Seismic Performance Evaluation On Steel Frame Structure Of Thermal Power Plant Main Buildings

Because of having the characteristics of light weight and flexible layout, steel frame structure of thermal power plant main buildings are widely applied in high earthquake intensity zone in recent years. With the demand of complex process, braces can’t be arranged in a rational way which is helpful for seismic design, leading to maldistribution of the structure, eventually affected its seismic performance. Besides, most of the steel main plants have only been analyzed the bearing capacity and deformation under frequent earthquake when designing at present, having not considered its seismic behavior under rare earthquake. Therefore, it is very meaningful to evaluate the elastic-plastic performance of the main plants under different seismic action.At first, this paper compares the difference of plastic hinge based on American and Chinese code in detail, and analysis effect of the differences on seismic performance of the structure. Then according to evaluate the seismic performance of main power plant under small and big earthquake, presenting the insufficient in design and verifying universality of this question. At last, this paper puts forward concrete measure to solve this question and verifies the rationalization of this measure.Based on the above-mentioned work, the main conclusions of this paper can be drawn as follow:①According to the result of nonlinear static analysis for a three bay concentrically braced frame, the structure which plastic hinge property is based on Chinese code will reach the plastic phase firstly, top displacement and base shear are less than the structure based on American code. The American standard will overrate structures’ seismic performance than Chinese code, and the structure shall be designed based on Chinese code.② According to the result of nonlinear tine history analysis, steel main plants have a common question that can’t satisfy the demand of seismic performance under rare earthquake. Mainly having two manifestation: one is interstory drift exceeds the demand of standard because of the structures’ weak story; the other is part of structures are destroyed because of portion component having reached ultimate bearing capacity.③ Putting forward a general optimization method for seismic performance of steel main plants: Select appropriate optimization method according to stiffness ratio of brace and column each story, and through controlling the axial compression ratio of brace and the plastic strength of column, make sure the structure can satisfy the demand of seismic performance under rare earthquake.