Civil Engineering Calculations, Formulas and Site Layout

[SeaMac]

I have searched the forum and realize there isn't one thread/place where all this information is provided. I think it would be useful for the younger generation and seasoned veterans as well to have a single reference source for such matters as Civil Engineering Calculations, Formulas and Site Layout Techniques.

Your posts could include shortcuts, diagrams, links, formulas etc. This gives all of us much needed information without having to search the earth to find it. If anyone knows of a decent Android or iOS app for smartphones, that information would be very valuable since we all seem to be moving in that direction.


An example:

Calculating cubic yards of fill; Length x Width x Height or Depth / 27 = cubic yards, 20'x30'x6" would be 20x30x.5=300 cubic feet divided by 27=11.11 cubic yards.

Where (L)ength times (W)idth times (H)eight provides cubic feet you then divide the sum by 27 to obtain cubic yards.

There are swell and shrinkage matters to consider for different types of material which also need to be included in the calculations to obtain the most accurate number.

As we all are aware, dirt is not always cheap and it is the best practice to purchase the correct amount, not too much and definitely, not enough.

So, you get my drift. There are long drawn-out ways to figure such things and the easy shortcuts that we use daily. If we can get them all in one place, we all benefit.

Do you know how to use a grade rod and transit?

Do you know how to establish a radius with and without a Surveyor's Radius Point (RD)?

 

[dirtmonkey]

I agree, this would be nice. I could also see a liability disaster:beatsme
I grew up in this business but have no college education. A lot of things were common sense ( to me ) but years ago I decided to learn more. I borrowed the course books from a friend ( who graduated from OU const sciences ) and things were clearer ,not to mention the piece of mind I had . No I don't have the degree but along with the experience from the field I feel better about how I do business. I love to learn more about this profession when I can , so could see where this would be helpfull to me and others. We must always do our due diligence to provide our customers with professional service. My point being , there are many ways to learn this trade and this forum has been a wealth of knowledge from GOOD people ! 15 years in this business and I still don't know it all :idontgetit

 

[SeaMac]

Could you elaborate on what you mean by this statement? I do have a college degree in construction management but not civil engineering, I can't see where calculations, formulas and site layout techniques if learned and applied correctly would lend to liability issues. We are only applying the information provided to us on civil drawings/blueprints. It's when we get it wrong is when liability could be an issue. Having said that, I am not sure what you meant.

I could also see a liability disaster

 

[Acivil]

I think he just meant if someone goes out into the workplace and misuses information from this thread causing a catastrophe financial or otherwise the misuser could try and place liability on the party who originally posted the information. That said, I think this is a cool idea and I will preface my statements by saying USE THESE STATEMENTS AT YOUR OWN RISK!!! Finding percentage of slope: (Elevation Change/By Run)X100= Percentage of Slope (100' Long Slope with 5 Feet of Slope 5/100=0.05 (or 5 hundreths... each hundreth being a percent) X100=5. Another handy rule of thumb that I like to use: 1 acre 1 foot deep (cut or fill) equals +/- 1600 CY... Actual math is 43560/27=1613.4074

 

[SeaMac]

Ha, I like your answer and think it will work, we'll just add disclaimers. However, we all must learn how to use a grade rod and transit, I believe most of us know how swing a radius too. But I understand competely, this is no longer a world without cost or consequence, disclaimers it shall be. !!FELLOW MEMBERS, READ AND USE THE FOLLOWING INFORMATION AT YOUR OWN RISK!!

I think he just meant if someone goes out into the workplace and misuses information from this thread causing a catastrophe financial or otherwise the misuser could try and place liability on the party who originally posted the information. That said, I think this is a cool idea and I will preface my statements by saying USE THESE STATEMENTS AT YOUR OWN RISK!!! Finding percentage of slope: (Elevation Change/By Run)X100= Percentage of Slope (100' Long Slope with 5 Feet of Slope 5/100=0.05 (or 5 hundreths... each hundreth being a percent) X100=5. Another handy rule of thumb that I like to use: 1 acre 1 foot deep (cut or fill) equals +/- 1600 CY... Actual math is 43560/27=1613.4074

 

[dirtmonkey]

I think he just meant if someone goes out into the workplace and misuses information from this thread causing a catastrophe financial or otherwise the misuser could try and place liability on the party who originally posted the information. That said, I think this is a cool idea and I will preface my statements by saying USE THESE STATEMENTS AT YOUR OWN RISK!!! Find

Nail on the head:exactly. C.Y.A ! :thumbsup. Don't want good people to be thrown under the bus due to that one village idiot! :duh:duh

 

[SeaMac]

Well then, we'll just have to keep a close eye out for the "village idiot". We surely don't want to find ourselves under the bus for any reason.

Nail on the head:exactly. C.Y.A ! :thumbsup. Don't want good people to be thrown under the bus due to that one village idiot! :duh:duh

 

[SeaMac]

I suppose the idea of this thread was good in theory, since no one really seems interested in adding I have to assume the application is a bust. Exactly how is it that a thread author deletes a thread? Absolutely futile!

 

[dirtmonkey]

Patience grasshopper . Give it time. Y'all have already posted things that some one WILL find helpful.

 

[CM1995]

Exactly how is it that a thread author deletes a thread? Absolutely futile!

Once posted on HEF and after the allowed user edit time, it's here forever.:cool2 We have a policy to not delete threads or posts unless there is a special circumstance.

Be patient with the replies, more will come.

On topic of the thread, I too have a degree in Building Science. I choose the management side over the civil/design side of the business and haven't regretted it. The dirt calculation and swell factors have been discussed in depth on the board in multiple threads.

As far as layout techniques here's my take on that - Engineers and surveyors get paid and paid well, to design and layout jobs. Contractors are paid and paid poorly here-lately, to construct the project. I want the surveyor to layout the job so he takes on that liability. I want the Engineer to design the job where it works, even if I could fix it in the field.

For example, I am currently negotiating the sitework for a small restaurant. Grading plan had water holding between the drive-through and an existing retainer wall. On paper, I could have gotten the water to drain around the dumpster pad but I told the owner to send it back to the civil. The result of this was the addition of 200 LF of 10" ADS and two catch basins...

Now I could have told the owner that I could take care of it but what if by some unforeseen circumstance I couldn't, the parking lot was in and the water wasn't draining? It would be my arse inside the fryer....ointhead

Now I'll get off my :soapbox on the topic of liability and see what kind of tricks I can learn.

 

[blademan150]

Maybe , just maybe the others think like I do, that if a knot head like me knows something everyone else does too. That being said from day one when I started checking grade for my Dad in the early 60's I've carried a peep sight (what others called a hand level) til the day I retired, it was invaluable for spot checking grades. Also how we V'd off stakes to offset them out of the way or if I had to bury something and needed to find it later on. These are things that are so out of date they get laughed at...........but they work, now the jobs are pretty much left to lasers and GPS......

 

[dirtmonkey]

Maybe , just maybe the others think like I do, that if a knot head like me knows something everyone else does too. That being said from day one when I started checking grade for my Dad in the early 60's I've carried a peep sight (what others called a hand level) til the day I retired, it was invaluable for spot checking grades. Also how we V'd off stakes to offset them out of the way or if I had to bury something and needed to find it later on. These are things that are so out of date they get laughed at...........but they work, now the jobs are pretty much left to lasers and GPS......

Lol! That sounds like my child hood ! I still carry a hand level and old David White transit with me, along side the laser. Funny thing, the transit never needs batteries Never had a strobe light screw with it either! :Banghead

 

[CM1995]

I have a demo formula that works pretty well for residential and light commercial type structures.

Basically it's this:



I copied from my Excel spreadsheet and posted it here, sorry for the small pic I am still figuring out how to use my Mac. If you set the cells up to automatically calculate, it makes producing an estimate easy. The "Factor" in the calculation of how many cans needed pertains to the different things you run across doing this type of demo like household contents, excess brick or stone, etc. One can plug in the can rate, equipment rate and hours, overhead and profit to determine a cost. You can also adjust the profit and overhead percentages to your rates.

 

[TrentNz]

I've gotten pretty good at estimating how many loads to take out etc just by looking at it, i usually get right within 1-3 loads

 

[SeaMac]

Good,

Glad to see there's finally some interest in this thread and topic. I am not wanting to relieve Civil Engineers and Surveyors of their responsibilities but there are those times when we do work that we need to know basic techniques. That was my intent with this thread, one place to find good info so we don't look like fools when we're asked questions. I am a firm believer in a grade rod and transit, I know how to swing a radius with or without an RD, I wish I could find a way to demonstrate some techniques in here but I don't think HEF and AutoCad are compatible.

Having said this, let's keep it going and keep the tips coming...

 

[CM1995]

May be old school but this is how I grade for curb and gutter:

Usually the surveyors lay out 4' off sets with grade hubs. All you need is a wooden folding engineers rule and a 4' level - I have graded a few miles of curb and gutter this way. Set one end of the level on the hub, get it level of course and use the engineers rule to determine the amount of cut or fill. As conditions change on site, you often have to switch which side you are measuring to - if the hub is lower than the grade place the level on the dirt and measure to the hub. It works quicker with a grade checker but I have done it checking my on grade as I go.

I usually request the surveyors to give off sets and hubs 20'-25' on center. Also double check with the surveyor which sub-grade he lays out to - curb or asphalt. Had this issue on the last bit of street we put in. It was a short street, only 250' long. The surveyor laid out sub-grade to curb sub-grade, which was fine by me as our part of the contract only included grading. The curb was 12" tall, 6" at the face of asphalt and the paving section was 11", so once curb was slip formed I would need to cut 5" out to asphalt sub-grade.

The curbing guy thought the surveyor laid out the asphalt sub-grade, so he begins to add back 5" of dirt and compacting it under where the curb is going. After about an hour or so of finger pointing and another hour of the curb guy removing the dirt he put in, the curb was slipped. The confusion was between the surveyor and the curb guy - it wasn't my problem since the developer was handling the curb and paving directly in order to save money.:cool2

 

[blademan150]

We did it about the same only we would measure up on the guard lath by the hub and mark up to an even number 2' - 3' or whatever (has to be the same from side to side at each station) that saved us from having to bend over so much and could also string line from those marks. The grade man would do this then if he wasn't around I could check it myself and if I found an error in his grade setting I would paint the stake a nice orange color so he knew where he needed to recheck his math.

 

[CM1995]

Typically in our area the surveyors use 12" grade stakes and set hubs for grade reference. Sometimes I may off-set the hub and use a longer 18-24" stake to mark it.

Here is a typical stake and grade hub that we use, the hub is next to the string line pin. This off-set is 3' off the back of curb and gives top of curb (T/C) -

 

[terrasmooth]

I recently started a website that is intended to help people with these and other questions about civil construction. I will be doing a post on "grade setting/checking" soon along with other interesting topics. www.terrasmooth.com

 

[forestroad]

I recently started a website that is intended to help people with these and other questions about civil construction. I will be doing a post on "grade setting/checking" soon along with other interesting topics. www.terrasmooth.com

Great site, made my favorites list.