Development of design rules for elliptical hollow sections

Imperial College London performed a series of precise full-scale laboratory tests on elliptical hollow sections (EHS) (grade S355), manufactured by Corus Tubes, and developed the structural response and the design rules. Tensile coupon tests were conducted to determine the basic engineering stress-strain behavior of the material for each of the tested section sizes. The second phase of this research focused on the in-plane bending response of EHS9 and a 18 in-plane bending tests were performed in three-point and four-point bending configurations to study the structural behavior of EHS under a moment gradient and constant moment scenarios respectively. Distinction between Class 3 and 4 cross-sections in bending relates to their ability to reach the elastic moment resistance. The transverse loading yields a plastic shear resistance equal to twice the product of the vertical projection of the elliptical section and the thickness given by 2(2b-t)t multiplied by the yield stress in shear.