Security Analysis Of Large-Scale Steel Structure During Hoisting Under The Wind

Due to excellent mechanical and environmental performance of steel as well as convenient handling methods in the process of installation,steel structure has been widely used in China.But due to the fact that prefabricate components are more likely to be used in the construction phrase of steel structure and transported to the site for hoisting construction,the stress of steel structure in this phrase is different from that in the design phrase.Under the influence of gravity and wind load,it is prone to appear insufficient strength,instability and other phenomena,resulting in steel structural accidents.Therefore,in order to check the security of the steel structure in hoisting phrase,it is necessary to check the safety of the steel structure under the influence of the wind load according to its stress calculation.Based on an analysis example of a national peripheral protection of steel structure hoisting a nuclear power station project,this paper uses the finite element analysis software Midas Gen and the fluid calculation software Fluent to simulate the security and response induced by wind of the structure in the hoisting phrase.The main works are as follows:1.Summarize the key points of the steel structure security checking during hoisting under the windBy elaborating the hidden dangers in the hoisting phase of steel structure and the influence of wind load on the structure,the necessity of steel structure hoisting security check under the influence of wind load is presented.The basic characteristics of wind and the basic theories of computational wind engineering are introduced according to the research status of wind-induced response,which provides theoretical basis for structural surface wind pressure simulation.2.Analysis of the key security problems of structure during hoisting under itself-weightFirstly,based on the SC structure,calculates and analyzes the security of the two construction phrases under the influence of self-weight by means of Midas Gen,and assesses the situation of the SC structure's security,summarizes the most noteworthy problems and improvements in the two phrases:1)problems of module's hoisting point position in the hoisting phrase and the anti?deformation truss setting as well as improvements of the structural deflection;2)problems of grid frame design and the cable elevation in the overall hoisting phrase.3.The numerical simulation of structural surface wind pressure and wind induced response when considering only the gradient wind and the pulsation wind is conductedAccording to the characteristics of wind load,the numerical simulation of two kinds of hoisting phrase of SC structure are made by considering the gradient wind and the pulsation wind respectively.In the module hoisting phrase,the situations under the most unfavorable 0° and 180 ° wind direction are calculated.The calculated wind pressure results are compared with the wind tunnel tests results of other structures,and the wind pressure is converted into wind load applied to the surface of the structure.Finally,the wind induced response is calculated by Midas Gen.4.Analysis of the steel structure's security during hoisting under windCombined with the influence of self-weight,the security of the hoisting structure under the influence of wind load is analyzed.Structural response cloud of the same kind of hoisting phrase is analyzed only considering the effect of the self-weight,the effect of the gradient wind and the effect of pulsation wind and self-weight respectively.The analysis results show that the pulsation characteristics of the wind must be considered when analyzing the displacement response of structure and the stress response of the SC structure.The stress response of the hoisting system can be analyzed without considering the influence of wind load.When the wind induced responses caused by two wind directions are not very different,they could be considered by 180°?In the whole hoisting phrase of the two-tier SC structure,in addition to the stress analysis of upper sling,the influence of wind load should always be considered in the analysis of the rest parts.In this paper,the numerical simulation and analysis of the hoisting safety of the SC structure when considering the influence of the wind load are carried out.The results show that the response of the wind structure is obvious and the wind direction angle is small,and the maximum windward surface can be checked analysis.This conclusion provides the basis for the consideration of the load of SC structure hoisting safety checking,and its simulation analysis method is also applicable to other steel structure hoisting works.