Search results

1 – 10 of 23
Article
Publication date: 26 November 2021

Flávio Alexandre Matias Arrais, Nuno Lopes and Paulo Vila Real

Stainless steel has different advantages when compared to conventional carbon steel. The corrosion resistance and aesthetic appearance are the most known; however, its better…

Abstract

Purpose

Stainless steel has different advantages when compared to conventional carbon steel. The corrosion resistance and aesthetic appearance are the most known; however, its better behaviour under elevated temperatures can also be important in buildings design. In spite of the initial cost, stainless-steel application as a structural material has been increasing. Elliptical hollow sections integrate the architectural attributes of the circular hollow sections and the structural advantages of the rectangular hollow sections (RHSs). Hence, the application of stainless-steel material combined with elliptical hollow profiles stands as an interesting design option. The purpose of the paper is to better understand the resistance of stainless-steel-beam columns in case of fire

Design/methodology/approach

The research presents a numerical study on the behaviour of stainless-steel members with slender elliptical hollow section (EHS) subjected to axial compression and bending about the strong axis at elevated temperatures. A parametric numerical study is presented here considering with and without out-of-plane buckling different stainless-steel grades, cross-section and member slenderness, bending moment diagrams and elevated temperatures.

Findings

The tested design methodologies proved to be inadequate for the EHS members being in some situations too conservative.

Originality/value

The safety and accuracy of Eurocode 3 (EC3) design methodology and of a recent design proposal developed for I-sections and cold-formed RHSs are analysed applying material and geometric non-linear analysis considering imperfections with the finite element software SAFIR.

Details

Journal of Structural Fire Engineering, vol. 13 no. 2
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 12 December 2016

Flávio Arrais, Nuno Lopes and Paulo Vila Real

Steel beams composed of cold-formed sections are common in buildings because of their lightness and ability to support large spans. However, the instability phenomena associated…

Abstract

Purpose

Steel beams composed of cold-formed sections are common in buildings because of their lightness and ability to support large spans. However, the instability phenomena associated to these members are not completely understood in fire situation. Thus, the purpose of this study is to analyse the behaviour of beams composed of cold-formed lipped channel sections at elevated temperatures.

Design/methodology/approach

A numerical analysis is made, applying the finite element program SAFIR, on the behaviour of simply supported cold formed steel beams at elevated temperatures. A parametric study, considering several cross-sections with different slenderness’s values, steel grades and bending diagrams, is presented. The obtained numerical results are compared with the design bending resistances determined from Eurocode 3 Part 1-2 and its French National Annex (FN Annex).

Findings

The current design expressions revealed to be too conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the Annex E, the first having a better agreement with the numerical results.

Originality/value

Following the previous comparisons, new fire design formulae are tested. This new methodology, which introduces minimum changes in the existing formulae, provides safety and accuracy at the same time when compared to the numerical results, considering the occurrence of local, distortional and lateral torsional buckling phenomena in these members at elevated temperatures.

Details

Journal of Structural Fire Engineering, vol. 7 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 28 June 2021

Flávio Arrais, Nuno Lopes and Paulo Vila Real

Sigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible…

Abstract

Purpose

Sigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible to local, distortional and lateral-torsional buckling, as possible failure modes when compared to common I-sections and hollow cross-sections. However, the instability phenomena associated to these members are not completely understood in fire situation. Therefore, the purpose of this study is to analyse the behaviour of beams composed of cold-formed sigma sections at elevated temperatures.

Design/methodology/approach

This study presents a numerical analysis, using advanced methods by applying the finite element software SAFIR. A numerical analysis of the behaviour of simply supported cold-formed sigma beams in the case of fire is presented considering different cross-section slenderness values, elevated temperatures, steel grades and bending moment diagrams. Comparisons are made between the obtained numerically ultimate bending capacities and the design bending resistances from Eurocode 3 Part 1–2 rules and its respective French National Annex (FN Annex).

Findings

The current design expressions revealed to be over conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the general prescriptions, the first having a better agreement with the numerical results.

Originality/value

Following the previous comparisons, new fire design formulae are analysed. This new methodology, which introduces minimum changes in the existing formulae, provides at the same time safety and accuracy when compared to the numerical results, considering the occurrence of local, distortional and lateral-torsional buckling phenomena in these members at elevated temperatures.

Details

Journal of Structural Fire Engineering, vol. 12 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 16 August 2019

Carlos Couto, Élio Maia, Paulo Vila Real and Nuno Lopes

The purpose of this paper is to assess whether the adaptation to fire of current proposals/design methodologies at normal temperature is capable of producing accurate predictions…

Abstract

Purpose

The purpose of this paper is to assess whether the adaptation to fire of current proposals/design methodologies at normal temperature is capable of producing accurate predictions of resistance for the out-of-plane stability of tapered beams.

Design/methodology/approach

The adaptation of these methodologies to fire has been done by accounting for the reduction in steel material properties with the temperature. Results were then compared to FEM calculations by performing GMNIA analyses to determine the ultimate strength of the numerical models and to ascertain the validity and accuracy of the adapted methodologies.

Findings

Although all methodologies produce safe results at normal temperatures, only the general method is recommended for the safety verification at elevated temperatures, although the data points were overly conservative. This investigation demonstrates the need of proper and accurate design methods for tapered beams at elevated temperatures, which should be the subject of future developments.

Research limitations/implications

The research in this paper is limited to the adaptation of existing room temperature design methods to fire. Therefore, possible assumptions made during the conception of the initial formulae, which may be valid exclusively for 20ºC, may have been disregarded.

Originality/value

For the time being, design methodologies for the safety check of tapered beams for the case of fire are inexistent. This paper investigates the adaptation of existing room temperature design to the fire situation by providing insights on their accuracy level, as well as on how to proceed. Finally, a safe design methodology for tapered beams in case of fire is provided until improved design methods are developed.

Details

Journal of Structural Fire Engineering, vol. 10 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 13 October 2021

Sabine De Paris, Carlos Nuno Lacerda Lopes and Alvaro Neuenfeldt Junior

Investigation of housing adaptability is related to understanding factors that influence project transformation. Factors may be associated with the design and project stage as…

Abstract

Purpose

Investigation of housing adaptability is related to understanding factors that influence project transformation. Factors may be associated with the design and project stage as also alternative uses to existing buildings. To structure methodology for criteria analysis of adaptability, the research aims to verify the importance level of factors related to adaptability and flexibility context in architecture.

Design/methodology/approach

Employing a multicriteria analysis and a diagnosis performed with architecture professionals, criteria importance identified in a bibliographic survey is contacted.

Findings

With harmonious results, key elements highlighted in the diagnosis are discussed. Adaptability and flexibility are mainly related to balance in the design of spaces and their connections, so the user can have control administrating the organization of their habitat.

Originality/value

As a complex subject, involving legal, social and cultural issues, the multicriteria method supports the scientific analysis of data. The results can be used in a practical case study as assessment of housing adaptability and flexibility, as a useful tool to decision support in architectural project.

Details

Archnet-IJAR: International Journal of Architectural Research, vol. 16 no. 1
Type: Research Article
ISSN: 2631-6862

Keywords

Article
Publication date: 6 September 2018

Gilberto Santos, José Afonseca, Nuno Lopes, Maria João Félix and Federica Murmura

This research aims to focus on the idea management system (IMS) with the main purpose of identifying and describing the factors that promote success in managing ideas, grounded on…

Abstract

Purpose

This research aims to focus on the idea management system (IMS) with the main purpose of identifying and describing the factors that promote success in managing ideas, grounded on the analysis of case studies.

Design/methodology/approach

The method used consists of a case study and semi-structured interviews with those directly responsible for the management of ideas from four companies, which are presented in this paper.

Findings

The main findings, critical for the success of an IMS, are as follow: the involvement of top management, evidence of results, establishment of goals and objectives, dissemination of good results, willingness to share and develop ideas, complete transparency in the management of ideas, maintenance of dynamic and proactive attitudes and mainly recognition. All have been described.

Research limitations/implications

This work presents a preliminary framework for further research toward the study of CSFs inherent to IMSs that is still bound by the limited number of case studies presented. Further research should be undertaken to broaden and consolidate the presented CFSs and their pertinence.

Originality/value

This study, although limited to four case studies, presents conclusive results that support managers of suggestion systems/IMSs in improving or deploying such systems. The main factors were identified and described. They can contribute to the effectiveness of employee suggestion system. It can be reasoned from this investigation that the contributions from employees toward the success of a company leads to excellence in business.

Details

International Journal of Quality and Service Sciences, vol. 10 no. 3
Type: Research Article
ISSN: 1756-669X

Keywords

Article
Publication date: 9 February 2010

Nuno Lopes, Paulo Real, Luís da Silva and Jean-Marc Franssen

The simple model of Eurocode 3, for the fire resistance evaluation of stainless steel members, are based on the procedures used for carbon steel structural elements. However, due…

80

Abstract

The simple model of Eurocode 3, for the fire resistance evaluation of stainless steel members, are based on the procedures used for carbon steel structural elements. However, due to the existing differences in the constitutive laws of these two materials, it is expected that it would not be possible to use, in both materials, the same formulae for the member stability calculation, as proposed in Eurocode 3. This paper aims at increasing the knowledge on the behaviour of stainless steel axially loaded columns at elevated temperatures. For this purpose, a geometrical and material non linear computer code has been used to determine the buckling load of these elements. The Eurocode formulae are evaluated and a new proposal, that ensures accurate and conservative results when compared with the numerical simulations, is presented.

Details

Journal of Structural Fire Engineering, vol. 1 no. 1
Type: Research Article
ISSN: 2040-2317

Article
Publication date: 16 September 2013

Maria Manuela Cruz-Cunha, Isabel Miranda, Nuno Lopes and Ricardo Simoes

The health and social care sector is receiving growing attention due to the increased life expectancy and to the public demand for a better quality of life and better health…

Abstract

Purpose

The health and social care sector is receiving growing attention due to the increased life expectancy and to the public demand for a better quality of life and better health services. New cost-efficient approaches are required, and the paper aims to present and discuss the main results of a study undertaken in a Portuguese municipality on the perceived relevance of an e-marketplace of social and healthcare services for the inhabitants in general, and for people with special needs in particular, and the identification of the most relevant services to be offered through this platform.

Design/methodology/approach

A wide survey was undertaken to identify the needs of potential users and their expectancies with relation to the proposed platform. The results of the study are a support for the project promoters to understand the viability of the solution and the requirements to the deployment of the pilot experiment, as well as to drive the selection of domains of activities/classes of services to be offered by the platform.

Findings

Services such as information about healthcare services, home monitoring/accompanying services 24 hours per day, and personal hygiene services provided at home are the ones recognized by the inquired citizens as the most important, which indicates that the potential users will be mostly people with special needs or their family or caregivers.

Originality/value

While still at a preliminary development phase, the project represents a good opportunity to develop a totally innovative service with high potential impact for the senior population and for individuals with special needs.

Details

The Learning Organization, vol. 20 no. 6
Type: Research Article
ISSN: 0969-6474

Keywords

Content available
Article
Publication date: 16 September 2013

Joao Varajao

1076

Abstract

Details

The Learning Organization, vol. 20 no. 6
Type: Research Article
ISSN: 0969-6474

Article
Publication date: 24 October 2022

Rogério Lopes, Francisco Barros, Francisco Q. de Melo, Nuno V. Ramos, Rafael Cunha, Ricardo Maia, Rui Rodrigues, M.P.L. Parente and P.M.G. Moreira

The vehicle´s body front pillar should absorb most of the striker kinetic energy, while only a fraction of that is absorbed by the door structure. This study aims to discuss the…

Abstract

Purpose

The vehicle´s body front pillar should absorb most of the striker kinetic energy, while only a fraction of that is absorbed by the door structure. This study aims to discuss the aforementioned issue. In this test the striker is a virtual entity. Six uniaxial strain gauges are installed throughout the door. Additionally, contactless 3D digital image correlation (DIC) allows to assess the major door panel’s continuous deformation and strain fields.

Design/methodology/approach

A coach is a large and heavy long-distance passenger transport vehicle. Their structural certification, classifies coaches as M3 Class III vehicles. New coach structures’ designs need analyses of each sub-system for critical pre-validation of the entire structure, aiming driver and passenger carrier safety. Also, a thorough examination due to increased travel speed is needed.

Findings

Experimental pseudo-dynamic (PSD) results were compared and validated using finite element method (FEM) with two pieces of distinct FEM software (Abaqus® and PamCrash®). The time dependent solution was carried out by explicit techniques. Results by FEM and PSD test showed good agreement, evidencing the reliability of the tools selected. Results by PamCrash® were closer to the experimental data.

Practical implications

R-29 is truck-only regulation, however can be adapted to coaches in case of a frontal collision. The present work focuses on the impact behavior of the passenger front door subsystem.

Originality/value

As a first validation the entire structure, the behavior of a vehicle door, under in-plane impacts was studied. The corresponding deformation energy absorbed by the frontal passenger coach door under virtual impacts of a swinging striker was assessed using a PSD approach.

Details

International Journal of Structural Integrity, vol. 14 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

1 – 10 of 23