Residential Calculations 16

[jerseyshore]

I do a lot of residential projects and find myself approaching the calculations differently for nearly every job. For small jobs, not usually a big deal, but for the bigger ones it turns into a challenge.

I start off a bigger project thinking okay, I'm going to be organized this time and label everything neatly so that I can track loads, design posts, etc. But it's 2 days later and I am saving calcs as "Back left header kitchen long window". 40 members later and it's a mish-mosh of beams and joists and rafters that become a nightmare when I have to go back and change something.

So I'm starting a big brand new house next week and wanted to get some ideas how people normally approach these types of large projects. Hoping I can make my own system to save as much time on these PITA jobs as possible. Appreciate it.

 

[dik]

Even for small jobs, I'd label the beams or columms initially on the plan (even *.pdf plans) as B101, B102, etc for first floor beams, and B201, B202, etc for 2nd floor beams, etc. I'd then use those beam marks for my design notes... same with columns C01, etc... even my spreadsheets are set up that way... with the initial design info that stays throughout listed as variables, not as cell references... and then I'd just copy the block of design data and paste below... A sheet for simple floor beam design attached... one of many I use...

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1684560661/tips/Simple_Span_Beam_Design_fca7tu.xlsm[/url]

a more recent version...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

Haha. I could have written this post. I feel your pain.

I have a 'house design procedure' I worked up. I'll type it up and share it next time I'm at my computer. But like dik said, for beams and headers and such labeling them as B-X, H-X, C-X and so on is a good convention.

 

[Eng16080]

I have a procedure similar to dik's. For each floor plan, I'll have a layer in cad with beam and column labels, like Beam 1A, 1B, etc. for 1st floor, 2A, 2B, etc. for 2nd floor... The analysis software or spreadsheet I'm using for member design will reference these labels. I'll often also use this layer to keep track of loads coming from above the floor level and loads being transferred down.

When I first start designing a floor, I'll usually come up with a preliminary framing layout with beam and column labels as noted above, and I'll make the labels red in cad. After each member has been design, I'll change the label to white or green.

 

[jerseyshore]

I need a key plan for sure, but I kind of like the approach to do it in CAD. Especially for projects (like this one) that I will be drafting myself.

 

[phamENG]

The non-printing layer is a pretty genius idea.

I've been trying to get out of doing the drafting myself (it's about 3/4 of the time, and I can hire it out for about 1/8th of the fee...), so I may not adopt that one for myself, but something to keep in mind...

 

[phamENG]

Rough residential design procedure (can also help with formatting and organization of calcs):

Determine Loading

Dead Loads for Assemblies​

Live Loads​

Soil/Fluid Pressures for water and/or retaining walls​

Environmental (rain, snow, wind, seismic, flood​

Preliminary Lateral Analysis:

Check shear wall availability, make note of vertical load path discontinuities (T/C point load transfers to beams, headers, etc.)​

If steel frame, strong walls, or double sided shear walls are required, notify architect immediately​

Preliminary Gravity Analysis:

Layout framing plans with no annotations (but add beam tags, etc. for tracking in calcs)​

use rules of thumb to estimate beam floor and beam depths, notify architect of any potential conflicts with as-drawn floor depths​

Design Secondary (Joist/Rafter) Framing

Design Shear Walls and Diaphragms (need dead load reactions from secondary framing)

Design Primary Framing (need secondary framing reactions and shear wall chord reactions)

Design Foundations

Sketch sections and project specific detailing/connections

Write notes and/or specifications

Finalize drawings.

 

[jerseyshore]

The drafting stinks on these projects. I mean in general these big residential jobs are the worst $ per hour based on how much time we have to spend. I try to avoid them all together because they beat you down on your fees and make you feel bad for charging $10k when they can take twice as long as a much more profitable job.

 

[phamENG]

I've grown a thick skin in a short period of time. My fee is my fee. You either want me on the project or your don't. If you're just looking for someone's stamp to get you through permitting, go beat up someone else. If you believe I will add value to this project, then sign the proposal and let's get started.

I have a 4 month backlog of fees set on my terms, no negotiating.

 

[YoungGunner]

This would not help in the short term, but long term if you plan on continuing in this profession.

We have a pretty slick spreadsheet that has links for everything. The first few tabs set up the loads from snow, live, seismic, and wind, and allow you to select those different load sets through the rest of the spreadsheet. The spreadsheet itself handles 5 stories of shear walls with 15 different lateral lines and multiple options per line, 150 beams (simply supported with either or both ends cantilevered or multi-spanning with uniform loads), 20 checks for studs, 50 checks for foundation walls (simply supported), 30 checks for rafters/joists, and a check for a simple diaphragm. All points loads from beams can be "called" later in the spreadsheet, either applying to other beams or to the foundations. All of these calcs are linked to schedules in excel corresponding to the marks called out on the plan. The schedules can either be copied and pasted directly on a pdf or entered in as a data link into AutoCAD, which can automatically update. We have a word doc that has links to all those different calcs and by simply opening the word doc those reports filter and update. Our details are also auto populated in the spreadsheet depending on what beams/joists/shear walls you put in, and those details auto-filter at the end of the spreadsheet, and our AutoCAD tools will then bring in those details to our DWG.

Through all this automation we've found that even small $300 garages can be profitable because of the significant automation behind the scenes. This has taken YEARS for the company to develop and it was mostly accomplished through cheap yet innovative students. Residential work can be super profitable if you have automation for all those routine tasks. This also allows our time to be spent on the engineering aspects of the project rather than the reports.

 

[phamENG]

Residential work can be super profitable if you have automation for all those routine tasks.

This.

YoungGunner...I'm not in Utah and will never compete with you...what would it take to get a copy? (I'm kidding....unless you're willing to share)

I have one in the works - the goal is to be able to enter some basic parameters and have it automate the lateral analysis. I haven't figured out the best way to automate gravity calcs, though. I've tried software packages, etc., but none of them work as well as I'd like.

 

[dik]

I used to do a lot of stiffened slab foundation houses in rural Ontario, not the wood framing, but the foundations. I had a series of templates for rectangular, 'L' shaped, or 'T' shaped buildings and standard details and notes for them. I could 'stretch' the various elements to suit the new dimensions and with associative dimensioning, the plans were dimensionally correct, and detailed.

There was an hours work in producing a complete set of drawings, including standard notes, maybe more if I had to drive out to the country to look after a soil 'test pit' excavation. The standard drawings even had the soil profile included... Fees for these drawings were in the order of $1000, and it was easy to make money with them. For a simple house, there were three drawings to the set... there was even a drawing list included. About the only thing that changed was the Project Title.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[YoungGunner]

YoungGunner...I'm not in Utah and will never compete with you...what would it take to get a copy? (I'm kidding....unless you're willing to share)

Unfortunately it is a very proprietary spreadsheet. That is impressive you have one in the works to complete lateral analysis. While we have a lot of automation, on small jobs we are simply reduced to taking a plethora of measurements and entering them into our analysis, which will autosize most every member. Complicated structures still require a lot of thought and engineering judgement.

 

[phamENG]

Yeah, I figured as much. Certainly worth asking, though.

So I cheated a bit on mine for lateral. Since I'm in hurricane country with no real seismic activity (you can feel one distant quake every few generations), it's all wind. And the WFCM has these handy guides for simple houses, like this one: 115mph Exposure C

So I validated a couple of them, then entered a bunch of their results into a spreadsheet, used some interpolation to fill in between, and then did some validation on those results. The results were acceptable to me (within a few %), so now I use that to determine MWFRS loading at each level. It's a whole lot easier than trying to do a detailed directional or even envelope calculation in the background.

There's still plenty of manual alignment and summing of forces, but it's coming along...slowly.

 

[XR250]

Through all this automation we've found that even small $300 garages can be profitable because of the significant automation behind the scenes

$300 and Garage should never be used in the same sentence!

 

[phamENG]

Especially since construction costs for 3 car garages pushed up well over $200k in my area a year or two ago. Say what you will about basing a fee on construction costs, but 0.12% is just laughable.

 

[kissymoose]

I label the members on the plans. In CAD you can put the labels on a no plot layer, in Revit, which I've been preferring, I just have a text type that is big and red that is hidden on the plan, so you just select show hidden items whenever you want see them.

Then, my spreadsheets are setup so each member has one line in excel. There's a beam table, footing table, column table, and wall bracing table, and each member gets a new row in the corresponding table.

 

[DoubleStud]

I have a calculation autocad file where I XREF every floor 200 ft apart. I choose 200 ft because for sure it is big enough for any house I do. To help track load, I have a block with 4 circles that are 200 ft apart. It is a guide so if I move the circle, it moves it on all floor. I can do several circles if I want. I color coded by layers (whether the load will transfer down or not) and reference the beam # for calc.

 

[phamENG]

What I'd love is for Enercalc to hurry up and expand their "Enercalc for Revit" tool into wood members, columns, and foundations.

It seems odd to me that they didn't start with wood. After all, when I'm doing a steel framed building I'm in RISA - using Enercalc for anything more than assisting with wind analysis or something doesn't even cross my mind. But smaller projects and wood buildings...that's the ideal use for Enercalc for me. But perhaps I don't 'fit the mold'.

 

[Aesur]

$300 and Garage should never be used in the same sentence!

I'm with XR250 here, I wouldn't touch a garage for less than 1500 and that is for the most basic 2 car simple garage. Drafting alone will cost you over 300. I really wish more peopled valued their knowledge instead of providing a disservice for our industry driving prices down.