carpark ramp slope

[lorik]

hi to everybody.
i would like to ask, what should be the slope of a ramp inside a carpark for cars not to hit ground during climbing or going down. carpark is limited with cars 1.75 m. in width and 5 m. in length. thanks.

 

[RWF7437]

Go visit a few and measure the slopes used.

 

[ERV]

We generally limit slopes to 19%, another consideration is traction. If snow or ice is a contirbuting factor you may want to limit slope to less than that.

 

[lorik]

thanks evr, this carpark will be in moscow and unheated. however ramps will be electrically heated so sliding factor is not considered.
btw i ve just learned that in many countries` legislations, slope is limited to %15. it is surprising that you design steeper than this figure though the american cars are longer than any other countries` cars.

 

[ERV]

lorik,

19% is max slope, however, actual slope may be less than that. Regardless of the size (length) of the vehicle, it is ground clearance that determines drag of vehicle at top or bottom of slope. Most vehicle are designed to clear this requirement.

 

[dik]

With a 19% slope, a transition is required at both the top and bottom if abutting a flat surface. The transition should be 5' and 5' on either side of the vertex. This should be checked with a 'standard' short wheel based automobile to see that the undercarriage does not 'impact'.

 

[gibfrog]

I recently performed the "functionality" design of a precast concrete parking garage. I made it user friendly to vehicles. (There are even "levels of service" for parkign garage design.) Here are some rules of thumb -

1)Maximum slope for parking cars is 5%-6%. This is due the the physical arm strength required to open and close the car doors, especially for older drivers.

2)Maximum slope for a ramp is 10% with pedestrian access on the ramp and 12% if used by fork lifts. Slopes over 15% will be intimidating to older drivers, 20% is a good maximum, but steeper is possible.

3) Slopes over 8% will either require vertical curves or 10 foot transitions to flat to prevent bottoming out. If you go over 16% to flat, use a vertical curve.


Clifford H Laubstein
FL PE 58662

 

[gibfrog]

I forgot to add -

3a) The 10' transitions should be at 1/2 the slope difference.

4) Check out

http://www.pci.org.

Go to the knowledge bank and get downlaod their free booklet on parking structures. I downloaded it about 18 months ago. There are only a few pages that deal with slopes.

Best of luck....

Clifford H Laubstein
FL PE 58662

 

[lorik]

thanks gibfrog...