| In recent years,China's electric power equipment manufacturing industry has developed rapidly.The unit size has been increasing,and the capacity of a single unit of power generation boilers has exceeded 1000MW.With the continuous improvement of the strategic influence of national equipment manufacturing development,China's electric power equipment has also stepped out of the country to the world.The height of 1000MW power plant boiler equipment reaches 90 meters,the total load of equipment exceeds 40,000 tons,and all loads need to be transferred to the foundation through the boiler structural support steel.Therefore,as a heavy load-bearing boiler structural support steel,reasonable design is very important for the ultimate safe and effective operation of the boiler.Because of the high height,large weight of boiler equipment and the wide impact of secondary disasters after earthquakes,the seismic performance of large-scale utility boiler steel structure has been a concern of the industry.The demand of electricity market is very strong in Southeast Asia,because most of them are in areas of high seismic intensity,the seismic requirements are higher.In this paper,taking the structural steel supporting a 1000MW type ? boiler as the study subject,the seismic performance as the study content,the static analysis of the structure as the study basis,ASCE and AISC seismic provisions and the STAAD.Pro structural analysis software as the study methods,the seismic performance of the steel structure of the boiler is studied by the response spectrum method,and the dynamic characteristics of the structure are determined.(1)According to the specific requirements of American seismic provisions,this paper compares and analyzes the results of the fundamental period of boiler structural support steel calculated by approximate formula and structural analysis,and compares and analyzes the fundamental period obtained by structural analysis and calculation of several projects.It is found that for type ? boiler structural support steel of 75 to 100 meter height,which use concentrically braced frames,the fundamental period calculated by the approximate formula is conservative,while the period calculated by structural analysis is relatively convergent,and the period values are all about 2 seconds.(2)In this paper,through in-depth study of the relevant provisions and comments in the American seismic provisions,the background significance of the key parameters of seismic performance is understood,and the relationship between the response modification coefficient,structural overstrength factor and redundancy is analyzed.The selection principle of lateral force system and the influence of structural irregularities on the seismic performance of structures are given.The seismic design in accordance with the American provisions is summarized.The seismic design method based on American provisons is proposed and verified on a project.(3)Based on the study results of fundamental period and seismic design method of boiler structural support steel,this paper adjusts the design of a boiler structural support steel in three ways:Determining the effective seismic weight carefully,arranging the vertical bracings reasonably and using the period obtained by structural analysis and calculation.On the premise of ensuring that the adjusted structure can meet or even surpass the strength and stiffness requirements before the adjustment.Good economic benefits had been achieved. |
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