Steel Connection Design Report - Weakest Component

[Anonymous]

Hi,

I've modelled a simple shed structure as shown in the snap.

I am trying to design the structural steel connections.

The reports for all the connections says "connection confirms to the code".

However, for the "Fixed Column Base" and "Frame knee" connections, I get a statement at the end of the report with the heading "Weakest Component".

For "Fixed Column Base" - Weakest component: FOUNDATION - CONCRETE SPLITTING

For "Frame Knee" - Weakest component: COLUMN WEB PANEL - SHEAR

Attaching a sample design report (Column-Base) exported from Robot.

Is this just a warning? Or something that I should worry about?

Do I need to change something in the structure?

P.S:  

1. "Beam-Column (web)" connection doesn't show the "Weakest component".

2. I am new to Robot and am a learner still 🙂

[teixeiranh]

It is a warning and you should take it into account.

A steel connection should have a ductile mode of failure.

You should avoid having you "weakest component" associated with a brittle mode of failure. 

For example, if you have a Fin Plate connection resisting shear your "weakest component" should not be the bolts, but the plate. 

With this being said, you should, of course, always have a ratio less than 1. Ratios less than 1 and ductile connections, that is your objective.  

[Anonymous]

Hi Teixeiranh,

Thanks for the prompt response.

However, If there is a brittle failure, then I should see in report messages like "not OK" or "Connection does not conform to code".

Right?

Moreover, in all the connections in my structure the ratio is less than 1 (hence "OK").; but the statement about "Weakest component" is regarding concrete splitting in all the cases.

[Artur.Kosakowski · Accepted solution]

Hi @Anonymous

It is just the information which verification check gives the highest ratio. As long as all of them are below 1 the connection is OK.

If I managed to answer your question(s) press the Accept as Solution button please. This will help other users to find solution(s) much faster. Thank you.