Research on the Mechanical Properties of the Overall Lifting/Lowering Process of the Grid Structure Construction

The grid structure has been widely applied in various industrial and civil infrastructure buildings due to its advantages such as simple force-bearing， high stiffness， light self-weight， convenient construction， and good overall stability. The common construction methods for grid structures include the high-altitude bulk installation method， the strip/block installation method， the sliding method， the overall hoisting method， the overall jacking method， and the overall lifting method. Among these， the overall lifting method has the advantages of high assembly quality of the members， good structural stability during the lifting process， and fewer required formwork frames. Therefore， it has become one of the commonly used construction techniques for large-span spatial grid structures. This paper focuses on the non-synchronous lifting and breakage effect as the research objects， and systematically explores the mechanical properties of the lifting and lowering process in the construction of grid structures. Studies were conducted on the influence of non-uniformity of overall lifting on the mechanical properties of the overall lifting of the grid structure and the influence of non-uniform unloading on the unloading process. Considering situations such as displacement difference in a certain direction of the overall structure and displacement difference at a single lifting point， the impact of non-uniformity on the stress and reaction forces of the overall lifting structure was analyzed.The research results indicate that when the displacement difference exceeds 20 mm， the sensitivity of structural stress and lifting point reaction force to asynchronousity increases significantly. At a displacement difference of 60 mm， the maximum stress approaches the safety limit， and the maximum reaction force in the X-direction exceeds 3000 kN. After considering dynamic effects， the mid-span deflection of the structure increases by approximately 20% compared with the static analysis results. Based on the above findings， it is recommended that the construction step control limit be set at 20 mm， and a low initial lifting speed of 0.02 m/s be adopted to suppress dynamic fluctuations.