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This paper aims to describe current trends in probabilistic structural fire engineering and provides a comprehensive summary of the state-of-the-art of performance-based…
This paper aims to describe current trends in probabilistic structural fire engineering and provides a comprehensive summary of the state-of-the-art of performance-based structural fire engineering (PSFE).
PSFE has been introduced to overcome the limitations of current conventional design approaches used for the design of fire-exposed structures, which investigate assumed worst-case fire scenarios and include multiple thermal and structural analyses. PSFE permits buildings to be designed in relation to a level of life safety or economic loss that may occur in future fire events with the help of a probabilistic approach.
This paper brings together existing research on various sources of uncertainty in probabilistic structural fire engineering, such as elements affecting post-flashover fire development, material properties, fire models, fire severity, analysis methods and structural reliability.
Prediction of economic loss would depend on the extent of damage, which is further dependent on the structural response. The representative prediction of structural behaviour would depend on the precise quantification of the fire hazard. The incorporation of major uncertainty sources in probabilistic structural fire engineering is explained, and the detailed description of a pioneering analysis method called incremental fire analysis is presented.
The purpose of this paper is to review the development of leave policies in Europe, both at a regional and national level, and to consider what future directions such…
The purpose of this paper is to review the development of leave policies in Europe, both at a regional and national level, and to consider what future directions such policies might take to meet changing conditions and emerging needs.
The paper draws on the work of an international network that the authors founded in 2004, which brings together experts on leave policy from over 40 countries, and in particular on an annual review of national leave policies conducted by network members.
The article presents developments in European legislation on leave policy stretching from 1883 to the present day, and outlines the extent of leave policies in European countries and the wide variations in the design of these policies. It suggests that future directions in leave policy need to address the relationship between this and other policy areas; the need for a life course perspective to leave policy, getting beyond parental leave; and that leave should turn away from being considered an employment benefit towards becoming a universal right to care.
The paper provides a concise overview of leave policy in the global region where leave policies began and are today most developed, at both a regional and national level. It is also intended to stimulate debate about the future directions that leave policy might take.
Evidence to date shows a divergence in the methods and approaches used by companies to introduce empowerment and indeed a wide debate as to the meaning and appropriateness…
Evidence to date shows a divergence in the methods and approaches used by companies to introduce empowerment and indeed a wide debate as to the meaning and appropriateness of the term itself. The popularity of the concept has led many organisations to “dive in at the deep end”, wanting to experience the benefits of empowerment without perhaps stopping to consider the wider implications and consequences. This paper reports on the approach that one hotel company adopted to re‐introduce empowerment, a previous attempt having failed. It provides an insight into differing perceptions of the meaning of empowerment between employees and managers; the positive and negative experiences of those working in an empowerment culture and the changes required for a renewed attempt at introducing empowerment to be successful. The authors conclude that “quick fix” strategies will rarely be successful and urge the development of a longer‐term, more sustainable, approach.
Considers the concept of “employee child care” andargues that it is problematic for a number of reasons. An alternativeapproach is advocated, based on an integrated…
Considers the concept of “employee child care” and argues that it is problematic for a number of reasons. An alternative approach is advocated, based on an integrated, coherent and multi‐functional system of early childhood care and education services for all children and their carers, which does not treat children of employed parents in isolation from other children; examples of this broad approach are given. In conclusion, argues that an opportunity has been wasted to review services in the context of a wider consideration of policies to promote the reconciliation of parental employment and caring for children and of the role of employers with respect to reconciliation. Instead, a decontextualized advocacy of “employee child care” has been able to develop, virtually unchallenged, in a climate dominated by labour market concerns.
The fire resistance of precast prestressed concrete floor systems is heavily influenced by the end connections and the stiffness of the surrounding structure, both of…
The fire resistance of precast prestressed concrete floor systems is heavily influenced by the end connections and the stiffness of the surrounding structure, both of which must be considered in any analysis. Analysing floor slabs with beam or shell elements whose end nodes share the nodes of supporting beams leads to a major problem for precast prestressed flooring systems where the steel tendons terminate at the end of the flooring units, because the approach of sharing nodes of the supporting beam and floor assumes that these tendons are anchored into the supporting beams. In order to solve this problem, a "multi-spring" connection element has been developed. Experimental data available from previous research work has been used to validate the finite element model. It is concluded that the inclusion of the multi-spring connection results in more accurate predictions of prestressed hollowcore slab behaviour in fire conditions.
This paper describes numerical modelling to predict the fire resistance of engineered timber-concrete composite floor systems. The paper describes 3D numerical modelling…
This paper describes numerical modelling to predict the fire resistance of engineered timber-concrete composite floor systems. The paper describes 3D numerical modelling of the floor systems using finite element software, carried out as a sequential thermo-mechanical analysis. Experimental testing of these floor assemblies has also been undertaken to validate the models, with multiple full scale tests conducted to determine the failure mechanisms and assess fire damage to the system components. The final outcome of this research is the development of simplified design methods for calculating the fire resistance of a wide range of engineered timber floor systems, as part of a larger research project on multi-storey timber buildings.
The fire resistance evaluation of a timber member is an important and complex problem of structural design. In order to solve this problem, it is crucial to have reliable…
The fire resistance evaluation of a timber member is an important and complex problem of structural design. In order to solve this problem, it is crucial to have reliable information on the temperature distribution within a timber cross-section exposed to fire, and to develop a numerical model for the prediction of such a quantity. The paper reports the experimental-numerical comparisons in terms of temperature distribution within a timber member made from radiata pine LVL (laminated veneer lumber) exposed to fire. The experimental tests were performed at the University of Canterbury and BRANZ (New Zealand) on 146×60, 300×105 and 360×133 mm LVL members. The temperature distribution was monitored using several thermocouples. The numerical results were obtained using the Abaqus FE code with different conductive models. The Eurocode 5 and Frangi's proposals led to similar results characterized by acceptable approximation close to the surface. Since the accuracy reduced for deeper fibres, a new proposal based on a different variation of the conductivity with the temperature was made. The proposal led to acceptable approximation throughout the tested cross-sections.
This research investigated the fire performance and failure behaviour of timber-concrete composite floor systems currently under development in New Zealand, resulting in a…
This research investigated the fire performance and failure behaviour of timber-concrete composite floor systems currently under development in New Zealand, resulting in a design method for evaluating the fire resistance of these floors with different types of connections. Furnace tests were performed on two full-size floor specimens at the Building Research Association of New Zealand (BRANZ). Both floor specimens were 4 m long and 3 m wide, consisting of 65 mm concrete topping on plywood formwork, connected to double LVL (laminated veneer lumber) floor joists. They were tested over a 4 m span, subjected to a nominal design live load of 2.5 kPa. Both floors were subjected to the ISO 834 test fire for over 60 minutes. Two separate connection types were tested; concrete notches cut into the timber beams with an incorporated shear key, and metal toothed plates pressed between the double beams.
It was found that the reduction in section of the timber beams due to the fire governed the failure mode of the floors. The test data and visual observations aided in the development of an analytical model for evaluating the fire resistance of timber-concrete composite floors. This was implemented into a spreadsheet that is able to predict the expected fire resistance of these floors, taking into account some major time dependent variable properties that can have an effect on the overall performance. Load-span tables have been produced to give the estimated fire resistance of floors with differing dimensions, span lengths and applied loads.
THE SIX YEARS since the reorganisation of local government in Northern Ireland have seen a massive development of services in the public library field, with progress on…
THE SIX YEARS since the reorganisation of local government in Northern Ireland have seen a massive development of services in the public library field, with progress on almost all fronts simultaneously. Five Education and Library Boards were created under legislation which gave certain advantages to the library service, not least of which was the close link with education, and including a statutory library committee and a designated post of chief librarian. Another helpful feature is the close similarity of population, which ranges from 230,000 in the Western Board to 360,000 in Belfast.