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Load group calculations

Last modified by Hamid Richard Allili on 2022/03/29 13:54

The user can define a number of load groups, which can be assigned as permanent, stress, temporary, seismic or accidental. Every load group contains one or more earlier defined load cases. Depending on the active code, different partial safety factors could be defined. The program will then automatically combine and calculate every possible load combination in order to find the most unfavourable load position for the variable loads.

Load groups defined as permanent will be present in all load combinations and if a load group contains more then one load case they will never be simultaneously present.

Note: As the calculation requires the principal of superposition when load groups are used, it is not possible to use the option Consider cracking as this requires a non-linear calculation.

The calculation method vary from standard to standard (the Code independent standard doesn’t support load group calculations). For EuroCode (EC2), considering all defined load groups the load combinations will be created in the following way.

Ultimate Limit State

Design situations with only one variable action Qk1


Design situations with two or more variable actions Qki


Serviceability Limit State

Design situations with only one variable action Qk1


Design situations with two or more variable actions Qki


In this state the deformations and crack widths will be calculated. In the example below the way of producing load combinations is exemplified for a plate but the method used applies also for walls.


A plate with four parts. The load case StruDL_P and SoilDL_P acts on the entire plate while the variable loads Q1_T and Q2_T acts on the respective parts of the plate. We set the Combination method to “EC0 6.10.a,b”.

We define the first two load groups with the name G-Struct and G-Soil. It will contain the load case StruDL_P and SoilDL_P, which are defined as permanent with favourable safety factor 0.90 , unfavourable safety factor set to 1.35 and Xi factor to 0.5. Then we define two load groups LG1 and LG2 where we put load cases Q1_T and Q2_T respectively. These groups are all defined as temporary with the safety factor set to 1,5, the same time factor (Psi 0) to 0,5 and the other factors (Psi 1 and Psi 2) are 0.0. The program will now create and analyse the following 32 load combinations:

1.    1.35xStruDL_P + 1.35xSoilDL_P
2.    1.35xStruDL_P + SoilDL_P
3.    0.90xStruDL_P + 1.35xSoilDL_P
4.    0.90xStruDL_P + SoilDL_P
5.    1.35xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ1_T
6.    1.35xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ2_T
7.    1.35xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ1_T + 1.50x0.50xQ2_T
8.    1.35xStruDL_P + SoilDL_P + 1.50x0.50xQ1_T
9.    1.35xStruDL_P + SoilDL_P + 1.50x0.50xQ2_T
10.    1.35xStruDL_P + SoilDL_P + 1.50x0.50xQ1_T + 1.50x0.50xQ2_T
11.    0.90xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ1_T
12.    0.90xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ2_T
13.    0.90xStruDL_P + 1.35xSoilDL_P + 1.50x0.50xQ1_T + 1.50x0.50xQ2_T
14.    0.90xStruDL_P + SoilDL_P + 1.50x0.50xQ1_T
15.    0.90xStruDL_P + SoilDL_P + 1.50x0.50xQ2_T
16.    0.90xStruDL_P + SoilDL_P + 1.50x0.50xQ1_T + 1.50x0.50xQ2_T
17.    0.85x1.35xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ1_T
18.    0.85x1.35xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ1_T + 1.50x0.50xQ2_T
19.    0.85x1.35xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ2_T
20.    0.85x1.35xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ2_T + 1.50x0.50xQ1_T
21.    0.85x1.35xStruDL_P + SoilDL_P + 1.50xQ1_T
22.    0.85x1.35xStruDL_P + SoilDL_P + 1.50xQ1_T + 1.50x0.50xQ2_T
23.    0.85x1.35xStruDL_P + SoilDL_P + 1.50xQ2_T
24.    0.85x1.35xStruDL_P + SoilDL_P + 1.50xQ2_T + 1.50x0.50xQ1_T
25.    0.90xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ1_T
26.    0.90xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ1_T + 1.50x0.50xQ2_T
27.    0.90xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ2_T
28.    0.90xStruDL_P + 0.90x1.35xSoilDL_P + 1.50xQ2_T + 1.50x0.50xQ1_T
29.    0.90xStruDL_P + SoilDL_P + 1.50xQ1_T
30.    0.90xStruDL_P + SoilDL_P + 1.50xQ1_T + 1.50x0.50xQ2_T
31.    0.90xStruDL_P + SoilDL_P + 1.50xQ2_T
32.    0.90xStruDL_P + SoilDL_P + 1.50xQ2_T + 1.50x0.50xQ1_T

Created by IwonaBudny on 2018/11/29 15:26
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