Contributions to structural mechanics and durability in structural engineering

[摘要] ENGLISH ABSTRACT: Contributions to structural engineering have been made since 2001 from the basis of the Department of CivilEngineering of Stellenbosch University (SU). The inauguration of the Centre for Development of SustainedInfrastructure (CDSI) in 2002 has been instrumental in defining, directing and scoping the research anddevelopment in the categories Advanced cement-based construction materials, Crack formation and durabilitytowards durability design, Renovation and retrofitting towards extended life span and Sustainable energyharvesting structures. The contributions are structured along these categories as chapters of this dissertation.Early career background in structural Engineering at the Institute for Structural Engineering (1987-1989) andBureau for Mechanical Engineering (1989-1992) and higher education in computational and structuralmechanics (PhD 1995-1999, Research Fellow 1999-2001, TU Delft), shaped the research interests in thesefields. Continued affiliation with TU Delft (30%) and SU (70%) in the years 2001-2009 provided access tocollegial expertise in related fields of experimental research, materials engineering, risk and reliability, andstructural design at these institutions and beyond. In this way, national and international collaborationcomplemented structural and computational mechanics in well-rounded research programs in the mentionedcategories. Clearly, the contributions are the result of collaboration in which the author to various degrees led,participated in and supervised research and development. Highlights of the contributions in the four categoriesare described at a relatively high level towards conveying the contributions in the national and internationalcontext. To a degree selective reporting is done, and the reader directed to detailed elaborations in roughly 200dissertations, theses and technical papers supervised or co-supervised, authored and co-authored.Approach by the infrastructure pre-fabrication industry in South Africa towards development of accelerated andnew product lines led to the development of advanced cement-based construction materials (ACM) with localingredients, and appropriate adaption of the materials to industrial fabrication process of high-pressureextrusion. What started as fibre inclusion towards reduced traditional steel reinforcement in concrete pipes, ledto development, characterisation, manufacturing and constitutive modelling of steel fibre concrete and strainhardeningcement-based composites (SHCC). Roles of international leadership in co-chairing and chairingRILEM technical committees followed, as well as co-editing of books on the state-of-the-art of Durability ofSHCC and a Framework of durability design with SHCC respectively. Particular contributions of significantpotential towards the ability to design for durable, sustainable infrastructure, were made in chloride-inducedcorrosion and alkali silica reaction. In both cases crack formation and durability, i.e. structural durability inservice conditions are the points of departure in order to assess actual structural performance in presence of suchdeteriorating processes.The work in ACM was extended to ultra-high strength concrete, and recently to lightweight aerated concrete(LWAC) and lightweight foam concrete (LWFC). The thermal, acoustic and potential mechanical advantagesof LWAC and LWFC are subjects of a current significant research effort in the CDSI towards developing theselightweight materials for structural application in residential infrastructure. Constitutive models developed fortraditional construction materials, as well as several of the ACM, enabled the iterative computationalexperimentaldevelopment and validation of retrofitting strategies for both unreinforced load-bearing masonryand reinforced concrete structures for new functionality or extended structural life span. Finally, a role ofleadership and collaboration was fulfilled in research of the solar chimney power plant concept with nationaland international partners, bringing the concept for harvesting of sustainable energy to a pre-feasibility level.The contributions have laid the link between construction material properties, structural behaviour anddurability. Through the fundamental experimental research, structural mechanics and computational mechanics, it has been made possible to utilise the advanced properties of ACM to advance structural performance anddurability. Human capital well-versed in the fundamental principles of this multi-level structural engineeringapproach has been developed in the process of research supervision by the author.

[发布机构] Stellenbosch University