underground garage ramp gradient

lg123

hi all,


i know this is a very engineering question but i cant find an aussie online community where i can ask the question, hopefully some engineers frequent here!!

does anyone know the max slope gradient you can use for a ramp down into an underground carpark in NSW?
specifically for a block of apartments where the access would include driving across the footpath and then onto the slope down to the basement carpark.

irishmover

I'm not going to be huge help to you.

But did you come across this when you done a google search? Sydney 1996.

http://www.cityofsydney.nsw.gov.au/__data/assets/pdf_file/0004/119632/DCP11_Section4.pdf

Section 4.4

lg123

yes, found that too, thanks. i'm hoping someone is familiar with whats in the aus standard.

irishmover

lg123 wrote: »

yes, found that too, thanks. i'm hoping someone is familiar with whats in the aus standard.

Definitely look specifically for the NSW standard. Good luck.

AngryHippie

If its specified in a local council reg. you must abide by that, otherwise elevate to state regulation, or then to Austroads and Australian standards. That is the normal hierarchy for design. an Excerpt from Australian Standard below. It's not complete as there are templates which need to be modeled also during the design process. There are several software packages that can do it all for you....




2.6.2 Gradients
The maximum gradient of domestic driveways shall be 1 in 4 (25%). The maximum
gradient of the associated access driveway across a property line or building alignment shall
be 1 in 20 (5%) and across a footpath as specified in Clause 3.3(d).
Grade changes across a footpath and within the property shall be designed and checked in
accordance with Appendix C to ensure that vehicles will not scrape their undersides when
negotiating them. Transitions may be required (see Clause 2.5.3(d)). Checks may be
required along one or both edges of a driveway as well as along the centre line if there are
changes in the cross slope at or near a grade change.
NOTE: It is recognized that limiting domestic driveway grades to 25 percent maximum may not
be practicable in some particularly hilly residential locations. The services of a professionally
qualified person with appropriate experience may be required to make a judgement as to whether
a particular grade line design is safe and environmentally sustainable.


3.3 GRADIENTS OF ACCESS DRIVEWAYS
At entry and exit points, the access driveway should be graded to minimize problems
associated with crossing the footpath and entering the traffic in the frontage road.
Maximum gradients on and near access driveways, other than at domestic properties (see
Clause 2.6), shall be as follows:
(a) Property line/building alignment/pedestrian path—max. 1 in 20 (5%) between edge
of frontage road and the property line, building alignment or pedestrian path (except
as provided in Item (d)), and for at least the first 6 m into the car park (except as
provided below).
The grade of the first 6 m into the car park may be increased to 1 in 8 (12.5%)
provided all three of the following conditions are met:
(i) The grade is a downgrade for traffic leaving the property and entering the
frontage road.
(ii) The user class is Class 1, 1A or 2 only.
(iii) The maximum car park size is—
(1) for entry into an arterial road—25 car spaces, or
(2) for entry onto a local road—100 car spaces.
The maximum grade across the property line shall remain at 1 in 20 (5%).
(b) Vehicular control points—max. 1 in 20 (5%) for at least 6 m prior to the control
point.
(c) Queuing area—max. 1 in 10 (10%) for not less than 0.8 of the queue length
determined in Table 3.3.
(d) Across footpaths—where the driveway crosses a footpath, the driveway grade shall be
1 in 40 (2.5%) or less across the footpath over a lateral distance of at least 1.0 m.
NOTE: The advice of the relevant regulatory authority should be sought to obtain grade
requirements for footpaths.
(e) For ramps and circulation roadways at locations other than in Items (a) to (d), see
Clause 2.5.3.
(f) For domestic driveways, see Clause 2.6.

A base dimension for ground clearance based on measurements of actual vehicles has been
adopted as 120 mm (fully loaded vehicle). The following additional base dimensions have
been adopted:
(a) The vehicle is to be capable of negotiating a sharp 8 degree grade change, positive or
negative, without any part of the underside between axles grounding (adopted from
ADR 43).
(b) The departure angle is 10 degrees (determined by measurement of actual vehicles).
NOTE: Approach angles for most vehicles will be greater than 10 degrees, but for practical
purposes it has been adopted as 10 degrees.
This means in effect that if a grade change of more than 8 degrees (or 14 percent) is
required, it needs either to be effected in two or more stages, each separated by at least the
longest wheelbase among vehicles using the facility, or by design of a vertical curve which
will achieve the same objective. This grade change has been reduced to 12.5 percent in the
Standard (see Clause 2.5.3(d)) to provide an additional clearance
margin. The wheelbase of
the B99 vehicle is 3.05 m.
NOTE: It has been established that despite the foregoing, some of the more exotic sports cars can
have significantly lower ground clearances. If it is desired to provide a facility for this type of
vehicle, designers should consider modifying the design aids given in this Standard to suit.


Out of curiosity, is it because you live in an apt with a fcuked up car-park and ripped the skirts off your car ?
Because if thats the case, and you have lowered them from stock standard, you have your sh!te, they aren't liable.

Mellor

lg123 wrote:

yes, found that too, thanks. i'm hoping someone is familiar with whats in the aus standard.]Definitely look specifically for the NSW standard. Good luck.

That South Sydney Council DCP is quoting the Aus Standard. SSC doesn't exist anymore, and AS 2004 was updated a few years ago, but its still more or less the same.

Basically the max grades are;
Maximum Gradient Straight ramps <20m Straight ramps >20m
Public car parks 1in 6 (16.7%) 1in 5 (20%)
Private/Residential Car Parks 1 in 5 (20%) 1 in 4(25%)
Domestic driveways 1 in 4 (25%) 1 in 4 (25%)


Changes in grade need a half grade transition over a set distance too. (Angry Hippie, its from Clause 2.5.3 of AS 2890, is it 2m?)

And grades across public pathways, at entries etc need to be dealt with as listed by AngryHippie above.




What exactly is the issue, might be in easier to look at it directly, rather than bombarding you with all the different situations.

AngryHippie

Mellor wrote: »

Changes in grade need a half grade transition over a set distance too. (Angry Hippie, its from Clause 2.5.3 of AS 2890, is it 2m?)

.

From 2.5.3
(d) Changes of grade—To prevent vehicles scraping or bottoming, changes in grade in
excess of—
(i) 12.5 percent algebraically (1 in 8) for summit grade changes; or
(ii) 15 percent algebraically (1 in 6.7) for sag grade changes;
require introduction of a grade transition between the main grade lines as illustrated
in Figure 2.10.

lg123

thanks for that hippie.

the reason i am asking is similar to your suggested. on the top end of the ramp, the transition is very severe, if non-existent. my car is a stock standard commodore and the mrs is the same. it really tears the arse out of mine, her's not as bad, but mine was so bad i didn't bring it into the garage again.

we are paying top dollar for a double garage and i can never use it and she really shouldn't be using it. we only moved in a week ago.
our lease agreement has the following clauses:
a break fee of 6 weeks rent.
under general obligations, the landlord agrees to make sure the residential premises are fit to live in.
the garage is parking of vehicles only, not for storage of goods.

i want to get my head around my legal position before the agent tries to sting us with the break fee.

Mellor

Thanks Hippy, I found the diagram online myself. Bizarrely, the Kingdom of Bahrain borrowed AS 2890. The diagram doesn't state the transition length, but 2.5.3 (e) lists says its 2m, so still the same as the 1996 SSC document.


lg123, there should be a half grade transition at the top, it can be curved or straight, but it should be pretty obvious if its not there.
One point to remember though, If the building/carpark is older than the standard, then it doesn't apply retrospectively. Is it a less than 20 years old??

lg123

it wouldn't be far off the 20 years I'd guess but don't really know.

going to call the agent later to see his angle.

AngryHippie

lg123 wrote: »

thanks for that hippie.

the reason i am asking is similar to your suggested. on the top end of the ramp, the transition is very severe, if non-existent. my car is a stock standard commodore and the mrs is the same. it really tears the arse out of mine, her's not as bad, but mine was so bad i didn't bring it into the garage again.

we are paying top dollar for a double garage and i can never use it and she really shouldn't be using it. we only moved in a week ago.
our lease agreement has the following clauses:
a break fee of 6 weeks rent.
under general obligations, the landlord agrees to make sure the residential premises are fit to live in.
the garage is parking of vehicles only, not for storage of goods.

i want to get my head around my legal position before the agent tries to sting us with the break fee.

Was it the fenders that bottomed out, or the sump guard/floor ?

What year commodore is it ?
I only ask because I had an old VR at one stage a few years back, and there probably hadn't been 120mm clearance since 6 months after it was bought. luckily I didn't give a fook about it, so I just let it drag its ar$e around everywhere it went. (even got sparks a few times)

If they are older commodores, its the car. The suspension will be shot to sh!t, and she'll have dropped. You will find the same in some supermarket car-parks, and speed bumps will make your spine tingle with the noise.

It's probably worth having a look and checking the fall on the off chance, but to get out of a lease, you'll probably need to back it up with an engineers report etc. They can get pretty sticky. I'd be pushing for them to provide on-street or permit parking for you

lg123

na, i think mine is a 2012 VE model, and hers is a 2006ish VZ. i know its not the highest car on the market but the ramp is ridiculous.

rang the real estate agent anyways, he said we could pay him a weeks rent and he would advertise, find a new tenant. also, we would also be liable for rent during any gap in us moving out and the new tenant moving in. jees, i hate moving, major pain in the ass.

AngryHippie

I hear ya.

I've just re-signed for another 12 months on mine. even though it only has a single parking space. Couldn't be ar$ed moving.