Reduction of structural ductility factor due to variability of steel properties

The lower and upper bounds for the variability of the mechanical properties of two conventional steel grades (nominal yield stress Fy=235 and 315 MPa) are determined from mill coupon test results. Reduction of the ductility factors due to the differences between the actual yield stress and the nominal design value for the compact plate elements of welded box sections and for welded circular tube sections are investigated relevant to the design of seismic resistant structures.