Study On Framed Steel Chimney Based On Synergetic Theory

Tower frame steel chimney is made up of internal vent stack and external tower frames to form stable system.Internal vent stack mainly take on its own vertical load,while horizontal load is mainly borne by external tower frames.The article 10.2.4 and 10.2.6 in Code for Design of Chimneys(GB 50051-2013)provide:chute type connection can be used between tower frames and vent stack.During analysis calculation,tower frame and vent stack can be respectively calculated without regard to the mutual influence between them.Along with industry development and the enhancement of people environmental protection consciousness,the height of tower frame steel chimneys becomes higher and higher,the diameter of vent stacks get bigger and the stiffness of vent stacks get harder.Make full use of the strength and stiffness of vent stacks working together with the external tower frames to resist horizontal loads.So it is necessary to research synergy work system of tower frame-vent stack in-depth and the research results can be reference for engineering design.In this paper,the main works are as follows:1)Summarize the design principles regarding materials,type selection,load and calculation theories,etc.of tower frame steel chimneys,providing theoretical basis for further research work.2)Combining with engineering example,the design methods of specification and synergy work system are respectively used to put up finite element structure analysis for tower frame steel chimney.Comparing the dynamic characteristics with the results of finite element analysis shows that there are some differences in the sides of self vibration period,vibration mode,pillar internal force,horizontal displacement,etc.between them.The structure of tower frame steel chimney adopting synergy work system design not only have good structural integrity but also can decrease the amount of steel usage under the condition of the same target.The synergy work system of tower frame-vent stack is recommended for engineering design practice.3)Analyze the effect rules for the connection mode,the thickness of vent stack,the ratio of span to height of vent stack and other parameters to the dynamic characteristics of tower frame steel chimney adopting the synergy work system.By analyzing the effect parameters for dynamic characteristics of tower frame steel chimney,basically get the following conclusions:? Connection method of tower frames with vent stack and the wall thickness of vent stack have a little effect on the self vibration period of structures,all impact values are around 5%.? As the ratio of tower span to its height increases,the each rank structure cycle and the lateral displacement value of each high linearly increase accordingly.? For the design of tower frame steel chimney tower adopting synergy work system,strong connection should be adopted between tower frame and vent stack(layer by layer connection).It can be accepted that the wall thickness of vent stack just meet the design requirements.In the areas of wind load relatively strong,larger value should be used for the ratio of tower span to height.4)In this paper,the linear filtering methods are adopted to simulate the wind load to analyze wind vibration response for synergy work system of the tower frame steel chimney.The results show that:? Analysis of the vibration of tower of wind tower wind loads obtained by this method can replace the real time history sample.? From the peak of the nodal displacement and the wind vibration coefficient,the wind load time history analysis method and the equivalent static amplification coefficient of the load regulation are the static analysis method of wind vibration coefficient.The calculation results precision of equivalent static amplification coefficient method adopting load code can meet the requirements of engineering design.