A field trial of a reusable, hollow, cast-in-situ pile

This paper describes the concept and field testing of a hollow, cast-in-situ, rotary bored pile foundation 1200 mm diameter and 30 m deep. The aim of the foundation is to allow large-diameter piles to be constructed using less concrete than in an equivalent conventional solid pile, and with a view to allowing reuse at a later date. Reuse is made possible because the hollow core of the pile allows access for inspection after demolition of an existing structure. The new piles may also allow modification to enhance load capacity by augering through the base and extending their length. In addition, the piles are better suited than conventional piles for use as ‘energy piles' to allow environmentally friendly heating and cooling. The geotechnical performance of the hollow test pile was comparable with that of a conventional solid pile constructed during the same trial. Details of construction are given, including lessons learned

Spatial and Sex-Specific Variation in Growth of Albacore Tuna (Thunnus alalunga) across the South Pacific Ocean

Spatial variation in growth is a common feature of demersal fish populations which often exist as discrete adult sub-populations linked by a pelagic larval stage. However, it remains unclear whether variation in growth occurs at similar spatial scales for populations of highly migratory pelagic species, such as tuna. We examined spatial variation in growth of albacore Thunnus alalunga across 90° of longitude in the South Pacific Ocean from the east coast of Australia to the Pitcairn Islands. Using length-at-age data from a validated ageing method we found evidence for significant variation in length-at-age and growth parameters (L∞ and k) between sexes and across longitudes. Growth trajectories were similar between sexes up until four years of age, after which the length-at-age for males was, on average, greater than that for females. Males reached an average maximum size more than 8 cm larger than females. Length-at-age and growth parameters were consistently greater at more easterly longitudes than at westerly longitudes for both females and males. Our results provide strong evidence that finer spatial structure exists within the South Pacific albacore stock and raises the question of whether the scale of their “highly migratory” nature should be re-assessed. Future stock assessment models for South Pacific albacore should consider sex-specific growth curves and spatial variation in growth within the stock

Social work and advanced marginality

This chapter explores the impact of broader social and economic policies on social work practice. It argues that the increasing inequality and polarisation of modern urban societies that is outlined in the other chapters of this book has had a direct impact on the role of social workers. The chapter begins with a brief outline of the reaction of British Governments to the banking and Eurozone crises of 2008. It then goes on to argue that the introduction of “austerity” the Conservative-Liberal Democrat Coalition Government in 2010 involved not only significant reductions in welfare spending but was a political project aimed at recasting and reducing the welfare state. The chapter then examines social work practice in the context of advanced marginality. It argues that the changes and processes examined in the other contributions have resulted in an environment where social work has an increasingly disciplinary role. The impact of neoliberal welfare retrenchment compounded by austerity is that social work practice is increasingly experienced by service users as negative or punitive interventions in their lives. This is, despite the profession clear ethical stance being one that is committed to empowermen

Optimising construction with self-compacting concrete

Winner of the 2018 ICE Publishing Awards (Thomas Howard Medal) for the best paper of the year in the Construction Materials journal. Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.Self-compacting concrete or self-consolidating concrete (as it is known in North America) (SCC) is used on the basis of its unique properties of flowability, passability and resistance to segregation. It requires no external energy to achieve full compaction, so is advantageous on site, but there is evidence that its higher cost is a significant barrier to greater adoption. The research entailed work measurement of 14 UK single-family home residential projects (eliciting data on construction time and labour productivity) and cost modelling of three slab scenarios (exploring the relationship between material and labour costs). The study found SCC was placed up to 73% faster than conventional concrete and, when labour and material costs are included, the supplier is able to price SCC to closely match conventional concrete, hence making SCC more viable for the contractor. This relationship between as-built costs for SCC and conventional concrete is clarified by developing Pmax, providing a new mechanism for understanding project profitability and viability of SCC

UK contractors’ views on self-compacting concrete in construction

This briefing was published in the journal Proceedings of the ICE - Construction Materials [© ICE Publishing]. The website is at: http://www.icevirtuallibrary.com/content/serial/coma. Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.Self-compacting concrete (SCC) is claimed to offer faster construction, safer sites and more consistent concrete quality, but little corroborative research data exist on performance advantages, particularly in comparison with traditional construction. Industry opinions also appear to be divided. For these reasons, an extensive interview programme was undertaken with UK contractors – from large national concrete frame contractors to small, locally based housebuilders – to assess whether benefits were being achieved and to try to understand the reasons why SCC is, or is not, being used. The 48 participants reported that decisions on the suitability of SCC were inherently complex and, if selected, there were challenges in understanding ‘how’ construction should be planned and managed to accommodate the use of SCC and to fully utilise its advantages. The findings identify the need for a step change in the industry’s perception of SCC, such that it should be considered as a construction method, not simply as a material

Long-term forest composition and its drivers in taiga forests in NW Russia

Understanding the processes behind long-term boreal forest dynamics can provide information that assists in predicting future boreal vegetation under changing environmental conditions. Here, we examine Holocene stand-scale vegetation dynamics and its drivers at the western boundary of the Russian taiga forest in NW Russia. Fossil pollen and conifer stomata records from four small hollow sites and two lake sites are used to reconstruct local vegetation dynamics during the Holocene. Variation partitioning is used to assess the relative importance of the potential drivers (temperature, forest fires and growing site wetness) to the long-term stand-scale dynamics in taiga forest. All the main tree taxa, including the boreal keystone species Picea abies (Norway spruce) and Larix sibirica (Siberian larch), have been locally present since 10,000 cal yr BP. The constant Holocene presence of L. sibirica at three small hollow sites suggests a fast postglacial immigration of the species in northern Europe. Picea was present but not dominant at all study sites until its expansion between 8,000 and 7,000 cal yr BP markedly changed the forest structure through the suppression of Betula (birch), Pinus (pine) and Larix. Our results demonstrate that in general, the Holocene forest dynamics in our study region have been driven by temperature, but during short intervals the role of local factors, especially forest fires, has been prominent. The comparison between sites reveals the importance of local factors in stand-scale dynamics in taiga forests. Therefore, the future responses of taiga forest to climate change will be predominantly modulated by the local characteristics at the site