Your Question:

Design the reinforced concrete ribbed slab building floor system , shown in the following figure , the slabs are supported by shallow column line beams cast monolithically with it .

• Determination of bending moments.

• Determination of reinforcement.

Step By Step Answers with Explanation

Estimation of Slab Thickness, Topping Slab Thickness, Ribs Dimensions and Spacing

Slab Thickness

• Concrete strength

• Reinforcement ratio

Ribs Dimensions and Spacing

The dimensions and spacing of the ribs are determined based on the following factors:

• Reinforcement ratio

For the given conditions, the following rib dimensions and spacing are estimated:

The beams are designed as simply supported beams with a uniform load. The load on the beams is the sum of the self-weight of the ribs, the finishing load, the partition load, and the live load.

For the given conditions, the following beam dimensions and reinforcement are estimated:

• Section: 300 mm x 400 mm

• Reinforcement: 4 x 16 mm bars at top and bottom

• Section: 400 mm x 500 mm

• Reinforcement: 6 x 16 mm bars at top and bottom

The bending moments at the critical sections of the slabs and beams are determined using the following methods:

• Slabs: The bending moments in the slabs are determined using the equivalent strip method.

The following table shows the reinforcement details for the slabs and beams:

Check for Design Limits

For the given conditions, all design limits are satisfied.