Study On Seismic Performance Of High-Rise Buildings With Tall Towers Mounted On Roofs

As the mobile communication industry develops rapidly, many communication towers have sprung up all over the country. In urban areas, in order to obtain a larger signal area, more and more engineering applications of hige-rise building with rooftop tall tower appear. Under earthquake, rooftop towers will produce obvious “whiplash effect”, while the main structures' dynamic properties and seismic response will also change because of the effect of rooftop towers. Therefore, the study on seismic performance of high-rise buildings with tall towers mounted on the roofs is of great significance.This thesis takes an engineering case of a high-rise building with a tall tower on its roof as an example, by changing the main structure's height, the structural form, the location and the height of the rooftop tower and whether to mount rooftop towers, 20 structural schemes are formed. Using SAP2000 to model each structure and conduct response spectrum analysis to each model, this thesis studies the effects of dynamic characteristics, structural displacements and internal forces of high-rise buildings due to the mounting of rooftop towers, different structural forms and locations of roof tower, and main structure's height. Using ABAQUS to model the whole building and the main structure and conduct pushover analysis to each model, this thesis studies the influence on seismic performance of high-rise buildings due to rooftop towers under rare earthquake.The research shows that rooftop towers increase the stuctures' natural periods, floor displacements and story drifts, but reduce the story shear forces. The height of the main structures has a great influence on the seismic performance of high-rise buildings. The research also shows that rooftop towers increase the target displacements of structures and have a great effect on the story drifts and story shear forces of high-rise buildings.