πŸ“„ Loads Tab
Sign in

Loads Tab

The Loads tab is used to add loads acting on the wall in addition to soil pressure. These may include vertical line loads, surcharge loads on the backfill, and horizontal loads applied above soil level.

Typical loads on a retaining wall are:
  • Loads from upper walls or floors bearing onto a basement retaining wall
  • Localised loads on the wall or base
  • Traffic barrier impact loads
  • Wind loads acting on an upstand wall

The loads entered here are combined with the soil pressures in the wall stability and structural design checks.

Line Loads

You can apply up to 5 vertical dead and live loads can be applied to the wall. Line loads can be applied to:
  • On top of the wall
  • To the back of the wall
  • To the front of the wall

Load position reference

Load positions are defined using X and Y coordinates in mm.

  • X is measured from the back face of the wall (the face in contact with the retained soil)

    • Positive X values place the load to the right of this face (on or within the retained soil)

    • Negative X values place the load to the left of this face (on the wall top or in front of the wall)

  • The Y dimension is measured downward from the top of the wall:

    • A positive Y value places the load below the top of the wall

Vertical loads placed in front of the wall are commonly positioned on the top of the base by entering a suitable Y dimension.

The loads and dimensions in the table above will place loads on the inner and outer leafs of the wall at the top, see diagram below. 

πŸ’‘

The small amount of bending moment at the top of the bending moment diagram is due to the positions of the line loads and is taken about the centreline of the wall.


The table below gives a 12 kN load placed on the base, at a Y dimension of 2.3m. The 16 kN load placed at -0.55m from the back of the wall not only produces a vertical load but also a moment. It is assumed to be a point load sitting on a bracket or beam protruding from the front of the wall.

πŸ’‘
Where a line load is applied eccentrically (for example in front of the wall face), it produces:
  • A vertical load, and
  • An additional moment on the wall

Full and Partial Surcharge Loads

Surcharge loads can be applied over the retained soil behind the wall. Surcharges are entered in kN/mΒ² (based on a wall length of 1 m into the screen depth).

For each surcharge, enter:

  • The surcharge value

  • The start position

  • The finish position

The start and finish positions are measured in mm from the back face of the wall.

This allows you to model:
  • Full surcharges acting across the full retained soil area
  • Partial surcharges acting only over a selected zone behind the wall

The dead load in the table above of 3.65 kN/m2 starts at 1.2m behind the wall and finishes at 2.5m. Note the shape of the pressure diagram below where a kink occurs part way down the wall. This represents the change in horizontal pressure applied to the wall due to the positioning of the surcharge load.

Effect on pressure diagram

A partial surcharge changes the horizontal pressure distribution on the wall. This is shown in the pressure diagram, where a kink appears at the depth where the surcharge influence changes.

This visual check helps confirm that the surcharge has been applied over the intended area.

Horizontal Loads

The Loads tab also allows you to define horizontal loading effects in addition to soil pressure.

Additional surcharge influence zone

An additional surcharge may be entered as a load applied from the back of the wall to a defined horizontal distance, beyond which it is assumed to have no influence on the wall pressure.

πŸ’‘
This surcharge is additional to:
  • Any other surcharges entered on this tab
  • Any minimum surcharge set on the Defaults tab

Horizontal surge force above soil level

A horizontal surge force can be applied at a height Y (mm) above the retained soil level.
This is typically used to represent loads such as:
  • Vehicle barrier impact
  • Other local horizontal forces acting above ground level
This load produces:
  • A horizontal force
  • An additional moment on the wall

Wind load on wall upstand

Where the wall includes an upstand above the back soil level (defined on the Wall Data tab), a wind load can be applied to the upstand.

This can be used to model walls such as:
  • Car park upstand walls
  • Garden walls
  • Fences or parapet type walls
As with other horizontal loads, wind loading produces both:
  • A horizontal force
  • An additional moment

Default Surcharge Loads

Default surcharge values are set on the ο»ΏπŸ“„ Defaults Tabο»Ώ. These can be reviewed or amended there as required.