The Key Issues Research Of Construction Process For Large-span Station Steel Roof Structure

New era, the spatial structure of large span and large posts system often used in railway station roof. However, the additional internal forces and deformations caused during the construction process can’t be neglected since there are many associated factors which affect the structure. Studying on the construction process key issues of steel structure roof in railway station can reflect the construction of the internal force and deformation condition, locating potential threat in the process of construction in advance, providing theoretical support to compile the optimized construction scheme and reliable digital basis for the construction structure safety and construction quality assessment during constructing process.In this paper, based on the large-span spatial pipe truss structure as the research object, with the steel structure roof in chongqing west railway station construction as the background, the main work is as follows:Firstly, the article introduces construction and installation measures and the corresponding engineering examples about conventional large-span space structure, the present research situation and progress were described in detail about construction mechanics, summarizing the article’s research content and significance; introducing the principle and system components of integral lifting, laying foundation for further research work.Secondly, with the steel structure roof in Chongqing west railway station construction II district as the background, the analysis model was established based on finite element analysis software Midas/Gen, developing three lifting point layout of ascension, lifting structure has been simulated synchronizing lift under three lifting point layout of ascension, comparative analysis of the results and chooses the optimal lifting point layout of ascension; according to lifting reaction to select the corresponding lifting equipment; choosing quantitatively analysis about worse operating condition of asynchronizing lift and replacing the mechanical overrun bar.Thirdly, with the composite arch trusses of the east elevation of chongqing west railway station as the background, stability analysis has been carried out under the construction phase by using finite element analysis software ANSY; checking theoretical stability of a circular steel tube concrete column and a box shape steel tube concrete column according to relevant regulations; doing finite element analysis of key nodes under lifting region and two sizes lifting spreaders by ANSYS, carrying on the hoisting simulation to worst hoisting section unit of the combined upper arch and the lower arch truss by Midas/Gen.Fourthly, doing analysis research about removing temporary supports for composite arch trusses of the east elevation, formulating three kinds of unloading programs, simulating according to corresponding unloading programs, getting the data of support reaction force and point vertical displacement, selecting contrastively analysis the optimal unloading program by making relevant charts; analyzing linear buckling and nonlinear buckling of the worst temporary supports, determining the stability bearing capacity of support, the analysis results can provide the basis for actual construction, ensuring the construction safety.In this paper, it is a great reference value that the research and the achievement for construction of the similar structures providing basic data and experience to the similar projects.