Study On Wind Resistance Design Of Super-high Chimneys Based On China Code And American Code

Chimney is one of the important special structures in thermal power plant.Chimney structure is a typical wind-sensitive structure because of its high flexibility,large volume and small damping.Wind load is one of the main factors affecting load.With China's economic development and other reasons,more and more overseas power plant projects have been built in China.However,a large number of foreign-related projects choose the American code as their design criterion.Therefore,it is necessary to learn the design method of American code and understand the differences between Chinese and American chimney design criteria.Therefore,this paper firstly uses the method of fluid numerical simulation to simulate the effect of wind on the chimney outer tube,and based on the chinese Load Code for the Design of Building Structural(GB 5009-2012),chinese Code for Design of Chimney(GB 50051-2013),American Code Requirements for Reinforced Concrete Chinmeys(ACI 307-08)and Commentary(ACI 307-08 for short)and American Minimum Design Loads for Buildings and Other Structures(ASCE 7-10 for short)carried out a comparative study on the wind resistance design of reinforced concrete chimneys in Chinese and American codes.The main research work is as follows:(1)Two-dimensional unsteady and three-dimensional full-scale steady numerical simulation of reinforced concrete chimney outer tube was carried out by fluent software.The distribution of pressure coefficient,drag coefficient and flow field on the outer surface were obtained.The results show that the distribution of wind pressure coefficient on the whole chimney coincides with the Chinese code,and the drag coefficient is less than 0.6 recommended by the Chinese code with the height.With the increase of the vortex separation point,the cross-wind vortex-induced resonance may occur according to the standard method.(2)Comparing the wind load calculation parameters between the two codes,it is found that the two codes basically agree on the classification of landform types,but the roughness classification is opposite,and the basic wind speed varies with the time interval of measurement.(3)Comparing the calculation results of the downwind wind loads with those of the two codes,the results show that the calculation methods of the downwind loads are different,and there are obvious differences in the calculation results.If the key parameters affecting the values of the wind loads are unified,the results are in good agreement.(4)The methods of judging the cross-wind vortex-induced resonance and calculating the response of the two codes are studied.It is found that the methods are quite different.The results of cross-wind wind load calculation are quite different,similar to those of the downwind wind load.However,if the values of key parameters are unified,the results are in good agreement.The criterion of the two countries is simplified.