In late 2001, engineers were working on designs for BP1 - a new tower for Canary Wharf, London. But following 9/11, they changed their plans. Together with steelwork specialists, they devised a pioneering system to strengthen beam and column connections.
Usually, each end of a floor beam is bolted directly to the face of a supporting column. But by pushing a short steel plate through the column, engineers found they could tie neighbouring beams together. Even with two adjacent columns removed, floor beams could hang from the remaining structure.