Analysis On The Isolation Of Megaframe Tube-Steel Subframe Structure

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.