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Parking (automated) Topping Slab

Parking (automated) Topping Slab

Parking (automated) Topping Slab

(OP)
I have little experience with parking structures - hopefully this is an easy one for someone that does.

I've got a residential highrise that has an internal parking tower. This is an internal area of the building where for 6 stories there will be parking. The parking system is Autonomous Guided Vehicle (AGV), i.e. a small robotic platform lifts your car after you drop it off at the ground floor and the robot takes your car up a lift and drives it to the designated spot (google shows some videos of the system).

Any guidance on a recommended topping slab - thickness, reinforced(?), bonded? The parking consultant indicated that the robot wheels are very hard and that it stops/starts very quickly so they've recommended a hardener, they also said that they've seen 4" topping used but since the system is relatively new they didn't have much backup info.

RE: Parking (automated) Topping Slab

Bookowski:
I’ve never done one of these automated parking structures, so what do I know? But, the travel paths and consistency of operation and the same size of the small robotic platform lifts and travelers would seem to lend themselves to being run on some sort of steel track system. Maybe some light above slab rail (railroad type) or a light stl. channel, legs up, set in the topping. There are also solid hardened rubber or plastic tires for the wheels on the car traveler platforms which treat the narrow conc. travel ways much more gently. It seems to me that this kind of slab is going to be hard to harden properly because 80% of the slab sees only foot traffic if any; while two parallel 6" wide pathways, 5-6' apart get all the hard traffic.

RE: Parking (automated) Topping Slab

I did a feasibility study mechanical parking and found that the queuing slots required to feed a mechanical garage like this never panned out. Of course a residential class parking would be better suited since vehicle arrival/departures don't coincide like they do for an office building.

As for the slab, a 4" reinforced slab should have no problem supporting a vehicle balanced on 4 points (garage design requires a 3,000 point load over a square foot). For wear and tear, a 5,000 psi mix should be used. What climate is the garage in? Cars bringing in salty snow in this area would definitely cause some difficulties for this type of automated parking.

RE: Parking (automated) Topping Slab

As to bonding new to old concrete, my experience has found that a thoroughly cleaned concrete surface (such as one having had deteriorated, salt effected removed), vacuumed and then gets this treatment works. Just before placing new topping, brush on to a BONE DRY surface a cream made from Portland cement and water, worked in with a broom. before it hardly has set much, place the new overlay. Later cut a few cores and try to break them with a chisel at the bond. Likely the bond will hold.

RE: Parking (automated) Topping Slab

The AGV's I have seen in auto plants simply follow a metallic wire or cable buried just below the finished floor in a slab on grade. Since you are asking about a topping slab, I will assume that there is some sort of main slab or precast tee's below. In any case, I would not provide a topping less than 2" thick and may consider 3" thick with some reinforcement. What does the parking consultant mean by "very hard" wheels....steel? hard plastic? If so, I would get the wheel size and specs from the AGV manufacturer and take a swag at a contact area, calculate the stress below, and see if the topping can handle it. I would use a bonded topping and provide surface hardener only in the travel path of the AGV. Surface hardeners can get $$$.

RE: Parking (automated) Topping Slab

(OP)
Thanks, my question wasn't very clear and I've got more questions after looking at it more.

Better description: For simplicity lets say I have a 100' x 100' plan building and within that is an area of say 30' x 30' for automated parking. The parking is a tower that occupies 6 floors of the building but since they need less clear height it is more than 6 stories tall, some of the parking levels align with building floors and some don't. The parking 'tower' is flat plate cip and supported from building columns. Where the slabs happen to be at the same elevation there is continuity with the slab, at other locations the parking slab is framed with beams between building columns.

I have almost no experience with parking structures, in particular I'm worried about durability and protection of the reinf:
- the agv will repeat the same route over and over with hard wheels (don't have 'hard' quantified yet) and parking consultant recommended topping slab w/hardener
- the architect has not left the height for a topping slab so wants to omit it.
- Should I be doing a cip parking system like this w/out a topping? If so should a sealer be used? Can a hardener and sealer be used together?
- Epoxy coated reinf?
- The fact that the parking slabs connect to building columns and slabs worries me - should I extend protection some distance beyond protection?

I've been reading up on parking but haven't found anything definitive to answer my questions.

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