Design Of Super-tall Buildings Research Articles

Investigation of the Aerodynamic Forces on a 600-m-High Supertall Building by Field Measurements and Wind Tunnel Test

This paper investigates the aerodynamic forces on a 600-m-high supertall building based on field measurements during Super Typhoon Mangkhut and wind tunnel test on a 1∶500 scaled model of the monitored building. The local wind force coefficients and their power spectral densities obtained by the full-scale measurements and the model experiment are compared and discussed. The comparative study shows that the wind tunnel test provides conservative mean local drag coefficients and root-mean-square (RMS) local lift coefficients, whereas for the RMS local drag coefficients, the model experiment reproduces smaller predictions at higher levels than those from the onsite measurements. Moreover, to explore the deviations between the full-scale and model-scale results, the Reynolds number effects in the range of 5.5×104 to 1.8×108 on the local wind forces and the Strouhal number are investigated. It is found that the Reynolds number has evident effects on the local wind force coefficients, although its influence on the Strouhal number is negligible. This combined study of field measurements and wind tunnel test aims to enhance the understanding of the aerodynamic forces on high-rise buildings during strong windstorms and provide useful information for the wind-resistant design of supertall buildings.

The Influence of Aeroelastic Effects on Wind Load and Wind-Induced Response of a Super-Tall Building: An Experimental Study

To investigate the wind-induced response and equivalent wind load of a super-tall building, an aeroelastic model of the building was designed to measure aerodynamic interference in wind tunnel tests. Experiments on pressure and vibration measurements were conducted in both uniform and turbulent wind fields, and the displacement response and surface wind pressure at different locations of the model were recorded. The displacement time-history response spectrum and aerodynamic spectrum in both fields were compared and analyzed. The research showed that the mean displacement responses of the model in the across-wind and along-wind directions gradually increased with velocity under different wind attack angles. The mean displacement response of torsion moment in a uniform wind field changed very little, and the mean and fluctuating wind pressures in each layer were significantly stratified, making it is easy to generate a coupled vortex-induced resonance. On the other hand, the mean displacement response of torsion moment in a turbulent field increased with wind velocity. Strong turbulence made the fluctuating wind pressure at the top and bottom of the model slightly more significant than in a uniform field. The resistance of super-tall buildings came from turbulence excitation in the along-wind direction and the self-excited resistance generated by the across-wind direction. The test methods and main research conclusions may provide a reference for glass curtain walls and the structural wind-resistant design of super-tall buildings.

Kunming tower: composite systems in supertall design

AbstractFor the past 20 years, composite systems have dominated supertall construction. This paper will present composite construction solutions at system and component level in the design of supertall buildings using the example of the 407m tall Kunming Tower. The tower utilizes an innovative tied‐braced frame structural system at the perimeter and strategically placed energy dissipating mechanisms to meet the Chinese code requirements and to achieve seismic performance objectives. Given the complexity of the non‐prescriptive structure, many advanced analyses were performed to verify building behavior and optimize the structural system.

Investigation of structural responses and dynamic characteristics of a supertall building during Typhoon Kompasu

In this paper, comprehensive field measurements were conducted on a 600-m-high skyscraper in Shenzhen during Typhoon Kompasu based on structural health monitoring (SHM) system and a remotely non-contact interferometric radar system called IBIS-FS. The SHM system recorded wind field and structural responses, including accelerations at 10 building heights by accelerometers and horizontal displacements atop the building by global positioning system (GPS). Meanwhile, the IBIS-FS simultaneously measured the horizontal displacements of the building at multiple heights. This is the first time that the interferometric radar system, i.e., IBIS-FS, is applied to the displacement monitoring of a supertall building under typhoon conditions. The effectiveness of the IBIS-FS is verified through comparing the building responses measured by the IBIS-FS with those measured by the SHM system. Then, based on the field-measured responses, the mean, background, and resonant responses of the monitored supertall building are extracted and analyzed; and the amplitude dependencies and time-varying characteristics of the structural modal parameters (i.e., natural frequencies and damping ratios) are presented and discussed. The results show that the IBIS-FS can provide convenient and accurate displacement measurements of the skyscraper under severe weather conditions. This paper aims to provide useful information for SHM and wind-resistant design of supertall buildings in tropical cyclone-prone regions.

Fast optimization of outriggers for super-tall buildings using a sensitivity vector algorithm

This study proposes a simple engineering method to fast determine the quantity and placement of outriggers for super-tall buildings. At first, a sensitivity vector algorithm (SVA) is proposed by applying the vector dot-product algorithm to optimize outriggers in super-tall buildings towards the constraints of the maximum interstory drift . The proposed SVA is then demonstrated by a super-tall building under the wind load control and verified by the exhaustive search algorithm (ESA). Finally, the SVA is applied to optimize the outriggers for a super-tall building in the high-intensity seismic area . The results show that the optimal outrigger scheme relates to both the quantity and placement, rather than simply proportional to the quantity. Increasing the quantity of outriggers can reduce the interstory drift in the adjacent area of the added outrigger but may increase the interstory drift in other zones. The sensitivity vector algorithm can be used for the optimization of outriggers not only for the single-mode-driven wind load, but also for the multi-mode-driven seismic load, which is very helpful for the preliminary design of super-tall buildings. • Sensitivity vector algorithm is proposed to optimize quantity and placement of outriggers using vector dot-product algorithm. • Optimal outrigger scheme relates to both the quantity and placement, rather than simply proportional to the quantity. • Sensitivity vector algorithm can be used for both the single-mode-driven wind load and the multi-mode-driven seismic load.

Wind-resistant structural optimization of a supertall building with complex structural system

Wind load is the most critical kind of loads in the structural design of supertall buildings. Performance-based wind-resistant structural optimization can effectively reduce the material cost of supertall buildings in the premise of ensuring their structural safety and serviceability. For modern supertall buildings with complex structural systems, the formulation of its structural optimization problem is highly complicated. Moreover, the optimization problem itself is also nonlinear and extensive in scale. This study first addresses the optimization formulation of complex structure system which includes concrete-filled steel tube (CFST) frame members and shear wall members. These structural members are often used in supertall buildings but are seldom discussed in existing literature of structural optimization. Then, the interior point algorithm, which is propitious for large-scale nonlinear optimization, is used to seek the optimal design solution. A real-life supertall building, the 432 m Guangzhou West Tower, is used as an example to examine the effectiveness of the proposed computer-based optimization method. The proposed method is shown to work effectively in the optimal wind-resistant design of supertall buildings with complex structural systems.

A study on main architectural and structural design considerations of contemporary supertall buildings

The design of supertall buildings (300m+) involves many professionals from several disciplines. The need for coordination among numerous experts, increases complexity of the entire process, which is typically conducted under the leadership of the architect, or sometimes the contractor. Consequently, the architects designing supertall buildings must be aware of architectural and structural design considerations and their interrelations. In this paper, the main architectural design considerations and structural system details of supertall buildings are studied; these include 93 completed or under construction buildings from the 1980s onwards. This study analyses the contemporary trends in main architectural and structural design considerations and corresponding interrelations. In addition, more inclusive and consistent classifications of structural system, building form, and core planning are proposed. The comparison between design considerations over the new proposed classifications is intended to aid and direct architects in the planning and development of supertall building projects as a basic guideline.

Assessment of TC-Dominated Extreme Wind in the Scenario of Climate Change for Wind-Resistant Design of Super-Tall Buildings

Assessment of TC-Dominated Extreme Wind in the Scenario of Climate Change for Wind-Resistant Design of Super-Tall Buildings

A practical fractional numerical optimization method for designing economically and environmentally friendly super-tall buildings

Due to the complexity of super tall buildings, many well-known optimization algorithms are not well applicable. Using structural lateral system of super tall buildings as engineering background, the paper developed a practical fractional numerical optimization method (FNOM), which applies fractional strategy and quasi-constant assumption, to reduce material cost and embodied carbon cost by searching the optimal structural dimensions. Firstly, two kinds of relationships among optimization variables (structural dimensions), driven design constraints (the interstory drift and the natural period) and optimization objective (cost including material cost and embodied carbon cost) are mathematically modelled. Genetic algorithm (GA) is then introduced to search the optimal structural dimensions based on the quasi-constant assumption of virtual work and internal work of the inactive components. Thirdly, fractional strategy is applied to create assemblies composed of different structural component sets, and the assemblies are then to be optimized in proper sequences. Fourthly, FNOM is implemented as a user-friendly software called C-FNO to practically support the preliminary design of super-tall buildings. Finally, a 700 m high super-tall building is employed to illustrate FNOM by using C-FNO, and the results show that only three design constraints of the interstory drift, the natural period and the stress ratio need to be solved during each optimization step. Belt truss, mega column, outrigger truss and shear wall of the super tall building should be optimized in sequence to save more cost. A great amount of cost can be still saved for the super tall building with the normal traditional design.

Optimal vertical configuration of combined energy dissipation outriggers

SummaryThe damped outrigger system emerged as an improvement of the conventional outriggers with the aim to provide supplemental damping and to contribute to the vibration control in super tall buildings where this system is usually applied. In addition to viscous dampers (VDs), buckling‐restrained braces (BRBs) have also been employed as energy dissipating members in outriggers. Nevertheless, the combined use of outriggers with VDs and BRBs in the same structure has not yet been studied. Such combination can contribute to achieve an effective multiperformance design of super tall buildings. This paper presents a study whose main objective was to determine the optimal vertical combination of two types of energy dissipation outriggers to control the seismic responses of a 9‐zone super tall model structure. Outriggers with VDs (OVDs) and outriggers with BRBs (OBRBs) were placed at the different zones of the structure considering all the possible combinations and in configurations of up to four outriggers. The effects of these combinations on the seismic performance of the structure were studied through parametric analysis and optimization methods. This form of the outrigger system is defined in this paper as combined energy dissipation outrigger system. The results indicate that when two energy dissipation outriggers are used, the combination of OBRB plus OVD shows superior seismic performance compared with other double‐outrigger configurations. In addition, the results show that the locations of OVDs and OBRBs play an important role in the structure behavior; it was found that it is more beneficial to place OBRBs above OVDs.

Monitoring of wind effects on 600 m high Ping-An Finance Center during Typhoon Haima

This paper presents analyzed results of field measurements of wind-induced pressures on building claddings and structural responses of 600 m high Ping-An Finance Center (PAFC) in Shenzhen, China during the passage of Typhoon Haima. The characteristics of cladding pressures during the typhoon were investigated with highlights on energy distribution, non-Gaussian probability and coherence features. Then, the natural frequencies, damping ratios and mode shapes of the skyscraper were presented. Based on the field measurements, the amplitude-dependent characteristics of the modal parameters were discussed and the range of selection of damping ratio for the wind-resistant design of super-tall buildings was recommended. Finally, the serviceability of the skyscraper under typhoon condition was assessed. This paper aims to further understand the wind effects on super-tall buildings and provide useful information for the design of skyscrapers in tropic cyclone prone regions.

Planetary Boundary Layer Modeling and Standard Provisions for Supertall Building Design.

According to recent results of planetary boundary layer research relevant to the design of tall buildings subjected to large-scale synoptic storm winds, for elevations of up to at least 1 km, the longitudinal mean wind speeds are monotonically increasing with height. It is shown that, for this reason, to avoid the possible unconservative design of supertall buildings significantly affected aerodynamically by neighboring buildings, an explicit derogation from the ASCE 7 standard specification of the gradient heights zg is necessary for buildings with heights greater than zg .

Observation of wind fields over different terrains and wind effects on a super-tall building during a severe typhoon and verification of wind tunnel predictions

Wind effects are of major concern in the design of super-tall buildings, especially those located in tropical cyclone-prone regions. In July 2012, Hong Kong encountered one of the most severe typhoons in the history, Vicente (1208). This study investigates the impact of Vicente to Hong Kong with emphasis on the wind fields over different terrain conditions and the wind effects on a 420-m-high super-tall building. Within a time period of 18h that covered the passage of Vicente in Hong Kong, six sets of wind data were collected from five meteorological stations and a structural health monitoring (SHM) system installed in the super-tall building. In this study, the typhoon wind fields over varied types of terrains are revealed, the structural dynamic properties of the super-tall building as well as its serviceability are evaluated, and finally wind tunnel predictions of structural responses are validated by the field measurements from SHM system. This study aims to investigate the typhoon-generated wind characteristics over different terrains and the wind effects on a super-tall building located in a metropolis during a severe typhoon as well as verification of the accuracy of wind tunnel testing results, so as to provide useful information for the wind-resistant design of high-rise buildings in tropical cyclone-prone regions.

Lateral drift constrained structural optimization of an actual supertall building acted by wind load

AbstractRecent trends towards constructing taller and increasingly slender buildings imply that these structures are more sensitive to wind excitation. This paper presents a technique for the wind‐resistant optimal design of supertall buildings with a complex structural system including concrete‐filled steel tube columns, shear walls, and various types of beams and columns. In each optimal design cycle, the dynamic wind load acting on a building is transformed into a set of multiple‐oriented equivalent static wind loads, which converts the optimal design for a building acted by dynamic loads into a simpler optimal design problem that considers only static loads. The objective function and constraint functions are explicitly formulated for various types of frame and area members, and consequently, the optimal design problem is mathematically modeled. The optimality criteria method is employed to seek a solution to the optimal design problem. A 68‐story actual supertall building with a height of 303 m is considered for a case study. The obtained results show that the presented technique is capable of giving a good numerical optimal solution for practical use. The technique and results obtained from this study are valuable for academic and professional engineers involved in wind engineering and structural design.

Application of earthquake-induced collapse analysis in design optimization of a supertall building

Summary In recent years, a combination of rapid construction of supertall buildings and frequent occurrence of strong earthquakes worldwide demands a rational seismic design method for structures of this kind. Although earthquake-induced collapse analysis is one of the most efficient methods to quantify the collapse resistance of buildings, little research has been reported on using the collapse analysis to evaluate the seismic safety of supertall buildings during the design stage. To optimize the design taking into account earthquake-induced collapses, a real-world supertall building with a height greater than 500 m is investigated in this work. Throughout its design procedure, earthquake-induced collapse analyses are performed to optimize the design at three different levels (i.e. the structural system level, design parameter level and component level). At the structural system level, the influence of different lateral force-resisting systems on the collapse resistance is discussed; at the design parameter level, the influence of minimum base shear force is discussed; and at the component level, the influence of high-performance shear wall on the collapse resistance is studied. Based on these discussions, the optimal design scheme of the building is established to improve the seismic safety while maintaining the cost of construction. Given more and more supertall buildings will be constructed with new structural system and components, this work will provide important references for the seismic design of supertall buildings and the corresponding collapse resistance research in the future. Copyright © 2016 John Wiley & Sons, Ltd.

Wind tunnel and full-scale study of wind effects on a super-tall building

This paper presents the analyzed results from a combined wind tunnel and full-scale study of the wind effects on a super-tall building with a height of 420m in Hong Kong. In wind tunnel tests, mean and fluctuating forces and pressures on the building models for the cases of an isolated building and the building with the existing surrounding condition are measured by the high-frequency force balance technique and synchronous multi-pressure sensing system under two typical boundary layer wind flow fields. Global and local wind force coefficients and structural responses are presented and discussed. A detailed study is conducted to investigate the influences of incident wind direction, upstream terrain conditions and interferences from the surroundings on the wind loads and responses of the high-rise structure. On the other hand, full-scale measurements of the wind effects on the super-tall building have been performed under typhoon conditions. The field data, such as wind speed, wind direction, structural acceleration and displacement responses have been simultaneously and continuously recorded during the passage of 12 typhoons since 2008. Analysis of the field measured data is carried out to investigate the typhoon effects on the super-tall building. Finally, the model test results are compared with the full-scale measurements for verification of the wind tunnel test techniques. The comparative study shows that the wind tunnel testing can provide reasonable predictions of the structural resonant responses. The resonant displacement responses are comparable to the background displacement responses so that the contribution of the background responses to the total displacement responses should not be underestimated. The outcome of the combined wind tunnel and full-scale study is expected to be useful to engineers and researchers involved in the wind-resistant design of super-tall buildings.

Structural System Embodied Carbon Analysis for Super Tall Buildings

Building construction has been the main fields of energy consumption and greenhouse gas emission in the world nowadays. With the increase of building height, the amount of carbon dioxide discharged by the building has increased significantly during the entire life cycle. The impact of super tall buildings on the environment has drawn increasing attention due to the huge energy and material consumption. In the life cycle of the building, the carbon emissions are composed of three parts, say embodied carbon, operating carbon and demolition and disposal carbon. Embodied carbon of structural system contributes the most carbon emission during the construction stage of a supper tall building and thus is an important index to measure the environmental impacts of different structural systems for a given super tall building. The embodied carbons and environmental costs of typical super tall building structures for different structural systems are thoroughly analyzed in this study. The distribution of embodied carbons of critical structural members, such as the frame columns, central core walls, structural floors and outrigger trusses are also discussed. At last, this paper analyses the fundamental factors which influence the environmental costs, and the analysis results will provide a guide for the sustainable structural design of super tall buildings.

Wavelet-transform-based damping identification of a super-tall building under strong wind loads

A new method is proposed in this study for estimating the damping ratio of a super tall building under strong wind loads with short-time measured acceleration signals. This method incorporates two main steps. Firstly, the power spectral density of wind-induced acceleration response is obtained by the wavelet transform, then the dynamic characteristics including the natural frequency and damping ratio for the first vibration mode are estimated by a nonlinear regression analysis on the power spectral density. A numerical simulation illustrated that the damping ratios identified by the wavelet spectrum are superior in precision and stability to those values obtained from Welch's periodogram spectrum. To verify the efficiency of the proposed method, wind-induced acceleration responses of the Guangzhou West Tower (GZWT) measured in the field during Typhoon Usagi, which affected this building on September 22, 2013, were used. The damping ratios identified varied from 0.38% to 0.61% in direction 1 and from 0.22% to 0.59% in direction 2. This information is expected to be of considerable interest and practical use for engineers and researchers involved in the wind-resistant design of super-tall buildings.

Study on Wind Load Characteristics of a Super Tall Building Based on Numerical Simulation

This paper present some selected numerical results of a typical super-tall building based on a new Large Eddy Simulation scheme. The spatial correlation of local wind forces were presented and discussed in detail. The probabilistic characteristics of fluctuating wind loads were evaluated. Furthermore, the along-wind and across-wind spectral characteristics were studied and compared with the von Karman spectrum. The output of this study is expected to be of considerable interest and practical use to professionals and researchers involved in the design of super-tall buildings.

Extreme Value Distribution and Peak Factor of Crosswind Response of Flexible Structures with Nonlinear Aeroelastic Effect

The crosswind response at the vicinity of vortex lock-in wind speed becomes an increasing concern in structural design of super tall buildings and other dynamically sensitive structures. Because of nonlinear aeroelastic effect of vortex shedding, the extreme value distribution and peak factor of crosswind response are distinctly different from traditional wind-induced stochastic buffeting response. This study establishes an effective approach for predicting extreme value distribution and peak factor of crosswind response of flexible structures on the basis of an improved understanding of the underlying mechanism. It is pointed out that the improved extreme theory of Gaussian processes with consideration of narrow-band feature cannot interpret the extreme crosswind response. This study, at the first time, reveals that the unique characteristics of extreme value distribution of crosswind response is primarily attributed to its hardening non-Gaussian distribution. An extensive analysis of simulated crosswind response illustrates that the extreme value distribution and peak factor can be estimated from those of an underlying Gaussian process based on the translation process theory. The translation function between non-Gaussian crosswind response and Gaussian process can be expressed in terms of Hermite polynomial model based on the first four statistical moments or quantified by mapping of cumulative distribution functions and curve fitting. Closed-form formulations are developed for calculating Hermite translation model coefficients, which permits the estimation of extreme value distribution and peak factor directly using the response kurtosis and bandwidth parameter. The characteristics of crosswind response and the proposed approach are also validated using full-scale vibration measurements of a wind-excited traffic-signal-support structure. This study not only clarified the mechanism responsible for the unique extreme value distribution of crosswind response with nonlinear aeroelastic effect but also established an effective simple approach for its estimation using the characteristics of response process.