| With the continuous promotion of industrialization in China,a growing number of cities are putting their main construction direction into various space steel structures with different functions.Single-layer reticulated shell structure is widely used in the fields of industry,civil and public buildings because of its beautiful appearance,light structure and large coverage span.However,due to the nonstandard construction process,the incomplete construction mechanics theory,and the inaccurate simulation results,construction collapses are easy to occur.This paper analyzes the mechanical properties of reticulated shell structure in the process of construction.Taking a steel structure project in Beijing as the research background,the single-layer reticulated shell structure in the process of hoisting and supporting is studied.The main work is as follows:1.The development,application and common construction methods of spatial structure are introduced,and the spatial structure is classified according to the difference of basic components.The development and research status of hoisting and supporting technology at home and abroad are combed,the characteristics of construction mechanics and hoisting restraint rope system mechanics are summarized,and the basic calculation principles of the finite element theory of rod and beam systems are derived.2.In order to study the layout rule of the lifting points of the reticulated shell structure,the numerical analysis model of the three-dimensional reticulated shell is established by using the finite element software,and the reasonable location of the lifting points under the influence of different aspect ratio,area,grid size and pipe thickness is compared and analyzed.Based on the principle of producing the minimum deformation and stress,through the statistics of the simulation results of a large number of reticulated shells,the optimal lifting point position of the reticulated shell is 0.208 l,and the minimum number of lifting points required for a certain scale of reticulated shell’s lifting is obtained.3.Taking a steel structure project in Beijing as the research background,MIDAS / Gen is used to model and simulate the hoisting process of each block of shell.According to the stress and deformation ratio of each scheme,the optimal scheme is selected,and the optimal position of the lifting point is compared with that obtained from the grid shell statistics to verify the correctness of the above conclusions.It is found that the stress and deformation of the structure change periodically in the process of dismantling the bracing.The influence of different dismantling sequence on the stress and strain of the structure and the internal force of the bracing column is obviously different.It is more reasonable to adopt the scheme of unloading the bracing alternately from both sides to the middle of the structure.4.Stability analysis was performed on the construction process of a steel structural reticulated shell,and it was found that the stability of the block structure increased as the construction progressed.The support construction process of the structure is a process of gradually increasing stability,and the stability decreases after the support is removed.At the same time,the buckling analysis is used to find the vulnerable parts of the structure,which provides a reference for the construction monitoring plan. |
