Keynote Speakers


João R. Correia


Professor

Dept. of Civil Engineering, Architecture and Georesources

IST, University of Lisbon

Portugal

FRP THIN-WALLED STRUCTURES. BEHAVIOUR AT ELEVATED TEMPERATURE AND UNDER FIRE EXPOSURE


This paper addresses one of the most critical issues regarding the use of fibre reinforced polymer (FRP) thin-walled structures in civil engineering applications: the behaviour at elevated temperature and under fire exposure. The first part of the paper presents an overview of the research activities on pultruded FRP structures at IST-University of Lisbon, focusing on different aspects and at different scales of analysis: short-term mechanical behaviour, creep behaviour and durability of the material; mechanical behaviour of structural members – beams and columns; connection technology (bolting, bonding); dynamic and seismic behaviour of frame structures. Examples of applied research projects, developed in collaboration with the industry, are also presented, namely the first two hybrid pedestrian bridges in Portugal and the modular emergency Clickhouse. The second part of the paper presents a review of the fire performance of pultruded glass-FRP (GFRP) thin-walled structures. First, the effects of elevated temperature on the thermo-physical and mechanical properties of the GFRP material are addressed. Subsequently, the fire reaction behaviour of the GFRP material and the effects of using different types of fire protection on such behaviour are discussed. Next, the available fire resistance tests on pultruded GFRP elements, including slabs, beams and columns, are reviewed and discussed, as well as the simulation studies that aimed at predicting their thermal and mechanical responses at elevated temperatures. Finally, international guidance for the fire design of pultruded FRP structures is summarized, and the most relevant research needs in this field are identified.




Leroy Gardner


Professor

Dept. of Civil and Environmental Engineering

Imperial College London

United Kingdom

STABILITY AND DESIGN OF STAINLESS STEEL STRUCTURES – REVIEW AND OUTLOOK


This paper provides a summary of recent developments in research and design practice surrounding the structural use of stainless steel, with an emphasis on structural stability. The nonlinear stress-strain characteristics of stainless steel give rise to a structural response that differs somewhat from that of structural carbon steel. Depending on the type and proportions of the structural element or system, the nonlinear material response can lead to either a reduced or enhanced capacity relative to an equivalent component featuring an elastic, perfectly plastic material response. In general, in strength governed scenarios, such as the in-plane bending resistance of stocky beams, the substantial strain hardening of stainless steel gives rise to capacity benefits, while in stability governed scenarios, the early onset of stiffness degradation results in reduced capacity. This behaviour is observed at all levels of structural response including at cross-sectional level, member level and frame level, as described in the paper. Current and emerging design approaches that capture this response are also reviewed and evaluated. Lastly, with a view to the future, the application of advanced analysis to the design of stainless steel structures and the use of 3D printing for the construction of stainless steel structures is explored.




Kim J.R. Rasmussen


Professor

School of Civil Engineering

University of Sydney

Australia

ON THE BEHAVIOUR AND DESIGN OF COLD-FORMED STEEL PORTAL FRAMES


The paper provides an overview of the behaviour, analysis and design of cold-formed steel portal frames. It describes a recent research program undertaken at the University of Sydney involving three PhD theses and full-scale testing of large span portal frames composed of singly symmetric C-section uprights and rafters as well as built-up doubly symmetric I-section uprights and rafters. The portal frames were composed of three parallel frames connected by purlins and cross-bracing to make up self-supporting 3D frames with realistic restraints of the uprights and rafters. Additional tests were performed on portal frames composed of a single laterally braced frame. For all types of frames, the loading was either applied vertically (gravity) or by combined vertical and horizontal (wind) loading. Moment-rotation relationships were obtained from the portal frame tests and separate tests on single joints. Accurate finite element models were calibrated against the tests and used for parametric studies. Analytical methods were developed for determining buckling loads by energy-based analyses as were beam-element based finite elements that account for the effect of local and distortional buckling. The paper summarises the test programs, the failure modes observed, the obtained moment rotation relationships for the joints, the procedures developed for the finite element modelling of portal frames, including the modelling of joints, the analytical methods developed, and the methods proposed for the design of large-span cold-formed steel portal frames.





Benjamin W. Schafer


Professor

Department of Civil Engineering

Johns Hopkins University

Baltimore, USA

(to be added soon)






Ben Young


Professor

The University of Hong Kong

Hong Kong, China

ADDITIVE MANUFACTURED HIGH STRENGTH STEEL TUBULAR SECTIONS


Additive manufacturing, commonly known as 3D printing, is an evolutional technology in the manufacturing industry. This technology has already been embraced by different industries, such as aerospace and biomedical engineering, and the recent advance in this technology has generated a vast of societal excitement for its future. Despite the exciting prospect of its application in civil engineering, additive manufacturing technology is still at a perceived stage for construction industry. The benefits and potential in construction industry are rarely known in the field at this stage. This paper aims to investigate the material properties and structural performance of additive manufactured high strength steel square and rectangular hollow sections (SHS and RHS) in crosssection level through experimental program. The specimens were additively manufactured from H13 steel powder by Selective Laser Melting (SLM) with three different printing patterns, where the typical yield strength of the conventionally manufactured H13 steel is around 1650 MPa. The test program comprised tensile coupon tests, hardness tests as well as geometric imperfection measurements and stub column tests. The anisotropy on material properties was examined through tensile coupon tests in both longitudinal and transverse directions. The influences of printing pattern on material properties and structural behavior of additive manufactured high strength steel SHS and RHS stub columns were also investigated. The test results were used to assess the applicability of existing design provisions in the American Specification, Australian Standard and European Code that originally developed for conventionally produced tubular sections to the additive manufactured high strength steel tubular sections in this study.