Static,aseismic And Wind-resistant Analysis Of Stell Mega-frame

Mega structure is a new Structural system of super high-rise building.Its primary structure is composed of huge truss or huge frame,worked together with secondary structure.As far as mega-frame.one typical form of mega structure,concerned its characteristic under static loads.dynamic loads.wind-induced vibration and earthquake is analyzed systematically in this dissertation.The mega-frame is discussed about its static characteristic when acted by vertical and horizontal loads.The internal force.displacement and force direction of structure induced by different loads are studied,so is the influence of structural mechanical characteristic acted by different parameters.Especially.when mega-frame acted by horizontal load,the influence of ream connection and fixation connection of the secondary structure with the primary structure is studied.Based on these analysis.the optimal design is carried out to obtain the optimal mechanical characteristic on the carpet of economic diathesis.Vibration characteristic of five kinds of models is anaiyzed.and the influence of component section area,the number and location of huge beams to vibration characteristic is investigated.Vibration shapes-separation-spectra-method is adopted to calculate the three-dimension dynamics characteristic of mega-frame,and the influence of stiffness, vibration shapes combination and mode superposition to seismic behavior is discussed.Elasto-plastic seismic behavior in rare seism is studied in step-by-step integration proceduce.Furthermore,in this dissertation, new category of seismic structures.called Damage Tolerant Structure(DTS),is studied and explored through the simplified method which cuts down the number of the nodes,the memory needed and the time used to solve the equation compared with the Finite Element Method.The comparison of the result with the precise method indicted that the simplified method is feasible and credible.According to the fluctuating property of wind,based on the stochastic vibration finite element theory,some calculation formulas of the response,including the along-wind response and the across-wind response,are obtained.The variance law of dynamic displacement and wind-induced vibration coefficient is derived through analyzing structure stochastic vibration,so is the effect of several parameters on dynamic displacement,acceleration and wind-induced vibration coefficient.The reason why the outcome is different from that of the code is also interpreted.The super high-rise building is sensitive to the wind load because of its height and flexibility,so time history analysis is necessary.and time history record of fluctuating wind is needed.In this dissertation,firstly,current wind-resistant design methods for the structure and the simulation techniques for wind action are reviewed and compared,and the main problems in wind-resistant research are presented.Secondly,considering time and spatial correlativity,useful artificial wind speed processes are generated with the autoregressive-type simulation methods.Then,the method is applied in the digital simulation of wind action on two small examples,which proves that this simulation method is effective.Using dynamic analysis program,the wind-induced vibration behavior of mega-frame is investigated.At the same time,the equivalent static method suggested by load criterion is used to analyze the wind action of the structure.Based on the analysis and comparison of two methods,some suggestions about wind-resistant analysis of mega-frame are presented.Finally,some conclusions about the theoretical analysis method are drawn,which provide the reasonable theory and reliable data for the revision of the high-rise building code.