Ribbed Slabs

Information to provide in scheme design:

     Statement that the design is a one way ribbed slab

     Thickness of topping on top of slab

     Depth of ribs, which are small downstand beams, and distance from center to center

     Size of flat beams

     Clear floor height

Reasons to use this slab type:

Capabilities

     Aesthetically pleasing due to regular patterns induced by ribbed slab and ceiling shape on the underside

     Accommodates for floor penetrations, service installations, and high headrooms in one direction

     Decreases the overall self weight of slabs, but at the same time, has strength and stiffness to limit deflection

     Provides robustness

     Standardized fabric glass formworks or lightweight formers on formworks can be used to decrease construction time and effort

     Parallel spans can accommodate for good service routing arrangements

     Appropriate for long spans

Disadvantages:

     Difficult to design and construct partition walls underneath ribbed slabs

     Difficult to detail and position reinforcements in ribbed slabs

     Not suitable for heavy and concentrated loads due to small shear capacity of ribs

     Difficult to construct structures with irregular shapes

     More finishes work required for large surface area of the structure

     Service penetrations through ribbed beams decreases beam strength and will lead to reinforcement congestion

     Long construction time for formwork construction due to void formers

Standard formwork used is expensive for low-rise structures