Responses Of Super-tall Buildings Research Articles

Tuned tandem mass dampers-inerters for suppressing vortex-induced vibration of super-tall buildings

Modern super-tall buildings with rectangular floor shapes are vulnerable to significant vibrations due to the vortex shedding effect formed around structural edges. Tuned tandem mass dampers-inerters (TTMDI) is extended in this study to suppress vortex-induced responses of super tall buildings for occupant comforts. The optimal TTMDI tuning problem for a 400 m super tall building exposed to crosswind loads is solved through frequency-domain analysis. Meanwhile, the control performance of TTMDI is explored and contrasted with that of the tuned mass damper (TMD), tuned tandem mass dampers (TTMD) and tuned mass damper‐inerter (TMDI) from various perspectives. A crosswind-resistant design framework of the TTMDI equipped super-tall building system is then devised to meet comfort requirements. Finally, results are further assessed in the time -domain using a virtual real time hybrid simulation (VRTHS) system based on the proposed hybrid model predictive controller. It is found that there are several optimal inertance coefficient redistribution points (i.e. R points) in the design process and the R points have a great impact on the optimal internal structure of TTMDI. Results clearly demonstrate that TTMDI has better effectiveness and robustness than TMD, TTMD, and TMDI. Moreover, the total demand for total damping coefficients of TTMDI is significantly smaller than TMDI after the R points, indicating that it is easier to implement in engineering practices.

An experimental study on the wind pressure distribution of tapered super high‐rise buildings

SummaryStudies on the effect of different shape strategies on wind‐induced responses of super tall buildings have been extensive. However, little systematic research on the influence of aerodynamic shapes on wind pressure distributions of super high‐rise building having a height more than 500 m is reported in the literature. In this paper, a series of wind tunnel tests are conducted on models simulating tapered buildings taller than 500 m with an aspect ratio of 9:1 by applying synchronous pressure measurement technology to investigate the influence of different shape strategies on the wind force coefficients of the cross section (Cs) and on the peak negative pressure distributions on surfaces. The shape strategies considered include tapering of the cross section of a building along its height, chamfered modification, and opening ventilation slots. It is found that the wind force coefficient Cs increase with an increase of the tapering ratio. It is shown that chamfered modification can effectively reduce most of the wind force coefficients Cs to less than 0.9. As for peak wind pressures, a zone having a higher negative pressure is found to locate at the bottom of the side faces of the model. With an increase of the tapering ratio, the peak negative pressure of side faces of the model slightly decreases. Chamfered modification can significantly increase the peak negative pressure at the chamfered location. Furthermore, it is demonstrated that opening ventilation slots had less effect on Cs, but the peak negative pressure can significantly increase at the area of opening ventilation slots and adjacent areas.

Effects of amplitude-dependent damping and time constant on wind-induced responses of super tall building

Full-scale measurements of wind-induced responses of a 79-storey tall building, Di Wang Tower, were conducted during the passages of several typhoons. The amplitude-dependent damping ratios of the super tall building were obtained from the measurements. A Monte Carlo simulation procedure was developed in this study to generate fluctuating along-wind and across-wind forces acting on this building. The wind-induced responses of Di Wang Tower were numerically evaluated in time domain on the basis of the generated fluctuating wind forces and the established finite element model of the building. The predicted dynamic responses of the building using the actual amplitude-dependent damping characteristics were compared to those computed with constant damping parameters assumed by the structural designers to evaluate the adequacy of current design practices and to investigate the effect of amplitude-dependent damping on the wind-induced responses. Finally, the effect of time constant on the wind-induced responses of Di Wang Tower was studied by comparing the time domain computational results with those from conventional spectral analysis method. Some of the research findings resulted from this combined experimental and numerical study are expected to be of interest and practical use to professionals and researchers involved in the design and analysis of super tall buildings.