Seismic Isolation Analysis Of Mega-Frame Structures

The mega-frame structure system is a new type of structural system. It has many significant characteristics and advantages, compared with the other structural systems. The force transmission of the structure is clear and direct and it has good integrity and flexible arrangement of the indoor space. Moreover, it saves material with short construction period, and it can make better balance between the material and structural performance. Thus, it is valuable in theory and practically meaningful to study the mega-frame structures.In this dissertation, two types of mega-frame systems were studied, i.e., one is the fixed link between the major frame and each story of the minor frames, and the other is isolated between the major frame and each story of the minor frames. CQC method is suggested for seismic response spectrum analysis since there exists the coupling effect among many vibration modes. Comparison and evaluation were made for these two types of mega-frame systems.The friction pendulum bearings were introduced into the mega-frame structure to form the seismic isolated mega-frame system. The numerical results indicate that the friction pendulum bearings can moderately reduce the seismic responses of the major frame, but they can significantly reduce the seismic responses of the minor frames.The parametric studies of the friction pendulum bearings were conducted. The analytical results show that the radius of sliding surface is one of the most important parameters, and the lager the radius is, the more effective for the minor frames but the less effective for the major frame. The frictional coefficient is another key parameter, and the lager the frictional coefficient is, the more effective for the major frame but the less effective for the minor frames.