Roadway Cross-sections

[ptmoss]

I'm curious how other engineers feel about what to include on roadway cross-sections (i.e. those sections shown for every 50' station).

When there are buried utilities - sewerlines, stormdrains, waterlines, etc. - do you show their location on every section? Or do you create sections only for road grading purposes, to show the relative cut/fill along the road and material depths, sidewalks, guardrail, things on the surface?

Or with those buried utilities do you just prefer to show them on a single typical section and let it go at that?

 

[Maury]

I almost always use the cross sections just for the roadway design and don't include buried utilities. I have included utilities where there are special design considerations, but special details seem to get more attention from contractors.

 

[GeoPaveTraffic]

As an engineer who has to build from roadway plans. You should show everything you know about on each section. Not showing a somehting on a section is a greatway to design a probem right into the plans. Such as placing a sidewalk in an existing tree or sign post. Or grading a ditch into the minimum cover over a utility line.

Show it all, and show it to SCALE. If the pipe is a 48 inch pipe, then show it that size.

 

[LHA]

I, as a Site/Civil designer, agree with GeoPaveTraffic. But our Transportation designers resist this very much. Sometimes they don't include utilities. It always comes back on them, only by then it is an emergency in the field. Show it all!!!

Engineering is the practice of the art of science - Steve

 

[cvg]

i believe the op was asking about earthwork cross sections, not typicals. most often the contractors don't even see these sections unless they ask to verify the quantities. I do recommend frequent typical sections with right of way, roadway and ug utilities shown. This is typically done with one section about every 500 feet (each sheet of plan & profile)

 

[jkellerfsu]

In my region we show EVERYTHING - it is especially important in urban areas. I deal with mostly reconstruction and that often includes utility work.

Showing all of the underground and surface features is RELATIVELY simple with today's engineering software. It requires a lot of "upfront" data input but is worth the effort. Any change you make in your alignments (vertical and horizontal is automated and shows the impacts on the features.

SHOW IT ALL and spend some money on the software to make your life easier.

 

[ptmoss]

Thank-you for all your good replies. I personally think buried utilities should be shown on all sections, but I also know that over the years I can think of a couple projects where preliminary sections that had none of that showing carried through without having the underground data added.

I do think it's important to show. Just going through the process will help ferret out possible conflicts. I review plans for a couple of municipalities, though mostly do design work (not where I review, of course), and on one project I was reviewing (not only did the sections not show ungerground utilities, but they were all done with different horiz & vertical scales (a 5:1 exaggeration) similar to profiles) I found two instances of waterlines designed to go straight through culverts. The comment I got back from the design engineer was that of course it wouldn't be built like that, the contractor will figure it out!!

So just where do our responsibilities as engineers lie, anyway? Do we sweat the details? Or just let it be figured out on the fly by the contractor?

 

[LHA]

The design engineer in your example is dead wrong. I would issue a written comment that you don't think the design as submitted is most prudent. If it meets Code, though, you can't make him change it.

The contractor is not obligated to "figure it out"; he/she is obligated to perform the scope of work as defined -and only as defined - in the Contract Documents on which he bid the job. If he hits a water main that isn't shown on the Contract Documents which he bid on, it is a change order to relocate/repair/adjust the culvert/or whatever to allow him to complete his scope of work. He was hired to install a culvert, not "figure out" what to do about a water main. The owner will have to grant the change order, then will most likely go after the designer for recompensation. At least, that has been my experience.

If, on the other hand, the CDs did have a water main to be relocated, contractor will have to "figure out" how to do that.

As a third example, if the CDs show the water main going straight through a culvert, contractor is legally obligated to put the water main through the culvert as specified on the design, which is sealed by a PE. For all the contractor knows, that is the intent.

Engineering is the practice of the art of science - Steve

 

[namdac]

Where we are we generally do not show utilities. But in one project that I am working on we have a water delivery system that we have to protect during the grading. The delivery system feeds a town of 300,000 so it is important on issues like that and so one.
Regards.
Namdac

 

[Civil3]

As a Construction Engineer on State projects I can tell you that the more information the better. The cross sections should always show utility information. Of course a good contract and set of plans will have language that states the contractor should field verify all existing utilities. Imagine running a new waterline or drainage pipe along side an existing duct bank. Without showing that duct bank on the cross sections you are opening up the owner for a change of condition change order. The designer who mentioned the contractor would "figure it out" with reference to the water line going through the culvert should be fired and his company should return his fees in my opinion.

 

[damone]

I review plans for encroachments onto State facilities. Even if the plans are drawn to standard I can request whatever I deem necessary to protect the state's facilities.

I just reviewed a plan that showed fiber in a cut bank in the typical. I requested sections every 50-ft to insure the plans show the location which may be in conflict if slope standards are applied etc..

I agree re...more is better. Sometimes separate utility plans may be needed as opposed to including them with roadway cross-sections that may have centerline, sawcut, etc... also shown. Sometimes it can get messy.

 

[Roadwork]

Having built roads for several years, I will add that unless you can provide accurate elevations and alignments of utilities, placing them on the cross-sections is not helping the contractor or the engineer in the field. Showing them on the site plan sheets is sufficient, in that case. Without accurate elevations and alignments, utilities would have to be physically located in the field...and a wise contractor is going to stop and hand dig anyway, if he starts getting close.

 

[Rockjoint]

I agree with Roadwork, as stated. As long as the plan sheets indicate them, I personally feel it not necessary to place the utilities in all the cross-sections (unless something is very unusual). Also, the numerous instances of improperly located utilities (in my limited experience, I must add) do relatively little to add value to the cross-sections, IF they are shown on the plan sheets.

 

[GregLamberson]

I'll agree with RockJoint and RoadWork. Contractors will be required to One Call and have all utilities located (should be in the contract language). That being said, if you do have informaiton, especially if there are some obvious ones and you know where they are located (i.e. a FOC that connects eastern US with western) it's prudent to give it to the contractor. You might think there would be liability in pointing out some and not others, not so, if you have the right contract - Contaractor is responsible for verifying all foreign crossings.

What I would do however, is ask the contractor to mark the all foreign crossings on their as-builts (location & depth & description) so you will have them for future maintenance operations activities, or in an emergency situation (rupture) you will know where everyone is at.

I wouldn't sweat the details, as was mentioned, the contractor will work it out in the field, that's what bending machines and beveling torches are for.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[GeoPaveTraffic]

I agree that the contractor is ultimately responsible for get the utilities field located verifying the locations. However, the biggest advantage to showing the utilities (to scale) on the cross sections is that if forces the designer to fully examine the design.

As both an owner and a consultant, I have had multiple occations when there were know utilities that conflicted with proposed improvements shown on the plan. If the designer had shown them on the cross sections, then he would have seen the conflict and done the required redesign before sending the project out for bid.

 

[FarmallFan]

i generally agree that all the utilities should be placed in the xsects. however if the client was cheap and didnt ask for them, then put the utlilies near the proposed excavation work as a min. for example, i never understood the why some clients wanted all utulites shown on repaving projects. i do not agree that the contractor should be ultimately responsible for poorly documented ultilites. i been on jobs where the locating companies couldnt find thier lines and problems keeping to the schedule were still on the contractors shoulders.
farmallfan