Study On The Key Technology Of Construction Of Large Span Saddle Shaped Orthogonal Monolayer Cable NET Structure

Saddle shaped orthogonal monolayer cable net structure is a kind of prestressed spatial structure system.This structure is formed by two sets of cables with opposite curvature.The concave cable is the bearing cable,which bears the roof dead load and live load;the convex cable is the stable cable,which bears the upward suction caused by the wind load.The intersection of the two groups of cables is connected by cable clamps,and the edge of the cable net is suspended on the peripheral rigid members.This structure is characterized by large span,high stress efficiency,light weight and less steel consumption.It is mainly used in large stadium roof structure.At present,the largest span of the existing saddle shaped orthogonal monolayer cable net structure has reached 100 meters.With the increasing design span of cable net structure,the difficulty of construction is also increasing.Therefore,it is of great significance and practical value to carry out the construction process analysis and construction error analysis of the large-span orthogonal monolayer cable net structure for the safety of the cable network structure in the construction process and the construction completion quality.In this thesis,the roof cable net and curtain wall cable engineering of the national speed skating pavilion are taken as the research object,and the comparative analysis of the structural construction forming plan,the simulation calculation of the whole process of the structural construction,and the structural construction error control technology are studied.Combined with the actual monitoring data,the simulation calculation results are verified.The main research contents and achievements of this thesis include the following:(1)According to the design data,the whole model of the structure is established by using the finite element software Midas/Gen,and the key points of the model establishment and the initial prestress application in the modeling process are briefly discussed.At the same time,the method and steps of construction simulation calculation are discussed.(2)A variety of support restraint plans,cable net lifting plans and cable net tensioning plans are proposed.The key parameters are calculated one by one and compared.Combined with the actual situation of the site,the construction method of "ground assembly cable net,overall lifting,synchronous tension forming" is determined.In the construction,the long axis support is used to constrain the X horizontal direction,the short axis support is used to constrain the Y horizontal direction,and all supports are used to constrain the vertical ring truss support.(3)According to the optimal construction plan,the whole construction process is simulated and analyzed.According to the calculation results,the key parameters such as cable force,shape and ring truss stress are obtained.According to the cable net lifting force and tension obtained,the appropriate lifting and tension equipment is selected.The accuracy and feasibility of the simulation analysis are verified by comparing the actual monitoring data with the theoretical data.(4)Cable net structure needs to rely on prestress to provide structural stiffness and maintain structural stability,so it is necessary to ensure the accuracy of prestress distribution in the form of structure according to the design requirements.In order to control the cable force error that may occur in the construction process,the influence of cable length error,ring truss padeye construction error and temperature deviation on the structure is analyzed.According to the error analysis results,the construction error limit and compensation measures are put forward.