Suspended Concrete Porch Slab

[pharmsmo]

I am in the process of building a new house and would like some structural design assistance in detailing the necessary requirements for the permit process to pour a suspended porch floor. The porch dimensions are as such if you start at the top of next to the house and go clockwise. 12'x4'x8'x4'x20'x8' ('L'shaped). This porch floor will be supported on the 20' side by a 9" thick 9'wall and the remaining sides will be supported by approx. 2"-4" of exposed wall. Wall is 9' Tall and 9" thick all around but due to sill plate locations the entire wall is not available to support the slab upon. What would be the necessary design guidelines to accomodate this for thickness and rebar size and placement. Their will be only minimal weight supported on the 20'edge (porch roof support posts). The remainder will be generally open for table and chairs.

 

[JAE]

Have you considered hiring a structural engineer to detail it out for you?

Are you in an area of high seismic activity?

 

[pharmsmo]

The location of building is not in an area of high seismic activity and is located upon very stable foundation. The basement foundation including the porch walls are all supported on very deep and hard bedrock that has had no movement for a very long period of time. As for hiring a structural engineer this project is so small that I was hoping to find out necessary requirements and put the details together myself. I can build anything with wood but when it comes to concrete this is an area of unfamiliarity.

 

[MGMtulsa]

Pharmsmo:

JAE is correct in that you need to hire a a structural engineer. You may have a few table and chairs most of the time. But then, there is the one time party that the next owner is going to have and his entire family will be closely gathered for a picture.

Occasionally, one reads about wooden decks that have suddenly failed, some with tragic outcomes.

The construction of a wood deck is one thing. But for a concrete deck as you describe, even the construction loads become significant and the novice could hurt himself and others during forming.

When you say "hard bedrock that has had no movement for a very long period of time", I immediately wonder why it moved in the first place.

Your permitting authority should not approve any plans unless they are stamped by an engineer who is registered to practice in that jurisdiction.

I don't intend to discourage, rather I am offering advice for the prudent. If you will provide contact information, I will correspond with you offline.

Michael Mills
Tulsa

 

[pharmsmo]

(MGMtulsa) Michael Mills please contact me @ pharms_mo@hotmail.com so we may discuss this offline.

Thanks