# SkyCiv ACI 360 Slab on Grade Calculator

The SkyCiv ACI 360 Slab on Grade Calculator allows for checks of slabs on the ground as per ACI 360 R-06. The calculator currently supports slab on two different types of soils including expansive soil and compressible soil. The checks are based on the procedure outlined in Cl 9.8 and Cl.9.9 of ACI 360 R-06 applicable for expansive and compressible soil respectively.

Starting SkyCiv ACI 360 Slab on Grade Calculator...

## What design method is used in the ACI 360 Slab on Grade Calculator?

The slab on grade design calculations are based on the Post-Tensioning Institute method of design (PTI method). The slab can be designed for uniformly distributed loading as well as the line load (perimeter load) due to walls present on the periphery of the slab under consideration. Vehicular loading is yet to be considered. The PTI design procedure considers the slab as a ribbed slab i.e. intermediate beams at specific intervals in long and short directions.

The stiffened slab is reinforced to provide sufficient strength and deflection control in swelling and compressible soil conditions. The 'T' type of cross section is considered in the design.

The PTI design procedure gives equations for moment, deflection, and shear checks which are developed by log-linear regression analysis based on full consideration of both center lift and edge lift conditions using a finite element plate on elastic foundations.

## How to use this calculator?

To run this Slab on Grade Calculator the following needs to be filled out before running the tool:

• Slab Geometry (for slab, beam and beam spacing)
• Soil Properties ( Expansive or Compressible and related properties)
• Deflection Ratios
• Material Properties
• Beam Reinforcement
• Slab Reinforcement

Once all the inputs have been filled out, click the "Run" button in the top right.

Which soils are considered for the design?
The calculator can design the slab on ground founded on either expansive soil or compressible soils.

What is the effect of soil on the design?
In the case of expansive soil, the effect of heavy formation at the center or the edge is considered due to swelling/shrinkage of the soil. In the case of compressible soil, the uniform settlement is considered for the design.

What all loads are considered in the design?
The uniform load on the slab area (pressure load) and the line load in the form of walls around the periphery of the slab panel are currently supported.