Design of cold-formed steel back-to-back c-channel built-up columns using modified direct strength method
Speaker:Prof. Hieng Ho LAU
Deputy Dean and Associate Professor of School of Engineering & Science
Curtin University Sarawak Campus, Malaysia
Date & Time:27 Nov 2014 (Thursday) 14:30 - 15:30
Venue:E11 - 1041
Organized by:Department of Civil and Environmental Engineering


Back-to-back C-channels built-up compression members are popular in the construction industry particularly for spanning over large space area, and carrying high loads while maintaining low self-weight. However, current design standards do not provide comprehensive design guidelines for complex section such as back-to-back C-channels built-up section. There is little literature available for the design calculation of back-to-back C-channels built-up columns. Current design methods, i.e. the Effective Width Method (EWM) and the Direct Strength Method (DSM) are unable to accommodate such complex section. Thus, enhancement to these design methods is necessary to improve the design of back-to-back C-channels built-up columns. Therefore, the Thickness Reduction Method (TReM) is proposed in this research to improve the current design methods for the back-to-back C-channels built-up column. Results from design calculations show that the proposed design method, TReM, is able to predict the capacity of the back-to-back C-channels built-up column well. Experimental investigation on the axially loaded cold-formed steel back-to-back C-channels built-up columns was carried out. A total of 66 specimens with two sizes of plain back-to-back C-channels built-up and lengths of 300mm, 500mm, 1000mm, and 2000mm were tested. Compression tests were carried out on stub columns with flat end conditions, whereas the short, intermediate and slender columns were tested with pinned-end conditions. Experimental results show that restraint at the mid-length of the plain back-to-back C-channels built-up columns is critical regardless of the number of fasteners along the length of the built-up column. Whereas, comparison of experimental results with results from design calculation using the proposed design method, TReM, shows good correlation.


Associate Professor Lau Hieng Ho is currently Deputy Dean of School of Engineering & Science Curtin University Sarawak Campus, Malaysia. Associate Professor Lau is attached to the Department of Civil &Construction Engineering in Curtin University Sarawak Campus and he was Head of the Department of Civil & Construction Engineering. Curtin University Sarawak Campus is the first off-shore university campus set up by Curtin University of Western Australia in partnership with the Sarawak State Government, Malaysia.

Associate Professor Lau received his B.Eng and Ph.D. degrees from Oxford Brookes University, United Kingdom in 1998, and 2002 respectively. Prior to joining Curtin University Sarawak Campus back in February 2003, he worked in the consulting industry. He is also a Professional Engineer (PEng), registered with Board of Engineers Malaysia.

Associate Professor Lau research interests include cold-formed steel structures, design of steel structures, structural stability and connections.