# Trenching and Pipe Work



## SlumberJack (Jun 18, 2009)

Hey I've been estimating for years now and always wondered about the way to correctly and accurately quantify trench (pipe) excavation... in other words if say you have a trench that's about 5 ft. deep and 4 ft. wide and a couple hundred feet long or more, you obviously have to (as per OSHA) provide a safety slope to a certain extent if you want to avoid providing shoring/sheeting or trench boxes.

My confusion lies in the fact that every drawing detail and/or spec I have ever seen for trench excavation shows vertical trench walls without a slope and they always have a max width on the trench itself therefore the walls of said trench must be fixed vertically at that given width as shown on the drawing detail ... I know we aren't all providing sheeting/shoring on all these jobs so:

1. Where does that safety slope come in? In order to dig that deep (5 ft. or more) OSHA says you must provide a slope of 1.5 ft. horizontal to 1 ft. vertical (depending on soil type) and if the trench walls are at a fixed width, how do you pull this off???

2. Let's say on a particular job you must provide controlled backfill at the trench (which in most cases we do) and the detail shows a fixed trench width but it's again around 5 ft. deep and you must therefore provide a safety slope...Do you provide controlled backfill at the width of the trench itself and then reuse the previously excavated material to fill in the safety slope areas?

Would appreciate any insight anyone can give... Due to the nature and delays in response times on the forum at times I would appreciate it if everyone would read the issue(s) noted above carefully so as to fully understand the nature of the question(s) and I'll do the same in reading your response(s)...thanks a million in advance for any light you can shed here!!! :thumbsup:


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## Elyrain (Dec 17, 2007)

Your last paragraph is sooo funny, I voted no, never, because I thought it said SAFETY ROPE! Leave it to an estimator to write that paragraph.

My answer is easy, I always follow osha. If I couldn't bench or slope I would slurry anything over 5'. Or use a box(es). Even a cave in at 5' high could kill someone.


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## SlumberJack (Jun 18, 2009)

Elyrain said:


> Your last paragraph is sooo funny, I voted no, never, because I thought it said SAFETY ROPE! Leave it to an estimator to write that paragraph.
> 
> My answer is easy, I always follow osha. If I couldn't bench or slope I would slurry anything over 5'. Or use a box(es). Even a cave in at 5' high could kill someone.


Elyrain thanks for the reply... that last paragraph may have been written a little prematurely...I haven't posted on this forum in a long time and didn't know how timely the responses would come and to be honest, we contractors don't always take the time to read carefully (trust me, after soliciting bids to a database of several hundred subs for a GC I worked with for years - if I had a penny for every time I had or could have said; did you read it? I'd be rich)...

Not knocking contractors here at all ... am one... been one... just wanted to get the answers right the first time if you know what I mean...

Hoping to hear some feedback on the actual issue though of my dilemma with fixed trench widths (vertical walls) when you need to provide a bench/safety slope... wracking my brain!


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## CanDoExcavating (Feb 11, 2010)

Sliding trench box


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## Anti-wingnut (Mar 12, 2009)

Bestimator said:


> :boxing:
> Would appreciate any insight anyone can give... Due to the nature and delays in response times on the forum at times I would appreciate it if everyone would read the issue(s) noted above carefully so as to fully understand the nature of the question(s) and I'll do the same in reading your response(s)...thanks a million in advance for any light you can shed here!!! :thumbsup:


Yes sir, your Highness


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## PipeGuy (Oct 8, 2004)

Bestimator said:


> ...I've been estimating for years...and [haven't yet learned the right way] to quantify trench excavation.
> 
> 1. Where does that safety slope come in? If the trench walls are at a fixed width, how do you pull this off???
> 
> ...


#8. Do you really expect me to answer this?


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## Anti-wingnut (Mar 12, 2009)

Shouldn't you ask the geo-tech? If they want a 5' deep trench no wider than 4', with the plans seemingly not allowing any terracing, shouldn't a RFI on your part be issued? Either that, or put in a lot of money for trench shoring.


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## SlumberJack (Jun 18, 2009)

Anti-wingnut said:


> Shouldn't you ask the geo-tech? If they want a 5' deep trench no wider than 4', with the plans seemingly not allowing any terracing, shouldn't a RFI on your part be issued? Either that, or put in a lot of money for trench shoring.


This was more of a general question than a job-specific one because this stands true on at least 80% of my jobs...and shoring/sheeting isn't always cost-effective so any trenches 5' deep or more (according to OSHA) need to be supported with some sort of shoring/sheeting system... but I know our competition is not figuring on the cost to shore/sheet all of these trenches... I'm looking at a job right now with 11,000 LF of trenching which is both under roads and under park property in NYC ... shoring sheeting will likely be required in certain sections but I'm definitely not figuring it on all 11,000 LF...so I'm going to figure on benching it out but ... here's my issue (on this and many other jobs I come across) ... the detail in the drawings for the trench excavation shows vertical walls (as do 95% of most trench excavation details you see on any given set of plans) as I'm sure most of you would agree...I can't be the only one seeing this...

I guess what I need to know more than anything; is there a geotechnical factor involved in why you would only want vertical trench walls instead of sloped walls (for safety purposes when diggin in excess of 5')? I mean, will sloping the trench walls compromise the pipe bedding and backfill in any way or are there any other variables affected by having vertical as opposed to benched trench walls that I don't see?

I'm sure there are; but more often than not aren't trenches benched anyway? I know we don't sheet/shore the majority of our trenches...

Thanks for the replies; appreciate any insight you can give!


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## SlumberJack (Jun 18, 2009)

PipeGuy said:


> #8. Do you really expect me to answer this?


PipeGuy, you came highly recommended to me by another user here on the forum in another recent post...

Exactly what are you getting at here with your quote and short response? I sense major sarcasm. I reached out here as it seemed to be the place a guy like me could receive and offer help on these very topics.

I realize the last paragraph may have read a little condescending or coarse and I meant no disrespect by it. We both know many contractors breeze through most things in written form and I just wanted to be sure people understood my actual question(s).

I don't mean to beat a dead horse here but if you look at the responses, there's one instance where it's obvious the person either misunderstood the question or just ignored what I was asking... that's exactly what I meant by the last paragraph so the proof is in the pudding.

I'm a humble guy trying to make a living doing the same thing you all do...I don't know it all and hope to gain some experience here by talking to you guys.

I just read a recent post about this forum possibly being considered to be taken off - and that people need to post more... you'd think when a newbie comes out and posts like I just did you'd be more apt to answer rather than be sarcastic. Just my humble opinion. Give me a break here.


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## Anti-wingnut (Mar 12, 2009)

Bestimator said:


> I mean, will sloping the trench walls compromise the pipe bedding and backfill in any way or are there any other variables affected by having vertical as opposed to benched trench walls that I don't see?


The only answer I know of here is ossibly.



Bestimator said:


> ... the detail in the drawings for the trench excavation shows vertical walls


Probably because it is not the responsibility of the drafter to detail, infer or specify how you maintain trench safety. If you feel that slopes and benches are the best way to ensure worker safety, but are concerned that you may violate geotechnical guidelines, you should seek out site specific answers. 

In answer to another question you had, I would maintain that if the plans call for controlled fill of your trench, that would apply to your entire trench, including the volume of sloping and benching. If your competitors do not seem to be doing this, some discreet questioning should answer whether this is a industry standard of your area


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## Sar-Con (Jun 23, 2010)

First, loose the condescending remarks, you're giving estimators a bad name:thumbsup:

If you've got good soil you can excavate straight up and down 4' max. The safe slope is considered 90. After four vertical feet, the geo-tech report will tell you safe sloping for the type of soil you're in. 

So, for example, if you're five feet deep only the top 1' is sloped. Since its the same triangle on both sides of the excavation, you have a very easy calculation. Length of trench x height of slope x distance of repose will give you your volume.

Generaly, you can only use native backfill if it will meet the compaction spec (ie 95% proctor)


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## SlumberJack (Jun 18, 2009)

Sar-Con said:


> First, loose the condescending remarks, you're giving estimators a bad name


Sar-Con...I appreciate the insight... even the extra tip on the calculations...boy if I don't know that after 10 years doing takeoffs I'm in trouble...thanks again.

And please you guys...we're men. We're in construction - tell me you'd be complaining like this on the job site if someone said something a little rough/coarse... again I meant no disrespect as I wrote to PipeGuy...

I resent what you said about giving estimators a bad name. We're focusing on the result but not the cause. My issue is with guys who fail to take the time to read through a post and respond incorrectly. If that's not you; ignore it and move on...again; so far it's been all men here. I better watch myself; mean no disrespect to the ladies in construction either. Have worked with a few remarkable women in the field. And not just in administration.


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## Anti-wingnut (Mar 12, 2009)

Sar-Con said:


> First, loose the condescending remarks, you're giving estimators a bad name:thumbsup:


Is that even possible?

Oops, my bad



Bestimator said:


> I resent what you said about giving estimators a bad name


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## Anti-wingnut (Mar 12, 2009)

Bestimator said:


> And please you guys...we're men. We're in construction - tell me you'd be complaining like this on the job site if someone said something a little rough/coarse...


I think you've been the chief complainer



> Mommy!!!! Sar-con is being mean to me again


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## SlumberJack (Jun 18, 2009)

Look I'm going to say something once and for all and I hope I can continue to post on this forum without people jumping on the bandwagon to make me out like I'm some condescending Pri*% because I'm not. 

I'm only in this side of the business 10 years; most guys I talk to are 15, 20, or more...I'd like to learn something from everyone but I don't want to take a ton of time rexplaining what I meant (as you see I try and take the time to write clearly), as I've done in the past, for everyone's sake. It's one thing to clarify, it's another thing entirely to pay half attention and run hastily through a post and respond short, sweet, but incorrectly.

Time is money. We all know that because most of us are in business for ourselves and we all value it. I'm no guru but I'm taking the time to sit here on this forum and offer any insights I may have; as I did to the other new guy looking for estimating/bidding help... and just the same, when I take the time to present myself to the forum to ask a slightly complicated question, I'm just asking that we all do the same.

I apologize sincerely to the forum - let's drop the slick talk and focus on what we love. It's really easy to talk sideways on the computer, which is probably why this happens a lot on the internet. Things get taken out of context a lot...had I been standing next to you I'd have probably smiled and chuckled as I was saying it so you would know I'm not being super serious or a jerk - just making a suggestion.

Wingnut your response will dictate who the chief complainer really is. Do you have the time for this?


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## Anti-wingnut (Mar 12, 2009)

Bestimator said:


> I'd have probably smiled and chuckled as I was saying it so you would know I'm not being super serious or a jerk - just making a suggestion.
> 
> Wingnut your response will dictate who the chief complainer really is. Do you have the time for this?


This is the inter-net, you come here and ask a question, which is fine. You get a lot of answers, all of which seem correct.

But you also tell us how to behave on "your thread", imply you are very busy and chide us for answers you do not believe are becoming.

You kind of seem full of self-importance


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## SlumberJack (Jun 18, 2009)

Anti-wingnut said:


> This is the inter-net, you come here and ask a question, which is fine. You get a lot of answers, all of which seem correct.
> 
> But you also tell us how to behave on "your thread", imply you are very busy and chide us for answers you do not believe are becoming.
> 
> You kind of seem full of self-importance


Wingnut don't manipulate what I wrote... you love the drama; I can see it in your other posts... Forum» Trade Talk» Specialty Trades» Property Preservation» A Joke - Fee's 

I can take it like the best of them...but in the above mentioned post, the main point by Ken (which you “Thanked”) after you offended OP, was that the nature of our profession is a little rough around the edges and a certain degree of this can be expected/accepted here; more to the point I was making originally... if this is the case why was my comment not: more of the same? If the type of talk you displayed in that post; calling someone with no provocation "a windbag" is accepted by you (or all here) then certainly without hypocrisy you should be able to take with a grain of salt my first post, which was the initial issue here.

Can we get off this now? If the ultimate goal here (or one of them) is to attract more like-minded, capable professionals, perhaps there’s another, slightly more attractive approach to go about it.


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## Anti-wingnut (Mar 12, 2009)

For somebody with ten posts, most if not all asking "how do I ?", you sure want to tell people how this place should be.

I promise I won't call you a "windbag". What I privately think is my own business though


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## Sar-Con (Jun 23, 2010)

Bestimator said:


> Sar-Con...I appreciate the insight... even the extra tip on the calculations...boy if I don't know that after 10 years doing takeoffs I'm in trouble...thanks again.


Is that sincere or are you being a "condescending Pri*%" (using your own words)


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## SlumberJack (Jun 18, 2009)

The ignorance must be bliss here with (hoping only) the two of you...I wouldn't have said this had you not again taken another jab but Sar-Con you're drowning in your own point here on that one...thinking logically; your original comment was actually condescending because what you did here was; you went beyond the issue and question at hand and offered entry level, basic calculations that I didn't ask for and that weren't even relevant to what I asked originally (more to my initial point) - that would be and was fine until you now throw my response in my face...I didn't ask about simple geometry or how to quantify trench excavation and for you to offer this is kind/harmless, yes, but a bit condescending in itself because I did state I've been doing this a full decade -- really didn't bother me any that you wrote it but I thought I'd address it in passing...I didn't retaliate and tell you this immediately - I only made a wise crack "If I can't do that after 10 years I'm in trouble" to sort of indirectly let you know it was a silly thing to offer being that I had not asked for that info...

But let's jump on the bandwagon here; come on...

And Wingnut: Just so the record is straight, your partially correct; I’ve posted 10 times but in only 2 threads - there wasn't 10 "how-do-I" posts (just 1). 1 thread someone else had started (that new guy who was looking for help which I offered) and the other I started (this one). Again, don’t manipulate to suit your point.
I’ll give you the last word here…I’ll concentrate on the trade relevant posts. Thanks for sharing, both of you.

Is this silly to anyone else?


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## Anti-wingnut (Mar 12, 2009)

Bestimator said:


> I’ll give you the last word here…


That doesn't seem to be a strong-suit of yours. Bet we hear from you again.

Gawd, I can't believe I promised not to call you a wind-bag. I painted myself into the corner there, didn't I?


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## rino1494 (Jan 31, 2006)

Doesn't anybody work during the day ?? Geez, I need to get some popcorn.

OSHA regs state that a trench may be vertical at 5', after that it must benched/sloped. But the bench/slope must start at 4'. This also depends on soil classifications. 

What we do is by soil conditions. Some may be benched at 3ft, others higher if the soil is good. Working in the street, we use boxes because it saves on backfill material. Deeper trenches, we use boxes and the bench/slope starts 1ft below top of box, per OSHA regs.


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## SlumberJack (Jun 18, 2009)

I hear you rino. Thanks for the response.

So if I understand you correctly, if say you had a 6'-6" deep trench, you'd start benching 2'-6" from grade which leaves the max vertical trench wall of 4'? Of course depending on soil conditions like you said. 

Would you figure the same thing when you're excavating for a precast manhole? If the manhole dig is 9' below grade let's say, and there aren't any connections to make below the top 3' or so then you'd be okay to bench from about 5' down from grade right?


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## dayexco (Mar 4, 2006)

i'm beginning to wonder why somebody with 10 yrs estimating experience, is asking questions "here"....that are explicitly answered in your OSHA regs book, or in the specifications provided to you by your engineer? do what they both require, and you're good to go. thank goodness it's only thursday nite. this time tomorrow and i'd probably have 3-4 crown royals into me and my response may be totally different

and know this. this is a great group of guys, VERY knowledgeable in their trade. there is a lot of back and forth banter that goes on, for the most part in fun. i am still trying to figure out just where you're going with all this line of questioning when i've seen 3-4 guys do a very good job of answering your question.


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## rino1494 (Jan 31, 2006)

Bestimator said:


> So if I understand you correctly, if say you had a 6'-6" deep trench, you'd start benching 2'-6" from grade which leaves the max vertical trench wall of 4'? Of course depending on soil conditions like you said.


Per OSHA regs, yes. What I do in the field depending on soil conditions, is a different story.



Bestimator said:


> Would you figure the same thing when you're excavating for a precast manhole? If the manhole dig is 9' below grade let's say, and there aren't any connections to make below the top 3' or so then you'd be okay to bench from about 5' down from grade right?


Sloping manhole excavations is too expensive. Way too much digging, backfill and compaction. It is alot cheaper to throw in a manhole box.


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## tgeb (Feb 9, 2006)

I tend to agree with Dayexco.

How can you estimate for 10 years, and yet appear to not be familiar with common day to day site conditions/practices? (Compaction of soil in a benched excavation?)

There are tons of posts on this site that address estimating, best working practices, and how to deal with uncertain conditions.

Welcome to the site.


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## Elyrain (Dec 17, 2007)

What he came here looking for was an answer that isn't to be found. There is no way to bid against people who don't follow osha/the rules/laws. Find a owner/agency that holds their contractors to the fire for not following osha is your best bet.


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## jmacd (Jul 14, 2009)

Elyrain said:


> What he came here looking for was an answer that isn't to be found. There is no way to bid against people who don't follow OSHA/the rules/laws. Find a owner/agency that holds their contractors to the fire for not following OSHA is your best bet.


I think you nailed it. Really only one answer if you do it according to OSHA regulations. The rules have no real gray area. 

If you don't plan on OSHA inspections or don't think any one will get hurt when the walls come caving in after a heavy rain than do what ever is cheapest for you. 

I was thinking that this thread was going to be boring before I opened it. I was so wrong. Very good read!:clap:


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## Sar-Con (Jun 23, 2010)

jmacd said:


> I think you nailed it. Really only one answer if you do it according to OSHA regulations. The rules have no real gray area.
> 
> If you don't plan on OSHA inspections or don't think any one will get hurt when the walls come caving in after a heavy rain than do what ever is cheapest for you.
> 
> I was thinking that this thread was going to be boring before I opened it. I was so wrong. Very good read!:clap:


It's like the job I bid and lost last year. The depth was 6'-6" for the storm tie in in the middle of the road. Out of curiosity I checked out the site a couple of months later - the patch in the road was only 2' wide


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## jmacd (Jul 14, 2009)

I open them up BIG. :thumbsup:








The extra fill etc. really is not that much compared to trying to work in a tiny hole filled with a trench box.


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## peteo (Jan 8, 2011)

Good point Jmacd. Why pin yourself into a tight spot when you dont have to? besides for what it costs for a few extra ton of gravel its a lot more cost effective than trying to go the other way. I've found that when I try to do a job "cheap" it usually ends up costing me more in the long run.


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## rino1494 (Jan 31, 2006)

Not always. I did a job last year where we ran 8" sewer main across a Penndot road, 14' deep. Penndot regs call for all open cuts to be backfilled under pavement with flowable fill. At $60/yd at 14' deep, we used 24" spreaders on the boxes.


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## Anti-wingnut (Mar 12, 2009)

> Due to the nature and delays in response times on the forum at times I would appreciate it if everyone would read the issue(s) noted below carefully so as to fully understand the nature of the post and I'll do the same in reading your response(s)...





dayexco said:


> and know this. this is a great group of guys


Me and Sarcon included! :laughing:



dayexco said:


> VERY knowledgeable in their trade. there is a lot of back and forth banter that goes on, for the most part in fun. i am still trying to figure out just where you're going with all this line of questioning when i've seen 3-4 guys do a very good job of answering your question.


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## Redneckpete (Feb 22, 2008)

With regard to the trench question. On a five foot deep trench, I’m not shoring regardless of the soil conditions. In solid, stable material I’m digging five feet deep straight down, pounding in the pipe and backfilling right behind me. In unstable material, I’m doing the same thing, except I’m sloping the sides of the trench until its safe for me and my employees to work in the bottom. Here, code says four feet then one to one slope. I don’t care what code says, I have to work in the hole. I’ll cut more if I have to feel safe. 

Typically I’d put the back of the bucket down on the bank about one and half times the width of the trench. If I can push down and cave it in, it’s coming out.

Pete


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## S.R.E. (Apr 8, 2010)

rino1494 said:


> Doesn't anybody work during the day ?? Geez, I need to get some popcorn.
> 
> OSHA regs state that a trench may be vertical at 5', after that it must benched/sloped. But the bench/slope must start at 4'. This also depends on soil classifications.
> 
> What we do is by soil conditions. Some may be benched at 3ft, others higher if the soil is good. Working in the street, we use boxes because it saves on backfill material. Deeper trenches, we use boxes and the bench/slope starts 1ft below top of box, per OSHA regs.


I'm not picking on Rino just making a point. :thumbsup:

If I followed this OSHA reg I would be Illegal. Here in WA you need to follow L & I Regulations which state that anything over 4' needs to be shored or sloped. How you slope or shore your trench depends on your type of soil classifications. If class "C" soil (Which you must assume all soil is class "C" unless you have a report from a Geo engineer stating otherwise.) anything over 4' deep must be sloped from the BOTTOM of the trench at a min of 1.5 to 1. There is a very detailed bunch of specs that detail what you can do.

My point is that you need to dig into the specs that your State goes by and you should probably attend a training that deals with the shoring /sloping requirements in your area where work will be preformed.


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## SlumberJack (Jun 18, 2009)

Great info guys... really very impressive and I appreciate your time and expertise...

I applaud everyone on the forum for their knowledge and I'll be the first one to say I spoke too soon in my first post on this thread. I apologize (again). I should clarify since I noticed a couple got the wrong impression; I wasn't griping about the responses I've received here thus far on this thread; I appreciate them all...it was before I had gotten any responses; in the initial post, where I was hoping guys would read the question(s) carefully.

You have to understand when I say I've been doing this 10 years; I haven't been digging trenches for 10 years...as I mentioned in another thread, I've been sitting behind a desk for 10 years so the difference in practical skills on the job are vastly different then yours...

I bid, do takeoffs, and cost engineer all day, every day....I win millions of dollars worth in jobs for my company... and it wasn't until the last few years did I start getting into utility work so this is where I'm coming from. Don't get me wrong; I've been on enough job sites and can get by in 97% of situations with practical knowledge from my previous/current co-workers both in the field and in the office but occasionally things come up that I need some clarification on.

In a nutshell; I think some misunderstood my intent; it wasn't a "how to" question as much as it was a "I'm used to doing it like this, but how do these other guys do it" type of question.

Thanks again guys; really looking forward to reading more here.


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