Sfe crossfall for delivery vehicles 1

[swazimatt]

It has been a while since i last posted here, (guess i have been learning!)

I am busy designing the platforms for parking and delivery to a new supermarket. I have searched all about the parking slopes etc and see that the consensus is to not exceed 10% on ramps which is fine, but the delivery area is parallel to a road that slopes at 2%.
The trucks will drive into the loading area with the grade, but to get all my levels to tie in (delivery and parking and FFL) i find that the loading apron will slope towards the road at between 7 and 7.5%. Will this be ok for a crossfall for delivery trucks?

 

[civilman72]

Is this a raised loading dock that trucks will back into? If so, the area the wheels are parked on should be level.

 

[swazimatt]

no this is a badly laid out dock (i can say this because i know the architect will never come on this forum!) they will reverse towards the refuse skips, with the loading doors ending up next to the truck cab, i guess they will off-load to the floor and then trolley into the building.
I am pretty confident that while it is inconvenient to load and work on a 7% slope the truck will not fall over at that cross-fall

 

[civilman72]

If they are going to hand deliver (with a dolly) I agree that having a flat parking area is not necessary.

 

[eea]

I have found the Kelly Dock product manual a great reference for slope and height considerations. They also have generic forklift tolerances, trailer heights / angles, dock cushions, ... It has been my go to reference book for truck docks and loading areas over a decade. The smaller panel vans are a different matter and harder to get at. I've done site visits of comparable installations to help define those with the owner, but it sounds like they are unloading only.

Also review semi backup movements. You might need full blown AutoTurn for the backup envelopes, the AASHTO radius templates are usually forward sweeps only. First pass rule of thumb is double the length of the tractor-trailer for a working length in front of the dock. Street departments normally do not let you use the public street as part of this, although in older business districts and on alleys they are more tolerant.

 

[swazimatt]

thanks
the more i look into this the less i think the architect has!!

 

[brandonbw]

That's why I have been hearing more and more that Civils are starting to design siteplan layouts completely bypassing Architects.

B+W Engineering and Design
Los Angeles Civil Engineer and Structural Engineer

http://bwengr.com

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http://bwstructuralengineer.com

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http://bwcivilengineer.com

 

[swazimatt]

I think the less involvement from architects the better, but would guess they may increase their fees for an offensive attack on their ego.

 

[eea]

I have had the Arch insist that they have to be the lead designer / consultant on any project due to their licensure act. This being on life safety reviews for zoning change of uses, remodels, thru new buildings. I think it best to demonstrate the site planning constraints and considerations that they have missed. Who knows, you might building a good alliance out of the project? I say that in the full acknowledgement that I'd rather have my toe nails pulled out one by one, but given the right relationship. I'll readily acknowledge my lack of an art-full eye on landscaping and building design, I'm basically a nuts and bolts PE. I've worked with some pretty impressive, down to earth practical architects as well. You'd be amazed when you can tell a client you have one to pull in on a project who's not looking to be the next Frank Lloyd Wright.

 

[TGLG]

If I am reading you right, swazimatt, you are saying that the 7% to 7.5% slope runs perpendicular to the axis of the truck.
If that is the case, given the width of a truck (about 8.5'), when the truck is sitting at the dock the back left corner will be about 7.5" higher (or lower) than the back right corner. This is not a generally a workable condition. Remember, they'll need to drive a forklift or pallet jack from the dock into the truck and back. If the tail of the truck is not level with the edge of the dock, that will not be possible.
You are probably going to need a retaining wall at one side of the loading berths.

Also, in general, it is best to have the loading berth pitch towards the building, rather than away (in other words, the tail of the truck is lower than the nose). That way, the truck is less likely to roll away from the dock when they drive the forklift onto the trailer.

Also watch out for sharp breaks in grade in truck access areas. If the break in grade is too severe, it is possible for the landing gear on a trailer to catch on the pavement. This can cause the landing gear to break and/or knock the trailer loose from the truck.