Super-tall Structures Research Articles

Impact of varying soil conditions on the design of tall building foundations

Above the past two decades, there has been a significant rise in the construction of tall structures over 150m in height, with an almost exponential development rate. Numerous similar structures have been built throughout the Middle East and Asia, and many more are proposed or now under development. Buildings over 300m in height are posing new engineering difficulties, especially in terms of structural and geotechnical design. Wind analysis is critical when it comes to big structures. Geotechnical engineers, in particular, are progressively abandoning empirical techniques in favor of state-of-the-art methods when designing foundations for super-tall structures. Numerous studies have investigated the structural behavior of tall structures with SSI by taking into account a variety of factors such as foundation type, soil conditions, lateral stresses, and the ratio of the flexural stiffness of the beam and column. Very few studies on the soil-structure interaction of tall structures in clayey soil conditions, especially in Indian seismic zones, have been conducted. In zone III, a G+18-story rectangular structure with a 3 m floor-to-floor height was assessed using the E-tabs software. The selected plan is rectangular in shape. The structure has been evaluated for static and dynamic wind and seismic forces. Structures have been developed for use in circumstances of hard, medium, and soft soil.

Modal identification with uncertainty quantification of large‐scale civil structures via a hybrid operation modal analysis framework

SummaryIn operational modal analysis (OMA), only structural responses are typically available. In this context, bias and variance (uncertainty) errors may exist in modal estimates (especially damping estimates), resulting in inaccurate determination of the modal properties of large‐scale structures under harsh excitations. To this end, a hybrid OMA framework based on the modal decoupling, the natural excitation technique, the random decrement technique (RDT), and improved eigensystem realization algorithm (ERA) with the automated stabilization diagram is presented to perform high‐accuracy modal estimates with uncertainty quantification for large‐scale structures under normal and severe ambient excitations. The accuracy and effectiveness of the hybrid framework for identifying the modal parameters are validated by numerical simulation study of a framework structural model. Furthermore, the hybrid framework is applied to analyze recorded acceleration responses of a supertall building with 600‐m height under normal excitations and typhoon condition to verify its applicability in field measurements. The numerical simulation and field measurement studies demonstrate that the hybrid framework can not only perform precise modal estimations with uncertainty quantification through a single ambient vibration measurement but also effectively reveal the variations of modal properties of supertall structures under harsh excitations from multiple perspectives. This paper aims to enhance the reliability and accuracy of modal estimation for engineering structures and further provide insight into the variations of dynamic properties of large‐scale civil structures under severe excitations.

Examining Space Efficiency in Supertall Towers through an Analysis of 135 Case Studies

This study addresses the critical need for a comprehensive exploration of space efficiency in supertall buildings, a crucial aspect of skyscraper architecture with profound implications for sustainability. Despite the paramount importance of spatial utilization, the existing literature lacks a thorough investigation into this domain. This research aims to fill this significant gap by conducting an exhaustive analysis based on data from 135 case studies. The proposed model for evaluating space efficiency yielded compelling technical insights. The key metrics employed in this examination include: (1) average space efficiency: the findings revealed an average space efficiency of about 72%. This metric provides a quantitative measure of how effectively space is utilized in supertall buildings. (2) core area proportion: on average, the proportion of core area to the gross floor area was around 24%. This metric sheds light on the distribution of core areas within the overall structure, impacting both functionality and spatial optimization. This study also highlighted notable trends and characteristics observed in the examined cases: (3) central core design: the majority of skyscrapers featured a central core design tailored primarily for mixed-use purposes. This architectural choice reflects a strategic approach to maximize functionality and versatility in supertall structures. (4) structural systems: The outriggered frame system emerged as the prevailing structural system, with composite materials commonly used for the structural components. This insight into prevalent structural choices contributes to the understanding of the technical aspects influencing space utilization in skyscraper design.

Automatic Identification of the Working State of High-Rise Building Machine Based on Machine Learning

High-rise building machines (HBMs) play a crucial role in the construction of super-tall buildings, with their working states directly impacting safety, quality, and progress. Given their extensive floor coverage and complex internal structures, monitoring priorities should shift according to specific workflows. However, existing research has primarily focused on monitoring key HBM components during specific stages, neglecting the automated recognition of HBM workflows, which hinders adaptive monitoring strategies. This study investigates the critical states of HBM construction across various structural layers and proposes a method rooted in vibration signal analysis to determine the HBM’s working state. The method involves collecting vibration signals with a triaxial accelerometer, extracting five distinct vibration signal features, classifying these signals using a k-Nearest Neighbors (kNN) classifier, and finally, outputting the results through a classification rule that aligns with the actual workflow of the HBM. The method was implemented in super-high-rise buildings exceeding 350 m, achieving a measured accuracy of 97.4% in HBM working state recognition. This demonstrates its proficiency in accurately determining the construction state and facilitating timely feedback. Utilizing vibration signal analysis can enhance the efficiency and safety, with potential applications in monitoring large-scale formwork equipment construction processes. This approach provides a versatile solution for a wide range of climbing equipment used in the construction of super-tall buildings and towering structures.

Experimental investigation on amplified multilayer viscoelastic damper and vibration mitigation evaluation subjected to wind loads

Methods to improve the damping efficiency of dampers have been extensively studied. This study proposes a multilayer viscoelastic damper with an amplified deformation device (MAVE), which combines a traditional viscoelastic damper (VE) with a lever amplification device. The proposed device utilizes multiple viscoelastic damping layers and a lever system to amplify the inter-story displacement, thereby increasing the damping force and enhancing energy dissipation capability. A mechanical model of MAVE was established, and model tests were performed to compare MAVE and VE. The test results demonstrate that MAVE can effectively amplify the deformation of the damper. The damping force of MAVE increased by 5.23 times, while the stiffness increased by 5.59 times, resulting in a 3.11 times increase in energy dissipation capacity. Furthermore, the deviations in the amplification factor and the comparisons between experimental and theoretical results were discussed. The experimental and theoretical deviations were within 10%. Finally, a numerical simulation was performed on a super-tall structure to demonstrate the vibration control capabilities of the MAVE system. By comparing the response of the structure and the energy consumption of the dampers, the vibration reduction efficiency of MAVE under wind loads was confirmed. The peak acceleration at the top floor was reduced by 51%, and the standard deviation (STD) acceleration was reduced by 37%. The peak displacement at the top floor was reduced by 80%, and the STD displacement of the same floor was reduced by 76%. MAVE effectively enhanced the comfort level of super-tall structures.

Theoretical and experimental research on damping performance of suspended multiple mass pendulums damper

Conventional suspended mass pendulum damper (SMPD) include suspended single mass pendulum damper (SSMPD), tandem suspended multiple mass pendulums damper without springs (TSMP), and parallel suspended multiple mass pendulums damper without springs (PSMP), these types of SMPD have the advantages such as clear mechanism, simple construction, and good damping effect, but they have a narrow tuning frequency band and the pendulum length needs to be set too long for low-frequency super tall structures and too short for high-frequency tall structures, limiting their application in practical engineering. Because of this, the paper proposes connecting the spring to the mass pendulum, forming a tandem suspended multiple mass pendulums damper with spring (TSMP-S) and a parallel suspended multiple mass pendulums damper with spring (PSMP-S), and establishing structural system dynamics equations and performing the dynamic characterization of the TSMP-S and PSMP-S, obtain their frequency resolved solutions to explain the damping mechanism. In order to study the vibration-damping performance of these two types of SMPD, through numerical simulations to compare the damping effect of the conventional SMPD, TSMP-S, and PSMP-S on the controlled structures, and a series of shaking table tests on controlled and uncontrolled structures to verify the effectiveness of SSMPD, TSMP, PSMP, TSMP-S and PSMP-S for damping control of controlled structures under conventional earthquake and earthquake at four types of sites. Numerical simulations and shaking table test results in both show that the TSMP-S has the best damping effect, with the advantages of increasing the tuning frequency band, achieving multi-order vibration control, and flexible adjustment of the pendulum length, which is suitable for actual engineering.

ASCE 7-22 Wind Speed Profiles and Velocity Pressure Exposure Coefficients for Structural Design

The ASCE 7-16 standard and its previous editions specify wind speeds for structural design that increase monotonically above the Earth’s surface up to heights between 200 and 400 m, above which they are considered constant. This model was proposed in the 1960s and based on research completed up to that time. Subsequent research has shown that the model is inadequate and may result in the significant underestimation of wind loads in the higher elevations of supertall and megatall structures. For this reason, a new model for the vertical variation of wind speeds and associated velocity pressure exposure coefficients, Kz, was developed for inclusion in the ASCE 7-22 standard. The purpose of this paper is to present and explain the logic of the new model based on physics-based meteorological research.

Full-scale monitoring of wind effects on a supertall structure during six tropical cyclones

Full-scale measurements under real wind conditions are viewed as the most reliable approach to investigating the wind effects on supertall structures. However, long-term monitoring on wind characteristics at the maximum atmospheric boundary layer height and the corresponding wind-induced responses of structures are very limited, especially under strong tropical cyclones. In this study, field monitoring of wind effects on a 600 m high supertall structure is obtained during 6 tropical cyclones by means of a sophisticated long-term structural health monitoring (SHM) system deployed on the structure. Wind characteristics (wind speed, direction, turbulence intensity, gust factor, power spectral density) of these tropical cyclones above 450 m height are presented and analyzed. The dynamic properties of the supertall structure are determined from the field measurements and compared with those stipulated in design. The damping ratios of the supertall structure are estimated by the virtual dynamic shaker (VDS) and the enhanced virtual dynamic shaker (EVDS) methods. In addition, the response amplitude-dependence of the structural natural frequencies and damping ratios is investigated. Finally, the comfort performance of the supertall structure during different tropical cyclones is assessed against four comfort criteria. The findings of this study would be beneficial to professionals and researchers engaged in wind-resistant design and practice of skyscrapers.

Analytical calculation of temperature‐induced strain of supertall structures

Estimating temperature-induced strain is of critical importance for structural safety assessment. Most previous studies estimated the temperature-induced strain by statistical analysis, resulting in the unexplainable physical meaning of the obtained model coefficients. In this paper, an analytical formula for the temperature-induced strain of supertall structures is derived based on the simulated temperature field. First, a supertall structure is simplified as a cantilever column, and the theoretical relationship between the sectional two-dimensional temperature field and strain is derived. Afterwards, the structure is extended to a generalised cantilever column bounded by springs at the top end, and the theoretical relationship of temperature and strain is derived as well. The formula shows that the sectional strain is composed of the sectional average temperature-induced strain and the gradient temperature-induced strain along two horizontal directions. A finite element (FE) model is established to verify the derived strain formula. Finally, the formula is applied to a real supertall structure, the Wuhan Yangtze River Navigation Centre, on which a long-term structural health monitoring system has been installed. The temperature field of the whole structure is obtained by the FE heat transfer analysis, and the temperature-induced strain is calculated according to the derived formula. The average difference between the theoretically derived and measured strains is less than 7 με. This study provides a simple theoretical formula for calculating the temperature-induced strain of supertall structures, avoiding the complicated FE structural analysis.

Comparison between an uncoupled one-way and two-way fluid structure interaction simulation on a super-tall slender structure

This paper presents a comprehensive analysis on a super-tall structure where a numerical approach is used to measure its structural response when subjected to turbulent wind. The aim of this study is to provide a feasible alternate approach, to the experimental multi-degree of freedom (MDOF) aeroelastic wind tunnel tests, which are commonly used in industry to estimate structural responses of super-tall structures. An innovative and time-efficient uncoupled one-way Fluid-Structure Interaction (FSI) simulation technique was used to measure the structural response. This novel method was evaluated against a commercially available two-way FSI analysis technique and validated with an experimental MDOF aeroelastic model. It is shown that the uncoupled one-way FSI analysis is capable of estimating structural responses and provides similar numerical accuracy to that of the experimental response. This performance was achieved in a total of 74clock hours which accounts for the CFD simulation and transient structural analysis calculated for eighteen different structural configurations. In comparison, the two-way FSI analysis, which uses a commercial code, took 4800clock hours to calculate for six configurations. The uncoupled one-way FSI technique also provided good correlations with experimentally observed trends such as vortex-induced resonance. In comparison the two-way FSI simulation was not as accurate due to the practical limitations (such as mesh size) that needed to be introduced in order to obtain results within a feasible time frame. Finally through validation, it is demonstrated that the proposed uncoupled one-way FSI analysis technique can provide accurate results at a feasible cost.

Wind loads on a super-tall slender structure: A validation of an uncoupled fluid-structure interaction (FSI) analysis

Abstract: The paper presents a numerical validation for an innovative and time-efficient uncoupled fluid-structure interaction (FSI) method used to evaluate structural responses of super-tall structures. An aeroelastic multi-degree of freedom (MDOF) model of a super tall structure was tested in a boundary layer wind tunnel (BLWT) where tip displacements and acceleration were recorded and compared with a numerical simulation. A validated computational fluid dynamics (CFD) numerical simulation was performed to obtain wind-induced pressures in the numerical analysis. The novelty in this study lies in the mechanism that these wind pressures are communicated to the structural model in an efficient manner, to obtain structural responses. An innovative numerical technique is used to convert the wind-induced pressures on the building surface to nodal time history loads, which were then used to perform an implicit modal analysis to obtain the structure's time history response. The proposed new method was shown to perform in 240 s of clock time and could provide similar numerical accuracy to that of the experiments. Other important observations on the structure's response with regard to vortex-induced vibrations (VIV), the impact of aerodynamic damping and structural damping on the performance of the structure are critically evaluated and discussed herein. Finally, it was demonstrated that the presented numerical method could be used as an alternative to full aeroelastic wind tunnel studies to efficiently obtain structural responses of super-tall structures.

Review on field monitoring of high‐rise structures

Structural health monitoring (SHM) has been developed and applied to bridge structures since the early 1980s. Numerous approaches and techniques have been proposed and applied to supertall structures during the recent decade. This paper reviews the SHM techniques and applications in supertall structures. The vibration analysis techniques, seismic effect monitoring, wind effect monitoring, comfort assessment, temperature effect monitoring, and construction monitoring of high-rise structures are described and summarised. The latest developments in codification and standardisation in SHM are also introduced.

A vision-based system for long-distance remote monitoring of dynamic displacement: experimental verification on a supertall structure

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

Multi-rate data fusion for dynamic displacement measurement of beam-like supertall structures using acceleration and strain sensors

Accurate measurement of dynamic displacement is important for the structural health monitoring and safety assessment of supertall structures. However, the displacement of a supertall structure is difficult to be accurately measured using the conventional methods because they are either inaccurate or inconvenient to be set up in practice. This study provides an accurate and economical method to measure dynamic displacement of supertall structures accurately by fusing acceleration and strain data, which are generally available in the structural health monitoring system. Dynamic displacement is first derived from the measured longitudinal strains based on geometric deformation without requiring mode shapes. An optimization technique is utilized to optimize the deployment of strain sensors for achieving more accurate strain-derived displacement. The strain-derived displacement is then combined with measured acceleration via a multi-rate Kalman filtering approach. Applications to a numerical supertall structure and a laboratory cantilever beam verify that the proposed method accurately estimates displacement including both high-frequency and pseudo-static components, under different noise cases and sampling rates. A full-scale field test on the 600 m-high Canton Tower is implemented to validate the applicability of the proposed method to real supertall structures. Error analysis demonstrates that the data fusion displacement is more accurate than the global position system-measured displacement in the time and frequency domains.

Numerical investigation of scale resolved turbulence models (LES, ELES and DDES) in the assessment of wind effects on supertall structures

Scale resolved turbulence models, such as large eddy simulation (LES), have been increasingly utilised in applications of computational wind engineering (CWE) for tall buildings, due to their proven numerical accuracy. The demand for computational time and resources in LES is still a concern in practical applications of CWE, where it is necessary to explore alternative modelling techniques. The main objective of this study is to critically investigate the possibility of using a computationally efficient hybrid RANS/LES approach, specifically embedded-LES (ELES), to predict wind effects on a supertall 406 m slender tower of non-standard geometry. Numerical predictions of LES and ELES are compared and critically analysed with experimental results obtained by performing boundary layer wind tunnel (BLWT) tests. It was shown that the choice of sub-grid scale (SGS) modelling in LES has an impact on the wind effects predicted on the structure. Out of the five SGS models tested, the wall adapting local eddy viscosity (WALE) model was the most suitable due to its treatment of the near wall region. An optimum domain configuration based on a parametric study was proposed for the application of ELES. The importance of overall mesh quality and its impact on fluctuating pressures and dynamic properties of wind is presented. Wind flow behaviour on the structure, such as Von-Karman vortex shedding and its dynamic implications, is also discussed. Finally, using the proposed modelling techniques, ELES can generate similar numerical accuracy to that of an LES model at a lower computational cost.

Efficient calculation and monitoring of temperature actions on supertall structures

Numerical heat transfer analysis and field monitoring have been developed to investigate the effects of varying temperature on supertall buildings. The conventional heat transfer analysis studies one or several components of a structure each time, causing the calculated temperature of the entire structure inaccurate. Moreover, the finite element (FE) model used for calculating temperature distribution cannot be directly used for computing the temperature-induced responses of the structure, which requires considerable manual inputs of the temperature load. This paper presents an automatic and efficient FE approach to calculating the temperature distribution and the associated responses of an entire structure using field meteorological monitoring data. The position of the sun relative to the structure can be determined by introducing a new radiation calendar timing system. A virtual sun is then created to determine the irradiation and shade elements of the structural model, from which the solar radiation intensity on the surfaces of all elements can be calculated at any particular time on any particular day. Consequently, the dynamic thermal boundary conditions of the FE model are formulated automatically. This enables the heat transfer analysis of the entire structure to be conducted and the temperature distribution of the entire structure to be calculated in real time. The calculated temperature distribution is transferred to the temperature load in the same FE model, and the temperature-induced stress and displacement responses of the structure can be obtained. The method is applied to the 335 m tall Wuhan Yangtze River Navigation Centre. A 3D solid FE model of this structure during the construction stage is established. Varying wind speed and air temperature along the height of the structure are taken into account from the SHM system. The calculated temperature distribution and temperature-induced stress of the structure are in good agreement with the field monitoring data. The proposed technique offers an effective and efficient real-time monitoring of the temperature actions on large-scale structures.

Comparison of Reynolds Averaging Navier-Stokes (RANS) turbulent models in predicting wind pressure on tall buildings

This paper presents a detailed comparison of using Reynolds Averaging Navier-Stokes (RANS) approach in predicting wind pressure on a super-tall 406 m slender tower with circular cross-section. The results obtained from wind tunnel tests using a rigid model approach in a boundary layer wind tunnel (BLWT) were compared to that of Computational Fluid Dynamics (CFD) numerical simulations. The main objective of this study is to critically investigate the possibility of using RANS turbulent model based CFD approach in tall building design. Three different RANS turbulence models were compared with the wind tunnel data in predicting flow characteristics. The detailed wind tunnel experimental procedure and numerical approach are discussed and presented. It was shown that the shear stress transport (SST) variant model, k−ωSST, could predict pressure coefficients comparable to that of the wind tunnel experiments. The influence of flow separation point on flow characterisation and pressure prediction is highlighted. The improvement that can be made in the near-wall region in the finite volume mesh to achieve an accurate separation point is presented. The effects of Reynolds number produced in the wind tunnel and scaled-down numerical models were compared with the anticipated full-scale flow Reynolds number. Hence, it is shown that a correct modelling technique in CFD using RANS turbulence models can be used as an alternative design approach of super-tall structures to estimate wind-induced pressures.

Temperature-induced displacement of supertall structures: A case study

For a supertall structure, the temperature effect is an important factor that must be considered during the design, construction, and performance assessment. In this article, temperature-induced displacement of the 600-m-high Canton Tower is studied by the data-driven approach based on the sufficient real measurement data obtained from the structural health monitoring system. A multiple linear regression model is employed to establish the quantitative relation between the displacement and temperature data at different facades and sections of the structure in different seasons. Results show that an ordinary linear regression model is able to fit the monitoring data well. However, the model fails to interpret the physical meaning of the model coefficients. A regularized linear regression model is then employed and validated to describe the temperature-induced displacement of the structure. The physical relationship between the temperature and displacement is provided. Finally, the model is also used to separate the temperature- and wind-induced displacement of the supertall structure.

Skyscrapers: Origin, History, Evolution and Future

From humble cottages to super tall structures, human beings have progressively developed the living and working space with time. This paper describes the origin and growth of modern skyscrapers, the subsequent challenges faced, and the way it was outdone. Research papers and case studies have been thoroughly studied and important excerpts from them have been explained to show how the modern structures have been evolved. The sources and causes of evolution is debatable among researchers, this paper has taken into account 7 most vital milestones in the growth of current generation skyscrapers and their contribution to the construction industry and concludes with the ideas and scopes where growth is still possible and challenges need to be solved.

High-Rise Urbanism in Contemporary Europe

This issue of Built Environment seeks to contribute to emerging debates around vertical urbanism by emphasizing the recent sharp upward trajectories of European cities. The skylines of London, Paris, Madrid, Milan, or even Saragossa and Malmo have been transformed dramatically by new tall buildings. This resurgence of skyscrapers that began in the early 2000s is a major phenomenon, both intense and widespread. This post-2000 boom is not necessarily exemplified in super-tall futuristic structures such as the ones that have been erected in Dubai or Beijing during this period, but in supposedly compact energy-efficient urban blocks according to new high-rise urbanism principles. Woven into the existing city fabric, these projects are often framed from the ground up, as initiatives to reinvigorate local deprived or de-industrialized neighbourhoods and to create urban amenities around transport nodes, embodying new sets of discourses and practices among built environment professionals and planning authorities.Through a combination of particular case-studies across Europe with wider analyses of national and international trends, this special issue investigates the relationship in European cities between high-rise built fabric and planning regimes, financial flows, cultural representations, technical innovations, and forms of modernist heritage. Developing cross-disciplinary perspectives and engagement with both academic and practitioner insights, the issue provides a sustained assessment of high-rise Europe in the context of a wider world of vertical urbanisms.