基于火电厂地震扭转性能的钢支撑布置分析

发布时间：2018-07-07 09:09

本文选题：火电厂主厂房 + 扭转效应　；参考：《西南交通大学》2017年硕士论文

【摘要】：地震作用下的扭转是火电厂主厂房设计中经常遇到的问题,而为了满足工艺的需求,通常将除氧间设计成多层框架结构,将汽机房做成单层排架结构,这样将两种结构形式相连所形成的框排架体系因质量和刚度的分布不均匀,具有很强的不规则性。加上设备种类繁多、纵横向尺寸差别大、空间布置复杂等特点,结构在地震作用下容易产生较大的扭转效应并存在多个薄弱层。因此,为了保证电力系统在地震作用下的正常运行,有必要对火电厂主厂房因结构的扭转效应进行分析,并在此基础上采取措施进行控制。本文以某火电厂框排架主厂房作为工程背景,采用振型分解反应谱分析和弹性动力时程分析的方法,通过从平面和空间两个维度上考察结构的自振特性、地震变形、结构内力、不规则参数及竖向构件扭转指标,得到了结构薄弱层分布、扭转特点、不规则分布及地震响应规律。在此基础上,在结构中布置符合工艺要求的钢支撑,并改变支撑布置形式和布置位置,分析其动力特性及扭转位移比的变化。选取最合理的钢支撑布置方式,对比分析了增加钢支撑以后,扭转效应对结构变形和构件内力影响的改变。分析结果表明:因质量和刚度的不均匀分分布,火电厂主厂房结构存在多个薄弱层,平面和竖向不规则,扭转效应强。对布置了钢支撑的模型分析结果表明:在单向布置支撑时,横向钢支撑分开布置能够有效的降低扭转指标,增大扭转刚度,而纵向钢支撑的单向布置只能增强结构的平动刚度;在结构端部双向分散布置两个方向的钢支撑不仅增大了结构扭转刚度,控制了扭转指标,并且有效的降低了偏心导致的结构变形放大,减缓了扭转效应对结构边柱及排架柱内力的放大,为合理的支撑布置方式。
[Abstract]:Torsion under earthquake is a common problem in the design of main building of thermal power plant. In order to meet the requirement of technology, the deoxygenation room is usually designed as a multi-story frame structure, and the steam engine room is made into a single-layer frame structure. Thus the frame bent system formed by connecting the two structural forms has strong irregularity due to the uneven distribution of mass and stiffness. In addition, there are many kinds of equipments, great difference in longitudinal and horizontal dimensions, complicated space arrangement, and so on. The structure is prone to produce large torsional effect and many weak layers under earthquake action. Therefore, in order to ensure the normal operation of power system under earthquake, it is necessary to analyze the torsional effect of the main building of thermal power plant and take measures to control it. In this paper, the natural vibration characteristics, earthquake deformation and internal force of the structure are investigated from two dimensions of plane and space by using the method of mode decomposition response spectrum analysis and elastic dynamic time history analysis, taking the frame bent main building of a thermal power plant as the engineering background, and using the method of mode decomposition response spectrum analysis and elastic dynamic time history analysis. Irregular parameters and torsional index of vertical members are obtained, and the distribution of weak layer, torsional characteristics, irregular distribution and seismic response are obtained. On this basis, the steel braces are arranged in accordance with the technological requirements in the structure, and the form and position of the bracing arrangement are changed, and the dynamic characteristics and the variation of the ratio of torsional displacement are analyzed. The most reasonable arrangement of steel braces is selected and the effect of torsional effect on structural deformation and internal force of members is compared and analyzed with the increase of steel bracing. The results show that due to the uneven distribution of mass and stiffness, there are many weak layers, plane and vertical irregularity, and strong torsional effect in the main building structure of thermal power plant. The results of the model analysis show that the lateral steel bracing can effectively reduce the torsion index and increase the torsional stiffness while the unidirectional arrangement of longitudinal steel braces can only enhance the translational stiffness of the structure. The bidirectional distribution of steel braces at the end of the structure not only increases the torsional stiffness of the structure and controls the torsional index, but also effectively reduces the distortion and magnification caused by eccentricity. The effect of torsion is reduced to enlarge the internal force of the side column and the bent column, and it is a reasonable support arrangement mode.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU352.11

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