Eurocode Load Combinations

[Tea Rochlitz]

TheEurocodes are a set of standards for how structural design should be conducted within the European Union. EN 1990:2002 (ECO) sets out the basis of structural design whereas EN 1991 (EC1) specifies the actions on structures. In conjunction, these two documents provide a methodology for the combination of actions (load combinations) for limit states design. In general terms, limit states are the conditions that result in the building ceasing to meet its function that it was designed for.

Limit states are categorized as being an ultimate limit state (ULS) or serviceability limit state (SLS). ULS is concerned with the safety of people and/or safety of structure (e.g. capacity, overturning, sliding, fracture). SLS is concerned with inhibited intended use, the comfort of people, and appearance of construction works (e.g. cracking, deformation).

1) Is there a way of getting a more detailed description of what these load patterns are? Do they include the axle forces etc specified in the different load cases in Eurocode 1991-2:2003? Do they include the idea of one lane of the bridge being fully loaded, but the other half not (as this can change where max stresses or moments occur)?

2) When you produce calculations from these loadings, such as 'deflection' or 'stress' etc, is the data calculated for each beam the worst case out of all load combinations for that particular beam? I.e. is that the maximum possible deflection or maximum possible stress that beam will experience according to Eurocode loadings, out of all possible combinations?

Is there a way of adding this to the model so when the 'Eurocode combinations' are ran, it includes this extra weight? Or do I need to model this as a plate and add a custom material with the properties of the asphalt, so it is automatically included in the 'self-weight' load case?

It depends on how you created this load. No, if you created only one load for the whole bridge deck. To get what you expect you must create separate loads each one in each half of the bridge, then when generating combinations with these loads use operator or (incl)

Hello,

I am working to Euro code. I am interested to know what RSA does with the factors for characteristic, frequent and quasi permanent load cases - the factors which vary dependent on the category of the live load. Do I have to apply these factors manually or does RSA apply them internally?

I have set up several SLS loadcases and ascribed them to SLS:CHR and SLS:QPR all with 1.0 load factors. When I go to RC slab design do I add all of the SLS load combinations to the SLS list? Will RSA then automatically choose the correct combination to check deflection then creep? I believe that SLS:QPR should be used in the creep calculation, but I may be wrong.

Thank you for any replies.

Regards

Cmcc

I am working to Euro code. I am interested to know what RSA does with the factors for characteristic, frequent and quasi permanent load cases - the factors which vary dependent on the category of the live load. Do I have to apply these factors manually or does RSA apply them internally?

Hi,

I spent few hours exploring load cases and load combination in Karamba. I read through manual and I could not understand it. I am just wondering if anybody could point me to a video or an example about karamba with load combination explanation. Appreciate your help.

Thanks

Hi @Manoochehr_a,

there is no inbuilt method to create load combinations. You will need to set it up in your scipt using manual multiplication methods to be able to calculate Load combinations. We are hoping to include this in future releases.

best,

Matthew

In the ModelView component, you can select which loadcase you want to visualise, this will update the load values in the Rhino viewport. When you input a value in the R-Factors, this only multiplies the loads for the ModelView/BeamView Output.

Results in the Utilization Component are not affected, as these are coming directly from the Analysis and any changes to the ModelView do not affect the results. You can however select a LoadCase to extract the Utilization values from, otherwise all loadcases are displayed.

@karamba3d - I was wondering if there is any future updates planned for the LoadCombination component? It would be very hand to define a set of load combination cases through a set of text rules referring to defined load cases rather than manually define each combination.

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