School Bus Parking Lot Design 2

[shppo]

Hi, I have recently received a project to improve an existing gravel parking lot to a concrete paved parking lot. The school bus parking lot is approximately 4 acres, and require a capacity of roughly 200 bus lots. The typical bus dimension is 8'x35'.Does anyone know any standard or design criteria specifically deal with bus parking lot in terms of turning radius, lot dimension, pavement thickness requirements, etc. Also, I was thinking about specifying pervious concrete for V-ditch between parking rows, which will also serve as service lane for buses;however, I am not familiar with gauging runoff pollutant concentration, and the effectiveness of the pervious concrete. Is there a way to estimate that? Any opinions, advices, directions, or tips are greatly appreciated. Thanks.

 

[ngneer]

aashto green book has templates for various turning radius of different vehicles. Also, software is available to model the movement - I think it's called autoturn or something similar. Not sure how expensive.

 

[CarlB]

Here's lots of information about turning movements of large buses:

http://www.mackblackwell.org/research/finals/MBTCOldFinals/MBTC1054-1.pdf

 

[TerryScan]

I have read what I believe was an earlier version of the document linked in CarlB's post. It's excellent, thanks Carl. School busses are actually quite different in turning template from the AASHTO bus or SU vehicle.

Autoturn is great software but it runs around $1200 last time I checked.

The one other thing I thought I'd comment on is your reference to a V-ditch between bus parking rows. I have usually seen bus parking designed so that one pulls through spaces (one does not have to back-up the bus). A V-ditch seems like it would be an obstruction.

 

[Focht3]

Talk to your geotech before using pervious pavement. It isn't always appropriate.

Where is the site located?



Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora.

 

[shppo]

Hi, I have found a copy of AutoTurn, and am testing the templates. The research paper was an excellent guide to the geometric design. Thanks a lot!

The concrete paved V-ditch is an existing structure. I initially thought about replacing it with vegetative cover to provide more room for infiltration. But, the V-ditch is meant to be utilized as service lane as well. So, the owner would prefer keeping it intact. Considering the amount of runoff, I was thinking may be pervious pavement could be helpful in reducing the runoff and filtering out the oil and grease. The superintendent has expressed his aversion towards detention&retention pond in fear of West Nile roaming the area. Therefore, I am considering a low-impact design scheme to avoid the need for detention&retention pond. However, I'm still trying to quantify the need.

Here is a good paper for low-impact design:

http://www.forester.net/sw_0206_infiltration.html

I'm in the Magnolia State. I have read about expansive soil not suitable for pervious concrete. But, I was hoping the existing conventional concrete would give a good indication of whether pervious concrete would be suitable, perhaps not. I'll have to pull out the soil map to check out the soil type. It would be nice to have a Geotech guy around.

Thanks all for the input!