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Study on Torsion Design for Horizontal Irregular Buildings under Effect of Earthquake

Author: ZhangLei
Tutor: LiYingMin
School: Chongqing University
Course: Disaster Prevention and Reduction Engineering and Protective Engineering
Keywords: Torsion Displacement ratio limit Period ratio Torsion angle
CLC: TU973.2
Type: Master's thesis
Year: 2008
Downloads: 257
Quote: 3
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Abstract

Often due to construction of modern high-rise building facade features and requirements arising from various non-regular structure. Where the problem is more prominent and irregular twist common. Poor ductility of such buildings, structures earthquake damage is sudden twist, serious damage. \Non-structural design of complex rules on how to take measures to meet two control indicators are structural designer must face each issue, but also more difficult to deal with the problem, so it is very necessary to study. This paper discusses the impact of structural factors torsion, torsion problem at home and abroad on current research are reviewed and elaborated China's current specification of the structure and the relevant provisions of twist control problems. Then design the structure of different eccentricity examples and identify structural displacement ratio, story drift ratio, maximum displacement between layers, layer average displacement, angular displacement between layers, layer plane torsion angle θ with the variation of floors. And deduced floor displacement ratio torsion angle θ with the relationship between the various levels of earthquake action to reverse the effects of the relationship between indicators. Through the above analysis of the main results obtained are: ① flat irregular tall buildings near the bottom layers, displacement ratio is often difficult to meet the specification, but the reverse effect is not large. The reason is that the displacement ratio is a relative indicator, if a maximum horizontal displacement are very small and the average displacement of the average displacement faster than the maximum displacement approaching zero displacement ratio in this case may be large, and the specification limit exceeded , thus losing their control to reverse meaning. ② This paper argues that structural plane is directly related to the interlayer torsional twist angle θ plane, whereas the inter-layer planar torsion angle θ is an absolute indicator of the structure at the top of each layer of the structure relative to the bottom of a torsion angle. As can be seen from the third chapter, the bottom layers of the structural displacement ratio overrun, but the structure of the interlayer twist angle θ, is not large, the maximum displacement between layers, layer average displacement, maximum drift angle are not large ; opposite twist angle of the intermediate layer is greater than the displacement but it decreases. ③ \Large structures such as T1, to meet the cycle than the case of Tt may be relatively large; T1 small structures, in order to meet the period ratio, Tt forced to be made very small, which makes the structure of the weak torsion translational strict control, and translational twist control over the structure just too strict. Frame period ratio easier to meet the requirements of the other parameters remain unchanged, if the added wall in the middle, compared to the frame structure to be more secure, but would be more difficult to meet the requirements of period ratio. According to the literature indicates that cycle ratio and displacement ratio of a certain relationship, and for the reverse, the structure of planar torsion directly reflected in the size of the structure on the interlayer twist angle θ. So this proposal can be canceled than the prescribed period.

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CLC: > Industrial Technology > Building Science > High-rise buildings > Tall Building Structures > Structural Analysis and Calculation
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