Analyis of Facade 4

[nikkuppi]

Hi,

I came across an interesting structure (please see attached figure)which need to be analyzed. I am sure that it is very simple for you guys but bit confusing for me as beginner in this field.
Please support with some sample calculation.

Thanks and Regards
Nidhin

 

[klaus.]

why not leave it to a structural engineer ?
As a structural engineer I will not design an Airplane as you do it

 

[bridgebuster]

If you get a copy of Statics and Dynamics by Beer and Johnson, there are several examples similar to yours.

 

[nikkuppi]

@ Klaus

Did I anywhere mention that I am designing an Aeroplane like this! I believe this platform is for serious Engineers!

@bridgebuster

Thank you very much.

Regards
Nidhin

 

[r13]

If the truss continues and was supported at the other end, you can assume the upper end of the column is supported as well, and run a calculation on a simply supported beam with all loads shown. I thing the G, Q, S indicate loads from the truss (acting on this joint) in varies case. (Gravity, Earthquake, Snow, I guess)

I don't understand those small circle though (not momently connected?).

 

[JLNJ]

An 8 meter cantilevered canopy is a serious structure which if not designed properly can fall and kill someone, so we must start with the statement, "Do not ask random people on the internet how to design such a structure. Hire a structural engineer."

If this is just for fun and your own edification, it should be a simple matter of statics. The small circles indicated the pinned ends of the members so there are only forces (i.e. no moments) at the connections. The canopy hanger is in tension (use the trigonometry you learned in school) and the canopy beam is primarily in compression with some flexure from the span. Apply the resultants of the tension and compression forces to the column and solve for the flexure in the column. The column design is a bit more complicated as you need to combine the axial forces from the roof with the reactions from the canopy. Other combinations will include wind and earthquake loading.

If there is snow, the drift on the canopy may be tremendous. If the canopy is made of very light material, there might be net uplift on the canopy due to wind. These things need to be thought through and investigated.

The most important items might be the connections of the canopy hanger tension member to the column and to the canopy beam. If a connection fails, the result is terrible!

 

[JAE]

Well I, for one, would not offer "sample calculations" for someone posting here for a structure that large who apparently can't do the analysis themselves.
I have too much respect for the engineering profession.

This sort of structure requires more than a sample calculation so we'd be doing you a disservice by offering you a sample.
You need to find someone to mentor you on this, walk you through it and check your work....you know....typical professional engineering practice.

 

[BridgeSmith]

Getting the the forces and moments is all statics - sum of the moments equals zero. Solve the trusses. The linearly varying load may require looking up a formula (superposition of a uniform and triangular load is probably the easiest).

After that, it's stresses due to the forces and moments, member capacities, and safety factors. That's where the structural engineering begins, and likely beyond the scope of what can be responsibly explained on an internet forum.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[glass99]

This doesn't seem like a serious question. It feels like a kid asking the forum to do their homework for them.

 

[r13]

This is not a cantilever structure (bottom pinned). The drawing is part of a complete design, with truss as top member. I think the OP wanted to add canopy like structure, but don't know how to handle it though. We don't need to work it out, but shall provide kind advices, if we can.

 

[dhengr]

“We don't need to work it out, but shall provide kind advices, if we can,” per Retired13, 23DEC19, 21:42. With about 50% of the OP’s these days, that’s a little like telling someone who wants to play with dynamite, a little bit about explosives, they go boom, but not very much, just because some jerk is willing to pay him a little to play with dynamite, irrespective of sufficient knowledge and experience, or the final outcome. Half of the questions these days are…, give me a set of calcs. which I can copy and plug my numbers into, assuming I know which numbers to use; give me a spreadsheet or software, even if I don’t know how to model the structure; tell me which code paragraph blesses what I want to do and what it means, or why there isn’t an explicit para./sec. for same; no need for any engineering knowledge, it’s just number juggling anyway, right? Hell, most of these people need to take a first course in Engineering Mechanics and Strength of Materials, let alone a few courses in Structural Analysis, if they want to pretend to be an engineer, besmirching our profession. The E-Tips site should not be the go-to place for free engineering, when the OP’er. doesn’t know enough about engineering to ask a meaningful question, without sufficient engineering design info. to generate a meaningful discussion.

 

[r13]

Note, the OP is an engineer too, but civil-structural.

The advice include " you shall talk to/see a structural engineer...", which he thought Eng-Tips has a bunch, but forgot there is no free lunch.

 

[bridgebuster]

Let's give the OP a break; it's Christmas. How about a little good will?

I got a different take from the original post. It seemed to me he just wanted to know how to design this. Who hasn't asked a similar question? Early in my career if I wanted to know something, I'd ask one of the older guys - 40+ years back all my coworkers were guys. They'd open a binder, pull out a calculation, tell me to make a copy, and then explain it. I do the same with the younger people in my office.


He's been a member for 8 years

Happy Chanukah & Merry Christmas everyone.

 

[rb1957]

yeah, no free lunches here !

if this is work, then either
1) figure what you can out. go back to your books and see what you remember. then/or

2) go back to your supervisor and say "I don't know where to begin". This is not a silly question … a Huge part of our experience is how to apply simple textbook solutions to the real world. Learning from us is not (IMO) a good path. Kidding your supervisor (based on our suggestions) is not a good path.

To help you, read up on free body diagram, then ask yourself "what would I want to include in my free body ?" (which structural elements).

There are many things in your sketch that aren't really clear what they mean (to me at least).

another day in paradise, or is paradise one day closer ?

 

[dhengr]

I’m all for helping young engineers learn the ropes, we all came up this very same way. But, after eight years of claiming to be an Aerospace engineer he/she should have a better handle on a simple problem like this, at least from the statics standpoint, or maybe they shouldn’t be implying that they are actually involved in designing them. The latter scares the hell out of me, and we should not be fostering this. Rb1957 has it about right, he/she shouldn’t be b.s’ing. their boss into thinking our answers are their own answers, and, E-Tips make this way to easy. They should be going to their boss with these questions, so the boss knows what they know and what they don’t know, and can guide them accordingly. This shouldn’t be an embarrassing question to the boss, unless they’ve been instructed on the same problem several times before, and still don’t get it. The best mentoring is from someone right there, who can look at the same plans, specs., details, etc., and draw sketches and pose questions, etc., and see his lack of understanding at any point in the process. There must be that trust between he and his boss to foster his learning process. Over the years, I have had a number of drafters who I would let take some engineering design processes to some level because they were sharp enough and wanted to learn how. We had worked out this trust level to some point, and I had come to trust them more than some engineers we worked with. The drafter was actually a better engineer than the guy who was actually entitled to call himself an engineer. And, today we have gone to the extreme of allowing anyone to be called an engineer, even if they couldn’t engineer their way out of a paper bag which was open at both ends. Again, we shouldn’t foster this if we care about our profession.

 

[r13]

Only a few notes here.

1) Assume "Q" indicates vertical component of earthquake load, where is the horizontal shear force (not on the drawing)?
2) I assume the uniform loads shown are due to wind. Where is the case that causing uplift on the canopy?
3) Upon solving the forces on hand, there should be a kick back/drag force on the truss level, how are you going to handle that without knowing the framing of the other half. Note, without a moment connection, or bracing, this structure is unstable. Once fixity is introduced, the entire picture might change.

So, please explain your project further, and provide complete information to draw on meaningful suggestions.

 

[r13]

Nothing personal, please.

 

[bridgebuster]

I agree with retired13. Keep in mind, 618 stars is nothing to sneeze at.

 

[Klitor]

Retired13, Q is usual designation for imposed/service load in Europe (since HEA profile is used Im guessing its mainland europe assignement).

 

[r13]

Klitor,

Thanks for the info. I think this is an airport hanger. But OP says nothing, I don't know.