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2024-07-11

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Add-on Concrete Foundations

External Stability - Geotechnical Checks
Internal Stability - Reinforced Concrete Checks
- Determination of the design moments
- Definition of reinforcement areas and design strips

Design Specifications

Types for Foundations
Concrete Foundations
Design properties of single foundations
- Foundation plate
  
  Main
  
  Geometry
  
  Reinforcement
  
  Concrete Cover
  
  Slab Reinforcement
  
  Mats
  
  Reinforcing Bars
  
  Mesh and rebars
  
  Soil Properties
  
  Geotechnical Configuration
  
  Concrete Configuration
Additional foundation loads

User-defined values for allowable soil stress

For this type of design, the existing soil pressure is compared to the specified allowable soil stress.

Determination of the stresses in the soil joint and the load eccentricities

The design shear force with additional foundation loads V_z,+add as well as the resulting design bending moments M_y,+add and M_x,+add in the foundation base are required to determine the eccentricity of the effective vertical loads:

e_{x} = - \frac{M_{y, + add}}{V_{z, + add}}

e_{y} = \frac{M_{x, + add}}{V_{z, + add}}

Eccentricity of Resulting Actions Including Additional Foundation Loads in x- and y-Direction

Determining the Effective Foundation Area

The ground failure analysis only considers a part of the actually available foundation base - the part where the resulting axial force acts in the middle.

L^{'} = m a x (w_{x} - 2 \cdot |e_{x}|; w_{y} - 2 \cdot |e_{y}|)

B^{'} = m i n (w_{x} - 2 \cdot |e_{x}|; w_{y} - 2 \cdot |e_{y}|)

A^{'} = B^{'} \cdot L^{'}

Effective Foundation Length L', Foundation Width L', and Base A'

Existing Soil Pressure

With this, you can determine the existing soil pressure:

σ_{v o r h} = \frac{{V^{'}}_{d}}{A^{'}}

Design Value of Ground Failure Action

Design check

The existing soil pressure is compared to the specified soil pressure:

η = \frac{{V^{'}}_{d} / A^{'}}{{R^{'}}_{d} / A^{'}} \leq 1.0

Design Criterion of Ground Failure

Parent Chapter

Ground Failure