Dr. W. W. Chan (F): I am privileged to be given the first opportunity of congratulating you and your associated companies for the efforts and costs which have been given to further the understanding of the resistance of large-panel structures to progressive collapse. The experiments have demonstrated the importance of mechanical steel connections and the importance of limiting the stagger at overlapping in order to develop the full strength in tension of the looped connections. Both of these factors were arrived at by, albeit intuition, when we first contrived Circular 62/68. The great controversy at the time was the shear friction resistance and the sliding of the wall connections which it was always recognized was real and present under loading. But, at that time and I believe still now, we are unable to relate the results of static experiments to their dynamic equivalent. Mr. Watson and I have in the past, for some polite reason, avoided the word ‘explosion’.