ANSYS parametric modeling system of the support frame is developed;and in view of the situation that the ANSYS software cannot be used,the matrix displacement method is used to calculate the horizontal displacement system.The results show that the ANSYS parametric modeling can quickly and conveniently establish the ANSYS model of the support frame and reduce the difficulty of modeling;the matrix displacement method can calculate the horizontal displacement of the support frame and calculate the horizontal displacement when the load is slightly higher than the ultimate bearing capacity of the code.4.The real-time monitoring system of high formwork is introduced,and the real-time monitoring of high formwork project is carried out to verify the accuracy of the above scheme of determining the early warning value.The results show that the monitoring results of the actual project are good,which can effectively monitor the changes of the displacement and axial force of the support frame in the whole process of concrete pouring.