## How do you calculate a cantilever slab?

Cantilevers, one way slabs

- ge=1.0kN/m2·1.00m=1.0 kN/m.
- G=4.0kN/m·1.00m=4.0 kN.
- p=γg·g+γq·q=1.35·6.0+1.50·5.0=15.6 kN/m.
- VA=P+p·L=5.4+15.6·2.00=36.6 kN.
- Vk=VA-p·L=36.6-15.6·2.00=5.4 kN.
- MA=-P·L-p·L2/2=-5.4·2.00-15.6·2.002/2=-42.0 kNm.
- I=b·h3/12=1.00·0.203/12=6.67·10-4 m4
- E·I=35.2·109N/m2·6.67·10-4m4=234.8·105 N·m2

**How will you design a cantilever slab?**

Slab loading

- Slab loading.
- Ultimate load = 1.35gk+1.5qk = 1.35×4.375+1.5×4 = 11.91 kN/mm2. Bending moment.
- n = 11.91 kN/mm2. Bending moment.
- Reinforcement.
- k’>kCompression reinforcement is not required.
- Provide T10 @ 200mm C/C (As pro. = 393mm2/m.
- Check for deflection (same method as two way slab)
- Deflection check is ok.

**How thick should a cantilever slab be?**

Cantilevered Slabs a) The minimum overall thickness should be– (i) 110 mm for span not greater than 500 mm; (ii) 125 mm for span greater than 500 mm but not greater than 750 mm; (iii) 150 mm for span greater than 750 mm.

### How does cantilever slab work?

Cantilever slabs are common features in buildings due to the need to have bigger spaces at upper floors. To achieve this, architects normally extend the slab beyond the ground floor building line, thereby forming a cantilever.

**What are the points to be considered in designing one way cantilever slab?**

ACI Provision for Design of One-way Slab

- Compressive Strength. The compressive strength of concrete is specified based on the following criteria.
- Minimum Thickness. Ad.
- Concrete Cover.
- Maximum Reinforcement Ratio.
- Minimum Reinforcement Ratio.
- Maximum and Minimum Spacing between Steel bars.
- Bar Size.

**What is the maximum span of a slab?**

The allowed recommended span lengths for continuous slabs are equal to 13.6m for two-way slabs and to 12.5m for unidirectional slabs. The published recommendations resulted in that the constant depth slabs are erected worldwide with the maximum span limit set at around 12÷13m.

## How far can a cantilever slab extend?

According to the new span tables and IRC provisions, cantilevers can extend up to one-fourth the backspan of the joist. This means that joists, such as southern pine 2x10s at 16 inches on-center, spanning 12 feet are allowed to cantilever up to an additional 3 feet (see illustration, below).

**What is the minimum percentage of steel in any slab?**

The highest proportion of steel used in a beam is 2%, with a low of 1%. The highest amount of steel used in a slab is 1%, with a low of 0.7%.

**What is the maximum length of cantilever beam?**

It is a horizontal beam structure whose free end is exposed to vertical loads. What is the maximum span of cantilever beams? Usually, for small cantilever beams, the span is restricted to 2 m to 3 m. But the span can be increased either by increasing the depth or using a steel or pre-stressed structural unit.

### How do you calculate the span of a slab?

The calculations based on IS 456 is given below: Clear span l n =4200mm….Effective span of continuous beams and slabs.

Support A | Support B | |
---|---|---|

Fig. to use | Fig.(a) | Fig.(b) |

h | 350 | 350 |

t | 300 | 300 |

ai = lesser of {h/2; t/2} | 150 | 150 |