Effect of web holes on web crippling strength of cold-formed steel channel sections under end-one-flange loading condition – Part I: Tests and finite element analysis

Web openings could be used in cold-formed steel beam members, such as wall studs or floor joints, to facilitate ease of services in buildings. In this paper, a combination of tests and non-linear finite element analyses is used to investigate the effect of such holes on web crippling under end-one-flange (EOF) loading condition; the cases of both flanges fastened and unfastened to the bearing plates are considered. The results of 74 web crippling tests are presented, with 22 tests conducted on channel sections without web openings and 52 tests conducted on channel sections with web openings. In the case of the tests with web openings, the hole was either located centred above the bearing plates or having a horizontal clear distance to the near edge of the bearing plates. A good agreement between the tests and finite element analyses was obtained in term of both strength and failure modes.

Effect of web holes on web crippling strength of cold-formed steel channel sections under end-one-flange loading condition - Part II: Parametric study and proposed design equations

A parametric study of cold-formed steel sections with web openings subjected to web crippling under end-one-flange (EOF) loading condition is undertaken, using finite element analysis, to investigate the effects of web holes and cross-section sizes. The holes are located either centred above the bearing plates or with a horizontal clear distance to the near edge of the bearing plates. It was demonstrated that the main factors influencing the web crippling strength are the ratio of the hole depth to the depth of the web, the ratio of the length of bearing plates to the flat depth of the web and the location of the holes as defined by the distance of the hole from the edge of the bearing plate divided by the flat depth of web. In this study, design recommendations in the form of web crippling strength reduction factor equations are proposed, which are conservative when compared with the experimental and finite element results.

FE simulation and experimental tests of high-strength structural bolts under tension

Experimental tests have been completed for high-strength 8.8 bolts for studying their mechanical performance subjected to tensile loading. As observed from these tests, failure of structural bolts has been identified as in one of two ways: threads stripping and necking of the threaded portion of the bolt shank, which is possibly due to the degree of fit between internal and external threads. Following the experimental work, a numerical approach has been developed for demonstration of the tensile performance with proper consideration of tolerance class between bolts and nuts. The degree of fit between internal and external threads has been identified as a critical factor affecting failure mechanisms of high-strength structural bolts in tension, which is caused by the machining process. In addition, different constitutive material laws have been taken into account in the numerical simulation, demonstrating the entire failure mechanism for structural bolts with different tolerance classes in their threads. It is also observed that the bolt capacities are closely associated with their failure mechanisms.

Catalysing the Irish Energy Transition: Capacities and Challenges

The transition to a “low carbon, climate resilient and environmentally sustainable economy by the end of the 
year 2050” has been conceptualised as the “national transition objective” in the Irish Climate Action and Low Carbon Development Bill, passed in late 2015. This has raised a myriad of questions over how this can be operationalised and resourced and whether it can maintain political momentum. This paper assesses the utility of framings informed by the transitions (MLP) and technological innovation systems perspectives in contributing to transformative societal processes, by examining their application in an Irish case study on policy and technology. Through a qualitative exploration of the broader societal and policy context of the energy sector and a more detailed examination of the innovation systems of selected niche technologies (bioenergy and electric vehicles), the Irish case study sought to identify potential catalysts for a sustainability transition in the energy sector in Ireland: where these exist, how these are being built or enabled, and barriers to change. Following a discussion on the theoretical approaches used, a description will be given of how these were applied in the conducting of the research on transition in Ireland case study and the key findings which emerged. A critical reflection will then be made on the utility of these perspectives (as applied) to contribute to broader processes of societal transformation in Ireland.

Genome-wide association study reveals greater polygenic loading for schizophrenia in cases with a family history of illness

Genome-wide association studies (GWAS) of schizophrenia have yielded more than 100 common susceptibility variants, and strongly support a substantial polygenic contribution of a large number of small allelic effects. It has been hypothesized that familial schizophrenia is largely a consequence of inherited rather than environmental factors. We investigated the extent to which familiality of schizophrenia is associated with enrichment for common risk variants detectable in a large GWAS. We analyzed single nucleotide polymorphism (SNP) data for cases reporting a family history of psychotic illness (N = 978), cases reporting no such family history (N = 4,503), and unscreened controls (N = 8,285) from the Psychiatric Genomics Consortium (PGC1) study of schizophrenia. We used a multinomial logistic regression approach with model-fitting to detect allelic effects specific to either family history subgroup. We also considered a polygenic model, in which we tested whether family history positive subjects carried more schizophrenia risk alleles than family history negative subjects, on average. Several individual SNPs attained suggestive but not genome-wide significant association with either family history subgroup. Comparison of genome-wide polygenic risk scores based on GWAS summary statistics indicated a significant enrichment for SNP effects among family history positive compared to family history negative cases (Nagelkerke's R(2 ) = 0.0021; P = 0.00331; P-value threshold <0.4). Estimates of variability in disease liability attributable to the aggregate effect of genome-wide SNPs were significantly greater for family history positive compared to family history negative cases (0.32 and 0.22, respectively; P = 0.031). We found suggestive evidence of allelic effects detectable in large GWAS of schizophrenia that might be specific to particular family history subgroups. However, consideration of a polygenic risk score indicated a significant enrichment among family history positive cases for common allelic effects. Familial illness might, therefore, represent a more heritable form of schizophrenia, as suggested by previous epidemiological studies.