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1 – 10 of 251Luis Laím and João Paulo C. Rodrigues
This paper is mainly aimed at the structural performance of compound cold-formed galvanised steel beams under fire conditions based on the results of a large programme of…
Abstract
Purpose
This paper is mainly aimed at the structural performance of compound cold-formed galvanised steel beams under fire conditions based on the results of a large programme of experimental tests and numerical simulations. The main objective of this research was to assess the critical temperature and time of the studied beams. Other important goals of this research work were to investigate the influence of the cross-sections (C, lipped-I, R and 2R beams) and, above all, of the axial restraint (0, 0.45, 3, 7.5, 15, 30, ∞ kN/mm) to the thermal elongation of the beam and the rotational restraint at beam supports (0, 15, 80, 150, 300, 1,200 and ∞ kN.m/rad) on the fire resistance of this kind of beams.
Design/methodology/approach
This paper still provides details of the simulation methodology for achieving numerical stability and faithful representation of detailed structural behaviour and compares the simulation and experimental results, including beam failure modes, measured beam axial forces and beam mid-span deflections.
Findings
Good agreement between Abaqus simulations and experimental observations confirms that the finite element models developed with the Abaqus/standard solver are suitable for predicting the structural fire behaviour of restrained cold-formed steel beams.
Originality/value
The results showed above all that the effect of the stiffness of the surrounding structure seems to decrease with the increasing slenderness of the beams.
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Tiago A. de C. Pires, João Paulo C. Rodrigues and Jose J.R. Silva
Nowadays, circular concrete-filled tubular (CFT) columns are largely used in construction because of structural and architectural advantages such as high load bearing capacity and…
Abstract
Purpose
Nowadays, circular concrete-filled tubular (CFT) columns are largely used in construction because of structural and architectural advantages such as high load bearing capacity and aesthetic appearance. The behavior of CFT columns at ambient and high temperatures is good; however, there are problems related to their behavior in fire when inserted in a real building structure, as for example, the influence of the restraining to thermal elongation that have to be addressed in order to improve their design. This study aims to present the results of a numerical study on the behavior of CFT columns with restrained thermal elongation in case of fire.
Design/methodology/approach
The parameters tested in the numerical simulations included column slenderness, load level, surrounding structure stiffness and steel reinforcement ratio. A sequentially coupled thermal stress analysis was carried out. The numerical model was validated with results from a large series of fire resistance tests carried out at Coimbra University, in Portugal. From these, simple equations to evaluate CFT column critical times were derived.
Findings
The results were also compared with the ones obtained from the current EN 1994-1-2:2005 simplified calculation and tabulated data methods. For the analyzed cases, it was verified that, while the simplified calculation method led to safe results on the evaluation of the fire resistance of CFT columns with restrained thermal elongation, the tabulated data method led, in certain cases, to unsafe results. This research showed also lower critical times than those from literature on similar type of columns.
Originality/value
The influence of the stiffness of the surrounding structure on the behavior of CFT columns subjected to fire was not yet clear in the major part of the studies already carried out. So, this paper has the originality to consider this parameter in the numerical simulations of this type of columns.
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Hélder Craveiro, João Paulo Correia Rodrigues and Luis Laim
The use of cold-formed steel members has increased significantly in the past few years; however, its design is only briefly addressed in the current design codes, such as the EN…
Abstract
Purpose
The use of cold-formed steel members has increased significantly in the past few years; however, its design is only briefly addressed in the current design codes, such as the EN 1993-1-3. To evaluate the compressive behavior of single and built-up cold-formed steel members, at ambient and simulated fire conditions with restrained thermal elongation, experimental and numerical tests were undertaken.
Design/methodology/approach
Four cross-section shapes were tested, namely, one single (lipped channel), one open built-up (I) and two closed built-up (R and 2R), considering two end support conditions, pinned and fixed. Two test set-ups were specifically developed for these tests. Based on the experimental results finite element models were developed and calibrated to allow future parametric studies.
Findings
This paper showed that increasing the level of restraint to thermal elongation and the initially applied load led to lower critical temperatures. Increasing the level of restraint to thermal elongation, the failure is governed by the generated axial restraining forces, whereas for lower levels of restraint to thermal elongation, the failure is controlled by the temperature increasing.
Originality/value
This paper is a contribution to the knowledge on the behavior of cold-formed steel columns subjected to fire, especially on the ones with a built-up cross-section, where results on thermal restrained ones are still scarce. It presented a set of experimental and numerical results useful for the development of numerical and analytical analysis concerning the development of new simplified calculation methods.
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Joao Paulo C. Rodrigues, Luis Laim and Hélder David Craveiro
This paper aims to present the results of a study on the behaviour of cold-formed galvanized steel beams subjected to fire, using the results of a large programme of experimental…
Abstract
Purpose
This paper aims to present the results of a study on the behaviour of cold-formed galvanized steel beams subjected to fire, using the results of a large programme of experimental tests.
Design/methodology/approach
The research investigated the influence of web stiffeners in the sections and the stiffness of the surrounding structure, including the axial and rotational restraining to the thermal elongation, on the flexural behaviour of the beams in case of fire. In other words, the structural response of different open cold-formed steel beams, with and without web stiffeners, was compared in case of fire.
Findings
The results showed that a good choice between using cold-formed steel beams, with and without web stiffeners, may depend on the section shape and the internal forces generated in these members during a fire.
Originality/value
Temperatures in the furnace and at several points of the beams, as well as deformations and restraining forces and moments, were measured to achieve those goals and consequently to assess the critical time and temperature of these beams.
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Seyed Milad Komsionchi Eslamzadeh, António Grilo, Pedro Espadinha-Cruz, João Paulo C. Rodrigues and José Pedro Lopes
The purpose of this research is to review literature about the performance assessment (PA) in urban fire departments (FDs) to gain state-of-the-art of the fire departments'…
Abstract
Purpose
The purpose of this research is to review literature about the performance assessment (PA) in urban fire departments (FDs) to gain state-of-the-art of the fire departments' performance assessment (FDPA) and identify its most applied methods and indicators.
Design/methodology/approach
A five-stage structured literature review (SLR) is conducted to review the FDPA-related studies; then, the statistical analysis is applied to reveal more information from the extracted data and design a general framework for FDPA.
Findings
The systematic literature review resulted in 336 independent variables for FDPA and finding the data envelopment analysis (DEA) as the most applied FDPA method among the mathematical and statistical models in the reviewed papers. By using analysis outcomes, a general conceptual framework for FDPA is proposed.
Research limitations/implications
The reviewed studies were limited to assessments at the strategic level and urban fire protection services.
Practical implications
The results of this research can support fire protection service managers, decision-makers, PA researchers and academicians to have a better understanding of FDPA and state-of-the-art in this field.
Originality/value
A considerable number of studies have been done about the FDPA to provide methods to improve the efficiency and effectiveness of FDs. Although there are reviews about PA in fire service areas, to the best of our knowledge, no study has been done about FDPA.
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This paper aims to investigate the interaction between the sustainability of the European social model and the European Union's revised Lisbon Strategy and its focus on jobs and…
Abstract
Purpose
This paper aims to investigate the interaction between the sustainability of the European social model and the European Union's revised Lisbon Strategy and its focus on jobs and growth. The success of this strategy – following its five‐year mid‐term review in 2005 – depends on attempts to renew European competitiveness through, for example, innovation and life‐long learning and well‐designed reforms of the European social model.
Design/methodology/approach
The paper reviews the evolution of the Lisbon Strategy and sets out the broader context for European policy on competitiveness. It provides the backdrop for discussions linking competitiveness to corporate responsibility.
Findings
The sustainability of the European social model depends on the success of the overall strategy for growth and jobs, in which innovation and life‐long learning are key. The concrete solutions to achieve a successful combination of those factors in each member state need to be found by countries themselves. That is why the preparation and implementation of Europe‐wide National Reform Programmes for growth and jobs opens an opportunity to drive competitiveness which should not be missed.
Practical implications
The paper addresses issues relevant for sustainable development, Europe's innovation potential and competitiveness and could open new areas for research. There is a need for a more forward‐looking approach to European citizens' aspirations that focuses on: sustaining their living conditions in a global economy; making Europe a stronger player in improving global governance; and creating a more democratic and effective political system.
Originality/value
The paper provides a new approach to renewing European competitiveness by fully exploiting the potential of Europe's own single and external market, as well sound macro‐economic management of its growth potential.
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Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…
Abstract
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.
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Sixty‐year‐old engineer and businessman, former minister of state and air force officer Ozires Silva has been inaugurated as Embraer's new chief executive officer in a ceremony…
Abstract
Sixty‐year‐old engineer and businessman, former minister of state and air force officer Ozires Silva has been inaugurated as Embraer's new chief executive officer in a ceremony presided over by the Minister for Air, brigadier Sócrates da Costa Monteiro, and attended by approximately 500 authorities and invited guests. Ozires replaces former CEO João Rodrigues da Cunha Neto, who resigned last June 26th.
João Carlos de Almeida Rodrigues Gonçalves, Fernanda Araujo Baião, Flavia Maria Santoro and Giancarlo Guizzardi
A literature review was conducted in order to establish a detailed definition of a knowledge-intensive process (KiP). Moreover, relevant theories from humanities – especially the…
Abstract
Purpose
A literature review was conducted in order to establish a detailed definition of a knowledge-intensive process (KiP). Moreover, relevant theories from humanities – especially the fields of linguistics and philosophy – were thoroughly researched and adapted for establishing descriptive and analytical foundations for the phenomena involved. Finally, a cognitive business process management (BPM) theory was proposed in order to assess how sufficient are its respective explanatory and predictive powers. This study aims to discuss the aforementioned objective.
Design/methodology/approach
This study proposes a novel theory for KiPs that describe the process flow based on the participants' interactions and their beliefs, desires and intentions as the main drivers of the process enactment and execution.
Findings
The proposal puts forth a comprehensive definition of a KiP, depicting knowledge intensity, participant interaction and decision-making. The inner dynamics of each of these two elements (as well as other associated elements) are described as an information systems (IS) theory that enables the study of KiPs in detail, going beyond the typical techniques of the BPM field and common obstacles.
Originality/value
A theory proposal for KiP that applies concepts from speech act theory and intentional states as the main drivers for understanding the process dynamics are, to the best of the authors' knowledge, not present at the literature. Being an original proposal, the real-world scenario discussed brings up the explanatory and predictive powers of the theory as well as its innovative value for research in the field.
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Alberto Martins and João Rodrigues
This paper presents the results of an experimental and numerical study to clarify the influence of the surrounding building structure in the fire behaviour of reinforced concrete…
Abstract
This paper presents the results of an experimental and numerical study to clarify the influence of the surrounding building structure in the fire behaviour of reinforced concrete columns with restrained thermal elongation. The parameters studied were: the longitudinal reinforcement ratio, the slenderness of the column and the stiffness of the surrounding structure to the column in fire. The experimental study was complemented by a numerical study carried out using the finite element program SAFIR. Simplified calculation methods proposed in EN1992-1-2 were also used to evaluate the fire resistance of the tested columns. From the application of the 500°C isotherm method, proposed in EN1992-1-2, it can be noticed that this method led to smaller values of the fire resistance than those obtained in the experimental tests. The tabulated data method A, proposed in EN1992-1-2, proved to be very conservative.