Research On Seismic Performance Of High-Rise Building Structure With Ultra Short Columns

It is likely to appear short column with shear span less than 2 and no less than1.5 or extremely short columns with shear span less than 1.5 in multistory-tall buildings, for the effect of storey height, beam height and load. And it is easier to appear shear failure under earthquake. Short column or extremely short column were found damaged in previous earthquake accident. How to improve short column and extremely short column behavior of seismic performance is the key to improve the whole building seismic performance. Existed specification has some specific of seismic measures for short column, but for extremely short column, specification in it required limited axis pressure value which should be specifically research and take special structure measures in high-rise building especially in super high buildings. It is inevitable to avoid extremely short column, so design of short column becomes a key issue, seismic behavior of short column in high-rise building structure research and analysis is particularly important.This paper carries out a comparative study on the short column of the project,ba sed on an example of the office building construction, which has 34 storeys, 142.3meters high,applies the frame core-tube system. In this building, the four layers of th e lower part are used for business, the 5th floor and the 20 th floor are transfer story.t he skirt building has 4 storeys,the basement has 2 storeys.The building belongs to th e B grade out-codes structure,and the main lateral force resisting elements of the str ucture is the core wall. Three species situation of substitution used equal axis pressure for design, by using PKPM-SATWE software, PUSH&EPDA and the MIDAS-BUILDING, mechanical behavior and whole seismic behavior of extremely short columns are compared in small earthquake, medium earthquake and large earthquake. The researching work as follows:(1)Establish different finite element models under the condition of the structure with different types of short column, and then analysis the seismic performance of the structure and the force performance of the short columns under different levels of earthquake. The results show that under the condition of original project, the common reinforced concrete short columns can meet the earthquake resistance design requirements without using any special structure measures.(2)Respectively analysis the static elastic-plastic and dynastic elastic-plastic for the structures with different types short columns and compare with the seismic perforce under the infrequent condition of earthquake, then check the collapse resistance under the frequent condition of earthquake and infrequent condition,research the failure forms and maximum stress distribution of the short column, hunt the weak parts of the structure, finally come to the conclusion that adopt concrete filled steel tubular columns is the best measures to improve the seismic performance of the structure(3)Analysis of the conclusions of this study, combined with the real project, the measures on the high-rise building structure with short column are put forward,which meet the design codes and requirements of seismic code, furthermore, the inadequacies of the study are explored and the directions that needed to continue to study are pointed out. Finally, the analytical method and the results are expected to provide ideas for the similar seismic design in the future.