Carport Design

[Reed D]

Hello,
I am currently designing a carport for a friend. I don’t have much experience in structural design as most of my experience is in roadway modeling and construction. I just started studying to take the SE exam (I have my PE in Civil) so when asked if I can design the carport, I figured it will be a good practice. Unfortunately, The more I am digging into this the more I am realizing that I underestimated the complexity of this design

The dimensions of the carport LxWxH = 80’x24’x9’. The carport is open on four sides. I am utilizing ASCE7-10, AISC 14th and IBC2015.

I started with ASCE Sec 27.4.3 (monoslope) for the wind load, IBC table 1607.1 for live load (20 psf) and the dead loads of the materials itself. Then I need to figure the required strength from IBC Sec 1605.2.1 (Load Combination Using Strength Design). Once I figure the required strength I would need to figure the size and locations of the HSS’s (AISC Table 4-3 or table 4-4).

Is this the correct approach? Are there any other loads that I need to account for? Does anyone have a design example for similar carport that can share with me?

Any help would be greatly appreciated.

 

[r13]

What is the roof made of? Snow in your area? Potential for ponding (on roof) may need to be investigated.

 

[dik]

Can you outline the general construction intended? Foundation type or stiffened slab, soils, frost heave if possible? Post and beam? any lateral bracing? attachment to existing building? Roof construction? etc.?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Reed D]

Thank you for the quick responses. The intent is to build a car shade roof similar to the ones in any parking lot or apartment complexes. The roof will be made of corrugated foam polycarbonate sheet or any similar cheap material (any suggestions for inexpensive sheet material?). The site location is Phoenix Arizona so I don't think there is a need for snow design. I am thinking to make the roof flat or with 2% slope which is the case for most of roofs that I have seen around the city.
As far as the foundation, I am thinking about 3'x3'x3.5' concrete,(4) #4's VERT 1 EA corner,#3 TIES @ 16"OC, and (2)-#4 x 1'-6" horizontal. I did uplift check on the footing using soil friction 100 and normal concrete weight and it seems ok.
There is no concrete slab. The structure will be built on dirt. No attachment to any other building, the structure will be standing on it's own. My understanding is the post size will be picked based on the load combinations and the tributary area of each column, am I correct?

 

[skeletron]

From observational experience, these structures have frequently been poorly designed/constructed. Here are details that always get overlooked:

1) Put some bar and cover in your slab.
2) Use proper footings down to frost depth (at least). Make sure they have bar in them. Don't use the deck blocks you get at a hardware store.
3) Support the posts off the ground. Build up a pilaster or curb off the footing, at least 6-8". Use a proper post base that has a standoff.
4) Trusses or rafters, which way do you go? Either way, put tie down anchors and have a continuous beam line.

As for the attachment to the structure and the rest of the details...those are all project specific.

 

[r13]

I didn't see you've mentioned roof beams, purlins, how the roof panels are to be attached to? Yes, in general, the post should be designed for the tributary weight and wind. skeletron made good suggestion on bringing the post above ground. The raised pedestal can prevent water, and incidental crash.

 

[JLNJ]

2000 square feet? That’s no joke.

It sounds like you need to work under someone who can be in responsible charge of this project, train you a little bit, seal the drawing, and be liable for the work.

 

[Reed D]

Thank you all for your input.

 

[1503-44]

What's the column location plan look like?
Span dimension is the 24' direction, no?

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[Reed D]

7.0. Here is the columns layout that I am thinking about. See attached.

 

[Reed D]

The roof dimensions are 74' x 27'.

 

[robyengIT]

I have some doubts about the central spans : if you park 3 cars I think you can have problem opening the door to get-in/out. But, of course it depends from the number of cars to be parked

 

[1503-44]

I wasn't expecting that layout. Interior columns? Framing carries all loads to cantilevers? Ssince you are using steel, not wood, I would have gone for more clear spans.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[robyengIT]

Agree with 7.0 (petroleum). Something like this but also mirrored

 

[1503-44]

Yeah. Unless you are trying to make an architectural statement, do it like that.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[IRstuff]

Are there supposed to be two cars parked in the 27' direction and 8 in the 74' direction? If so, from a user's perspective, the column placements appear to be awkward because it puts the columns close, or past, the front door hinges of the cars parked nose in.

Also, 27' seems a bit tight for 3 cars; OK for driving down the street, but tight if someone parks a bit too close to the line. Recommended widths are usually 10' per stall.



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[r13]

You can make small change to robyeng's suggestion, change it a T shade, if there is adequate space for the cars to back out.