The Collapse Behaviour of Cold-formed Steel Portal Frames at Elevated Temperatures

This paper describes the results of non-linear elasto-plastic implicit dynamic finite element analyses that are used to predict the collapse behaviour of cold-formed steel portal frames at elevated temperatures. The collapse behaviour of a simple rigid-jointed beam idealisation and a more accurate semi-rigid jointed shell element idealisation are compared for two different fire scenarios. For the case of the shell element idealisation, the semi-rigidity of the cold-formed steel joints is explicitly taken into account through modelling of the bolt-hole elongation stiffness. In addition, the shell element idealisation is able to capture buckling of the cold-formed steel sections in the vicinity of the joints. The shell element idealisation is validated at ambient temperature against the results of full-scale tests reported in the literature. The behaviour at elevated temperatures is then considered for both the semi-rigid jointed shell and rigid-jointed beam idealisations. The inclusion of accurate joint rigidity and geometric non-linearity (second order analysis) are shown to affect the collapse behaviour at elevated temperatures. For each fire scenario considered, the importance of base fixity in preventing an undesirable outwards collapse mechanism is demonstrated. The results demonstrate that joint rigidity and varying fire scenarios should be considered in order to allow for conservative design.

Optimal design of cold-formed steel portal frames for stressed-skin action using genetic algorithm

This paper describes a stressed-skin diaphragm approach to the optimal design of the internal frame of a cold-formed steel portal framing system, in conjunction with the effect of semi-rigid joints. Both ultimate and serviceability limit states are considered. Wind load combinations are included. The designs are optimized using a real-coded niching genetic algorithm, in which both discrete and continuous decision variables are processed. For a building with two internal frames, it is shown that the material cost of the internal frame can be reduced by as much as 53%, compared with a design that ignores stressed-skin action.

Optimal design of long-span steel portal frames using fabricated beams

This paper considers the optimal design of fabricated steel beams for long-span portal frames. The design optimisation takes into account ultimate as well as serviceability limit states, adopting deflection limits recommended by the Steel Construction Institute (SCI). Results for three benchmark frames demonstrate the efficiency of the optimisation methodology. A genetic algorithm (GA) was used to optimise the dimensions of the plates used for the columns, rafters and haunches. Discrete decision variables were adopted for the thickness of the steel plates and continuous variables for the breadth and depth of the plates. Strategies were developed to enhance the performance of the GA including solution space reduction and a hybrid initial population half of which is derived using Latin hypercube sampling. The results show that the proposed GA-based optimisation model generates optimal and near-optimal solutions consistently. A parametric study is then conducted on frames of different spans. A significant variation in weight between fabricated and conventional hot-rolled steel portal frames is shown; for a 50 m span frame, a 14–19% saving in weight was achieved. Furthermore, since Universal Beam sections in the UK come from a discrete section library, the results could also provide overall dimensions of other beams that could be more efficient for portal frames. Eurocode 3 was used for illustrative purposes; any alternative code of practice may be used.

The Robustness of Periodic Orchestrations in Uncertain Evolving Environments

A framework for assessing the robustness of long-duration repetitive orchestrations in uncertain evolving environments is proposed. The model assumes that service-based evaluation environments are stable over short time-frames only; over longer periods service-based environments evolve as demand fluctuates and contention for shared resources varies. The behaviour of a short-duration orchestration E in a stable environment is assessed by an uncertainty profile U and a corresponding zero-sum angel-daemon game Γ(U) [2]. Here the angel-daemon approach is extended to assess evolving environments by means of a subfamily of stochastic games. These games are called strategy oblivious because their transition probabilities are strategy independent. It is shown that the value of a strategy oblivious stochastic game is well defined and that it can be computed by solving a linear system. Finally, the proposed stochastic framework is used to assess the evolution of the Gabrmn IT system.

Gender, religion, and sociopolitical issues in cross-cultural online education

Cross-cultural education is thought to develop critical consciousness of how unequal distributions of power and privilege affect people’s health. Learners in different sociopolitical settings can join together in developing critical consciousness – awareness of power and privilege dynamics in society – by means of communication technology. The aim of this research was to define strengths and limitations of existing cross-cultural discussions in generating critical consciousness. The setting was the FAIMER international fellowship program for mid-career interdisciplinary health faculty, whose goal is to foster global advancement of health professions education. Fellows take part in participant-led, online, written, task-focused discussions on topics like professionalism, community health, and leadership. We reflexively identified text that brought sociopolitical topics into the online environment during the years 2011 and 2012 and used a discourse analysis toolset to make our content analysis relevant to critical consciousness. While references to participants’ cultures and backgrounds were infrequent, narratives of political-, gender-, religion-, and other culture-related topics did emerge. When participants gave accounts of their experiences and exchanged cross-cultural stories, they were more likely to develop ad hoc networks to support one another in facing those issues than explore issues relating to the development of critical consciousness. We suggest that cross-cultural discussions need to be facilitated actively to transform learners’ frames of reference, create critical consciousness, and develop cultural competence. Further research is needed into how to provide a safe environment for such learning and provide faculty development for the skills needed to facilitate these exchanges.

Hate crime legislation and violence against sex workers in Ireland: Lessons in Policy and Practice

Drawing on data from UglyMugs.ie (a reporting mechanism for sex workers) this paper considers whether crimes against sex workers should be considered as hate crimes. In many ways, the debates around hate crime in the UK are more developed than in Ireland. As yet the Irish State has yet to criminalise the ‘hate’ element of crime and has been severely criticised for its relatively lacklustre approach to recording incidents of bias or hate crimes against certain social groups. The paper adopts the structural understanding of hate crime espoused by Barbara Perry (2001) who frames the dynamics of hate crime within a complex interplay of political, social and cultural factors. In our analysis we consider what is termed ‘whorephobia’ through the ambit of criminalisation and stigmatisation, gender and heteronormativity in Irish society, and the gendered nature of policing in both parts of Ireland.

Narratively framing emergent identities in post-agreement societies: patterns of the Northern Irish identity within the provincial media

The research analyses ‘Northern Irish’ identity narratives post-agreement, and examines the configuration of frame agendas in terms of individual narrative components. A content analysis utilised news published through 1997–2014 within Northern Ireland daily newspapers – the Belfast Telegraph, the Irish News and the News Letter. A process of manifest coding produced an emergent coding scheme displaying the relative stability of media frames surrounding the Northern Irish identity as broadly partisan; however, there is also a subtle narrative shift of Northern Irish identity across the time periods; and findings of a dominant framing paradigm of political and social conceptions of identification post-agreement.