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Article

Brian Keyworth

It is not uncommon for designers of low rise buildings to be instructed by their clients that a requirement for a pitched roof is part of the design brief. This may…

Abstract

It is not uncommon for designers of low rise buildings to be instructed by their clients that a requirement for a pitched roof is part of the design brief. This may reflect an aesthetic preference by the client, but is more likely to be due to the opinion that the pitched roof is a traditional and well‐tried construction form. While it is true that pitched roofs do have a generally good record of satisfactory performance, especially when compared with some types of flat roof construction, the structural design of the majority of pitched roofs constructed in the last 25 years is very different from those illustrated in textbooks of ‘traditional’ roof carpentry. In addition to use of trussed rafters, other factors, such as increased insulation or the development of the roof space as habitable accommodation, have similarly changed the way in which the roof performs and the areas of consequent potential risk.

Details

Structural Survey, vol. 6 no. 3
Type: Research Article
ISSN: 0263-080X

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Article

Peter Falconer

Offers guidelines for surveyors dealing with pitched metal roofsbuilt between the early 1970s and the present. Discusses roof pitchrecommendations, insulation, linings…

Abstract

Offers guidelines for surveyors dealing with pitched metal roofs built between the early 1970s and the present. Discusses roof pitch recommendations, insulation, linings, fastenings, leaks, corrosion, and sealants. Summarises that surveyors should consider particular points of corrosion, condensation, leaks and insulations when dealing with metal roofs.

Details

Structural Survey, vol. 10 no. 4
Type: Research Article
ISSN: 0263-080X

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Article

Satyajit Ghosh, Krishna Siddharth Rajasekeran, Billton Joseph Vitus, Sai Aswin Srikanth, Suhaas Mohandas, Ashwin Ganesh Monikantan and Shiv Kulin Contractor

This study investigates the aerodynamics of the airflow over low-rise houses subjected to turbulent cyclonic winds along the South-eastern peninsular India, routinely…

Abstract

Purpose

This study investigates the aerodynamics of the airflow over low-rise houses subjected to turbulent cyclonic winds along the South-eastern peninsular India, routinely afflicted by tropical cyclones. The purpose of this paper is to demonstrate how the power of modern computational fluid dynamics (CFD) and its engineering application accentuate decision-making at the planning stage of house designing in vulnerable areas.

Design/methodology/approach

The Weather Research and Forecasting (WRF) model was used for first simulating the landfall of cyclone Hudhud, a real storm, and its effect in extant and new house designs. Results from the WRF model were utilized to configure further CFD simulations of airflow around house designs. The analyses yielded deep insights, often non-intuitive, into airflow patterns around these houses with disparate roof forms indicating new possibilities in redesigning houses along Indian coastal areas.

Findings

This study shows that storm-induced high TKE values warranted a fuller CFD-based study. The second major finding showed that for a 90° angle of attack, arguably the most destructive attack angle, a pitched roof (with a pitch angle of 10°) worked best – this is about half the recommended angle sourced from earlier empirical estimates dating back to the British Raj period. There is a thin layer of padded air cushion shielding the roof's vulnerable surface from the storm's most energetic parts.

Originality/value

The originality of this research lies in its discourse to systematically resolve the TKE distribution of a cyclone impacting a standalone house. In particular, the study presents a lucid demonstration of all the probable scenarios connecting cyclonic stresses with a roof response, inferred from a careful combination of results garnered from cyclonic storm modelling coupled with CFD analysis. Additionally, the paper also shows a graphic visual representation of the forces induced on different roof designs, presented as a checklist for the first time. This should serve as a ready reckoner for civic authorities involved in disaster management over cyclone-ravaged areas.

Details

Smart and Sustainable Built Environment, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2046-6099

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Article

Ka Yee Kok, Hieng Ho Lau, Thanh Duoc Phan and TIina Chui Huon Ting

This paper aims to present the design optimisation using genetic algorithm (GA) to achieve the highest strength to weight (S/W) ratio, for cold-formed steel residential roof truss.

Abstract

Purpose

This paper aims to present the design optimisation using genetic algorithm (GA) to achieve the highest strength to weight (S/W) ratio, for cold-formed steel residential roof truss.

Design/methodology/approach

The GA developed in this research simultaneously optimises roof pitch, truss configurations, joint coordinates and applied loading of typical dual-pitched symmetrical residential roof truss. The residential roof truss was considered with incremental uniform distributed loading, in both gravitational and uplift directions. The structural analyses of trusses were executed in this GA using finite element toolbox. The ultimate strength and serviceability of trusses were checked through the design formulation implemented in GA, according to the Australian standard, AS/NZS 4600 Cold-formed Steel Structures.

Findings

An optimum double-Fink roof truss which possess highest S/W ratio using GA was determined, with optimum roof pitch of 15°. The optimised roof truss is suitable for industrial application with its higher S/W ratio and cost-effectiveness. The combined methodology of multi-level optimisation and simultaneous optimisation developed in this research could determine optimum roof truss with consistent S/W ratio, although with huge GA search space.

Research limitations/implications

The sizing of roof truss member is not optimised in this paper. Only single type of cold-formed steel section is used throughout the whole optimisation. The design of truss connection is not considered in this paper. The corresponding connection costs are not included in the proposed optimisation.

Practical implications

The optimum roof truss presented in this paper is suitable for industrial application with higher S/W ratio and lower cost, in either gravitational or uplift loading configurations.

Originality/value

This research demonstrates the approaches in combining multi-level optimisation and simultaneous optimisation to handle large number of variables and hence executed an efficient design optimisation. The GA designed in this research determines the optimum residential roof truss with highest S/W ratio, instead of lightest truss weight in previous studies.

Details

World Journal of Engineering, vol. 15 no. 5
Type: Research Article
ISSN: 1708-5284

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Article

A. Hunter‐Cairns and J. Stewart Stirling

Examines modern roof coverings and their associated problems over the past decade. Discusses the designers’ and suppliers’ dependence on and compliance with British…

Abstract

Examines modern roof coverings and their associated problems over the past decade. Discusses the designers’ and suppliers’ dependence on and compliance with British Standards. Provides details of the problems and their technical solutions.

Details

Structural Survey, vol. 16 no. 1
Type: Research Article
ISSN: 0263-080X

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Abstract

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Structural Survey, vol. 19 no. 4
Type: Research Article
ISSN: 0263-080X

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Article

Briggs Amasco Ltd

Various guides, learned papers and trade articles have dealt with roofing maintenance and refurbishment in the past. This brief paper can therefore only act as a general…

Abstract

Various guides, learned papers and trade articles have dealt with roofing maintenance and refurbishment in the past. This brief paper can therefore only act as a general guide to specifiers requiring information on roofing. Further assistance is obtainable from reputable specialist roofing contractors, British Standards, the British Flat Roofing Council, the Flat Roofing Contractors Advisory Board (FRCAB), the Mastic Asphalt Council & Employers Federation (MACEF) and the National Federation of Roofing Contractors. In addition the Tarmac book ‘Flat Roofing — a Guide to Good Practice’ and the PSA Flat Roof Guides are valuable sources of reference.

Details

Property Management, vol. 5 no. 3
Type: Research Article
ISSN: 0263-7472

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Article

David J Lowe, Margaret W Emsley and Anthony Harding

This paper seeks to redress the omission in recent literature on the influence of project strategic, site related and design related variables on the cost of construction…

Abstract

This paper seeks to redress the omission in recent literature on the influence of project strategic, site related and design related variables on the cost of construction. It presents, in part, the results of an investigation into the influence of 41 independent variables on both construction cost and client cost, concentrating on design related variables. Data were collected from 286 construction projects in the United Kingdom and correlation and test for differences were used to determine the relationships that exist between the dependent and independent variables. The analysis ascertains the cost ranking of many design related variables and establishes other relationships which exist within the data, confirming many of the relationships that had been anticipated from the literature. It also established the ordinal sequence of several nominal variables. These data, therefore, can be confidently used to develop models of the total cost of construction as verified by the development of both regression analysis and neural network cost models

Details

Journal of Financial Management of Property and Construction, vol. 12 no. 1
Type: Research Article
ISSN: 1366-4387

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Article

C. Briffett

Perhaps one of the least attractive aspects of making a structural survey is the roof space inspection which can be a cold, dark, and dirty activity in which the surveyor…

Abstract

Perhaps one of the least attractive aspects of making a structural survey is the roof space inspection which can be a cold, dark, and dirty activity in which the surveyor may encounter a number of dangers and surprises. One danger to guard against is professional negligence and it is imperative that the inspection is not reduced to a quick look round from the trap door access or becomes an excuse to use one's inexperienced office assistant to do the dirty work.

Details

Structural Survey, vol. 3 no. 2
Type: Research Article
ISSN: 0263-080X

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Article

Sara J. Wilkinson and Richard Reed

The purpose of this paper is to illustrate the potential for green roof retrofit to commercial buildings in a city centre to property managers and other property professionals.

Abstract

Purpose

The purpose of this paper is to illustrate the potential for green roof retrofit to commercial buildings in a city centre to property managers and other property professionals.

Design/methodology/approach

This paper addresses the research question: what is the potential of existing buildings in the CBD to accommodate a retrofitted green roof? Furthermore, it questions how many buildings are suitable for green roofs? The researchers compile a unique building database incorporating information about 536 commercial buidings and evaluate the potential suitability of each building to undergo a green roof retrofit. Assisted by other commercially available databases and software, the researchers are able to assess each roof based on criteria derived from an extensive literature review.

Findings

A relatively small proportion of roofs are found to be suitable, partly a result of local climate conditions and rainfall patterns, and the physical property stock. On a purely physical assessment, only a very small proportion of CBD stock is found to be suited. These buildings are most likely to be in low secondary locations, ungraded or B grade buildings, privately owned, concrete framed and not overshadowed by adjoining properties.

Practical implications

Property managers and other property professionals can now determine the potential of their portfolio stock for green roof retrofit based on the review of building attributes required for success adaptation in this paper. It possible that greater potential for green roof retrofit exists in the suburbs or regional towns where lower rise buildings may reduce the amount of overshadowing found in city centres. Follow‐up research could focus on a comparison of regional and suburban developments.

Originality/value

This is the first study of its kind and has assessed such a large number of buildings for their suitability for green roof retrofit; the findings provide a reliable guide for policymakers regarding the potential number of city centre buildings which would be possible to retrofit. Such findings should influence policymaking and incentives to target effective sustainability policies with regards to existing buildings.

Details

Property Management, vol. 27 no. 5
Type: Research Article
ISSN: 0263-7472

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