Load Combinations

Last Updated on April 12th, 2024 by

All design standards are usually defining different load combinations to be applied to the finite element analysis model. At the beginning stages of verification it is important to make sure that design load combinations are properly set to meet the requirements of the code.

SDC Verifier brings to the users an interface to combine all the design loads into load combinations in a quick and convenient way.

Instead of focusing on the complete load combination (in SDC Verifier we call them Load Sets), SDC Verifier separately calculates the influences of different basic loads (named as Individual Loads in the program) on the structure. The overall response of a structure and the load effect in real life situations is retrieved by combining the outcome of these basic loads into load combinations.

SDC Verifier Calculation core:

  • Individual load – single basic load result. Can be either a Step from Ansys analysis or combination of FEM load plus Constraint in Simcenter and Femap;
  • Load Set – linear load combination. With taking into account safety factors and partial load factors;
  • Load Group – envelope set of results. Using SDC Verifier user is able to create a group of Individual Loads, Load Sets or even Group of Groups. And combinations, of course, are also possible.
Visual representation in a table of Individual Loads, Load Groups and Load Sets (Load Combinations)


Both live loads and dead loads, like Wind Load, Storm Load, Earthquake Load (Seismic Load), Snow Load, Roof Live Load, Gravity Load, or load from function, for example, Hoisting Load, Moving Load, Acceleration Load, etc. can be set as Individual Loads.

Basic loads of different types, acting on the structure at the same time, can be combined into Load Sets. In SDC Verifier Load Sets are multiplied with load factors. Safety factors, or resistance factors can be defined for every combination.

Load groups are allowing to determine a minimum, maximum and absolute values of any outputs like stresses, displacements and forces, etc for your stress design or any other evaluation. Check results like fatigue damage, strength design, buckling factors or utilization factors.

Create/Edit Multiple Load Sets (Load Combinations) in SDC Verifier

With even a little numbers of individual loads, over 1000 load combinations can be generated using partial load factors. The total calculation time remains short because the CPU usage is based on the much lower number of basic loads.

Watch the video tutorial on Load Combinations in SDC Verifier

Results of these large numbers of load combinations are organized in Load Groups. For example, the minimum or maximum stresses or maximum reaction forces at all locations and even more complicated results as fatigue life can be represented in one plot or table. A complete structural check according to any standard can now be represented with a few pictures or tables!

In conclusion, it does not matter what code or method you use, calculation core of SDC Verifier gives user an opportunity to combine the basic loads into infinite amount of load combinations and group them for a proper check.

Moreover, SDC Verifier’s Governing load and Peak finder tool will help user to determine the crucial effects and handle big amount of load combinations.

Here some examples of load combinations according to different standards.

Symbols and abbreviations for Load Combinations for EN13001

Here you can buy EN13001 standards

Symbols and abbreviationsDefinitions
ϕ1Dynamic factor acting on the mass of the crane
ϕ2Dynamic factor on hoist load when hoisting an unrestrained grounded load in regular operation
ϕ2cDynamic factor on hoist load when hoisting an unrestrained grounded load under exceptional conditions
ϕ3Dynamic factor for inertial and gravity effects by sudden release of a part of the hoist load
ϕ4Dynamic factor for loads caused by travelling on uneven surface
ϕ5Dynamic factor for loads caused by acceleration of all crane drives
ϕ6Dynamic factor for test loads
ϕ7Dynamic factor for loads due to buffer forces
ϕ9Dynamic factor for unintentional loss of hoist load
ϕL,ϕMLFactors for calculation of force in case the load or moment limiter is activated
ηWFactor for remaining hoist load in out of service condition
McMass of the crane
MhlMass of the hoist load
TsTravelling on uneven surface
AnhAcceleration: hoisting movements excluded
AmAcceleration: all movements
DDisplacements
W_inIn-service wind loads
SnSnow and ice loads
TvTemperature variations
SkSkewing
W_outOut-of-service wind loads
TestTest loads
BBuffer forces
TTilting forces
E-_stopDrive forces due to E-stop
FmDrive forces due to failure of mechanism
EExcitation of the crane support
γpPartial safety factor
Symbols and abbreviations for Load Combinations for EN13001

Loads, load combinations and partial safety factors (General)

Regular Loads

Load CombinationClause referenceDescription
A14.2.2.2Hoisting and moving loads; Accelerations of those movements only, which occur regularly with hoisting movement, are to be taken into account
A24.2.2.3Sudden release of part of the hoist load; Effects from other movements than hoisting are combined as in A1.
A34.2.2.5Load or lifting attachment suspended; With a suspended load or lifting attachment, any combination of accelerating or decelerating forces caused by any of the drives, including the hoist drive, or of their sequence during positioning movements, shall be taken into account in accordance with the intended normal operation as well as the control of the drives.
A44.2.2.4Travelling with load on an uneven surface or track, without the effects from hoisting movement
Allowable stress method
A1(ϕ1 x Mc) + (ϕ2 x Mhl) + (ϕ5 x Anh) + D
A2(ϕ1 x Mc) + (ϕ3 x Mhl) + (ϕ5 x Anh) + D
A3Mc + Mhl + (ϕ5 x Am) + D
A4(ϕ4 x Ts) + (ϕ5 x Anh) +D
Note:Overall safety factor γf=1.48, only for “Allowable stress method”
Limit State Method
A1( γp* x ϕ1 x Mc) + (1.34 x ϕ2 x Mhl) + (1.34 x ϕ5 x Anh) + (γp** x D)
A2(γp* x ϕ1 x Mc) + (1.34 x ϕ3 x Mhl) + (1.34 x ϕ5 x Anh) + (γp** x D)
A3(γp* x Mc) + (1.34 x Mhl) + (1.34 x ϕ5 x Am) + (γp** x D)
A4(1.22 x ϕ4 x Ts) + (1.34 x ϕ5 x Anh) + (γp** x D)
Note:γp* – is partial safety factors shall be taken in accordance with Table 9, with due consideration to variable factors shown in the table; γp** – partial safety factors to be applied to loads due to displacements shall be taken in accordance with 4.3.5. Resistance coefficient γm(safety factor for “Limit state method”).

Occasional loads

Load CombinationClause referenceDescription
B1 to B44.2.3.1Equivalent to A1 to A4 but with the addition of in-service wind and loads from other environmental actions taken into account;
B54.2.3.4Crane under normal operation, travelling on an uneven surface at constant speed and skewing, with in-service wind and loads from other environmental actions.
Allowable stress method
B1(ϕ1 x Mc) + (ϕ2 x Mhl) + (ϕ5 x Anh) + D + W_in + Sn +Tv
B2(ϕ1 x Mc) + (ϕ3x Mhl) + (ϕ5 x Anh) +D + W_in + Sn +Tv
B3Mc + Mhl + (ϕ5 x Am) +D + W_in + Sn +Tv
B4(ϕ4 x Ts) + (ϕ5 x Anh) +D + W_in + Sn +Tv
B5(ϕ4 x Ts) + D + W_in + Sn +Tv + Sk
Note:Overall safety factor γf=1.34, only for “Allowable stress method”
Limit State Method
B1(γp* x ϕ1 x Mc) + (1.22 x ϕ2 x Mhl) + (1.22 x ϕ5 x Anh) + (γp** x D) + (1.22 x W_in) + (1.22 x Sn) +(1.16 x Tv)
B2(γp* x ϕ1 x Mc) + (1.22 x ϕ3x Mhl) + (1.22 x ϕ5 x Anh) + (γp** x D) + (1.22 x W_in) + (1.22 x Sn) +(1.16 x Tv)
B3(γp* x Mc) + (1.22 x Mhl) + (1.22 x ϕ5 x Am) + (γp** x D) + (1.22 x W_in) + (1.22 x Sn) +(1.16 x Tv)
B4(1.16 x ϕ4 x Ts) + (1.22 x ϕ5 x Anh) + (γp** x D) + (1.22 x W_in) + (1.22 x Sn) +(1.16 x Tv)
B5(1.16 x ϕ4 x Ts) ++ (γp** x D) + (1.22 x W_in) + (1.22 x Sn) +(1.16 x Tv) + (1.16 x Sk)
Note:γp* – is partial safety factors shall be taken in accordance with Table 9, with due consideration to variable factors shown in the table; γp** – partial safety factors to be applied to loads due to displacements shall be taken in accordance with 4.3.5. Resistance coefficient γm(safety factor for “Limit state method”).

Exceptional loads

Load CombinationClause referenceDescription
C14.2.4.1Crane under in-service conditions, hoisting a grounded load at exceptional hoisting speed, applying ϕ2c, see Table 3
C24.2.4.2Crane under out-of-service conditions, including out-of-service wind and loads from other environmental actions.
C34.2.4.3Crane under test conditions; Effects from different movements are combined as relevant for the testing procedure; wind load as specified in 4.2.4.3 for test conditions.
C44.2.4.4Crane with hoist load in combination with buffer forces.
C54.2.4.5Crane with hoist load in combination with tilting forces.
C64.2.4.6Crane with hoist load in combination with loads caused by emergency cut-out. Value of factor ϕ5, shall be that relevant for the emergency cut-out situation.
C74.2.4.7
4.2.4.8		Loads due to operation of the overload protection; Loads in accordance with 4.2.4.7 and 4.2.4.8 shall be taken into account separately and where relevant. In case of crane stability only loads in accordance with 4.2.4.8 shall be taken into account.
C84.2.4.9Crane with unintentional loss of hoist load.
C94.2.4.10Crane with hoist load in combination with loads caused by failure of mechanism.
C104.2.4.11Crane with hoist load in combination with loads due to external excitation of the crane support.
C114.24.12Crane during erection, dismantling and transport.
Allowable stress method
C1(ϕ1 x Mc) + (ϕ2c x Mhl) + D
C2Mc + (ηW x Mhl) + D + Sn + Tv + W_out
C3(ϕ1 x Mc) + (ϕ5 x Anh) + D + W_in + (ϕ5 x Test)
C4Mc + Mhl + D +  (ϕ7 x B)
C5Mc + Mhl + D +  T
C6Mc + Mhl + D +  (ϕ5 x E_stop)
C7Mc + (ϕL x Mhl) + D 
C8Mc + (ϕ9 x Mhl) + D 
C9Mc +  Mhl + D + (ϕ5 x Fm)
C10Mc +  Mhl + D + E
C11Mc + D + W_in
Note:Overall safety factor γf=1.22, only for “Allowable stress method”
Limit State Method
C1(γp* x ϕ1 x Mc) + (1.1 x ϕ2c x Mhl) + (γp** x D)
C2(γp* x Mc) + (1.1 x ηW x Mhl) + (γp** x D) + (1.1 x Sn) + (1.05 x Tv) + (1.1 x W_out)
C3(γp* x ϕ1 x Mc) + (1.1 x ϕ5 x Anh) + (γp** x D) + (1.16 x W_in) + (1.1 x ϕ5 x Test)
C4(γp* x Mc) + (1.1 x Mhl) + (γp** x D) +  (1.1 x ϕ7 x B)
C5(γp* x Mc) + (1.1 x Mhl) + (γp** x D) +  (1.1 x T)
C6(γp* x Mc) + (1.1xMhl) +(γp** x D) +  (1.1 x ϕ5 x E_stop)
C7(γp* x Mc) + (1.1 x ϕL x Mhl) + (γp** x D)
C8(γp* x Mc) + (1.1 x ϕ9 x Mhl) + (γp** x D)
C9(γp* x Mc) +  (1.1x Mhl) + (γp** x D) + (1.1 x ϕ5 x γpm)
C10(γp* x Mc) +  (1.1 x Mhl) + (γp** x D) + (1.1 x E)
C11(γp* x Mc) + (γp** x D) + (1.1 x W_in)
Note:γp* – is partial safety factors shall be taken in accordance with Table 9, with due consideration to variable factors shown in the table;  γp** – partial safety factors to be applied to loads due to displacements shall be taken in accordance with 4.3.5. Resistance coefficient γm(safety factor for “Limit state method”).

Load combinations and partial safety factors for the proof of crane stability

Regular Loads

Load CombinationClause referenceDescription
A14.2.2.2Hoisting and moving loads; Accelerations of those movements only, which occur regularly with hoisting movement, are to be taken into account
A24.2.2.3Sudden release of part of the hoist load; Effects from other movements than hoisting are combined as in A1.
Allowable stress method
A1Mc + Mhl + Am + D
A2Mc + (ϕ3 x Mhl) + Am + D
Note:Overall safety factor γf=1.48, only for “Allowable stress method”
Limit State Method
A1(γp x Mc) + (1.22 x Mhl) + (1.22 x Am) + (1.1 x D)
A2(γp x Mc) + (1.22 x ϕ3 x Mhl) + (1.22 x Am) + (1.1 x D)
Note:γp – is partial safety factor of the mass of crane and shall be taken in accordance with Table 13. Resistance coefficient γm(safety factor for “Limit state method”).

Occasional Loads

Load CombinationClause referenceDescription
B14.2.3.1Equivalent to A1 to A4 but with the addition of in-service wind and loads from other environmental actions taken into account;
Allowable stress method
B1Mc + Mhl + Am + D + W_in + Sn
Note:Overall safety factor γf=1.34, only for “Allowable stress method”
Limit State Method
B1(γp x Mc) + (1.16 x Mhl) + (1.16 x Am) + (1.05 x D) + (1.16 x W_in) + (1.16 x Sn)
Note:γp – is partial safety factor of the mass of crane and shall be taken in accordance with Table 13.   Resistance coefficient γm(safety factor for “Limit state method”).

Exceptional Loads

Load CombinationClause referenceDescription
C24.2.4.2Crane under out-of-service conditions, including out-of-service wind and loads from other environmental actions.
C34.2.4.3Crane under test conditions; Effects from different movements are combined as relevant for the testing procedure; wind load as specified in 4.2.4.3 for test conditions.
C44.2.4.4Crane with hoist load in combination with buffer forces.
C54.2.4.5Crane with hoist load in combination with tilting forces.
C64.2.4.6Crane with hoist load in combination with loads caused by emergency cut-out. Value of factor ϕ5, shall be that relevant for the emergency cut-out situation.
C74.2.4.7
4.2.4.8		Loads due to operation of the overload protection; Loads in accordance with 4.2.4.7 and 4.2.4.8 shall be taken into account separately and where relevant. In case of crane stability only loads in accordance with 4.2.4.8 shall be taken into account.
C84.2.4.9Crane with unintentional loss of hoist load.
C94.2.4.10Crane with hoist load in combination with loads caused by failure of mechanism.
C104.2.4.11Crane with hoist load in combination with loads due to external excitation of the crane support.
C114.24.12Crane during erection, dismantling and transport.
Allowable stress method
C2Mc + D + W_out
C3Mc + Am + D + W_in + Test
C4Mc + Mhl* + D + B
C6Mc + Mhl + D + E_stop
C7Mc + (ϕML xMhl) + D 
C8Mc + (ϕ9 xMhl) + D 
C9Mc + Mhl + D + Fm
C10Mc + Mhl + D + E
C11Mc + D + W_in
Note:C4 Mhl* Only to be applied if unfavourable deadweight effects. Overall safety factor γf=1.22, only for “Allowable stress method”
Limit State Method
C2(γp x Mc) + (1.0 x D) + (1.1 x W_out)
C3(γp x Mc) + (1.1 x Am) + (1.0 x D) + (1.1 x W_in) + (1.1 x Test)
C4(γp x Mc) + (1.1x Mhl*) + (1.0 x D) + (1.1 x B)
C6(γp x Mc) + (1.1 x Mhl) + (1.0 x D) + (1.1 x E_stop)
C7(γp x Mc) + (1.1 x ϕML xMhl) + (1.0 x D)
C8(γp x Mc) + (1.1 x ϕ9 xMhl) + (1.0 x D)
C9(γp x Mc) + (1.1 x Mhl) + (1.0 x D) + (1.1 x Fm)
C10(γp x Mc) + (1.1 x Mhl) + (1.0 x D) + (1.1 x E)
C11(γp x Mc) + (1.0 x D) + (1.1 x W_in)
Note:C4  Mhl* Only to be applied if unfavourable deadweight effects; γp – is partial safety factor of the mass of crane and shall be taken in accordance with Table 13. Resistance coefficient γm(safety factor for “Limit state method”).

Subscribe to Newsletter

Get SDC Verifier insights, news, and updates, straight in your inbox