Study On The Mechanical Behavior And Optimization Design Of Steel Truss Support Platform During The Construction Of Silo Roof

To solve the construction problems of silo roof,scholars have proposed different forms of support platforms.However,the stress variation of the support platform during the whole construction process is not considered in the design process,and the repeated utilization rate is low.This paper chose a 26 m diameter silo expansion project as an example and monitored the stress state of steel truss support platform during the construction process.Based on the steel truss support platform,a modular space steel truss support platform was proposed.The specific work and conclusions of this paper are as follows.By monitoring the stress state of steel truss support platform during the construction of silo roof,the stress condition of the main members of the steel truss support platform was studied,and the finite element model of steel truss support platform was established,the numerical simulation was conducted and the simulated values were compared with the measured values.The results indicated that the stress of each measuring point had a large fluctuation because the steel truss support platform had a certain degree of inclination in the lifting stage.In the stage of pouring inclined conical shell concrete,the members of steel truss support platform had greater stress,and this stage is the main stress stage of steel truss support platform during the construction of silo roof.In the stage of pouring flat roof concrete,because the concrete in the inclined conical shell area had hardened and can bear most of the vertical load,the stress variation at each measuring point of the steel truss support platform was small.Due to the ideal simulation conditions in the lifting stage,the simulated values were smaller than the measured values.In the stage of pouring inclined conical shell concrete,the measured values were in good agreement with the simulated values,which verified the validity of numerical simulation.In this paper,a space steel truss support platform was proposed.Through modular design,it can be applied to 18 m,24m,26 m,28m,32 m and 34 m diameter silo projects,which improved the utilization and versatility of space steel truss support platform.In order to compare the mechanical performance of the space steel truss support platform and the steel truss support platform used in this project,the numerical analysis was conducted on the two kinds of steel truss support platform with 34 m diameter.The results showed that space steel truss support platform had higher bearing capacity and lower steel consumption.Considering the influence of full load and eccentric load on the space steel truss support platform,the finite element analysis of the space steel truss support platform with different diameters was carried out.The results showed that the eccentric load was more disadvantageous to the space steel truss support platform.With the decrease of the diameter of the space steel truss support platform,the maximum stable stress ratio tends to decrease.Finally,the joint design of the space steel truss support platform was carried out,and the corresponding construction technology was formulated,which provided a reference for the application of the space steel truss support platform.