Research

21 pages, 5476 KiB

Open AccessArticle

Structural Identification of a 90 m High Minaret of a Landmark Structure under Ambient Vibrations

by Hanzlah Akhlaq, Faheem Butt, Mamdooh Alwetaishi, Mamoon Riaz, Omrane Benjeddou and Enas E. Hussein

Buildings 2022, 12(2), 252; https://doi.org/10.3390/buildings12020252 - 21 Feb 2022

Cited by 7 | Viewed by 2270

Abstract

This paper presents the operational modal analysis of a 90-m-high RC minaret of an iconic mosque considered as a landmark of the city. The minaret was monitored for three days with 11 tri-axial MEMS accelerometers. The purpose of the study was to observe [...] Read more.

This paper presents the operational modal analysis of a 90-m-high RC minaret of an iconic mosque considered as a landmark of the city. The minaret was monitored for three days with 11 tri-axial MEMS accelerometers. The purpose of the study was to observe the behavior, develop a representative finite element (FE) model, and establish baseline data for health monitoring studies. The modal properties were extracted using three operational modal analysis techniques (OMA): Enhanced Frequency Domain Decomposition (EFDD), Stochastic Subspace Identification (SSI), and Natural Excitation Technique with Eigensystem Realization Algorithm (NExT-ERA). The first 10 identified modes were below 7 Hz. Eight modes out of the ten were bending-dominant, while the remaining two were torsion-dominant. A FE model was also developed in ETABS to ascertain and compare the response of the structure with the identified results. From the FE model, the modes corresponding to the first ten identified modes were considered for comparison with the identified frequencies from ambient monitoring. The maximum 7.71% error was observed between the experimental and numerical frequencies. The error was minimized by using the manual updating the material properties and adding the weight of nonstructural elements. The variation of identified modal frequencies with ambient temperature was observed to be linearly dependent to a reasonable degree. A general trend of decreasing identified frequencies was observed with the rise in temperature. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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19 pages, 5794 KiB

Open AccessArticle

Fire Spread Characteristics of Metal-Polyethylene Sandwich Panels

by Ru Zhou, Zhihao Chen, Yinke Fan, Zhengjiang Yu, Jianan Qian and Juncheng Jiang

Buildings 2021, 11(9), 396; https://doi.org/10.3390/buildings11090396 - 05 Sep 2021

Viewed by 2425

Abstract

An experimental study was conducted to determine the characteristics of the flame spread and droplets of metal-polyethylene (PE) sandwich panels during combustion. The mass-loss rate, average flame height, temperature, and fire spread rate were investigated. The results showed that the fire spread rate, [...] Read more.

An experimental study was conducted to determine the characteristics of the flame spread and droplets of metal-polyethylene (PE) sandwich panels during combustion. The mass-loss rate, average flame height, temperature, and fire spread rate were investigated. The results showed that the fire spread rate, mass change of the droplets, average flame height, and temperature increased with an increase in the sample length, except for the mass loss rate of the 40 cm-long sample. The time interval between the droplets decreased, and the flame pulsation frequency increased. The relationship between the flame height and sample length was determined. During the combustion process, bending deformation and top flame phenomena occurred due to the shrinkage of the PE, which increased the fire risk. The distance between the outer surface of the expanded metal aluminum layer and the insulation panel increased with an increase in the panel length. A schematic diagram of the fire spread of the metal sandwich panel was established based on the observations and theoretical analysis. The mechanism and combustion behavior of the metal sandwich panels were determined to provide references for the construction of metal sandwich panels of exterior walls. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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20 pages, 3762 KiB

Open AccessArticle

Numerical Analysis on Global Serviceability Behaviours of Tall CLT Buildings to the Eurocodes and UK National Annexes

by Xuan Zhao, Binsheng Zhang, Tony Kilpatrick and Iain Sanderson

Buildings 2021, 11(3), 124; https://doi.org/10.3390/buildings11030124 - 19 Mar 2021

Cited by 4 | Viewed by 2748

Abstract

Cross-laminated timber (CLT) is an innovative engineered timber product and has been widely used for constructing tall timber buildings due to its excellent structural performance and good strength with its multi-layers of boards in both perpendicular directions. However, the global serviceability performance of [...] Read more.

Cross-laminated timber (CLT) is an innovative engineered timber product and has been widely used for constructing tall timber buildings due to its excellent structural performance and good strength with its multi-layers of boards in both perpendicular directions. However, the global serviceability performance of tall timber buildings constructed from CLT products for the lift core, walls, and floors under wind load is not well known yet, even though it is crucial in a design. In this study, the finite element software SAP2000 is used to numerically simulate the global static and dynamic serviceability behaviours of a 30-storey tall CLT building assumed in Glasgow, Scotland, UK. The maximum horizontal storey displacement due to wind is only 16.6% of the design limit and the maximum global horizontal displacement is only 13.8% of the limit set to the Eurocodes. The first three lowest vibrational frequencies, modes and shapes were obtained, with the fundamental frequency being 19.9% larger than the code-recommended value. Accordingly, the peak acceleration of the building due to wind was determined as per the Eurocodes and ISO standard. The results show that the global serviceability behaviours of the building satisfy the requirements of the Eurocodes and other design standards. Parametric studies on the peak accelerations of the tall CLT building were also conducted by varying the timber material properties and building masses. By increasing the timber grade for CLT members, the generalised building mass and the generalised building stiffness can all be adopted to lower the peak accelerations at the top level of the building, so as to reduce human perceptions of the wind-induced vibrations with respect to the peak acceleration. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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21 pages, 10645 KiB

Open AccessArticle

A Structural Grammar Approach for the Generative Design of Diagrid-Like Structures

by Francesco Cascone, Diana Faiella, Valentina Tomei and Elena Mele

Buildings 2021, 11(3), 90; https://doi.org/10.3390/buildings11030090 - 01 Mar 2021

Cited by 15 | Viewed by 3467

Abstract

An innovative generative design strategy, based on shape grammar, is proposed for the minimum-weight design of diagrid tall buildings. By considering the building as a three-dimensional vertical cantilever beam with a tubular section under horizontal load, it is evident that bending and shear [...] Read more.

An innovative generative design strategy, based on shape grammar, is proposed for the minimum-weight design of diagrid tall buildings. By considering the building as a three-dimensional vertical cantilever beam with a tubular section under horizontal load, it is evident that bending and shear stiffness demands vary along the width and elevation of the building. Further, while the structural design of tall buildings is usually governed by stiffness, the predominant design criterion for diagrids could be the local strength demand, especially for low slenderness values, thanks to the inherent rigidity of the triangular pattern. Starting from these considerations, in this paper, a generative design strategy is proposed, able to find diagrid patterns that accommodate the differentiated stiffness demand along width/elevation and satisfy the predominant design criterion, stiffness or strength. The design strategy is applied to tall building models characterised by different slenderness values. The comparison to diagrid patterns analysed in previous literature works in terms of structural weight and performance parameters highlights the effectiveness of the design strategy and the efficiency of the generated patterns. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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17 pages, 4787 KiB

Open AccessArticle

Building Drainage System Design for Tall Buildings: Current Limitations and Public Health Implications

by Michael Gormley, David Kelly, David Campbell, Yunpeng Xue and Colin Stewart

Buildings 2021, 11(2), 70; https://doi.org/10.3390/buildings11020070 - 16 Feb 2021

Cited by 15 | Viewed by 9001

Abstract

National design guides provide essential guidance for the design of building drainage systems, which primarily ensure the basic objectives of preventing odor ingress and cross-transmission of disease through water-trap seal retention. Current building drainage system design guides only extend to buildings of 30 [...] Read more.

National design guides provide essential guidance for the design of building drainage systems, which primarily ensure the basic objectives of preventing odor ingress and cross-transmission of disease through water-trap seal retention. Current building drainage system design guides only extend to buildings of 30 floors, while modern tall buildings frequently extend to over 100 floors, exceeding the predictive capability of current design guides in terms of operating system conditions. However, the same design guides are being used for tall buildings as would be used for low-rise buildings. A complicating factor is the historic roots of current design guides and standards (including the interpretation of the governing fluid mechanics principles and margins of safety), causing many design differences to exist for the same conditions internationally, such as minimum trap seal retention requirements, stack-to-vent cross-vent spacing, and even stack diameter. The design guides also differ in the size and scale of the systems they cover, and most make no allowance for the specific building drainage system requirements of tall buildings. This paper assesses the limitations of applying current building drainage system design guides when applied to the case of tall buildings. Primarily, the assessments used in this research are based on codes from Europe, the USA and Australia/New Zealand as representative of the most common approaches and from which many other codes and standards are derived. The numerical simulation model, AIRNET, was used as the analysis tool. Our findings confirm that current design guides, which have been out of date for a number of decades, are now in urgent need of updating as code-compliant systems have been shown to be susceptible to water-trap seal depletion, a risk to cross-transmission of disease, which is a major public health concern, particularly in view of the current COVID-19 pandemic. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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22 pages, 4331 KiB

Open AccessArticle

A New Modular Structural System for Tall Buildings Based on Tetrahedral Configuration

by Giulia Angelucci, Fabrizio Mollaioli and Roberto Tardocchi

Buildings 2020, 10(12), 240; https://doi.org/10.3390/buildings10120240 - 14 Dec 2020

Cited by 6 | Viewed by 6132

Abstract

Inspired by the high mechanical performance of diagrid structures, the minimization of material consumption on braced tubes and the expressive potency of tensegrity modular structures, this work proposes an innovative three-dimensional system for tall buildings. A new modular structural system generated from the [...] Read more.

Inspired by the high mechanical performance of diagrid structures, the minimization of material consumption on braced tubes and the expressive potency of tensegrity modular structures, this work proposes an innovative three-dimensional system for tall buildings. A new modular structural system generated from the assembly of tetrahedral units is investigated. The paper integrates insights on the architectural implications and mechanical performance of the reticular system arranged in repetitive triangular-based modules. The impact of different geometric configurations of the structural members on the economic design is also discussed and recommendations for the optimal topology are made. Guidelines for the design and analytical formula for accessing preliminary member sizes are proposed on the basis of stiffness requirements. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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17 pages, 2437 KiB

Open AccessArticle

Observation and Interpretation of Closely Spaced Fundamental Modes of a High-Rise Building

by Sergio Sanchez Gómez and Andrei V. Metrikine

Buildings 2020, 10(7), 132; https://doi.org/10.3390/buildings10070132 - 16 Jul 2020

Cited by 2 | Viewed by 3410

Abstract

In this paper the dynamic behaviour of a high-rise building with complex structural system is studied. In some cases, to optimize the building design, the horizontal stability of the building is accomplished by the contribution of several structural components. This is the case [...] Read more.

In this paper the dynamic behaviour of a high-rise building with complex structural system is studied. In some cases, to optimize the building design, the horizontal stability of the building is accomplished by the contribution of several structural components. This is the case of the JuBi tower, the building studied in this paper. The horizontal stability of the building is accomplished by three cores and outer walls. The cores and the walls are connected through the floors and the foundation. The data recorded during the experimental campaign carried out in this building show a double-peak behaviour corresponding to two closely spaced modes in the translational directions. This is caused by the weak coupling between the structural components. To study this phenomena, in this paper, a yet unique double-beam model is used. The parameters of the model are tuned so as to resemble the experimental response of the building. Results of the model evidence that the weak coupling is caused by the beams and the foundation. Also, it is shown that the two closely spaced modes correspond both to bending shape modes. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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34 pages, 9067 KiB

Open AccessArticle

Turbulent Flows and Pollution Dispersion around Tall Buildings Using Adaptive Large Eddy Simulation (LES)

by Elsa Aristodemou, Letitia Mottet, Achilleas Constantinou and Christopher Pain

Buildings 2020, 10(7), 127; https://doi.org/10.3390/buildings10070127 - 10 Jul 2020

Cited by 7 | Viewed by 4029

Abstract

The motivation for this work stems from the increased number of high-rise buildings/skyscrapers all over the world, and in London, UK, and hence the necessity to see their effect on the local environment. We concentrate on the mean velocities, Reynolds stresses, turbulent kinetic [...] Read more.

The motivation for this work stems from the increased number of high-rise buildings/skyscrapers all over the world, and in London, UK, and hence the necessity to see their effect on the local environment. We concentrate on the mean velocities, Reynolds stresses, turbulent kinetic energies (TKEs) and tracer concentrations. We look at their variations with height at two main locations within the building area, and downstream the buildings. The pollution source is placed at the top of the central building, representing an emission from a Combined Heat and Power (CHP) plant. We see how a tall building may have a positive effect at the lower levels, but a negative one at the higher levels in terms of pollution levels. Mean velocities at the higher levels (over 60 m in real life) are reduced at both locations (within the building area and downstream it), whilst Reynolds stresses and TKEs increase. However, despite the observed enhanced turbulence at the higher levels, mean concentrations increase, indicating that the mean flow has a greater influence on the dispersion. At the lower levels (Z < 60 m), the presence of a tall building enhanced dispersion (hence lower concentrations) for many of the configurations. Full article

(This article belongs to the Special Issue Advancement of Technologies in Tall Buildings: Evolution and Emerging Developments)

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