Two-story slab on grade foundation footing in California

[bill1952]

You seal a 1501 ft house in NY?...Sure is easy to spend OPM.....

Well, I don't.

 

[bill1952]

for 3-#4 As=0.6 in sq and for 2-#5 As=0.62 in sq thus essentially the same for material. But if you consider the labor to install the reinforcement since there are fewer bars to be handled #5 bars would be cheaper.

Even though you can't bend them on site?

 

[Msradell]

Even though you can't bend them on site?

Bending them really isn't an issue, when you buy the rebar they carried you the same for bent as they do straight rebar at most places. Just order appropriate number of corners, offsets or whatever else you need. Obviously if you are doing 2 layers you are also going to need some chairs anyway.

 

[Ed Cooke]

I just looked all over the internet for a detail for a two-story slab on grade footing. I was wondering if anyone had called out #4 rebar instead of #5.

I am a building designer and always have to listen to my engineer. He calls out 2-#4 rebar top and bottom, 4 rows total, in my 12″ wide x 12″ into grade one story footings. He calls out #5 in my two-story footings.

But I was curious if I could use #4 rebar in a 15″ wide x 18″ into grade two-story footing.

Well, I didn’t find anything. No detail or thread that explicitly discussed this. Then a contractor called and I asked him. He said he has always seen 2-#5 T&B.

I thought I would post this to see if anyone had any comments on the matter. Also, if anyone asks this question in the future, maybe they will find this thread.

Thanks

Hello, my first question is what did your soil report state? 2nd, in the 2019 CRC, section R403.1.3.3 provides the minimum reinforcement in Seismic Zones D.
The normal reinforcement for footings seem to be 2-#5's, but that is more than the code requires. All I can say is, how quickly do you want to get through plan review? Taking time to look up design details offers opportunity to find relevant code sections that need also to be adhered to!!

 

[atvjoel]

Why do we do things the way we do? Sometimes it is simply years of experience and we know what will work.

Where does it say it in the code or juris. Muni code? We have footing and foundation details that have been designed by an engineer that the city has been using for decades. Not adopted or in the code but is code compliant and is now the standard details on residential projects.

What's the best explanation? Just stuff like that. See above

Other side of the coin is you can have people that just want to pass plan review the 1st time so they way over engineer everything, I had this on a Foundation I built. Two story and had to install 4 - 1 1/4 all through through my footing up to nearly the top of my stem wall on each side of my gable end with windows, #5 rebar 15" on centers in my footing along with bunch of other things, insanity. I have seen bridges built not as solid (joke). Never a bad thing but at the end of the day its still got to come out of everyones pocketbook. Not that #5 rebar is really going to cost much more in this case though.

 

[atvjoel]

Other side of the coin is you can have people that just want to pass plan review the 1st time so they way over engineer everything, I had this on a Foundation I built. Two story and had to install 4 - 1 1/4 all through through my footing up to nearly the top of my stem wall on each side of my gable end with windows, #5 rebar 15" on centers in my footing along with bunch of other things, insanity. I have seen bridges built not as solid (joke). Never a bad thing but at the end of the day its still got to come out of everyones pocketbook. Not that #5 rebar is really going to cost much more in this case though.

Why do we do things the way we do? Sometimes it is simply years of experience and we know what will work.

Where does it say it in the code or juris. Muni code? We have footing and foundation details that have been designed by an engineer that the city has been using for decades. Not adopted or in the code but is code compliant and is now the standard details on residential projects.

What's the best explanation? Just stuff like that. See above

All thread*