Mr C. W. Brown (Freeman Fox & Partners): I should like to congratulate the authors on their most refreshing approach to the design of the structures in question and on not being tied up in all the advanced mathematics that one is apt to meet these days. They have a fairly simple extension to BS 153. I do notice, however, that shear lag has appeared in the paper; what were the shear lag factors actually used for? Did the authors calculate the peak stresses in their box girders and compare these with allowable stresses, or did they use shear lag purely for fatigue analysis-or what? I should have thought that, from the proportions of the ramps, shear lag would not play a very large part in overall behaviour.