| After the 2008 Olympic Games, large-span space steel structure has been an unprecedented development in china, all kinds of structure form, span and large-scale buildings appear. Steel structure has excellent material properties, fast construction speed, and sustainable utilization etc, shows that human beings have the ablity to construct 300-1000m large span, and more large space steel structure.At present the building’s span many within the 300m at home and abroad, China’s largest span is up to 153m, Millennium Dome which has built in 2000 with wire and cable membrane structure, whose diameter is 320m. Houston has the Hurricanes and severe heatwave, proposed the ETFE air pillow as maintenance structure, whose span is 1600m, high is 450m. In 2010, the Russian company put forward to built a 1200m diameter of three storey building which can contain 10000 people in Siberia abandoned mine. With global warming, environmental degradation, the shortage of resources, we shall deal with the more difficult environment in future, so the human beings are yearning for the construction of large span, high rise public buildings, They not only can meet some great social economic activities, has self independent system, give people a comfortable working environment, maintain a normal life, but also can prove a safe refuge when it occurs earthquake and other natural disasters.This article selects the double-layer spherical reticulated shell structure, whose span is 400m, high is 70m, the lower steel column 12m, do the structural design and construction technology research. Basing on the site characteristic conditions in Taiyuan, on the whole structure model of a gymnasium as research object to do the following work:1) installation method. It summarizes the installation method of the long-span spatial steel structure, according to major large span structure has the characteristic of big weight and complex bar, we conducte the feasibility analysis of several commonly used installation methods. The panda, wholly lifting, integral lifting and deployable method is applicable, but still need to design the key technical difficulties.2) model design. First Setting up the 400mX400m Kiewitt double-layer spherical reticulated shell model in 3D3S, then importing to the Midas/Gen software, and dividing the member rods,finally, doing the steel structure design and section optimization, reduces the consumption of steel. The final shell roof total steel quantity is 27058t, namely the steel amount for 191.92 kg per square meter.3) static analysis. Under the control of each load combination we calculate the structure stress, displacement, reaction force and internal force by Midas/Gen software, analysis the structure static performance, stress ratio is 0.85, the maximum displacement is 349.04mm, which meet the requirements of the specification.4) the construction stage. According to the need of engineering practice and site construction, it puts forward the modified wholly lifting, The maximum displacement is 38.92mm, the maximum stress is -194.16N/mm2, the maximum reaction is 6442.77kN, the maximum lifting load is 1019.01tons.5) deformation preconditioning. While using the forward iteration method for deformation presetting, after the fold the maximum vertical displacement has reached -41.40mm, after two iterations, the maximum displacement control in 0.014mm. The construction position gets close to the original design position.6) Distribution of unloading. The 80 temporary support is divided into 11 steps of unloading, the maximum displacement is 41.39mm.7) fold temperature. Studied the temperature is -40℃～40℃. the biggest influence on the structure is -20℃, the mini is 20℃, fold temperature should be controlled at 10℃～20℃.8) The combination of lifting bracket and cable, and the prestressed cable, the overall effect of horizontal thrust. |
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