Design of rectangular and square hollow sections under concentrated bearing forces: A proposal for AS 4100

Abstract

A design proposal for rectangular and square hollow sections (RHS and SHS) under concentrated bearing forces to Australian Standard AS 4100 is presented. Both interior bearing and end bearing conditions, as codified in the design standard, were studied. A series of localised loading tests on cold-formed steel RHS and SHS with nominal yield strength of 460 MPa was conducted due to the shortage of available data for this steel grade. A parametric study was supplemented by utilising validated finite element models to generate additional data. The experimental and numerical web bearing capacities were compared with nominal resistances computed by the current AS 4100 design provisions. Reliability levels of the codified provisions were also appraised. It is revealed that the current AS 4100 provisions for RHS and SHS under interior bearing and end bearing need to be improved for better accuracy and reliability. New design rules are therefore proposed by using Direct Strength Method. The applicability of the proposed rules was assessed by verifying against a total of 478 test and numerical data. It is showcased that the proposed rules can be applied to both normal strength and high strength steels, and can provide improved predictions than the codified rules. The proposed DSM based design rules have been developed by adopting the bearing yield load and bearing buckling load calculations as codified in the current AS 4100, leading to rather user-friendly rules for designers and therefore recommended to the Australian standard for the design of RHS and SHS under concentrated bearing forces.