Highway Drainage Design

[WaterGirl]

I work on many roadway improvment projects, which of course include highway drainage. In my company, the highway group is "running things" for a certain project for the state DOT. To do drainage, as you know, you must first delineate areas, figure flow to inlets, check spread, design sizing and pipe material for adequate cover, and lastly make sure the structures do not go flying off during the design storm (HGL). But we all know this, right?

Okay, so our highway guy tells me that the main road's geometrics are finalized. But the side streets are not. This was an urban area with about 9 or 10 side streets flowing into or out of the main roadway. So we made assumptions (with his guesses) on the side streets and proceeded to design the drainage for the main road and put two inlets at the bottom of side streets, like you usually see.

Problem was, where we assumed normal crown, he ended up superelevating in some areas. Our pipe cover was always good because he was told to raise the roadway, but not lower it. Design was done over and over again. Sometimes inlets on the main road had to be moved closer to the side street because the by-pass we estimated was off. Then draiange area boundaries had to be modified, pipes had to be shortened and so on.

Next phase - same thing. New road added to contract. This road had a culvert to be replaced under it. Two weeks before the submission, the highway dude give me a "working surface" in Inroads that I should be able to use to do my design (no profiles, no typicals, no grades, just a working surface). I delineated areas for SWM using the working surface, but everytime I went into the network to access the surface, I found that it had changed since the last time I had delineated. In the mean time the draiange area maps were done over and over again.

Fast forward - the highway dude could not even finish his highway work before the original deadline, so it was postponed a week - at which time, we were to told to hurry up and finish our design. Three days before the new deadline, I was again redelineating areas and modifying draiange area maps fo rthe umpteenth time. So many hours....so much money....And the day before the deadline, I was finally able to get around to designing the culvert - since I finallly had real elevations on the roadway.

I worked my butt off and we got our stuff in one day late. But there were many mistakes that I hope the client does not see. This is because we were forced to do an entire stormdrain and culvert design in maybe three days. And when I say "we", I mean "me". I'm the only person who knew how to do everything on the job, so I had my hands in all of it, which meant I was responsible for all of it (except maybe some CADD work and a Report)

Is this fair? In my last company, I never was asked to even touch drainage until highway geometrics were set and approved of. My current supervisor says this is how every job is...

Which is it? Do we design drainage alongside of and concurrently with the highway design? Or is it one totally after the other?

 

[EM_PS]

Hmm, sounds relatively atypical actually to me. Although by geometrics, i'm taking it to refer to grades being changed / adjusted as project slogs on, and not horizontal alignments / placements jumping around. Where exactly is this? Urban or rural? sand, clay, hardpan, rock? Is drainage that highly complex with the roadway projects you're dealing with? I do agree with where you're coming from (seat of your pants design team = pain in the pants) but overall, IMO [roadway] drainage is just another utility (except in FLA ) to deal with & bury.

 

[roadwreck]

It sounds pretty unusual to not have the basic geometrics set two weeks before a submittal, but with that said things change with our designs all the time "at the last minute". Something will come up or the client will ask us to modify something which causes changes to other portions of a project and the modifications cascaded down to every facet of the design. Resulting in last minute redesigns of drainage systems etc. In a perfect world the roadway design would be finished before the drainage design, but this world isn't perfect.

 

[WaterGirl]

Hmm, sounds relatively atypical actually to me. Although by geometrics, i'm taking it to refer to grades being changed / adjusted as project slogs on, and not horizontal alignments / placements jumping around. Where exactly is this? Urban or rural? sand, clay, hardpan, rock? Is drainage that highly complex with the roadway projects you're dealing with? I do agree with where you're coming from (seat of your pants design team = pain in the pants) but overall, IMO [roadway] drainage is just another utility (except in FLA ) to deal with & bury.

This area is a very urbanized area. The soil types are Keyport loam mostly (HSG C). And what I mean by geometrics is: No, the actually horizontal alignment changing has not been a problem, but maybe it did. The roadway edge will be shifted one day with no warning, the slopes and elevations have changed at different offstes on the roadway. Either that means the profile or grades or both have changed at the last minute. Side street tie-ins are never done until the very last minute. The drainage is difficult on some parts of the job because of (as you mentioned) utilities being just everywhere and the companies will not relocate the sanitary lines and we are bobbing and weaving around these lines using non-standard pipe boxes custom-designed by the structural team. Sheesh!

But this last added-on road with the culvert, fortunately has very few utility conflicts. My point is that in order to finalize our calculations, maps, and hydrologic/hydraulic models, we need the real, actual information, not the "best guess" given to us by them (when they really should have it done by then). Then when they refine their numbers and revise according to their own parameters, most of what we have down is now incorrect, inaccurate, and just plain wrong. And even though we have expended a terrific level-of-effort to that point, we still must put in about the same amount more. Then they wonder why the budget is blown.

No one sees this as a major unacceptable problem?

Shouldn't we be able to force them into a deadline on their geometrics that corresponds with the time it'll take us to advance the draiange design once, or maybe twice? I'm no fool and I know the world is not perfect, but shouldn't we try a little harder not to make the next man's job more stressful and difficult?

I think the problem is that we all lay down for this crap - and we should not be subjected to this kind of mistreatment from fellow engineers.

In college, out of all the engineering disciplines, civil was the least respected by other engineering majors.

Now, in business, water resources is the least respected of all civil disciplines - with the highway dudes always trying to rip up roads, fill in wetlands, who cares about the fish, and on and on.

They act like, "Who cares, just put a pipe in the ground to carry the darn rainwater. It's not that serious."

Tell that to the agencies that review our work.

Hmm. Ya think I'm a little pissed off?

 

[WaterGirl]

It sounds pretty unusual to not have the basic geometrics set two weeks before a submittal, but with that said things change with our designs all the time "at the last minute". Something will come up or the client will ask us to modify something which causes changes to other portions of a project and the modifications cascaded down to every facet of the design. Resulting in last minute redesigns of drainage systems etc. In a perfect world the roadway design would be finished before the drainage design, but this world isn't perfect.

Now, if the client asks us to change something at the last minute, no problem. That does fall on everyone. And I would expect in most cases the client to extend a deadline and/or add to the budget when the change was requested by them at the last minute. I mean - the submission is the 16th - that does not mean that highway dude can finish his stuff by the 16th or the 15th or even the 14th. This is par-for-the-course at other employers?

Maybe I was just lucky at my last job. Like I said, I had never, ever designed drainage on a changing roadway surface before I got my present job.

 

[roadwreck]

do what I do, design the road and the drainage. Then you have nobody but yourself to blame for missed deadlines.

 

[EM_PS]

Two words: permeable pavement :joke:

I figured you must be in an urban locale for this to be such thorn in the side. I guess I have a hard time understanding why they can't seem to nail down their 'geometrics' more succinctly, because SO much of the project is SO heavily contingent on that - just so you know, alot of my exp is in running a roadway project from initial topo thru design to inspection & even as-builting, if required (cradle to grave). So i couldn't get ticked at the surveyors (i was one of em) or the alignment / geometrics design (me again) or. . .well you get the point.

This is what they tout building information modeling (BIM) technology for right? Your firm or company seems to have too many players involved in the design, while 'one hand doesn't know what the other is doing', or maybe more appropriately, doesn't care - Anyways, it is a major problem you speak of; but unfortunately (fortunately?), its working. . .designs are getting out. . .just very inefficiently & over-budget - is there any way to attempt proactive measures in meshing the design processes w/out pissing peops off or ruffling feathers? Get a higher-up involved, and maybe do a pilot design on an upcoming project either utilizing BIM processes or ad hoc task assignments / meetings for greater fluidity in the design process.

otherwise, pour yourself a strong one - keeps me civil :winko:

 

[WaterGirl]

Two words: permeable pavement :joke:
I figured you must be in an urban locale for this to be such thorn in the side. I guess I have a hard time understanding why they can't seem to nail down their 'geometrics' more succinctly, because SO much of the project is SO heavily contingent on that - just so you know, alot of my exp is in running a roadway project from initial topo thru design to inspection & even as-builting, if required (cradle to grave). So i couldn't get ticked at the surveyors (i was one of em) or the alignment / geometrics design (me again) or. . .well you get the point.

This is what they tout building information modeling (BIM) technology for right? Your firm or company seems to have too many players involved in the design, while 'one hand doesn't know what the other is doing', or maybe more appropriately, doesn't care - Anyways, it is a major problem you speak of; but unfortunately (fortunately?), its working. . .designs are getting out. . .just very inefficiently & over-budget - is there any way to attempt proactive measures in meshing the design processes w/out pissing peops off or ruffling feathers? Get a higher-up involved, and maybe do a pilot design on an upcoming project either utilizing BIM processes or ad hoc task assignments / meetings for greater fluidity in the design process.

otherwise, pour yourself a strong one - keeps me civil :winko:

Thank you for that good advice. I do have a meeting scheduled with my supervisor and someone higher than he. We are going to discuss how and why the budget was blown and what we can do about it in the future. I think the highway group just needs to understand that we have a product to get out which depends directly on when and how good the product is that you get to us.

I'll have to do some "squeaking", but I think I can get the oil. Thanks for all input.