Steel Buildings in Europe

Part 2: Concept Design 2 - 53 Figure 5.12 Composite floor construction with precast concrete hollow core units, showing transverse reinforcement bars placed within open cores 5.5.3 Services integration Main service ducts are located below the beams with larger services equipment located between beam s. Allow for 1200 mm overall depth including ceiling and services. Openings can be provided in the beam web but the beams should be designed as non-composite in this case. 5.5.4 Fire protection Spray, board or intumescent coating may be used as the fire protection systems to beams supporting precast concrete units. Transverse bars m ust be carefully deta iled into the pre cast units – extending 600 mm into each un it. For 90 to 120 minutes fire resistan ce, a 50 mm (minimum) concrete topping is required. 5.6 Non-composite beams with precast units 5.6.1 Description Precast units m ay be s upported on the top fl ange of the steel beams, or supported on ‘shelf’ angles. The P.C. units are either in the form of hollow core units, norm ally 150 – 400 mm de ep, or solid planks of 75 mm to 100 mm depth. Hollow core p recast concrete un its can be us ed to span up to 15 m