PreSlab Construction

[msquared48]

Got asn old Days Inn from circa 1958 that is owned by another chain, and the roof framing details refer to a "preslab". Looks like a 2" deep fluted section of precast concrete used as a form for a 5" total slab thickness. The positive moment steel for the floor is in the Preslab, and the negative moment steel is in the CIP portion.

Anyone know where I can get any info on this? It looks like it ends up being a composite section... Just want to be sure...

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[JAE]

Mike - I've seen that used in bridges a lot as substitutes for formwork for bridge slabs where forming would be difficult. I've used it on a camp tornado shelter as well. Basically the pre-slab supports the wet weight of concrete with its small "d" - then compositely serves as part of the total slab.

Do your drawings show the reinforcement? You probably only need the As values and the f'c right?

 

[msquared48]

Got both on the drawings, to include the negative steel too. Just wanted to make sure it becomes composite to develop the full section.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[slickdeals]

Maybe it is a system with truss web stiffeners, as shown here.

http://www.concreteconstruction.net...tay-in Place Forms for Slabs_tcm45-346045.pdf

 

[hokie66]

As slickdeals posted, this system is used quite a lot in Australia. What did you mean by "fluted"? It needs the truss stiffeners for transport, and the truss webs also tie the precast and cast in place together.

http://www.humes.com.au/holcimcms/uploads/HUMES/HumeSlab.pdf

 

[msquared48]

By "fluted" I meant an uneven surface - sinusoidal if you can imagine - probably to develop the bond between the PC and CIP portions. Similar in shape to a 1" metal form deck. No trusses involved that I see on the plans, only a total 5" thick flat slab spanning the 12.5 feet of the units.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[slickdeals]

I think it is also called a "filigree" slab.