Response and damage evaluation of reinforced concrete frames subjected to blast loading

Bomb attacks carried out by terrorists, targeting high occupancy buildings, have become increasingly common in recent times. Large numbers of casualties and property damage result from overpressure of the blast followed by failing of structural elements. Understanding the blast response of multi-storey buildings and evaluating their remaining life have therefore become important. Response and damage analysis of single structural components, such as columns or slabs, to explosive loads have been examined in the literature, but the studies on blast response and damage analysis of structural frames in multi-storey buildings is limited and this is necessary for assessing the vulnerability of them. This paper investigates the blast response and damage evaluation of reinforced concrete (RC) frames, designed for normal gravity loads, in order to evaluate their remaining life. Numerical modelling and analysis were carried out using the explicit finite element software, LS DYNA. The modelling and analysis takes into consideration reinforcement details together and material performance under higher strain rates. Damage indices for columns are calculated based on their residual and original capacities. Numerical results generated in the can be used to identify relationships between the blast load parameters and the column damage. Damage index curve will provide a simple means for assessing the damage to a typical multi-storey building RC frame under an external bomb circumstance.

Challenging 'best practice' subtropical design

Genuine sustainability would require that urban development provide net positive social and ecological gains to compensate for previous lost natural capital and carrying capacity. Thus far, green buildings do not contribute to net sustainability. While they reduce relative resource consumption, they consume vast quantities of materials, energy and water.i Moreover, they replace land and ecosystems with structures that, at best, ‘mimic’ ecosystems. Elsewhere, the author has proposed a‘sustainability standard’, where development would leave the ecology, as well as society, better off after construction than before.ii To meet this standard, a development would need to add natural and social capital beyond what existed prior to development. Positive DesignTM or Positive DevelopmentTM is that which expands both the ecological base (life support system) and the public estate (equitable access to means of survival). How to achieve this is discussed in Positive Development (Birkeland 2008). This paper examines how net positive gains can be achieved in a ubtropical as well as temperate environment.

The implication of a term of good faith in commercial leases — A brief response

By way of response to Professor Duncan's article,1 this article examines the theoretical basis for the implication of contractual terms, particularly the implication of a term at law. In this regard the recent decision of Barrett J in Overlook v Foxtel [2002] NSWSC 17 is considered, to the extent that it provides guidance concerning the implication of an obligation of good faith in the context of a commercial contract. A number of observations are made which may be considered likely to have application to the relationship of commercial landlord and tenant. The conclusion reached is that although the commercial landlord and tenant contractual relationship is highly regulated, this may not deny a remedy to a tenant who is the victim of a landlord's 'bad faith'. Finally, the article concludes by considering the extent to which it may be possible to contractually exclude the implied obligation of good faith.

Impact response and parametric studies of reinforced concrete circular columns

This paper presents a detailed description of the influence of critical parameters that govern the vulnerability of columns under lateral impact loads. Numerical simulations are conducted by using the Finite Element program LS-DYNA, incorporating steel reinforcement, material models and strain rate effects. A simplified method based on impact pulse generated from full scale impact tests is used for impact reconstruction and effects of the various pulse loading parameters are investigated under low to medium velocity impacts. A constitutive material model which can simulate failures under tri-axial state of stresses is used for concrete. Confinement effects are also introduced to the numerical simulation and columns of Grade 30 to 50 concrete under pure axial loading are analysed in detail. This research confirmed that the vulnerability of the axially loaded columns can be mitigated by reducing the slenderness ratio and concrete grade, and by choosing the design option with a minimal amount of longitudinal steel. Additionally, it is evident that approximately a 50% increase in impact capacity can be gained for columns in medium rise buildings by enhancing the confinement effects alone. Results also indicated that the ductility as well as the mode of failure under impact can be changed with the volumetric ratio of lateral steel. Moreover, to increase the impact capacity of the vulnerable columns, a higher confining stress is required. The general provisions of current design codes do not sufficiently cover this aspect and hence this research will provide additional guidelines to overcome the inadequacies of code provisions.

Report on the Development and Validation of the Best Practice Decision Matrix

The Co-operative Research Centre for Construction Innovation (CRC-CI) is funding a project known as Value Alignment Process for Project Delivery. The project consists of a study of best practice project delivery and the development of a suite of products, resources and services to guide project teams towards the best procurement approach for a specific project or group of projects. These resources will be focused on promoting the principles that underlie best practice project delivery rather than simply identifying an off-the-shelf procurement system. This project builds on earlier work by Sidwell, Kennedy and Chan (2002), on re-engineering the construction delivery process, which developed a procurement framework in the form of a Decision Matrix

Psychological predictors of the propensity to omit short-response items on a high-stakes achievement test

This article presents the findings of a study of the psychological variables that discriminate between high and low omitters on a high-stakes achievement test using a short-response format. Data were obtained from a questionnaire administered to a random sample (N = 1,908) of students prior to sitting the 1997 Queensland Core Skills (QCS) Test (N = 29,273). Fourteen psychological variables were measured including test anxiety (four subscales), emotional stability, achievement motivation, self-esteem, academic self-concept, self-estimate of ability, locus of control (three subscales), and approaches to learning (two subscales). The results were analyzed using descriptive discriminant analysis and suggested that the psychological predictors of the propensity to omit short-response items include test-irrelevant thinking and academic self-concept, with sex of candidate being a mediating variable.

Being the best

Being the Best investigates the ways in which highly innovative contractors sustain their market leadership. The businesses consulted are quoted extensively, as a means of sharing their insights. This report is intended as a resource for contractors that want to improve their innovation outcomes and business performance.

Final report : feasibility study linking best value procurement assessment to outcome performance indicators

This feasibility study was established to investigate the application of the concept of ‘best value’ in construction procurement in Australia. In the case of ‘best value’ in the business enterprise, ‘best value’ is that which returns greatest value to the business enterprise’s shareholders. However, in the case of the public sector, ‘best value’ is more complex. For that reason, this research project focuses mainly on public sector construction project procurement.

Best value second interim report

This first interim report on ‘best value’ reviewed the academic literature relating to ‘best value’ and illustrated the varying interpretations that the concept of ‘best value’ has attracted. It also examined current state of the literature on best value in construction project procurement. ‘Best value’ was explored from the perspective of both the business enterprise and public sector. It was concluded that ‘best value’ in the public sector is considerably more complex. This second interim report explores how ‘best value’ has been implemented in the UK. Focus is directed towards the UK, particularly Scotland’s approach to examine the complexity of implementation of ‘best value’ in the public sector context. Scotland has been recognised as a leader in the field of ‘best value’ in the public sector (Curry, 1999; Wisniewski and Stewart, 2001, 2004; Jaconelli and Sheffield, 2000)

Multiple-choice versus short-response items: Differences in omit behavior

The overall rate of omission of items for 28,331 17 year old Australian students on a high stakes test of achievement in the common elements or cognitive skills of the senior school curriculum is reported for a subtest in multiple choice format and a subtest in short response format. For the former, the omit rates were minuscule and there was no significant difference by gender or by type of school attended. For the latter, where an item can be 'worth' up to five times that of a single multiple choice item, the omit rates were between 10 and 20 times that for multiple choice and the difference between male and female omit rate was significant as was the difference between students from government and non-government schools. For both formats, females from single sex schools omitted significantly fewer items than did females from co-educational schools. Some possible explanations of omit behaviour are alluded to.