Car Park Floor Loading
Car Park Floor Loading
(OP)
I am at the initial stage of designing a multi-storey car park but have doubts on floor loading. I have been using imposed loading 2,5kN/m2 for vehicles not exceeding 2.500Kg gross mass as provided in BS 6399 Part 1 but some one is advising me to increase the loading by 25% to cater for dynamic effect induced on the structure during braking and acceleration. I thought the dynamic effect is already catered for by 2,5kN/m2. Am I wrong? Please advise.






RE: Car Park Floor Loading
RE: Car Park Floor Loading
RE: Car Park Floor Loading
No dynamic effect is need , 2.5kN/m2 as you have it is applicable. Your natianl annex may dictate a specific value but according to EN a range value 1,5 to 2,5 kN/m2 and point load of 10 to 20 kN is specifed for:
Traffic and parking areas for light vehicles ( < 30 kN gross vehicle weight and 8 seats not including driver)
-Access to areas should be limited by physical means built into the structure & posted with the appropriate warning signs.
RE: Car Park Floor Loading
RE: Car Park Floor Loading
Brian C Potter, PE
http://simplesupports.wordpress.com
RE: Car Park Floor Loading
Wow, that makes me nervous. While that may, perhaps, be justifiable if the garage is never loaded beyond it's design load, it's tough to ensure that at some point someone won't drive something onto the garage that doesn't belong there. To wit, see this video:
http://www.youtube.com/watch?v=EKRz2WThyf0
Unfortunately that type of thing happens more that people realize because snow removal is a serious logistical undertaking. People such as ajk1, who have to deal with this regularly (in Canada), design for this with that heavy loading in the staging area he referenced. But, ironically, areas where there is less snow fall might be more susceptible to such problems because they don't have to have as rigorous a snow removal program in place and the maintenance personnel may not be aware of the dangers involved.
And then there's the issue of corrosion and periodic maintenance...
RE: Car Park Floor Loading
The reduction is only permitted for vertical members (columns, walls) supporting 2 or more floors. So it'd take quite a few rogue vehicles before the loading became dangerous.
However, I tend to agree - the loading for garages skirts a lot closer to the max a garage is likely to see than I'm comfortable with. A fully loaded pickup truck or SUV will weigh a lot more than 40 psf, so it's only by taking into account the drive aisles won't be full and that people will obey the striping that the design works.
Brian C Potter, PE
http://simplesupports.wordpress.com
RE: Car Park Floor Loading
Oh. Thanks for the clarification.
And those things do bounce a lot...
RE: Car Park Floor Loading
RE: Car Park Floor Loading
Corrosion is a bigger issue, and we have a separate standard for parkade design.
Dik
RE: Car Park Floor Loading
RE: Car Park Floor Loading
RE: Car Park Floor Loading
http://webarchive.nationalarchives.gov.uk/20120919...
http://webarchive.nationalarchives.gov.uk/20120919...
RE: Car Park Floor Loading
Mike McCann
MMC Engineering
RE: Car Park Floor Loading
Dik
RE: Car Park Floor Loading
Realistically, a stopping vehicle, esp. one stopping suddenly, will exert a (small) lateral force into the structure, via the horizontal diaphragm- which will surely distribute it into the MFRS.
More interesting than this stopping force, would be an impact force- 10,000 pounds at 18" above grade. No ABS action to attenuate a bumper crashing into the parapet or spandrel.
The Steel Deck Institute does say 35 psf is more realistic. However, the ASCE 7 lists 40 psf, and calls it irreducable.
Curiously, however, reducing the 2.5 kN by 25% is about 41 psf, very close to the ASCE 7 live load. Perhaps there is a 25% increase. But, more likely, the Canadian code uses the same sources as the US codes, and has not (yet) decreased the design value.