Dynamic response characteristics of super high-rise buildings subjected to long-period ground motions

Spectrum characteristics of different types of seismic waves and dynamic response characteristics of super high-rise building structures under long-period ground motions were comparatively analyzed. First, the ground response wave （named LS-R wave） of a soft soil site with deep deposit, taking long-period bedrock seismic record as input, was calculated by wave propagation method. After that, a TOMAKOMAI station long-period seismic record from the Tokachi-Oki earthquake and conventional E1-Centro wave were also chosen. Spectrum characteristics of these waves were analyzed and compared. Then, a series of shaking table tests were performed on a 1：50 scale super high-rise structural model under these seismic waves. Furthermore, numerical simulation of the prototype structure under these excitations was conducted, and structure damages under different intensive ground motions were discussed. The results show that： 1） Spectrum characteristics of ground response wave are significantly influenced by soft soil site with deep deposit, and the predominant period has an increasing trend. 2） The maximum acceleration amplification factor of the structure under the TOM wave is two times that under the E1-Centro wave; while the maximum displacement response of the structure under the TOM wave is 4.4 times that under the E1-Centro wave. Long-period ground motions show greater influences on displacement responses than acceleration responses for super high-rise building structures. 3） Most inelastic damage occurs at the upper 1/3 part of the super high-rise building when subjected to long-period ground motions.

Effects of high modes on the wind-induced response of super high-rise buildings

For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise buildings are very sensitive to fluctuating wind. The wind load is one of the key loads in the design of super high-rise buildings. It is known that only the basic mode is needed in the wind-response analysis of tall buildings. However, for super high-rise buildings, especially for the acceleration response, because of the frequency amplification of the high modes, the high modes and the mode coupling may need to be considered. Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response. The conclusions can be drawn as follows. First, for the displacement response, the basic mode is dominant, and the high modes can be neglected. Second, for the acceleration response, the high modes and the mode coupling should be considered. Lastly, the strain energy of modes can only give the vibration energy distribution of the high-rise building, and it cannot describe the local wind-induced vibration of high-rise buildings, especially for the top acceleration response.

Discussion on the Construction of Anti-smoke Construction Technology in Super High-rise Buildings

In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper analyzes the smoke control technology of super high-rise buildings.The paper analyzes the importance of the application of anti-smoke construction technology in super high-rise buildings,analyzes the problems in the construction of smoke control and super high-rise buildings.The anti-smoke construction technology was studied and I hope that it can benefit the application of anti-smoke construction technology in high-rise buildings.

Collapse simulation of a super high-rise building subjected to extremely strong earthquakes

In recent years, super high-rise buildings (>500 m) are developing very quickly and become an important frontier of civil engineering. The collapse resistance of super high-rise buildings subjected to extremely strong earthquake is a critical problem that must be intensively studied. This paper builds up a nonlinear finite element model of the tallest building in China, Shang- hai Tower (632 m), and proposes the modeling method and failure criteria for different structural elements. The dynamic char- acters of this building are then analyzed, and the possible failure modes and collapse processes due to earthquakes are pre- dicted, as well as the corresponding collapse mechanism. This work will be helpful in collapse prevention and the seismic design of super high-rise buildings.

An improved ground motion intensity measure for super high-rise buildings

Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.

超高层锥形钢屋架高空累积滑移施工技术

根据武汉长江传媒大厦屋面锥形钢屋架结构特点,通过方案对比确定采用超高层高空累积滑移施工技术,并对高空累积滑移施工步序进行了阐述。针对累积滑移施工实际,采用ANSYS有限元软件对累积滑移施工工况进行了仿真分析,并对滑移轨道进行了详细设计。施工时,选用了计算机控制液压同步顶推滑移系统,实现了各个滑移顶推点的同步性。整个施工过程安全、经济、高效,各项检测指标符合设计要求。

深圳湾总部大楼罕遇地震作用弹塑性分析

深圳湾总部大楼为一栋高度为400 m的复杂超高层建筑,采用密柱框架-核心筒结构体系。密柱外框架由56根钢柱组成,梁柱连接采用完全偏心节点,外框架的刚度相对较弱。塔楼高区由于建筑体型收进,核心筒采用2层斜墙过渡收进。设计采用箱型钢梁和箱型钢柱组成密柱外框架,在核心筒剪力墙内埋设型钢加强,密柱外框架与核心筒剪力墙的抗震性能要求均提高至中震弹性。运用ABAQUS和BEPTA程序,将梁、柱和剪力墙的材料非线性在应力-应变层次上予以精确模拟,同时考虑结构的几何非线性,进行结构在罕遇地震作用下的弹塑性时程分析,研究结构在罕遇地震作用下的抗震性能。结果表明:密柱外框架具有较高的抗震承载力,可以起到第二道抗震防线的作用;结构的层间位移角满足规范的限值要求;密柱外框架与核心筒剪力墙的主承重构件均未出现明显损坏,结构具有较好的抗震性能。