Senior Lecturer
University of Waikato, Hamilton
New Zealand
Abstract
Thin-walled cold-formed metals are increasingly being used in the construction industry both in New Zealand and globally. These materials offer several advantages, including a high strength-to-weight ratio, ease of fabrication, transportation, and installation due to their lightweight nature, and the corrosion resistance of metals like aluminum, stainless steel, and copper.
This presentation discusses the development and applications of cold-formed metals, with a focus on cold-formed steel (CFS). CFS is commonly used in beams, columns, connections, roofing, and wall claddings, and it is designed to withstand static loads, earthquakes, wind, and fire.
One significant innovation in this field is the introduction of unstiffened and stiffened circular and slotted holes in CFS sections, which does not compromise their structural integrity. These holes are beneficial as they allow easy access to building utilities. Additionally, the earthquake resilience of CFS connections has been enhanced through the development of new connectors, such as the Howick Rivet Connector (HRC) and T-stub connections.
CFS sections also exhibit better fire resistance, making them suitable for use in fire-prone areas. Over the years, CFS has emerged as an excellent alternative to traditional, heavier, and less aesthetically pleasing roofing and wall cladding materials. Popular CFS profiles include long-run options like corrugated, trapezoidal, and drape-curved, as well as architectural tray profiles like standing seam and weatherboard. While not entirely failure-proof, CFS has demonstrated superior wind performance compared to conventional roofing materials such as tiles, asphalt shingles, and concrete tiles in extreme wind events like cyclones, typhoons, and storms. Furthermore, aluminum and copper roof and wall cladding profiles have shown remarkable durability in harsh coastal and chemical environments.
The Cold-formed Steel Research Group at the University of Waikato, led by Dr. Krishanu Roy, consists of other academics including Prof. James Lim, and Dr. Arthur Fang, is engaged in cutting-edge research aimed at advancing knowledge and transferring technology to the industry. Their work involves full-scale testing, finite element modeling, machine learning, artificial intelligence, and probabilistic analysis. The group's innovations are already being adopted by the industry and recognized within the scientific community, as evidenced by their overall citation count of 14000, and more than 400 scientific papers.