The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Emil Simiu - One of the best experts on this subject based on the ideXlab platform.
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Planetary Boundary-Layer Modelling and Tall Building Design
Boundary-Layer Meteorology, 2016Co-Authors: Emil SimiuAbstract:Characteristics of flow in the planetary boundary layer (PBL) strongly affect the Design of Tall structures. PBL modelling in Building codes, based as it is on empirical data from the 1960s and 1970s, differs significantly from contemporary PBL models, which account for both “neutral” flows, and “conventionally neutral” flows. PBL heights estimated in these relatively sophisticated models are typically approximately half as large as those obtained using the classical asymptotic similarity approach, and are one order of magnitude larger than those specified in North American and Japanese Building codes. A simple method is proposed for estimating the friction velocity and PBL height as functions of specified surface roughness and geostrophic wind speed. Based on published results, it is tentatively determined that, even at elevations as high as 800 m above the surface, the contribution to the resultant mean flow velocity of the component V normal to the surface stress is negligible and the veering angle is of the order of only 5 $$^{\circ }$$ ∘ . This note aims to encourage dialogue between boundary-layer meteorologists and structural engineers.
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evaluation of mean recurrence intervals of wind effects for Tall Building Design
Journal of Structural Engineering-asce, 2014Co-Authors: Rene D Gabbai, Emil SimiuAbstract:AbstractMean recurrence intervals (MRIs) of wind effects for the strength Design (SD) of flexible Buildings by the wind-tunnel method are based on estimates of total uncertainties that do not account for uncertainties in the dynamic parameters. This paper presents a procedure for assessing this practice. The procedure accounts for the probability distributions of total uncertainties in basic wind effects corresponding to MRIs of 50 or 100 years. The total uncertainties are estimated for two cases. For Case 1, only uncertainties in the wind loading are taken into account. For Case 2, uncertainties in both the wind loading and the dynamic parameters are considered. Cumulative distribution functions (CDFs) of the total uncertainties in the basic wind effects are determined by Monte Carlo simulation. To assure risk consistency, the MRIs of wind effects considered for SD correspond in both cases to the same upper confidence bound of the basic wind effects. For a 305-m-Tall symmetrical steel Building, the requi...
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Assessment of ASCE 7 Standard Wind Load Factors for Tall Building Response Estimates
Journal of Structural Engineering-asce, 2008Co-Authors: Rene D Gabbai, William P. Fritz, Amelia P. Wright, Emil SimiuAbstract:Wind load factors incorporated in the ASCE 7-05 standard are based on rough approximations of wind effects and the uncertainties inherent in them. These factors are routinely applied to Tall Building Design, even though the original calculations on which they are based disregard two important facts characterizing Tall Building response to wind. First, wind effects on flexible structures are proportional to the wind speeds raised to powers larger than two, instead of the power two, as is the case for rigid Buildings. Second, dynamic response parameters, that is, the natural frequencies of vibration and the damping ratios affecting the response, exhibit significant uncertainties. It is shown that, for these reasons, the use of ASCE 7-05 wind load factors for the Design of Tall flexible Buildings results in safety levels that can be significantly lower than safety levels typical of common, rigid structures.
Ziona Strelitz - One of the best experts on this subject based on the ideXlab platform.
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Tall Building Design and sustainable urbanism london as a crucible
Intelligent Buildings International, 2011Co-Authors: Ziona StrelitzAbstract:Tall Buildings offer important scope for sustainable urbanization through their architectural and urban Design potential, but they are also resource intensive and inclined to negative impacts. Recognizing these helps to inform and promote sustainable urban development. The prospect is promising. Significant advances in energy-saving and modelling technologies can shift Tall Buildings towards more sustainable Design, operation and social impact. The scope is signified by new Designs for London, where the combination of heritage controls, sustainability focus, high land values and appetite to build Tall has created a de facto ‘Design laboratory’. London's conditions have galvanized Design strategies that target a wide range of sustainability credentials, encompassing: energy consumption, use of renewables and embodied energy; occupier benefits – including environmental comfort, spatial quality and flexible internal planning; and positive urban conditions in terms of accessibility, microclimate, visual perme...
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Tall Building Design and sustainable urbanism: London as a crucible
Intelligent Buildings International, 2011Co-Authors: Ziona StrelitzAbstract:Tall Buildings offer important scope for sustainable urbanization through their architectural and urban Design potential, but they are also resource intensive and inclined to negative impacts. Recognizing these helps to inform and promote sustainable urban development. The prospect is promising. Significant advances in energy-saving and modelling technologies can shift Tall Buildings towards more sustainable Design, operation and social impact. The scope is signified by new Designs for London, where the combination of heritage controls, sustainability focus, high land values and appetite to build Tall has created a de facto 'Design laboratory'. London's conditions have galvanized Design strategies that target a wide range of sustainability credentials, encompassing: energy consumption, use of renewables and embodied energy; occupier benefits - including environmental comfort, spatial quality and flexible internal planning; and positive urban conditions in terms of accessibility, microclimate, visual permeability and public realm. In combination, these establish a wider range of success factors than energy efficiency alone, supplementing the widespread global foci on height metrics and commercial viability with a more holistic Tall Building Design agenda. Despite relatively modest heights in international terms, London's new exemplars offer strategies to inform more sustainable Design, wherever Tall Buildings are developed. © 2011 Ziona Strelitz.
Kyoung Sun Moon - One of the best experts on this subject based on the ideXlab platform.
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Sustainable Selection of Structural Systems for Tall Buildings
2020Co-Authors: Kyoung Sun MoonAbstract:Selecting a particular structural system for Tall Building Design involves many complex factors such as availability of material and labor, structural efficiency, architectural aesthetics, spatial configurations. Among these various factors, this study investigates lateral stiffness-based structural efficiency of today's prevalent structural systems for Tall Buildings. The two most important requirements for structural Design are strength and stiffness, and for a very Tall Building with a large height-to-width aspect ratio, the stiffness constraint generally governs the Design. Among various structural systems developed for Tall Buildings, the systems with diagonals, such as braced tubes or more recently-developed diagrids, carry lateral loads very efficiently by axial action of the primary structural members on the Building perimeter. This paper presents important Design considerations for these structural systems, which will lead to more efficient and, in turn, more sustainable built environments through the use of less amount of resources.
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Sustainable Structural Systems and Configurations for Tall Buildings
AEI 2011, 2011Co-Authors: Kyoung Sun MoonAbstract:Tall Buildings are built with an abundant amount of resources because of their enormous scale. This paper presents sustainable structural engineering strategies for Tall Buildings, which will lead to the construction of Tall Buildings with less amount of structural material to meet Design requirements. Selecting a particular structural system for Tall Building Design involves many complex factors such as availability of resources, architectural aesthetics, spatial organizations and structural efficiency. Among these various factors, this study mainly investigates lateral stiffness-based structural efficiency of today’s prevalent structural systems for Tall Buildings, such as diagrids, braced tubes and outrigger systems. Design optimization strategies for important structural geometric configurations are studied. Further, optimal stiffness distribution between the Building core and perimeter structure is discussed. Through the most appropriate system selection and Design optimization, more sustainable built environments can be accomplished.
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Optimal Grid Geometry of Diagrid Structures for Tall Buildings
Architectural Science Review, 2008Co-Authors: Kyoung Sun MoonAbstract:Abstract The use of diagrid structural systems for Tall Building Design has continued to increase. Characteristics and stiffness-based preliminary Design methodology of diagrid structures are discussed. The Design methodology is applied to a set of diagrid structures, 40, 50, 60, 70, and 80 stories Tall. The diagrid structure of each storey height is Designed with diagonals placed at various uniform angles as well as gradually changing angles along the Building height in order to determine the optimal uniform angle for each structure with a different height and to investigate the structural potential of diagrids with changing angles. Based on these Design studies, Design guidelines are provided for the optimal configuration of the diagrid structure grid geometry within a certain height range.
Julie Jupp - One of the best experts on this subject based on the ideXlab platform.
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Tall Building Design exploration : Designing for wind resilience
2017Co-Authors: Mohamed Khallaf, Julie JuppAbstract:The paper presents a performance-based Design method that combines Building and urban objectives for the control of winds impacting on Tall Buildings at the pedestrian, podium and upper levels. The performance-based method accounts for wind flow and wind load in a form optimization technique that considers a variety of criteria defining urban microclimates, defined by high-density, multi-level Building forms subject to acute variations in seasonal wind conditions. The approach is based on the theoretical foundations of ‘Designing for urban resilience; and highlights the different objectives of this approach relative to existing (Tall) Building Design standards and urban city planning guidelines.
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Performance-based Design of Tall Building Envelopes using Competing Wind Load and Wind Flow Criteria ☆
Procedia Engineering, 2017Co-Authors: Mohamed Khallaf, Julie JuppAbstract:Abstract This paper investigates performance-based Tall Building Design and the development of a combined architectural-urban Design method focusing on the effects of wind loads on- and wind flows around Tall Buildings. The paper provides an overview of related Buildings codes and city development Design guidelines that define requirements for structural facade wind loading and urban ventilation. A review of performance-based Design methods for the generation, analysis and optimization of Buildings is also presented. Within this frame, an approach to performance-based Tall Building envelope Design is proposed. The approach is aimed at addressing wind loading and wind impact requirements based on generative parametric modelling and performance analysis that integrates physical parameters at the architectural and urban scales and performance criteria can support filtering and optimization relative to prevailing wind conditions.
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performance based Design of Tall Building envelopes using competing wind load and wind flow criteria
Procedia Engineering, 2017Co-Authors: Mohamed Khallaf, Julie JuppAbstract:Abstract This paper investigates performance-based Tall Building Design and the development of a combined architectural-urban Design method focusing on the effects of wind loads on- and wind flows around Tall Buildings. The paper provides an overview of related Buildings codes and city development Design guidelines that define requirements for structural facade wind loading and urban ventilation. A review of performance-based Design methods for the generation, analysis and optimization of Buildings is also presented. Within this frame, an approach to performance-based Tall Building envelope Design is proposed. The approach is aimed at addressing wind loading and wind impact requirements based on generative parametric modelling and performance analysis that integrates physical parameters at the architectural and urban scales and performance criteria can support filtering and optimization relative to prevailing wind conditions.
M. Nuray Aydınoğlu - One of the best experts on this subject based on the ideXlab platform.
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Developments in Seismic Design of Tall Buildings: Preliminary Design of Coupled Core Wall Systems
Perspectives on European Earthquake Engineering and Seismology, 2020Co-Authors: M. Nuray Aydınoğlu, Eren VuranAbstract:Performance-based seismic engineering has brought new dimensions to Tall Building Design, leading to a major transformation from the prescriptive/linear strength-based approach to the explicit non-prescriptive/nonlinear deformation-based Design approach. In this context, current Tall Building seismic Design practice is based on a well-established Design methodology, which starts with a preliminary Design followed by two performance evaluation stages. In this methodology, preliminary Design represents the critical phase of the Tall Building Design where all structural elements have to be preliminarily proportioned and reinforced for the subsequent performance evaluation stages. However, there are several problems inherent in the existing preliminary Design practice. Preliminary Design based on linear analysis could lead to unacceptable sizing and reinforcing of the main structural elements of Tall Buildings. In particular, linear preliminary Design procedures applied to coupled core wall systems would most likely lead to an overDesign of coupling beams with inappropriate and heavily congested reinforcement requirements. In addition, linear analysis with reduced seismic loads may result in under-Designed wall elements especially in terms of their shear strength. Simple procedures based on first principles have been developed to estimate base overturning moment capacity, total coupling shear capacity and overall ductility demand of the coupled core wall systems, which can be efficiently used in the preliminary seismic Design of Tall Buildings.
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Capacity and ductility demand estimation procedures for preliminary Design of coupled core wall systems of Tall Buildings
Bulletin of Earthquake Engineering, 2016Co-Authors: Eren Vuran, M. Nuray AydınoğluAbstract:Performance-based seismic engineering has brought new dimensions to Tall Building Design, leading to a major transformation from the prescriptive linear strength-based approach to the explicit non - prescriptive nonlinear deformation-based Design approach. Current Tall Building seismic Design practice is based on a well-established Design methodology, which starts with a preliminary Design followed by two performance evaluation stages. However the Designer has no reliable analysis tools at preliminary Design stage other than linear response analysis and application of capacity Design principles, which in fact may not insure for an acceptable nonlinear response in performance evaluation stage under maximum considered earthquake. In order to fill the gap an attempt is made to develop simple capacity and ductility demand estimation tools for coupled core wall systems to be implemented during the preliminary Design stage.
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Challenges and Problems in Performance-Based Design of Tall Buildings
Performance-Based Seismic Engineering: Vision for an Earthquake Resilient Society, 2014Co-Authors: M. Nuray AydınoğluAbstract:Tall Building Design is becoming a major area application of performance-based seismic Design, as evidenced by several Design guidelines and consensus documents published in the last few years. In general, performance-based earthquake engineering has brought new dimensions to Tall Building Design, leading to a major transformation from the linear strength-based approach to the nonlinear deformation-based Design practice. Consequently it becomes possible that the structural restrictions imposed on Tall Buildings by traditional prescriptive seismic Design codes can be removed. However Design guidelines have not fully matured yet and there are several issues, on which consensus has not been reached yet. On the other hand, it has to be admitted that the Design profession is not prepared yet to fully implement the requirements of the performance-based Design. Conceptual transformation from the prescriptive code-based Design to a non-prescriptive Design based on completely new features including nonlinear modeling, response-history analysis and deformation-based acceptance criteria represents a great challenge. Tall Building Design engineers are in need of appropriate Design tools to help them, at least in the preliminary Design stage, for a smooth transition to the performance-based Design. The present paper is intended to identify some of the critical problems the Design engineers face in the challenging new era of performance-based Tall Building Design.