Dead Load Due to Soil Combinations

Sizer allows separate input of a Dead (soil) load type (Ds) to comply with the following design code clauses:

NBC

4.1.3.2 7) p 4-4 increases factor for Dead loads due to soil to 1.5 from 1.25, and provides an equation based on depth of soil.
Note 3 Table 4.1.3.2 p 4-5 refers to 4.1.2.1 7)
4.1.4.1 6) says dead load due to soil cannot be counteractive unless under circumstances provided by A4.1.4.1 6)

NBC Structural Commentaries

Table A-3, commentary A-12, note 1, refers to 4.1.3.2 7), for non-counteracting combinations only.
Commentary A-15 refers to 4.1.3.2 7)

CSA O86-14

Table 5.2.4.1 refers to the NBCC for dead loads due to soil, for ultimate limit states

Load combinations containing Ds

Refer to table in Canadian Load Combinations for load combinations containing Ds. Essentially wherever 1.25 D appears in the load combinations without Ds, one can replace it with 1.25D + 1.5Ds, and wherever 1.0D appears, it is replaced with 1.0D + 1.0Ds.

The load combination with D only. or 1.4D, becomes 1.4D + 1.5Ds, as per 4.1.3.2 (9) of NBC .

Counteracting Load Combinations

There are no load combinations containing Ds and the dead-load-resisting failure combinations with 0.9D.

According to 4.1.4.1 6), dead load due to soil cannot be counteractive unless it is part of a load resisting system, and A4.1.4.1 6) gives examples of such systems. These are things like pylon signs, towers, and retaining walls. The case of a retaining wall in Sizer employing a vertical dead soil load to resist other forces is too unlikely for consideration.

Pattern Loads

Live and snow loads in load combinations containing Ds are patterned if the corresponding load combination without Ds is patterned.