Eight Degrees Fortification Area Super-rise Frame-core Tube Structure Scheme Selection And Design

High-rise building is not only a good solution for the land shortage caused by growing population of big cities, but also represents the economic development and engineering technical level of a country. With the rapid development of Chinese economic, more and more super-rise buildings have been built. China is a country where earthquakes happen frequently, many large cities located in the 8 degrees fortification area. With the increase in building height, horizontal load is becoming a key factor in structural design process. How to find the best scheme for the structure design to control the lateral deformation under seismic load and ensure structural safety has become an important issue to be studied. The structural layout selection and optimization during the preliminary design has a direct impact on the overall performance and economical efficiency of the structure.In this paper, 8 models have been established based on a super high-rise engineering example--350 meters high Xi'an Ricoeur international financial center project. Structural system, column spacing, the size of the core walls and the section type of the frame beam have been compared to study the impact on the seismic performance and the economical efficiency. After comparing, some conclusions have been got: first, frame-core tube structure will cost more than mega frame structure; second, when the column span increases, in order to meet the requirement for lateral stiffness, more material will be used; third, increases the size of the core tube will improve the lateral stiffness of the structure. So 30mX30 m core tube, 6 meters column spacing frame core tube structure scheme has been selected. By then, 5 models have been established. Without changing the size of the core tube and the frame member, different strengthened story arrangements have been studied. It shows that installs the strengthened story in the second, fourth refuge floors and belt truss in the fifth refuge floor can effectively control the lateral displacement, gives a certain reference for engineering design.According to the final structural scheme, a model has been built using a sturctural design software called PKPM. Based on the elastic analysis in accordance with regulatory requirements, the result shows that after a reasonable design, the performance of structure meets the standard index and each component capacity satisfies the design requirements. Elastic-plastic time history analysis has been done to verify the safety of the structure under rare earthquake. The result proves that the structure meet the seismic design principles "No damage under minor earthquake, can repair after middle earthquake, don't collapse under rare earthquake". And design proposals for the weak position have been presented. In order to study the weak part of the structure, finite element models have been built using Abaqus. Result shows the internal force distribution of the structure under rare earthquake. According the result some design recommendations are given.This paper emphasizes the importance of the pre-selection and optimization during structure design. The summary of the optimization process will provide a reference for similar high-rise structure design and simplify the design process.