Analysis Of Seismic Behaviour Of High-rise Steel Structure With Buckling-restrained Braces

The system of composite concrete filled square steel tubular column-steel beam structure is a promising application architecture structure. When used in the framework of bending resistance, concrete filled steel tubular column controlled structure lateral displacement, so it can give full play to its light weight and good ductility. Steel beam has the advantage of light weight. high intensity, short duration and ease of opening. With the height increase of high—rise buildings, the influence of horizontal actions will become evident and lateral displacement will be large. It is an effective means for decrease of structural horizontal displacement to set up braces.Support is usually divided into general support and energy support. General support under the earthquake is easily to be yielded and quit working, resulting in a sharp decline in overall stiffness and bearing capacity. Buckling restrained braces not only can increase stiffness of the structure under small earthquakes, but also can reach fully sectional yielding of the core under compression, its stable hysteretic behavior keep the BRB braced steel frames working well under rare earthquakes.Several possible failure forms were separately introduced and analyzed on buckling-restrained braces, and the corresponding restrictions were given. Some other corresponding analysis made to related parameters, and given the whole design process of the braces. Finally, capacity and node welds were calculated and studied.Design philosophy focuses on performance-based design methodology, establishment of standards for different degrees of intensity earthquake of structure must meet performance goals. The Finite element program ETABS and PKPM on the practical engineering applications with common support and BRB support square steel tube concrete column-steel beam composite frame structure seismic performance analysis. Reference the related research, modeling the beams, columns, and node supports. The models both considered the material nonlinearity and geometric nonlinearity characteristics. First of all, modal analysis of the two models are conducted to get basic dynamic characteristic which is the foundation of most structure dynamic analysis. Then, response spectrum method and elastic time-history analysis on the two models under frequent earthquakes are conducted to get their Interlayer displacement, displacement of floor and the floor shear, and the seismic response of the both under frequent earthquakes is analyzed.Finally, the elastic-plastic time-history analysis and static elastic-plastic analysis are completed to evaluate the structural behavior through ETABS and SAP2000, the results indicate that BRB could effectively decrease structural lateral displacement and act as the first line of defense role. In the non-linear time history analysis process, using several rare earthquake adjusted to the required level of intensity earthquake acceleration record the model is loaded, the adjusted seismic acceleration response spectra recorded should meet the specification requirements of the target response spectrum. Through the properties of the structure reactions at different levels of seismic action, compared to the performance index of norms, examine and verify the results of finite element analysis on seismic performance meets the design requirements.