Risk-based infrastructure design and assessment

Infrastructure forms the backbone of society and substantial resources are tied up in creating and maintaining these structures. Design, assessment and maintenance planning for infrastructure should ensure adequate structural performance, taking due account of uncertainties. Provisions in standards for structural design and assessment directly impact on the safety, economy and environmental sustainability of infrastructure solutions. This paper explains how probabilistic principles of structural reliability are utilised in standardised design to allow typical structures to achieve close-to-optimal reliabilities. I review our contributions towards improving the models and calibrations on which standardised design depends for South African extreme wind loading, shear design, buckling of cold-formed steel elements and design of liquid-retaining structures. Contributions towards advancing the risk-based design principles that should underpin infrastructure decisions include quantification of acceptable and optimal target reliability classes, recommendations to improve dam rehabilitation decisions in South Africa, risk-based estimation of sample sizes and exploring how provision for assessment of existing structures and climate change could be incorporated into design standards. Research forms an important component of the work, but so does teaching, presentation of continuing professional development courses to industry and community engagement through active participation in the technical committees of the South African Bureau of Standards, the International Organization for Standardization and the international Joint Committee on Structural Safety. Future advances in standardised design need to direct solutions to be significantly more sustainable. This will require a greater focus on using environmentally sustainable materials, extending the useful life of existing structures and exploiting advances in information technology, structural health monitoring, advanced analysis and risk-based methodologies.

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Short biography

Celeste Viljoen is a professor of structural engineering at Stellenbosch University. She is a registered professional engineer with a PhD in structural health monitoring. Colleagues who have visited the Brackenfell area have likely crossed bridges designed by her. Her research focus is on risk-based decisions and structural reliability. She is widely involved in the standardisation of structural design and the advancement of probabilistic design principles that underpin this undertaking. She serves on the technical committees of the South African Bureau of Standards and the International Organization for Standardization and is a member of the international Joint Committee on Structural Safety. She contributed to updates in national and international standards for structural design. She regularly presents continuing professional development courses to practising engineers to disseminate advances in the field. To date she has graduated two DEng, 10 PhD and 10 MEng candidates with whom she authored and co-authored 31 journal articles, 44 peer-reviewed conference papers and three books. She has taught undergraduate and postgraduate courses on strength of materials, structural design, structural analysis, structural reliability and construction risk management. In September 2020 she was appointed as the first female vice-dean of the Faculty of Engineering. Celeste is married to Braam and they have two children, Joshua (8) and Lisa (6).