300mm Slab with B1 concrete hollow blocks

grabcad

Rib and block slabs are constructed using pre-cast concrete ribs spaced 650mm "center to center". Concrete hollow blocks are placed between these ribs. The width of the block dictates the beam spacing and provides a flush soffit. A 25 MPa in-situ structural concrete topping is placed on top of the ribs and blocks with welded wire mesh reinforcement placed inside the topping to reduce shrinkage cracks on the surface of the slab. Every fifth to seventh row of blocks is omitted and cross-rib steel (2Y10's, 2Y12's, 1Y16) are placed perpendicular to the rib direction above each line of temporary propping, these cross-ribs prevent possible stress fractures caused by the slab settling to its final position. B1 190mm concrete hollow blocks are used with a slab depth of 300mm. Temporary propping is used with rib and block slabs and are placed on the cross-ribs at a maximum of 1000mm apart "center to center".