Concrete (rib and block) Slabs
SPANCON CONCRETE SLABS
engineering, design, Building Contractors
Rib and block slabs are made up of precast concrete rectangular shaped ribs spaced 660mm apart. Non-structural hollow concrete rebated filler blocks are placed between these ribs. The size of the block determines the beam spacing and provides a flush soffit. A structural concrete topping should have a minimum strength of 25 MPa at 28 days and a minimum thickness of 40 mm, or 1/10 x clear distance between the ribs. Welded mesh reinforcement is placed in this topping to control possible shrinkage cracks. The filler blocks are available in different heights ranging from 110 mm to 285 mm which produces an overall depth of slab from 170 mm to 340 mm, or more if double blocks are used. This type of slab requires temporary supports at approximately 1,5 m to 1,8 m centres.
The advantages of rib and block slabs are as follows: ·
They provide an economical, versatile lightweight monolithic slab system. Components are relatively light and no mechanical handling is necessary. ·
Slabs may be designed as either simply supported or fully continuous. ·
They are ideal for soffit plaster but fixing of suspended ceilings is also easy and simple. · Electrical and plumbing services are readily catered for by omitting hollow blocks at specific locations.
, Concrete Slabs
, rib and block
, Roof Slabs
, Specialised Construction