How are you all typically sizing wood members, specifically beams? I've used FORTE, I do some hand calculations but there always seems to be some level of uncertainty. (2) 2x10's, an LVL, maybe a flitch beam. So many options and variables and simple IRC span charts and code information usually do not apply to all the unique existing conditions in residential construction. What is the best and sure fire way? I think any decent architect should be able to handle these as opposed to sending everything to an engineer. Save that for the complicated steel stuff. Thanks
Yes - architects should be able to. The problem is that no one wants to, and so after they pass their structures exam, most architects brain dump that knowledge and focus on the interior designer stuff...
Jan 15, 18 12:02 pm ·
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senjohnblutarsky
Generally, it's faster and cheaper to sub such things to a Structural Engineer. I'm perfectly capable of doing the calcs. But, they do it every day. They're a hell of a lot faster at it than I am.
Jan 15, 18 12:39 pm ·
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BulgarBlogger
So can I; but there's a difference between people who are "Paper Architects" and people who know their shit. You'd be surprised at how many architects in NYC working on high-end residential projects don't know the slightest thing about doing a structural calculation.
Jan 15, 18 1:06 pm ·
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On the fence
Some cant even follow the load paths. Years of paying a structural engineer for something they should know has wiped it from their memory.
I do my own framing specs and calculations. I feel like it makes me a better designer for the residential projects I work on. I even do some steel calculations; it's not that scary. When a project or aspects are complicated I bring in a structural engineer, and make sure I learn something from them, to make me a better designer. Engineers may be faster (and smarter) but they regularly oversize things, so the money saved does not necessarily stay in the clients' pocket.
I made my own excel spreadsheet to do structural calculations - never used any of the software designed for that. I did them myself for the first 15 years or so of my practice, though some municipalities' officials insisted on an engineer's stamp anyway. These days my insurer doesn't want to cover architects doing their own calcs and wants there to be a structural engineer on every project.
Never even considered it was possible to do calcs yourself (on residential projects, duh), but if they are anything like commercial... can you find a product rep and have them do the calcs without going to a single-source spec? We do this all the time with, well, everything. Lighting, specialty structures, shades, whatever...
Jan 15, 18 11:23 pm ·
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joseffischer
??? asking a product rep to do structural calcs on lumber??? worrying about single-sourcing???
I mean, I guess the lumber yard is going to know most of the time what size you need based on experience, but I already know that. I don't think anybody there would give you calcs or something to show a permit office.
Jan 16, 18 12:30 am ·
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On the fence
Are you an architect archanonymous?
Jan 16, 18 10:46 am ·
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archanonymous
Yep. I wasn't really thinking of sizing dimension lumber, but engineered wood products and trusses. I've never worked on anything residential though so I'm just giving you my jaundiced commercial architect perspective. The answer is usually to have someone else do it, preferable for free!
Jan 16, 18 11:24 am ·
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On the fence
Outside of the prescriptive span tables found in the residential building codes or the WFCM manual, you should be able to use Forte which will accomplish even more. But, as an architect, you should be able to do simple calcs and understand them. Following the load path is critical and if you still can do that I would suggest Strucalc software or a similar product.
Wow so it really seems most architects are not doing these for one reason or another. If you were presented with a 10' clear span on the first floor, supporting ceiling joists and another wall on the second floor supporting its own ceiling joists. Say there are 2x8 floor joists and you want a flush condition. How are these being resolved? Seems almost embarrassing to have to ask a client for money because an engineer needs to get involved because we are not able to do it.
Jan 16, 18 8:58 am ·
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Wood Guy
You have to understand how to apply contributing load areas. Most normal situations are covered in the building codes, and most engineered lumber manufacturers have their own prescriptive specs. I don't understand the wording of your question but if you're asking how to deal with a point load on a floor system, you do a moment analysis, essentially converting it to a distributed load. Once you know the loads on the members, you find the right structural connectors from Simpson Strongtie or a competitor. If my description is confusing, you should probably stick with hiring a structural engineer.
Jan 16, 18 10:00 am ·
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JeromeS
For what you describe, I do the calcs myself. I do use the Weyerhauser/Forte also, for beams which have multiple loads considerations; floor, roof, point, cantilever, etc (often with varying trib areas)
Only time I hire an engineer for residential projects is when dealing with wind design. They can do it simpler and quicker
Jan 16, 18 10:05 am ·
·
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Sizing wood members
How are you all typically sizing wood members, specifically beams? I've used FORTE, I do some hand calculations but there always seems to be some level of uncertainty. (2) 2x10's, an LVL, maybe a flitch beam. So many options and variables and simple IRC span charts and code information usually do not apply to all the unique existing conditions in residential construction. What is the best and sure fire way? I think any decent architect should be able to handle these as opposed to sending everything to an engineer. Save that for the complicated steel stuff. Thanks
Span tables are prescribed by wood species in my Code... although I would love to use something like flitch. Sounds refreshingly different.
yes, and a split ring connector.
Yes - architects should be able to. The problem is that no one wants to, and so after they pass their structures exam, most architects brain dump that knowledge and focus on the interior designer stuff...
Generally, it's faster and cheaper to sub such things to a Structural Engineer. I'm perfectly capable of doing the calcs. But, they do it every day. They're a hell of a lot faster at it than I am.
So can I; but there's a difference between people who are "Paper Architects" and people who know their shit. You'd be surprised at how many architects in NYC working on high-end residential projects don't know the slightest thing about doing a structural calculation.
Some cant even follow the load paths. Years of paying a structural engineer for something they should know has wiped it from their memory.
I do my own framing specs and calculations. I feel like it makes me a better designer for the residential projects I work on. I even do some steel calculations; it's not that scary. When a project or aspects are complicated I bring in a structural engineer, and make sure I learn something from them, to make me a better designer. Engineers may be faster (and smarter) but they regularly oversize things, so the money saved does not necessarily stay in the clients' pocket.
I did it when I was 20 years old working for an engineer. Haven't done it since but I don't recall it being difficult.
I made my own excel spreadsheet to do structural calculations - never used any of the software designed for that. I did them myself for the first 15 years or so of my practice, though some municipalities' officials insisted on an engineer's stamp anyway. These days my insurer doesn't want to cover architects doing their own calcs and wants there to be a structural engineer on every project.
Never even considered it was possible to do calcs yourself (on residential projects, duh), but if they are anything like commercial... can you find a product rep and have them do the calcs without going to a single-source spec? We do this all the time with, well, everything. Lighting, specialty structures, shades, whatever...
??? asking a product rep to do structural calcs on lumber??? worrying about single-sourcing???
I mean, I guess the lumber yard is going to know most of the time what size you need based on experience, but I already know that. I don't think anybody there would give you calcs or something to show a permit office.
Are you an architect archanonymous?
Yep. I wasn't really thinking of sizing dimension lumber, but engineered wood products and trusses. I've never worked on anything residential though so I'm just giving you my jaundiced commercial architect perspective. The answer is usually to have someone else do it, preferable for free!
Outside of the prescriptive span tables found in the residential building codes or the WFCM manual, you should be able to use Forte which will accomplish even more. But, as an architect, you should be able to do simple calcs and understand them. Following the load path is critical and if you still can do that I would suggest Strucalc software or a similar product.
Wow so it really seems most architects are not doing these for one reason or another. If you were presented with a 10' clear span on the first floor, supporting ceiling joists and another wall on the second floor supporting its own ceiling joists. Say there are 2x8 floor joists and you want a flush condition. How are these being resolved? Seems almost embarrassing to have to ask a client for money because an engineer needs to get involved because we are not able to do it.
You have to understand how to apply contributing load areas. Most normal situations are covered in the building codes, and most engineered lumber manufacturers have their own prescriptive specs. I don't understand the wording of your question but if you're asking how to deal with a point load on a floor system, you do a moment analysis, essentially converting it to a distributed load. Once you know the loads on the members, you find the right structural connectors from Simpson Strongtie or a competitor. If my description is confusing, you should probably stick with hiring a structural engineer.
For what you describe, I do the calcs myself. I do use the Weyerhauser/Forte also, for beams which have multiple loads considerations; floor, roof, point, cantilever, etc (often with varying trib areas)
Only time I hire an engineer for residential projects is when dealing with wind design. They can do it simpler and quicker
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