Manager Says Keep the Restraints — I Think They’re Unnecessary. Who’s Right?

[ALphaSpace]

I’m working on a project where the architect has asked us to revisit the column and beam arrangement supporting an internal staircase. Image 1 shows the current set-up and image 2 is what i have said we can achieve:

• The column is an SHS 200x200x16, total height 10.8m to roof.
• It supports only a steel stair, no slabs or significant floor structure
• Axial load ≈ 150kN
• The column is currently laterally restrained at 3.6m and 7.2m, and again at roof level

The column sits in a 3-storey atrium space within a school, and the architect is concerned about the risk of pupils climbing on the restraint beams from the stairs. They have asked for these beams to be removed.

To accommodate this, I proposed that the column be cut back and terminated at Level 2 half landing (7.2m), which is where the stair ties in and is the final level it needs support. I checked the column assuming it’s unrestrained in the other axis, using buckling length factor of 2.0. The utilization came out at just 0.38, well within capacity.

I told the architect that, the restraints could be removed and the column could stop at Level 2 half landing.

However, my manager has now taken the opposite view and insists that the column must be restrained every 3.6m and extend up to the roof, regardless of the actual structural demand. He has already communicated this to the wider design team and has asked me to go back and tell them that the restraint beams are required, essentially reversing what I previously said.

While I initially agreed to do so, the more I think about it, the more uncomfortable I am. From a structural point of view, I don’t believe the restraints are necessary, and my calculations support that which i have shown my manager. It feels wrong to go back and push for a detail that I don’t believe is justified, particularly when it’s been requested to be removed for genuine safety reasons.

I would appreciate any thoughts? Opinions?

 

[Ron247]

Just a preliminary look, but why terminate the column before it hits the roof? It looks like you can get rid of the horizontal beam braces without turning the entire thing into a double-cantilever (arm is a cantilever and column is a cantilever). How bouncy would this thing be if the column is not stabilized at the top?

I am pretty sure some student would climb on it, and I am just as sure the stairway will load-up fully with students more than 1 time in its life. The design load for a stair does not take into account the intelligence of the occupants. If it is bouncy, I also bet the students will try to amplify the movement.

 

[3DDave]

It looks like the over-restraint costs about 0.02% of what the remainder of the building costs.

It offers future use to hang lights and banners or some other decoration.

Is this a budget problem?

 

[dik]

When you get into practice, you will find that you would retain the restraints for legal reasons, even if not necessary. If an owner/client wants you to do something that has no negative effect if it was removed... it stays. Should a failure occur, even for another reason, you would have no defence.

One of an engineer's main jobs is to keep your client/employer out of court.

 

[waross]

Engineering 101:
The boss is not always right but he's always the boss.
But do get a memo or something in writing.
Or send a Memo;
"This is to confirm our conversation of the 3rd of April, 2025. etc."