Combinator is a plug-in tool for the generation of load combinations sets based on Eurocode provisions. SAP2000 and the other CSi programs allow for the automatic generation of a limited number of design combos. There are good reasons for this. Among Eurocode users, however, the tendency seems to be for larger numbers. Combinator helps speed up the process of defining these larger numbers, while avoiding unmanageable excesses.
- Hello once again. This video focuses on load combinations. Precisely: Automatic Design Combos for use with the Eurocodes.
- The question is: how many of these design combos do we really need?
- SAP2000 and the other CSi programs allow for the automatic generation of a limited number of design combos.
- There are good reasons for this. Among Eurocode users, however, the tendency seems to be for larger numbers.
- COMBINATOR will help you speed up the process of defining these larger numbers, while avoiding unmanageable excesses. The definition is accurate and entirely under your control.
- Let’s go back to our SAP model and click COMBINATOR from the Tool menu.
- This pops up a window for parametric input. These parameters are all that’s necessary for the automatic generation of your load combinations.
- First you tell the program how each load case needs to be classified. This is done in accordance with the type of action, load and category set forth by Eurocodes 0 and 1. The notations are consistent.
- These types are slightly different from those used by SAP. They are more attuned to the Eurocodes Limit State approach. Note that the types are assigned directly to the load cases, not the load patterns.
- Now you decide what to do with Imposed loads of categories deriving from different occupancy areas. You have the option to consider these various loads as part of a single Action. That is: have them contemporaneity share the same factors. (Roof loads are excluded if there is Wind or Snow). This is the option recommended by the Eurocodes. Be wary of the other option: considering different imposed loads as autonomous may significantly affect the combinations and the results could be less conservative.
- Next you set filters: these filters allow you to exclude those load combinations that have little impact on the design results. This is fundamental in keeping under control the number of combinations. You should try out these filters and decide which set provides the number of combinations you are most comfortable with. If you check all filters and keep the imposed loads as single action, the result is the same as that generated by SAP directly.
- Finally, you decide which limit states you are going to work with. The program can generate combinations for most Ultimate and Serviceability Limit States. Precisely: Structural (STR), Seismic (QKE), Equilibrium (EQU), Geotechnical (GEO), Characteristic (CHR), Frequent (FRQ), and Quasi permanent (QP). Some of these are beyond the scope of VIS design but can nevertheless be generated for analysis purposes.
- OK
- In case of multiple instances of the same load type, you can decide whether you want the combinations to be generated in a skip load pattern, to maximize effects.
- That’s all the input that was needed needed. The program can now generate all the required load combinations…. The load combinations can be viewed here.
- We are done with Combinator. You can exit and go back to the SAP interface. You’ll see that the same combinations are now incorporated into the main program, for further refinement and analysis.
- Thank you….
If you would like to know more about VIS
Contact us on info@vis-concretedesign.com, or see our youtube channel.