Steel Buildings in Europe

Part 2: Concept Design 2 - 17 The floor-to-floor height was only 3,9 m, which necessitated a beam depth of only 650 mm as part of a 1050 mm overall floor zone. The 9 m span heavily loaded primary beam s had larg e recta ngular openings, and were tapered in depth close to the concrete cores to allow for distribution of large ducts. Secondary beams were designed as fabricat ed steel sections with a series of 425 mm diameter circular openings for services and two rectangular openings of 425 mm depth × 750 mm length close to m id-span. An im posed load deflection limit of only 30 mm was specified, which was achieved by beams of 138 kg/m weight with no stiffening. Figure 3.2 View of long span cellular beams in the Bishop’s Square project