Composite SOMD with a 3 foot cantilever

[Torres_Structural]

(Location: USA)

Currently working on a walkway that spans about 15 feet between supports. The I'm going with a deck that's about 2" in height and 6 inches of concrete cover. The deck sits on top of two Wx steel beams that span the 15 ft and are 8ft apart, with 3 foot cantilever deck on each side of the walkway. The steel beams are designed for composite action. My question lied more on the metal deck composite action. The deck was checked for the construction loads, i.e., weight of wet concrete and construction live load. the deck works with a 18ga 2CL deck (Vulcraft product). What would be the approach of designing the reinforcement on the metal deck slab. The cantilever gives a negative moment that needs to be resisted, and most of the literature of the composite action of deck and concrete (from vulcraft) does not mention a cantilever condition. Can anyone point me in the direction for resources or help on the reinforcement calculation for the applied loads at the cantilevered portion of the SOMD. Im superimposing 50 psf dead load and 90 psf live load. TIA

 

[dik]

Unless you have some extraordinary loads, with 2" floor deck you might be looking a 3" topping over the deck for a slab total thickness of 5". I'd run #4@12 top in the slab into the 3' cantilevers. For 15' spans, I likely wouldn't use composite construction. Puddle welds will secure the deck to the beams. You can use headed studs for attachment if you need. Calc and see what you really need. Supports? Hangers from something over?

The bigger problem may be in connecting the guards into the concrete topping.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[jerseyshore]

Vulcrafts older catalog had info for cantilever composite deck. It was the blue/grey one. Not sure why they removed it in the new book.

You can also send in your question to Vulcraft, their engineers have always been super helpful with design help.

 

[Torres_Structural]

Thanks @dik and @Jerseyshore

The deck is also being designed for H10 vehicle loads, assuming that someone could drive a maintenance vehicle over the deck. SO the wheel load of 8 kips, assuming it was close to the edge of the cantilever creates higher moments and that's where the reinforcement comes in hand.

Appreciate the input, I will be reaching out to Vulcraft.

 

[dik]

Didn't know that... I'd consider that an extraordinary load... frequent traffic might come into play?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[jerseyshore]

That's a big load. Any time I get any significant point load, cantilever or not, I send it in to Vulcraft. They are more than happy to perform designs usually.