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巨型框筒—钢子框架结构的隔震分析
Analysis on the Isolation of Megaframe Tube-Steel Subframe Structure
【作者】 徐长春;
【导师】 邓志恒;
【作者基本信息】 广西大学 , 结构工程, 2008, 硕士
【摘要】 本文提出了巨型框筒-钢子框架结构,总结了基础隔震的优缺点,提出了子框架隔震,利用拉格朗日原理推导隔震结构的运动方程。对这种新型结构利用ANSYS建立了两种方案模型,一种是设有隔震装置,一种是不设隔震装置。对两种方案做了谱分析和时程分析,比较了两种方案下的响应值,分析在地震作用下结构体系的抗震性能和设有隔震装置的隔震效果,并且分析了隔震参数对结构的影响。通过模态分析,方案二的第一阶周期比方案一的第一阶周期长38.16%,结构的前四阶振型非常相似,第一阶都是Y向平动,第二阶X向平动,第三阶扭转振型;通过地震反应谱分析,方案二的柱子剪力和子框架剪力都比方案一的要小,虽然方案二位移要大,但是隔震以后其刚度变小,致使剪力变小。对剪力墙剪力响应而言,方案二要大于方案一,但是总剪力方案二要小于方案一,总剪力减小的比率在27%以上,有明显减震效果;通过动力时程分析,比较两种方案的位移响应图,可知,结构体系在输入X向地震之后,X向地震反应比较大,Y向和Z向的反应很小。与无隔震结构体系相比,隔震结构体系的位移要大,平均大40%;隔震结构体系的速度要小,平均小70%;隔震结构体系的加速度要小,平均小60%;隔震结构体系的底层柱子剪力要小,平均小30%;隔震结构体系的剪力墙剪力要大,平均大30%;隔震结构体系的子框架剪力要小,平均小70%;在其余参数不变的情况下,改变隔震装置的水平刚度,随着水平刚度的变大,结构的周期、位移变小,速度和加速度变大,结构的剪力墙剪力变小,柱子剪力和底层子框架剪力变大。分析结果表明设有隔震装置的巨型框筒-钢子框架结构具有良好的减震效果。
【Abstract】 This paper proposed a new structure megaframe tube-steel subframe structure, summed up the base isolation of the advantages and disadvantages, proposed framework of isolation, maked use of Lagrange principle to deduce the motion equation of isolated structure. This paper has established two kinds of plan models to this kind of new structure using ANSYS, one kind is equipped with isolation device, one kind does not suppose isolation device, has made the spectrum analysis and the time-history analysis to two kind of plans, compared with two kind of plan’s under response values, has analyzed under the earthquake function the structure system’s earthquake resistance performance and the structure is equipped with isolation device’ s isolation effect. The isolation parameters on the structure has done analysis.Through modal analysis, the first order of the first option cycle is 38.16 percent longer than the second option, the structure of the former fourth-order vibration mode is very similar, the first order is to the Y-moving, the second is to the X-moving, third Order is to reverse mode .through the earthquake response spectrum analysis, the shear force of the pillars and the sub-frame of the first option smaller than the second, while the second option’s displacement is larger, but its stiffness smaller after isolated, resulting in the shear force is smaller . Shear response to shear walls, the second option is greater than the first, but general shear force is less than the first option, the shear decreases in the rate is about 27 percent, has the effect damping the vibration obviously, through dynamic time-history Analysis, comparing two options displacement response plans, we can see that structure in the X axis input impose, X axis response is relatively large, Y and Z axis respond is smaller. compared with the non-isolated structure system , the displacement of isolated structure is 40 percent lager, the speed of isolated structure is with an average 70 percent smaller, the acceleration of isolated structure is with an average 60 percent smaller , the shear force of bottom pillar of isolated structure is with an average 30 percent smaller ,the shear force of shear wall of isolated structure is with an average 30 percent larger,the shear force of sub-frame of isolated structure is with an average 70 percent smaller. in the other parameters remain unchanged, change the structure of the level of isolation Stiffness, with the rigidity of the larger,the structure of the cycle and displacement is smaller,velocity and acceleration increace, the structure’s shear force of shear wall is smaller,pillars shear force and the bottom sub-frame shear force larger.The results show that megaframe tube-steel subframe structure that equiped with isolation device has good earthquake absorption effect.
【Key words】 megaframe tube-steel subframe structure; isolation; ANSYS; Spectrum analysis; time-history analysis; isolation parameter;