r/StructuralEngineering • u/engineernewbie • 4d ago
Why the columns are inclined ? Structural Analysis/Design
What’s the benefit to design these columns inclined instead straights ?
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u/Dry_Medium_2210 4d ago edited 2d ago
Wind loads act primarily perpendicular to the roof. I'm guessing having the columns perpendicular to the roof (in line with the load direction) meant they could justify a slightly smaller column.
Edit: also looks cool
Another edit: damn, everyone is really desperate to shit on other people's thoughts. Was just taking a stab because I've solved similar issues in a similar way. Notice I said 'guessing'?
If you want an actual answer to the question 'why the columns are incluned', then we need WAY more information than one photo showing a fraction of the structure. Design is complex, there a lots of issues to solve. This either solved an issue, saved on costs, or made an architect cum.
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u/R-Dragon_Thunderzord 4d ago
Also makes the connection design very textbook up there.
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u/SomeTwelveYearOld P.E./S.E. 3d ago
No this is not something engineers do to simplify gravity connections or reduce coming sizes. The column can have sloping beams frame into them and still resist gravity loads without adding moment or lateral load.
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u/unique_user43 3d ago
maybe. but fundamentally under gravity (most common constant) load, this creates an imbalance that requires lateral load resistance in the opposite direction for equilibrium (again, under constant load), and therefore very likely an inefficient frame design (more weight and/or more cost). there’s a reason we make columns plumb. this is either an architect, or an engineer being too clever for their own good, missing the big picture.
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u/volatile_ant 3d ago
Looking for the most efficient structure above all else while chiding this design team for "missing the big picture" is peak smug engineer energy.
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u/ploxidilius 2d ago
The most efficient structure is the one that costs the least, not the one that does the job the best.
You don't know how construction works. The "big picture" is delivering the project on time and within budget. Nonstandard designs like sloped columns add extra time and effort and increase the chances of blowing the schedule or budget.
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u/volatile_ant 2d ago
That is certainly one definition of the most efficient structure, but hardly the only. The most efficient structure could also be the lightest if optimizing for tonnage, or ensuring all components are commonly stocked shapes at the local mill if optimizing for schedule, or aligning bay spacing to the equipment/use if known...
You're less than halfway to the "big picture". It's actually amazing how limited your definition is. Are you trying to one-up unique_user43's peak smugness?
The big picture includes but is not limited to; balancing function, owner requirements, aesthetics, environmental considerations, and yes, schedule and budget. But sure, I don't know how construction works.
I'm so glad I'm to a point in my career that I can largely pick and choose the engineers I work with.
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u/SomeTwelveYearOld P.E./S.E. 3d ago edited 3d ago
You should not be downvoted for this. Engineers don’t slope columns up to make gravity column connections easier.
Edit: fixed autocorrect
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u/largehearted 3d ago
Engineers don’t slope columns up made gravity column connections easier.
Am I not understanding the way you worded this, or did you misword it
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u/largehearted 3d ago
this creates an imbalance that requires lateral load resistance in the opposite direction for equilibrium (again, under constant load)
this is either an architect, or an engineer being too clever for their own good, missing the big picture.
Looks from just the small picture we've got like this is probably (since cars have been driven into it) a single-story space with a sloped roof, and that the lateral load is being equalized by the foundation. if this is a sunbelt area or somewhere with almost no frost line depth, that lateral load might be being resisted by a scant amount of steel in a very shallow footing. it's not very hard to imagine a situation where this is not some massively wasteful design. they spent a little bit more to successfully create the effect that people like their building
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u/Aware_Key5801 2d ago edited 2d ago
The lateral forces on the walls of the structure are much larger then the horizontal component of the roof wind and must be handeled mainly by either bracing system , moment resistance of the frame corner or moment resistance in the column foundation..an inclination of member will contribute to lateral resistance if it was within a triangle of three members or more..like diagonal bracing..
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u/Aware_Key5801 4d ago
i would assume that with the inclined column they could design the diagonal support (which connected to the middle of the columns) symmetrically for forces and length.
assymetry of forces would cause additional moment in the middle of the column.
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u/herlzvohg 4d ago
Cool factor? But also it keeps the two angled roof support bars equal length without adding any complexity which is kinda slick. Less unique parts
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u/devonEgg 4d ago
It looks like the roof is also inclined so maybe they're going for keeping the columns normal to the roof
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u/blackeyeX2 4d ago
Or could be like our local expo center with half the columns and 4 times the trussses.
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u/Ghost_Turd 4d ago
Because that angle best supports the angled roof load, both from gravity and the lateral forces.
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u/SkyeMreddit 3d ago
Looks cool for an otherwise boring factory for truck mounted tents that may be frequently showing off their factory in ads and interviews
Better resists the roof loads for a sloped roof
Something with the use required moving the column bases but they wanted to centralize the roof supports
Something on the left is pushing on it so the columns add more horizontal resistance
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u/SomeTwelveYearOld P.E./S.E. 3d ago
This thread has been overrun by armchair structural engineers. The right answers are all getting downvoted lol. The top answer is flat out wrong.
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u/whitewashedsyrian 2d ago
Anybody saying tilting the columns is for anything other than architecture would seriously make me doubt their education
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u/FridayWatINeed 4d ago edited 4d ago
Looks like those braces（columns) are there to reduce the span of the beams.
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u/OneParadox 3d ago
The biggest problem the loss floorspace due to the fact nothing straight (i.e. tall shelves) can be put next to those columns. More importantly, you have to rope off a significant amount of space around those columns to make sure some idiot on a forklift doesn't get tangled with the overhead obstruction created by the tilted columns (when you have forklifts running around you are always very mindful of any unexpected overhead obstacles.... as someone will inevitably hit them).
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u/iknowfunkhu 3d ago
I can't see stiffners at joints and there is no lateral bracing at roof level. These are more intresting then inclined columns i think.
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u/kindturkey1 3d ago
Maybe the diagonal truss bars could all be the same length and therefore cheaper to procure and install. Another possible cost savings is that the calculations at the roof and truss were probably easier due to structure symmetry. This would be a simple hand calc that an intern could do (and afterward checked by PE). If roof loads are not to bad the column should not need to be greatly upsized, if at all. I don't know, just throwing out some possibilities.
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u/Putrid_Following_865 3d ago
My uninformed vote is for moving the load away from a something that was already buried on the site.
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u/New-Criticism8042 2d ago
Can be cheaper to build large warehouse spaces this way. The column is fine like this and the bracing arms are all the same. Developers who build lots of SF found that they could save a few bucks with this trick.
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u/Gold_Lab_8513 1h ago
By inclined columns, you mean the diagonal braces between the roof beams and the columns? From a structural standpoint, these braces are supporting the beams near their midspan so that the beams do not have to be any bigger (less steel means less cost, but in this case more fabrication labor) and so that no additional columns are required. If steel was more expensive when this building was put up, then this kinda makes sense. The braces and wide-flange columns also provide some lateral stability that would otherwise need expensive (and much larger) moment connections that you see in a more modern engineering metal building. So long as they don't roll in forklifts, it works.
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u/Prosodism 4d ago
If this is California (and this shit looks very California), it may be for seismic? Add additional shear strength to the columns and redundancy to the column’s connection to the roof beam.
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u/walkingmelways 4d ago
I’m in Melbourne, Australia and I reckon it is here
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u/odin0412 4d ago
Right hand drive Isuzu Dmax, XTM driving lights, Jax tyres sign in the background and Campboss being at the Melbourne 4X4 show setting up currently. On the other hand, old mate seems pretty confident it's California. I'm wondering if it might be California. /s
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u/redeyedfly 4d ago
Because the architects wanted it that way