Load combinations

Actions of loads that act simultaneously are introduced into the analysis with the help of load combinations defined in EN 1990 Basis of Structural Design. Most of the loads are considered as permanent. Surcharges and inputted forces can be specified as variable loading. The program automatically determines the values of individual partial factors depending on whether a given load acts in favor or unfavorably.

By default the variable loadings are considered as primary. Nevertheless, the "Verification" and "Dimensions" frames allow for specifying the variable loads as secondary – such a load is then pre-multiplied by the corresponding coefficient reducing its magnitude. Providing that all loads are considered in the basic combination as secondary the program prompts a warning and the verification is not accepted.

Four types of combinations can be specified in the frame "Setting":

Persistent and transient design situation:

where:	Gk,,j	-	characteristic value of j-th permanent loading
	γG, j	-	partial factor of j-th permanent loading
	Qk,i	-	characteristic value of secondary j-th variable loading
	Qk,1	-	characteristic value of primary variable loading
	γQ, i	-	partial factor of j-th variable loading
	ψ0	-	factor for quasi-permanent value of variable loading

Accidental design situation:

where:	Gk,,j	-	characteristic value of j-th permanent loading
	Qk,1	-	characteristic value of primary variable loading
	ψ1	-	factor for frequent value of variable loading
	ψ2	-	factor for combination value of variable loading
	Ad	-	design value of extreme loading

Seismic design situation:

where:	Gk,,j	-	characteristic value of j-th permanent loading
	Qk,i	-	characteristic value of secondary j-th variable loading
	ψ2,i	-	factor for quasi-permanent value of variable loading
	AEd	-	design value of seismic loading

Load partial factors and combination coefficients are introduced in the "Partial factors" dialog window.

Input of secondary loads