Combination generator (Eurocode)

The Combination generator is accessed via the Generate... button. This automatically sets up combinations for both strength and serviceability.

Combination generator - Initial Parameters

At the start of the generator, you need to define certain parameters so that the correct combinations are created - these are described below:

Combination for design of structural members (STR)

You can chose between:

Table A1.2(B) - Eq 6.10, or
Table A1.2(B) - Eq 6.10,a&b

Eq 6.10 is always equal to or more conservative than either 6.10a or 6.10b. The most economic combination of 6.10a or b will depend on if permanent actions are greater than 4.5 times the variable actions (except for storage loads).

Include GEO combinations - Table A1.2(C) - Eq 6.10

You should check this option in order to create the GEO combinations required for foundation design.

Include Accidental combinations - Table A2.5 Eq 6.11a&b

If you have defined an accidental load type such as Snow drift you should check this option for the correct load combinations to be generated.

Note: The Combinations Generator refers to the relevant National Annex when determining the g factors to apply in the above combinations, as they may vary from the Base Eurocode values.

Include Seismic combinations - Table A2.5 Eq 6.12a&b

If you have defined seismic loads you should check this option for the correct load combinations to be generated.

Note: Temperature and settlement load case types not included in the Generator at all - these have to be added manually.

Combination generator - Combinations

The second page of the generator lists the combinations applicable (with appropriate factors) for the selections made on the first page. Any factors in bold will be multiplied by the relevant psi factors for that load case.

The type of structure chosen on the previous page affects which combinations default to being generated.

The combination names are automatically generated as per the table below:

No.	BS EN 1990 State and eqn	Type	Load combination
1	Str – 6.10	Gravity	Str ₁ - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q RI
2	“	“	Str ₂ - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S
3	“	Lateral (EHF)	Str _3.n -Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q RI + EHF
4	“	“	Str _4.n - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ S + EHF
5	“	“	Str _5.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + EHF
6	“	Lateral (Wind)	Str _6.n - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ S + Ɣ _Q Ψ ₀ W + EHF
7	“	“	Str _7.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + Ɣ _Q Ψ ₀ W + EHF
8	“	“	Str _8.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S + Ɣ _Q W + EHF
9	“	Uplift	Str _9.n - Ɣ _GJ,inf D + Ɣ _Q W + EHF

1	Str – 6.10a&b	Gravity	Str ₁ - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ RI
2	“	“	Str ₂ - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S
3	“	“	Str ₃ - ξƔ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q RI
4	“	“	Str ₄ - ξƔ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S
5	“	Lateral (EHF)	Str _5.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ RI + EHF
6	“	“	Str _6.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S + EHF
7	“	“	Str _7.n - ξƔ _GJ,sup D + Ɣ _Q I + Ɣ _Q RI + EHF
8	“	“	Str _8.n - ξƔ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ S + EHF
9	“	“	Str _9.n - ξƔ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + EHF
10	“	Lateral (Wind)	Str _10.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S + Ɣ _Q Ψ ₀ W + EHF
11	“	“	Str _11.n - ξƔ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ S + Ɣ _Q Ψ ₀ W + EHF
12	“	“	Str _12.n - ξƔ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + Ɣ _Q Ψ ₀ W + EHF
13	“	“	Str _13.n - ξƔ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S + Ɣ _Q W + EHF
14	“	Uplift	Str _14.n - Ɣ _GJ,inf D + Ɣ _Q W + EHF

1	Geo - 6.10	Lateral (EHF)	Geo _1.n - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q RI + EHF
2	“	“	Geo _2.n - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ S + EHF
3	“	“	Geo _3.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + EHF
4	“	Lateral (Wind)	Geo _4.n - Ɣ _GJ,sup D + Ɣ _Q I + Ɣ _Q Ψ ₀ W + Ɣ _Q Ψ ₀ S + EHF
5	“	“	Geo _5.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q S + Ɣ _Q Ψ ₀ W + EHF
6	“	“	Geo _6.n - Ɣ _GJ,sup D + Ɣ _Q Ψ ₀ I + Ɣ _Q Ψ ₀ S + Ɣ _Q W + EHF
7	“	Uplift	Geo _7.n - Ɣ _GJ,inf D + Ɣ _Q,1 W + EHF

1	Acc 6.11	Lateral (EHF)	Acc _1.n - G + A _d + Ψ ₁ I + EHF
2	“	Lateral (Wind)	Acc _2.n - G + A _d + Ψ ₂ I + Ψ ₁ W + EHF
	Seis 6.12	Seismic	Seis _.n - G + A _Ed + Ψ ₂ RI + Ψ ₂ S + EHF
			Seis _.n - G + A _Ed + EHF

Combination Generator - Service Factors

This page indicates which combinations are to be checked for serviceability and the factors applied.

Combination Generator - Wind/EHF Directions

This page is used to select which EHF direction goes with each combination containing a specific wind load case.

All wind load cases are listed vertically, and the four EHF options (+Dir1, -Dir1, +Dir2, -Dir2) are each displayed with a factor (default 1.000).

By default (on first entry), none of the directions are set for any wind load case. You are required to set at least one for every wind load case and can set two, three or all four if you wish- these are then used when generating the combinations.

Combination Generator - EHF

The last page is used to set up the equivalent horizontal forces. You can specify EHF’s and factors in each of four directions.

For each direction selected a separate EHF combination will be generated. Any combination with wind in is automatically greyed as all the required information has already been set via the previous page.

Click Finish to see the list of generated combinations.