trench drain question

[Hidden_Brain]

sorry for the off-topic question. does anyone know if you can create a "T" intersection with sections of a trench drain? if yes, any suggestions on what the joint will be like?

Image below shows what I am intending to do. we have a shallow electric conduit (3' depth) we have to cross, with at least 1'  of clearance. I am planning to cross with trench drains (18inch deep), but need to provide trench drain on both sides of the curb return. major portion of the trench drains will be along the gutter line of both main road and side road (12ft shoulder width), and away from 30mph and 25 mph traffic.

is this doable or absolutely preposterous?

[Neilw_05]

I don't see any issues as long as you can make the grates match up at the junctions. The concrete boxes should not be a problem. As for traffic loads, it may require a support across the gap where the concrete boxes intersect. I can't answer that question. I'm sure the grate manufacturer could. It might be best to consult with the manufacturer(s) with this idea.

[cwr-pae]

A trench drain is just a small concrete channel/ditch with vertical sides and a grate over the top, so make connections and intersections just like you would do a paved channel with vertical sides. Design wise I think I would use a channel corridor under my road corridor to allow targeting the roadway surface. and then paste appropriate surfaces together for cross sections.

[fcernst]

I wouldn't recommend protruding a trench drain grate system into an intersection. Not the correct place or application for a trench drain system.

..Poor engineering practice.

[Neilw_05]

I had that concern as well. Again I think it would be best to consult with the manufacturer for this scenario. They will make recommendations.

[cwr-pae]

On my way to lunch I crossed some drainage structures called "rabbit runs" that where used extensively locally way back when all the drainage was surface flow at the gutter lines. Essentially they are trench drains that were originally decked with timbers crossing intersecting streets to allow the flow of water under the pavement. Over time the timbers (over 100 years in some cases) have decayed and been replaced with steel plates, concrete caps or the runs were rebuilt with bolted trench drain grates. Perhaps this approach can work for you. Shallow (9 or 10") box culverts under the pavement with catch basin grates at the start and intersections.

[Joe-Bouza]

Maybe pervious pavement 

[Hidden_Brain]

kudos to everyone who weighed in, I appreciate the suggestions.

i understand the dilemma with having trench drain protruding into intersection of 30mph roadway. I spoke with Aco Drain this afternoon, they have a monolithic trench drain for use in highway scenarios just like this:

http://www.acoinfrastructure.us/hd200.html

only drawback is the monolithic drain does not have ADA compliant grates. I decided to leave a section of pavement in front of the curb ramps and grates on either side connected by piping.

pavement reconstruction is proposed for the entire main road. might be a hard sell to state DOT to have a patch of porous pavement within regular asphalt.

thanks again everyone.

*Edit": additional information

Speaking with Aco Drain, they indicated that they can fabricate trench drains that have the "T" intersections like my schematic above.

[cwr-pae]

ABT has the same stuff as ACO. In addition they have a foam inner form system that can be field cut to accommodate any configurations, including a concrete cap to avoid small pipes in the areas of your ADA ramps (the rabbit run concept).

[Anonymous]

Essential inner form system sort of cable screening on the lower finish to keep the critters out of the lines. An open pipe like that varieties an exceptionally decent settling area.

https://medium.com/@addrainage/3-ways-to-achieve-better-yard-drainage-5efb91617e4c