Fire Tests of Cold-formed Steel Wall Systems

Cold-formed steel stud walls are an important component of Light Steel Framing (LSF) building systems used in commercial, industrial and residential buildings. In the conventional LSF stud wall systems, thin-walled steel studs are protected from fire by placing one or two layers of plasterboard on both sides with or without cavity insulation. However, there is very limited data about the structural and thermal performance of these wall systems while past research showed contradicting results about the benefits of cavity insulation. This research proposed a new LSF stud wall system in which a composite panel made of two plasterboards with insulation between them was used to improve the fire rating of walls. Full scale fire tests were conducted using both conventional steel stud walls with and without the use of cavity insulation and the new composite panel system. Eleven full scale load bearing wall specimens were tested to study the thermal and structural performances of the load bearing wall assemblies under standard fire conditions. These tests showed that the use of cavity insulation led to inferior fire performance of walls while also providing good explanations and supporting test data to overcome the incorrect industry assumptions about cavity insulation. Tests demonstrated that the use of external insulation in a composite panel form enhanced the thermal and structural performances of stud walls and increased their fire resistance rating significantly. This paper presents the details of the full scale fire tests of load-bearing wall assemblies lined with plasterboards and different types of insulation under varying load ratios. Test results including the temperature and deflection profiles of walls measured during the fire tests will be presented along with their failure modes and failure times.

Fire tests of load bearing steel stud walls exposed to real building fires

Abstract. Fire resistance has become an important part in structural design due to the ever increasing loss of properties and lives every year. Conventionally the fire rating of load bearing Light gauge Steel Frame (LSF) walls is determined using standard fire tests based on the time-temperature curve given in ISO 834 [1]. Full scale fire testing based on this standard time-temperature curve originated from the application of wood burning furnaces in the early 1900s and it is questionable whether it truly represents the fuel loads in modern buildings. Hence a detailed fire research study into the performance of LSF walls was undertaken using real design fires based on Eurocode parametric curves [2] and Barnett’s ‘BFD’ curves [3]. This paper presents the development of these real fire curves and the results of full scale experimental study into the structural and fire behaviour of load bearing LSF stud wall systems.

Coping with aggressive driving : driver accounts of how they manage themselves and others to reduce conflict on the road

Dealing with the aggression of other drivers on the road is an important skill given that driving is a common activity for adults in highly motorised countries. Even though incidents of extreme aggression on the road (such as assault) are reportedly rare, milder forms, some of them dangerous (such as tailgating or deliberately following too closely) are apparently common, and may be increasing. At the very least, this is likely to render the driving environment more stressful, and at worst elevates the risk of crashing by increasing both the level of risky driving behaviours and the likelihood of responses that escalate the situation. Thus the need for drivers to manage incidents of conflict is likely to become increasingly important. However, little research examines how drivers manage their own or others’ aggressive driving behaviour. Recently greater attention has been paid to driver cognitions, especially the attributions that drivers make about other drivers, that then might influence their own driving responses, particularly aggressive or risky ones. The study reported below was the first in a larger exploration of aggressive driving that focussed on driver cognitions, emotions and underlying motivations for aggressive behaviours on the road. Qualitative, in-depth interviews of drivers (n = 30, aged 18-49 years) were subjected to thematic analysis to investigate driver experiences with aggressive driving. Two main themes were identified from these accounts: driver management of self; and driver attempts to influence or manage other drivers. This paper describes the subthemes falling under the management of self main theme. These subthemes were labelled ‘being magnanimous’, ‘chilling out’, ‘slowing down’, and ‘apology/acknowledgment’. ‘Being magnanimous’ referred to situations where the respondent perceived him/herself to be a recipient of another’s aggressive driving and made a deliberate choice not to respond. However, a characteristic of this sub-theme was that this choice was underpinned by the adoption of morally superior stance, or sense of magnanimity. ‘Chilling out’ was a more general response to both the milder aggressive behaviours of other drivers and the general frustrations of driving. ‘Slowing down’ referred to reducing one’s speed in response to the perceived aggressive driving, often tailgating, of another. This subtheme appeared to consist of two separate underlying motivations. One of these was a genuine concern for one’s own safety while the other was more aimed at “getting back” at the other driver. ‘Apology’ referred to how drivers modified their more negative reactions and responses when another driver made gestures that acknowledged their having made a mistake, indicated an apology, or acknowledged the recipient driver. These sub-themes are discussed in relation to their implications for understanding aggressive driving and intervening to reduce it.

Influence of organic matter in road deposited particulates in heavy metal accumulation and transport

The research study discussed in the paper investigated the influence of organic matter on heavy metal adsorption for different particle size ranges of build-up solids. Samples collected from road surfaces were assessed for organic matter content, mineral composition, particle size distribution and effective cation exchange capacity. It was found that the organic matter plays a key role in >75µm particles in the adsorption of Zinc, Lead, Nickel and Copper, which are generated by traffic activities. Clay forming minerals and metal oxides of Iron, Aluminium and Manganese was found to be important for heavy metal adsorption to <75µm particles. It was also found that heavy metals adsorbed to organic matter are strongly bound to particles and these metal ions will not be bio-available if the chemical quality of the media remains stable.

Impact and energy absorption of road safety barriers by coupled SPH/FEM

Road safety barriers are used to minimise the severity of road accidents and protect lives and property. There are several types of barrier in use today. This paper reports the initial phase of research carried out to study the impact response of portable water-filled barrier (PWFB) which has the potential to absorb impact energy and hence provide crash mitigation under low to moderate speeds. Current research on the impact and energy absorption capacity of water-filled road safety barriers is limited due to the complexity of fluid-structure interaction under dynamic impact. In this paper, a novel fluid-structure interaction method is developed based on the combination of Smooth Particle Hydrodynamics (SPH) and Finite Element Method (FEM). The sloshing phenomenon of water inside a PWFB is investigated to explore the energy absorption capacity of water under dynamic impact. It was found that water plays an important role in energy absorption. The coupling analysis developed in this paper will provide a platform to further the research in optimising the behaviour of the PWFB. The effect of the amount of water on its energy absorption capacity is investigated and the results have practical applications in the design of PWFBs.

Travel behavior of workers in Dhaka and their attitude towards road pricing

Dhaka, the capital of Bangladesh, is facing severe traffic congestion. Owing to the flaws in past land use and transport planning decisions, uncontrolled population growth and urbanization, Dhaka’s traffic condition is worsening. Road space is widely regarded in the literature as a utility, so a common view of transport economists is that its usage ought to be charged. Road pricing policy has proven to be effective in managing travel demand, in order to reduce traffic congestion from road networks in a number of cities including London, Stockholm and Singapore. Road pricing as an economic mechanism to manage travel demand can be more effective and user-friendly when revenue is hypothecated into supply alternatives such as improvements to the transit system. This research investigates the feasibility of adopting road pricing in Dhaka with respect to a significant Bus Rapid Transit (BRT) project. Because both are very new concepts for the population of Dhaka, public acceptability would be a principal issue driving their success or failure. This paper explores the travel behaviour of workers in Dhaka and public perception toward Road Pricing with regards to work trips- based on worker’s travel behaviour. A revealed preference and stated preference survey has been conducted on sample of workers in Dhaka. They were asked limited demographic questions, their current travel behaviour and at the end they had been given several hypothetical choices of integrated BRT and road pricing to choose from. Key finding from the survey is the objective of integrated road pricing; subsidies Bus rapid Transit by road pricing to get reduced BRT fare; cannot be achieved in Dhaka. This is because most of the respondent stated that they would choose the cheapest option Walk-BRT-Walk, even though this would be more time consuming and uncomfortable as they have to walk from home to BRT station and also from BRT station to home. Proper economic analysis has to be carried out to find out the appropriate fare of BRT and road charge with some incentive for the low income people.

Fatalism and its implications for risky road use and receptiveness to safety messages : a qualitative investigation in Pakistan

Given the increasing vehicle numbers and expanding road construction in developing countries, the importance of safe road user behaviour is critical. Road traffic crashes (RTC) are a significant problem in Pakistan, however the factors that contribute to RTC in Pakistan are not well-researched. Fatalistic beliefs are a potential barrier to the enhancement of road safety, especially participation in health-promoting and injury prevention behaviours, and also contribute to risk-taking. Fatalistic beliefs relating to road safety have been found in some developing countries, although again research is scarce and indicates that the nature and extent of fatalism differs in each country. Qualitative research was undertaken with a range of drivers, religious orators, police and policy makers to explore associations between fatalism, risky road use and associated issues. Findings indicate that fatalistic beliefs are pervasive in Pakistan, are strongly linked with religion, present a likely barrier to road safety messages and contribute to risky road use. Fatalism appears to be a default attribution of RTC and the intensity of belief in fate surpasses the kinds of fatalism noted in the limited existing literature. These findings have importance to developing road safety countermeasures in countries where fatalistic beliefs are strong.

Adsorption of heavy metals by road deposited solids

The research study discussed in the paper investigated the adsorption/desorption behaviour of heavy metals commonly deposited on urban road surfaces, namely, Zn, Cu, Cr and Pb for different particle size ranges of solids. The study outcomes, based on field studies and batch experiments confirmed that road deposited solids particles contain a significantly high amount of vacant charge sites with the potential to adsorb additional heavy metals. Kinetic study and adsorption experiments indicated that Cr is the most preferred metal element to associate with solids due to the relatively high electro negativity and high charge density of trivalent cation (Cr3+). However, the relatively low availability of Cr in the urban road environment could influence this behaviour. Comparing total adsorbed metals present in solids particles, it was found that Zn has the highest capacity for adsorption to solids. Desorption experiments confirmed that a low concentration of Cu, Cr and Pb in solids was present in water-soluble and exchangeable form, whilst a significant fraction of adsorbed Zn has a high likelihood of being released back into solution. Among heavy metals, Zn is considered to be the most commonly available metal among road surface pollutants.

Travel behaviour of workers in Dhaka and their attitudes towards road pricing

Dhaka, Bangladesh faces chronic traffic congestion Funding for major infrastructure proves challenging This research is investigating feasibility of adopting: -Road Pricing -with significant Bus Rapid Transit (BRT) project

Human factors at the interface between road and rail systems

Railway level crossings present an arguably unique interface between two transport systems that differ markedly in their performance characteristics, their degrees of regulation and their safety cultures. Railway level crossings also differ dramatically in the importance they represent as safety issues for the two modes. For rail, they are the location of a large proportion of fatalities within the system and are therefore the focus of much safety concern. For the road system, they comprise only a few percent of all fatalities, although the potential for catastrophic outcomes exist. Rail operators and regulators have traditionally required technologies to be failsafe and to demonstrate high levels of reliability. The resultant level of complexity and cost has both limited their extent of application and led to a need to better understand how motorists comprehend and respond to these systems.

Sustainable road infrastructure procurement in Australia

According to Tan et al. (2011), the establishment of a clear sustainability policy in the construction industry is paramount, if only as a statement of the commitment of the top management to protecting the environment and enhancing social responsibility. The resulting policies should then translate into proactive strategies and action plans that improve the sustainability performance of contractors and provide a competitive advantage by integrating “long-run profitability” with sustainable development efforts. The strategies should also take into account climatic protection issues through greenhouse gas emissions (GHGe) monitoring and reduction initiatives (Stocker & Luptacik, 2009)...

A qualitative investigation of older pedestrian views of influences on their road crossing safety

With Australia’s population rapidly ageing, older pedestrian safety has begun to receive greater attention from road safety researchers. However, reliance on simulator studies and observational techniques has limited current understanding of why older pedestrians adopt particular crossing behaviours, and how they perceive crossing the road. The current study aimed to investigate the psychological factors that may contribute to older pedestrians’ crash risk by examining their perceptions of the issues they encounter on the road. Qualitative semi-structured interviews with 18 pedestrians aged 55 years and older were conducted, and the interview transcripts underwent thematic analysis. From this analysis, four key themes emerged. Firstly, the physical design of the road was perceived as posing a significant threat for older pedestrians, particularly sloped, semi-mountable kerbs and designated crossings. Secondly, declines in older pedestrians’ confidence in their ability to cross the road were evident through fewer reported risks being taken. Additionally, older pedestrians sensed an increased threat from other road users when crossing the road, particularly from drivers and cyclists. Finally, older pedestrians referred to the informal rules and strategies used to guide their road crossing. The results suggest that the road environment is perceived as increasingly dangerous and hazardous environment for older pedestrians. Implications regarding the physical road design in areas with an existing high proportion of elderly people are discussed.

Visual motion perception predicts driving hazard perception ability

PURPOSE: To examine the basis of previous findings of an association between indices of driving safety and visual motion sensitivity and to examine whether this association could be explained by low-level changes in visual function. METHODS: 36 visually normal participants (aged 19 – 80 years), completed a battery of standard vision tests including visual acuity, contrast sensitivity and automated visual fields. and two tests of motion perception including sensitivity for movement of a drifting Gabor stimulus, and sensitivity for displacement in a random-dot kinematogram (Dmin). Participants also completed a hazard perception test (HPT) which measured participants’ response times to hazards embedded in video recordings of real world driving which has been shown to be linked to crash risk. RESULTS: Dmin for the random-dot stimulus ranged from -0.88 to -0.12 log minutes of arc, and the minimum drift rate for the Gabor stimulus ranged from 0.01 to 0.35 cycles per second. Both measures of motion sensitivity significantly predicted response times on the HPT. In addition, while the relationship involving the HPT and motion sensitivity for the random-dot kinematogram was partially explained by the other visual function measures, the relationship with sensitivity for detection of the drifting Gabor stimulus remained significant even after controlling for these variables. CONCLUSION: These findings suggest that motion perception plays an important role in the visual perception of driving-relevant hazards independent of other areas of visual function and should be further explored as a predictive test of driving safety. Future research should explore the causes of reduced motion perception in order to develop better interventions to improve road safety.

Reducing road related injuries for young adolescents : an investigation of truancy as a risk factor

Truancy is recognised as an indicator of engagement in high-risk behaviours for adolescents. Injuries from road related risk behaviours continue to be a leading cause of death and disability for early adolescents (13-14 years). The aim of this research is to determine the extent to which truancy relates to increased risk of road related injuries for early adolescents. Four hundred and twenty-seven Year 9 students (13-14 years) from five high schools in Queensland, Australia, completed a questionnaire about their perceptions of risk and recent injury experience. Self-reported injuries were assessed by the Extended Adolescent Injury Checklist (E-AIC). Injuries resulting from motorcycle use, bicycle use, vehicle use (as passenger or driver), and as a pedestrian were measured for the preceding three months. Students were also asked to indicate whether they sought medical attention for their injuries. Truancy rates were assessed from self-reported skipping class or wagging school over the same three month period. The findings explore the relationship between early adolescent truancy and road related injuries. The relationship between road related injuries and truancy was analysed separately for males and females. Results of this study revealed that road related injuries and reports of associated medical treatment are higher for young people who engage in truancy when compared with non-truant adolescents. The results of this study contribute knowledge about truancy as a risk factor for engagement in road related risks. The findings have the potential to enhance school policies and injury prevention programs if emphasis is placed on increasing school attendance as a safety measure to decrease road related injuries for young adolescents.