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Gibbons M.P.M.,Rowan Williams Davies and Irwin Inc. RWDI | Chapman R.J.,RWDI AIR Inc. | Cherneski D.M.,RWDI AIR Inc. | De Jong C.,City of Calgary | Gauthier M.,RWDI AIR Inc.
Proceedings, Annual Conference - Canadian Society for Civil Engineering | Year: 2013

Environment Canada, the National Centers for Environmental Prediction (NCEP), and private weather companies provide numerical weather forecast products that cover Canada and the United States. While the spatial and temporal resolution of these numerical weather forecast products are sufficient for public consumption there are limitations to the application of these products for predicting winds at multiple working heights for construction projects. This paper summarizes an advanced wind warning system that was developed for the City of Calgary. This system combines weather forecast technology with wind engineering best practices to predict winds at multiple working heights and provide alerts to reduce incidents of falling debris and the impacts of catastrophic wind related events. Technical, scientific and operational characteristics of the system as well as the results of preliminary model verification studies will be presented.


Gilani S.,Carleton University | O'Brien W.,Carleton University | Gunay H.B.,Carleton University | Carrizo J.S.,Rowan Williams Davies and Irwin Inc. RWDI
Energy and Buildings | Year: 2016

Occupants account for a significant impact on building performance through their interactions with zone level building components. Empirically-derived occupant models, despite their potential to represent occupants' impact in building performance simulation (BPS), have minimal penetration in design and code compliance processes. Instead, occupants are represented with static schedules or simple deterministic triggers. The objective of this paper is to better understand the influence of assumptions made in representing occupant interactions with building components over a BPS model's energy use and comfort predictions, as well as their ability to promote better design decisions. To this end, the energy and daylight performance of a generic perimeter office space in Ottawa, Canada were evaluated using a set of comprehensive performance metrics. Results indicate that representing dynamic occupant-building interactions lead to different energy predictions from the static schedules. The maximum difference in the total electricity use was for window-to-wall area ratios (WWR) of 20%, which was about 30% higher with the stochastic cases than the blind-open static cases. WWR 60% and 40% generally yielded the lowest lighting electricity use with the static and stochastic cases, respectively. This paper emphasizes the importance of incorporating empirically-derived dynamic occupant models for simulation-aided design and code compliance. © 2015 Elsevier B.V. All rights reserved.


Viise J.,Halvorson and Partners HP | Halvorson R.,Halvorson and Partners HP | Morava B.,Rowan Williams Davies and Irwin Inc. RWDI | Weismantle P.,Adrian Smith Gordon Gill Architecture ASGG | Stafford J.,Adrian Smith Gordon Gill Architecture ASGG
Structures Congress 2012 - Proceedings of the 2012 Structures Congress | Year: 2012

The following paper outlines key challenges inherent in the design scheme of a super-tall linked tower (mega-structure) and the unique considerations associated with developing the design of such a complex project. Although 1 Dubai was put on hold as a consequence of the global financial crisis in October 2008, the early phases of building optimization, high performance material utilization, and constructability considerations provided unique lessons that can be applied in future ventures. Intuition and experience on comparable projects is essential in their design but so is keeping a thoughtful approach to building system performance and remaining flexible enough to allow modifications in response to unexpected challenges. To attain an end product that is both rational and efficient, all team members must be able to respond quickly and in a coordinated fashion. © ASCE 2012.


Pridham B.,Rowan Williams Davies and Irwin RWDI Inc. | Morava B.,Rowan Williams Davies and Irwin RWDI Inc. | Purnode B.,Owens Corning Science and Technology Center | Mighton S.,Owens Corning Science and Technology Center
Conference Proceedings of the Society for Experimental Mechanics Series | Year: 2011

Characterization of dynamic forces generated by industrial processes is an important part of the design of the process support structure and foundation. Forces generated by reciprocating industrial machinery are often characterized using sinusoidal functions; however, more complex processes, such as those involving fluid-structure interactions, may not be easily approximated by simplified periodic functions. When possible, operational measurements of the acceleration and displacement response of the supporting structure can be used in conjunction with dynamic Finite Element Modeling (FEM) to estimate force spectra associated with the process. In this paper a case study on dynamic force characterization for an industrial process is presented. The study included static and dynamic response measurements of an existing process installation. A FEM of the system was developed and used in conjunction with the response measurements to estimate the force spectra for the process. The force spectra were then used to generate random time histories of the forces for use in the design of the supporting structure and foundation for a future, similar process installation. ©2010 Society for Experimental Mechanics Inc.


Brooks A.,Rowan Williams Davies and Irwin Inc. RWDI | Gamble S.,Rowan Williams Davies and Irwin Inc. RWDI | Dale J.,Rowan Williams Davies and Irwin Inc. RWDI | Gibbons M.,Rowan Williams Davies and Irwin Inc. RWDI
Proceedings, Annual Conference - Canadian Society for Civil Engineering | Year: 2015

Although the installation of solar arrays on buildings is becoming commonplace, the determination of snow loads for installations is currently not covered by building codes in North America, namely the NBCC or ASCE 7 standards. The presence of a solar array on a roof can alter snow load patterns, leading to inconsistencies between the loading scenarios in building codes and what is expected for roofs with solar arrays. Available tools for the more comprehensive evaluation of snow loads for these structures include water flume model simulations, boundary layer wind tunnel testing and numerical simulations where the cumulative effects of numerous winter storms are simulated and parametrically analyzed for different climate regions. The results of these analysis methods are commonly reported as load cases or patterns, similar in form to the recommendations in the NBCC and ASCE 7 standards. Calculation procedures developed to assist civil and structural engineers in interpreting the results of these analyses are presented for different climate regions. Options for reducing rooftop snow accumulation are discussed. © Copyright (2015) by the Canadian Society for Civil Engineering. All rights reserved.


Sinclair R.,Rowan Williams Davies and Irwin Inc. RWDI | Du X.,Rowan Williams Davies and Irwin Inc. RWDI
ASHRAE Transactions | Year: 2012

Buildings with large open spaces such as an atrium require a smoke management system. Natural smoke venting is not common in North America but it is receiving more consideration in new building design to integrate with sustainable aspects that utilize natural ventilation and also for the reason that, if it can be shown to be reliable, it can save money. This paper discusses the effects of: wind; temperature of the fire smoke plume; and stack effect for natural smoke venting. It also presents CFD modeling illustrating these effects for a 4-story atrium and an 8-story atrium. The results show that natural smoke venting performs satisfactorily during calm wind conditions without stack effect and also during cold outdoor temperatures. With very hot outdoor temperatures reverse stack effect can cause temporary fumigation of smoke throughout a tall atrium. During frequently occurring windy conditions higher make-up air speeds can cause adverse mixing of smoke throughout an atrium since natural venting schemes have significant area of open inlets and outlets.


Garber J.,Rowan Williams Davies and Irwin Inc. RWDI | Stone G.,Rowan Williams Davies and Irwin Inc. RWDI | Irwin P.,Rowan Williams Davies and Irwin Inc. RWDI
Advances in Hurricane Engineering: Learning from Our Past - Proceedings of the 2012 ATC and SEI Conference on Advances in Hurricane Engineering | Year: 2013

Design for wind loading is of particular importance in Florida due to the influence of hurricanes. The design wind speeds when applied to analytical code provisions result in significant wind pressures compared to other locales. This places a premium on the need for refinement of design wind loads through wind tunnel testing. Accurate measures of pressure and force coefficients, in the presence of the surrounding built environment, account for much of the benefit. Occupant comfort is also an issue, although the treatment of hurricanes can be a source of confusion. Use of lower return periods in the evaluation of comfort should address this. The Florida Building Code contains specific provisions for High Velocity Hurricane Zones that exclude the consideration of Exposure B, which would otherwise be used in many instances. Wind tunnel studies are designed to satisfy the intent of the code with respect to safety while still reflecting realistic conditions for serviceability. © ASCE and ATC 2013.


Browne M.,Rowan Williams Davies and Irwin Inc. RWDI | Gamble S.,Rowan Williams Davies and Irwin Inc. RWDI | Gibbons M.,Rowan Williams Davies and Irwin Inc. RWDI
Advances in Hurricane Engineering: Learning from Our Past - Proceedings of the 2012 ATC and SEI Conference on Advances in Hurricane Engineering | Year: 2013

Solar arrays installed on roofs of low-rise commercial buildings are especially popular since it makes good use of previously unexploited real estate. These systems are usually restrained to resist wind-induced lift-off and sliding using ballast, penetrations, adhesives, or combinations thereof. In the case of ballasted systems, reducing the added weight on the roof is often the primary objective of designers, while maintaining a certain level of reliability. This can be accomplished through aerodynamic design and other methods, but sometimes more simply through the utilization of load sharing between adjacent panels. This is accomplished through the vertical bending stiffness of the racking system. This paper presents a discussion of the varied wind tunnel testing and analysis methods currently employed around the world, with a focus on the correlation effects associated with load sharing. A finite element model, in conjunction with wind tunnel data on a roof-top array, is used to demonstrate the impact of array stiffness on wind loads in a time- and spatiallyvarying sense. Practical guidance to determine ballast requirements is also provided. © ASCE and ATC 2013.

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