Ultimate strength of bolted moment-connections between cold-formed steel members

The behaviour and design of bolted moment-connections between cold-formed steel members, formed by using brackets bolted to the webs of the section, is considered. The particular problem of the moment-capacity of such joints being lower than that of the cold-formed steel sections being connected because of web buckling, caused by the concentration of load transfer from the bolts, is addressed. In this paper, a combination of laboratory tests and finite element analyses is used to investigate this mode of failure. It is demonstrated that there is good agreement between the measured ultimate moment-capacity and that predicted by using the finite element method. A parametric study conducted using the finite element model shows that the moment-capacity of a practical size joint can be up to 20% lower than that of the cold-formed steel sections being connected. Web buckling so-caused must therefore be considered in the design of such connections. (C) 2003 Elsevier Ltd. All rights reserved.

Dependency: An inhibitor to the Irish Case for Corporate Social Responsibility

This paper addresses the potential resurgence of post imperial “dependency theory” of the 1960s and 1970s. Suggesting that the initial premise of the theory was just – the article proposes the reworking of the theory in order to incorporate globalisation processes – namely the importance of global capital generated by Multi National Corporations. By considering that capital is now the “core” we have the idea of a much wider catchment of states “dependent” on global capital. Using Ireland as an example therefore, the article pursues the idea that a dependent state’s ability to implement CSR legislation is inhibited by the constraints of capital.

Telling stories of 21st Century welfare: the UK Coalition Government and the neo-liberal discourse of worklessness and dependency’ Critical Social Policy

Policy documents are a useful source for understanding the privileging of particular ideological and policy preferences (Scrase and Ockwell, 2010) and how the language and imagery may help to construct society’s assumptions, values and beliefs. This article examines how the UK Coalition government’s 2010 Green Paper, 21st Century Welfare, and the White Paper, Universal Credit: Welfare that Works, assist in constructing a discourse about social security that favours a renewal and deepening of neo-liberalization in the context of threats to its hegemony. The documents marginalize the structural aspects of persistent unemployment and poverty by transforming these into individual pathologies of benefit dependency and worklessness. The consequence is that familiar neo-liberal policy measures favouring the intensification of punitive conditionality and economic rationality can be portrayed as new and innovative solutions to address Britain’s supposedly broken society and restore economic competitiveness.

Cube, cylinder, core and pull-off strength relationships

This limited experimental investigation examined the relationships between the compressive strengths of cubes, cylinders, cores and the estimated compressive strengths derived from pull-off tests for a relatively low-strength structural-grade concrete (<35 N/mm2). Test specimens were cast and tested at 7, 14, 28, 56 and 84 days. The relationships of the trends of the test results to the trends of results of standard cube specimens and standard cylinder specimens were compared. It was found that the mean strength of each type of specimen tended to increase as a function of the natural logarithm of the specimen age. The mean strength of cylinders of length/diameter ratio 2.0 was found to be slightly greater (by about 7.5%) than the generally accepted value of 80% of the mean cube strength. Core results were corrected using correction factors defined in BS 6089 and the UK national annex to BS EN 12504-1. The mean corrected cube strength of cores taken from cubes was approximately 12% greater than the mean companion cube strength. The mean corrected cylinder strength of cores taken from cubes was approximately 5% greater than the mean companion cylinder strength. The potential cube and cylinder strengths of cores taken from slabs cured under different environmental conditions correlated well with companion cube and cylinder strengths respectively at 28 days. The pull-off test results gave a variable but, on average, slightly conservative estimate of the cube compressive strength of the relatively low-strength structural-grade concrete, using a simple general linear estimated compressive cube strength to tensile strength correlation factor of 10.

The use of a GA to improve the postbuckling strength of stiffened composite panels susceptible to secondary instabilities

The use of genetic algorithms (GAs) for structural optimisation is well established but little work has been reported on the inclusion of damage variables within an optimisation framework. This approach is particularly useful in the optimisation of composite structures which are prone to delamination damage. In this paper a challenging design problem is presented where the objective was to delay the catastrophic failure of a postbuckling secondary-bonded stiffened composite panel susceptible to secondary instabilities. It has been conjectured for some time that the sudden energy release associated with secondary instabilities may initiate structural failure, but this has proved difficult to observe experimentally. The optimisation methodology confirmed this indirectly by evolving a panel displaying a delayed secondary instability whilst meeting all other design requirements. This has important implication in the design of thin-skinned lightweight aerostructures which may exhibit this phenomenon.