Experimental Research And Theoretical Analysis On Space Truss With Rotating Fastening Members

Recently,a type of silo with large diameters is widely applied in industrial buildings.The space truss structure of silos is short of theoretical analysis.A new steeltube truss platform which can be applied in practical engineering is proposed in this paper.Through the study of the experiments and finite element simulations on the new type of rotating-fastening members and the spacial truss platform,the mechanical characteristics and performance parameters are systematically analyzed as well as the bearing capacity,deformability and rod stress,which is useful in the practical application of the guide.Based on finite element analysis,the new space truss is analyzed with multi-scale parameters to obtain the bearing capacity and deformation performance,respectively.According to the analysis,it is easily determined the optimal combination of truss rod and the influence of parameters,such as the depth of truss,length of chord and etc.to the bearing capacity.The basic mechanical properties tests on members of the new steel-tube truss platform and connecting nodes are conducted to determin the failure characteristics and deformations under different loading conditions.On that basis,a site test has been completed in the new steel-tube truss platform with 21 m diameter to simulate mechanical characteristics in actual constructions and verify finite element analysis results and applicability.It is indicated that the finite element analysis results and the test results of truss are basically identical and the truss platform has a better bearing capacity and deformation performance.Through the study of the truss platform with multi-scale parameters,the best suspension form is determined and the security analysis of the suspensory construction process is also carried out.It is shown from the analysis that under the condition of local suspensory failure of cable or member in this paper,the truss platform will not damage and has good safety reserves to meet the engineering application security.Based on the ultimate bearing capacity and failure mode of the rotating-fastening truss with large diameters,the truss is strengthened to perform the contrastive analysis.It is revealed that the 3×3 double-layer turss is the most reasonable local reinforcement scheme,in which the maximum deflection decrease 28% in second stage and 33% in third stage compared to the truss without reinforcement.Prestressed cables are placed at the inner-ring anchorage locations at the underside of truss to study the mechanical characteristics of the rotating-fastening truss.The results imply that the application of prestressing force could reduce the maximal deflection of turss effectivity by 41% at most and the stress of the members decrease significantly by 54% with the increasing of the prestress at most.