Design Checks

In the Design Checks navigator category, you can control which design checks are displayed graphically with the respective ratios on the designed objects. This category contains further subcategories for the specific design checks:

• Geotechnical Design: You can select from the specific design types for the ultimate limit state and the serviceability limit state.
• Concrete Analysis: The reinforced concrete design checks are divided into the design checks for the ultimate limit state and for detailing.

Geotechnical Design Checks

The geotechnical design includes an assessment of the interaction between the foundation and the subsoil and is performed for the ultimate limit state and the serviceability limit state. The results are displayed graphically below the foundation plate.

Geotechnical Design in Navigator for Concrete Foundation in RFEM 6

UL7300 | Ultimate Limit State (Ground Failure)

This design verifies the load capacity of the subsoil beneath the foundation. In the Navigator, the following result variables can be selected for graphical display:

• V_d/R_d – Design ratio
• V_d/A' – Design value of the ground failure action
• R_d/A' – Design value of the bearing resistance
• φ_A,k – Design value of the effective friction angle beneath the foundation
• Z_s,A – Sliding surface depth

The results are displayed as isobands beneath the foundation plate and show the distribution of soil pressures as well as the design ratio for the subsoil.

Design Ratio of Ground Failure Design for Concrete Foundations in RFEM 6

UL7301 | Ultimate Limit State (Sliding)

This design verifies the safety against foundation sliding caused by horizontal actions. In the Navigator, the following result variables can be selected for graphical display:

• H_x,d – Design value of the horizontal force in the x-direction
• H_y,d – Governing design value of the horizontal force in the y-direction
• R_d – Resistance to sliding

The results show the governing horizontal forces and the available resistance to sliding.

Sliding Resistance Design Ratio for Concrete Foundations in RFEM 6

UL7400 | Uplift Limit State (Buoyancy)

This design checks the safety of the foundation against uplift forces.
In the Navigator, the following result variables can be selected for graphical display:

• V_d – Applied vertical load

The results show the balance between buoyancy-generating and stabilizing forces.

Vertical Resultants for Uplift Limit State Design of Concrete Foundations in RFEM 6

UL7200 | Ultimate Limit State (Static Equilibrium)

This design check verifies the stability of the foundation against overturning due to moment loads.

In the Navigator, the following result variables can be selected for graphical display:

• M_d,stb – Stabilizing moment
• M_d,dst – Destabilizing moment

The analysis is performed separately for each foundation edge. The governing design ratio is determined from the individual design checks and displayed. The results allow for the evaluation of the foundation’s stability against overturning.

Design Ratio for Static Equilibrium of Foundation Edge

SE7800 | Serviceability Limit State (Eccentric Loading)

This design evaluates the serviceability of the foundation under eccentric loading. In the Navigator, the following result variables can be selected for graphical display:

• e_x – Eccentricity in the x-direction
• e_y – Eccentricity in the y-direction
• e_max – Maximum eccentricity in the x- and y-direction

The results show the location of the resultant forces within the foundation area and allow for an evaluation of the load distribution.

Design Ratios in Concrete Foundation Under Highly Eccentric Loading

SE7801 | Serviceability Limit State (Highly Eccentric Loads in Core)

This design checks whether the resultant force from the load remains within the allowable core area of the foundation, thereby ensuring that no impermissible rotation or lifting of the foundation plate occurs.

The following result variables can be selected in the Navigator for graphical display:

• e_x – Eccentricity in the x-direction
• e_y – Eccentricity in the y-direction
• e_lim – Limit value of the allowable eccentricity

The analysis is based on the location of the resultant force relative to the foundation dimensions. If the allowable eccentricity is exceeded, the compressive force leaves the core area, which can cause tensile stresses in the soil joint.

Design Ratio for Highly Eccentric Loads in Core of Concrete Foundation

Concrete Design Checks

The concrete design includes a verification of the foundation plate at the ultimate limit state and the determination of the required reinforcement.

UL2400 | Punching Shear Resistance

This design checks the punching shear resistance of the foundation plate in the area of load introduction.

The following result variables are available for graphical display:

UL2400 – Punching shear resistance according to EN 1992-1-1 (V_Rd,c)

• V_Ed,red – Reduced applied shear force
• V_Rd,c – Punching shear resistance without punching reinforcement
• σ_z – Governing compressive stress beneath the foundation plate
• β – Increasing factor to account for moments

UL2401 – Punching shear resistance at the perimeter section of the column or the perimeter section of the loaded area according to EN 1992-1-1 (V_Rd,max)

• V_Ed – Applied shear force
• V_Rd,max – Maximum punching shear resistance

The results are displayed in the load introduction area and allow for the evaluation of the design ratio as well as the governing parameters of the punching shear design.

Graphical Visualization of Concrete Foundations

For stepped foundations, two additional design checks are available for the first foundation step (UL2402 and UL2403). For more information, see the section Design Strips .

Stepped Foundation – Punching Shear Design: Graphical Results

UL2100 | Bending Failure of Plate

This design checks the bending resistance of the foundation plate in the x- and y-direction, as well as for the top and bottom reinforcement.

The results are organized by direction (x- and y-direction) and position (top or bottom side of the foundation plate) and are evaluated for individual punching cases.

Analysis of Concrete Foundation: Design Strip

The following result variables are available for graphical display:

Statical longitudinal reinforcement areas by design strip

• a_{s,stat,1,x,(bottom)} to a_{s,stat,4,x,(bottom)} – Statical longitudinal reinforcement areas in the x-direction for the bottom reinforcement
• a_{s,stat,1,y,(bottom)} to a_{s,stat,4,y,(bottom)} – Statical longitudinal reinforcement areas in the y-direction for the bottom reinforcement
• a_{s,stat,1,x,(top)} to a_{s,stat,4,x,(top)} – Statical longitudinal reinforcement areas in the x-direction for the upper reinforcement
• a_{s,stat,1,y,(top)} to a_{s,stat,4,y,(top)} – Statical longitudinal reinforcement areas in the y-direction for the upper reinforcement

Design moments

• M_x,(bottom),d, M_y,(bottom),d – Design moments for the bottom reinforcement
• M_x,(top),d, M_y,(top),d – Design moments for the top reinforcement

Additional result variables

• σ_z – Compressive stress below the center of the foundation plate

The results allow for a detailed evaluation of the bending stress as well as the required reinforcement in the individual design strips.

Furthermore, the distribution of compressive stress in the soil joint is graphically displayed using values at corner nodes and below the center of the foundation plate.

Analyzing Concrete Foundations with Compressive Stress Distribution

Display Model

The Display Model category in the lower navigator area allows you to display the results as isobands or isolines. You can also switch off the graphical display completely.

Display of Concrete Foundations with Different Graphic Types