topic Loading combination generator - unreliable when more than 1 live load case? in Robot Structural Analysis Forum

Loading combination generator - unreliable when more than 1 live load case?

mathias_peron — Fri, 20 Nov 2020 09:56:07 GMT

Hi everybody,

It seems that when I have more than 1 live load case, the loading combination generator has trouble giving me all relevant combinations to the Eurocode. See below my example.

Case 1:

Load cases:

1 - DL

2 - LL (cat. E) - phi0 = 1.0

3 - LL (cat. H) - phi0 = 0.0

4 - Wind - phi0 = 0.6

5 - Snow - 0.7

I should have 3 types of design combinations : dominant live / dominant wind / dominant snow

But as you can see below, only the dominant live combination is proposed by the generator.

Case 2:

I have tried this again with only 1 live load case, and it seems to work. See below.

Load cases:

1 - DL

2 - LL (cat. E) - phi0 = 1.0

3 - Wind - phi0 = 0.6

4 - Snow - 0.7

This time I have the 3 types of design combinations : dominant live / dominant wind / dominant snow

It is possible that I made a mistake with the generator parameters, but I don't think so. Could someone confirm please?

PS: please find Robot files attached.

Regards,

Mathias.

@Re: Loading combination generator - unreliable when more than 1 live load case?

Simau — Fri, 20 Nov 2020 13:56:58 GMT

@mathias_peron

When you generate the combinations try this, and look if you get what you expect

Re: @Re: Loading combination generator - unreliable when more than 1 live load case?

mathias_peron — Tue, 24 Nov 2020 13:34:42 GMT

Hi Simau,

Thanks for your answer but it doesn't work. Any other idea?

Regards,

Mathias.

Re: @Re: Loading combination generator - unreliable when more than 1 live load case?

Simau — Tue, 24 Nov 2020 13:58:02 GMT

Hi @mathias_peron

In your first message you hilighted some combinations as dominante live (wind, snow).
Why do you think that these comb are dominante.
When you made a code verification, each bar or panel have its dominante combination, in an other word each comb may be dominante for a particlar element and not for another.

Re: @Re: Loading combination generator - unreliable when more than 1 live load case?

mathias_peron — Tue, 24 Nov 2020 14:16:57 GMT

Simau,

According to Eurocode 0, when there are more than one variable load we should use φ0 factors to determine different loading combinations with MAIN and ACCOMPANYING variable actions. See table below:

So if I have, lets say:

Load case 1 - Dead load

Load case 2 - Variable load 1

Load case 3 - Variable load 2

I should have loading combinations with Variable load 1 dominant (Variable load 1 MAIN and Variable load 2 ACCOMPANYING) and vice versa.

Has anyone else trouble with this?

@Artur.Kosakowski ?

Regards,

Mathias.

Re: @Re: Loading combination generator - unreliable when more than 1 live load case?

Simau — Tue, 24 Nov 2020 17:03:24 GMT

@mathias_peron

You have set LL2 as Category H. Change it to cat A for example

Re: @Re: Loading combination generator - unreliable when more than 1 live load case?

mustafahesenow — Wed, 18 Oct 2023 13:51:23 GMT