Checked following Eurocode 7 Design Approach 1 - Combination 1
Overturning result
Overturning (x) utilisation
%
Overturning (y) utilisation
%
Foundation weight
kN
Soil overburden
kN
Self-weight lever arm (x)
m
Axial force lever arm (x)
m
Foundation axial force moment (x)
kNm
Total design stabilising moment (x)
kNm
Destabilising design moment (x)
kNm
Self-weight lever arm (y)
m
Axial force lever arm (y)
m
Foundation axial force moment (y)
kNm
Total stabilising design moment (y)
kNm
Destabilising design moment (y)
kNm
Foundation sliding summary
Checked following Eurocode 7 Design Approach 1 - Combination 1
Sliding result
Sliding (x) utilisation
%
Sliding (y) utilisation
%
Foundation weight
kN
Soil overburden
kN
Axial force
kN
Total vertical force
kN
Coefficient of friction (based on soil friction angle)
Horizontal resistance to sliding
kN
Design horizontal force (x)
kN
Design horizontal force (y)
kN
Structural assessment on column X-axis
Checked following Eurocode 2
Design transverse shear force
kN
Min. reinforcement area required
mm2
Transverse shear resistance provided
kN
Structural assessment on column Y-axis
Checked following Eurocode 2
Design transverse shear force
kN
Min. reinforcement area required
mm2
Transverse shear resistance provided
kN
Structural assessment on foundation base
Checked following Eurocode 2
Design punching shear at column face
kN
Punching shear resistance at column face
kN
Design punching shear at 1D
kN
Punching shear resistance at 1D
kN
Design punching shear at 2D
kN
Punching shear resistance at 2D
kN
Pad foundation design theory
How are building foundations designed?
All structures require foundations to stand and these foundations resist the dead load (self-weight) of the structure and any applied live loadings. Footing are typically designed for either low rise buildings where the generally weaker layers of ground found at the surface level are sufficient to resist the imposed forces on the foundation. In some cases of hard ground or rock a shallow footing is used as digging or piling to deeper layers is not necessary to achieve the necessary bearing capacity. Many temporary structures also use shallow footings as they are generally easier to install.
Bearing capacity is the maximum pressure a soil can support before failure. Geotechnical Engineers use their understanding of bearing capacity to design foundations to safely transfer loads (such as self-weight of the structure) from building foundations into the underlying soils.
How are pad footing foundations designed?
Pad foundations and shallow footings require several different checks including both geotechnical and structural assessments for a complete design. There are several main considerations when designing pad footing foundations:
Bearing capacity of the foundation base
Horizontal sliding of the foundation
Overturning of the foundation
Structural design of the foundation
How to calculate bearing capacity of a building foundation?
The bearing capacity of shallow pad foundations can be assessed using the Terzaghi bearing capacity equations, using closed form calculations and correlations between the geotechnical design parameters, foundation geometry (shape factors) and applied loading.
How to calculate the horizontal sliding of a building foundation?
Horizontal sliding of a building foundation can be assessed by considering the total vertical forces applied to the foundation, including the self-weight, dead load and imposed service loads and multiplying these by a friction coefficient based upon the friction angle of the soil beneath the foundation. The overall stability of the foundation can then be assesed by comparing the applied horizontal force to the horizontal resistance. It is also possible to consider the strength of the vertical wall of the foundation against the soil if friction alone is not sufficient.
How to calculate overturning of a building foundation?
Overturning of a pad foundation is often one of the governing critial cases for assessment. This calculation compares the applied destabilising design bending moments applied on the foundation to the stabilising moments. Stabilising moments are calculated from the self-weight of the foundation multiplied by it's lever arm from the point of rotation, axial compressive force applied to the foundation multiplied by it's lever arm from the point of rotation and the soil overburden if available and it's centre of gravity over the foundation from the point of rotation.
What are the structural calculations for building foundations?
Several structural checks for building foundations are required including checks on the transverse shear force applied on the joint between the pad foundation base and the column itself. Another structural check required is of the punching shear effect of the column on the foundation base. This requires analysis at the column face and at a distance 1d and 2d from the column face.
What's this calculator used for?
This free calculator can be used by Geotechnical Engineers and Structural Engineers to design pad foundations and shallow footings. Check the geotechnical design considerations including sliding, overturning, and bearining stability of the foundation in accordance with Eurocode 7 Design Approach 1 Combination 1. Check the structural aspects of the foundation inclduding transverse shear and punching shear of the foundation.
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Any design properties predicted with the dropdowns are for estimate only