2 Way Slab Reinforcing

[BadgerPE]

I am reviewing some existing plans and reinforcing drawings for a 2 way slab constructed in the 1960s. This is a 9" slab with drop panels and column capitals. I haven't designed one myself in the past, so my question is this, is it normal to have the top mat oriented 1 direction (say east-west) and the lower mat oriented the opposite (north-south)? I am in the preliminary stages of budgeting for analysis only, but that seems a bit strange to me. Maybe I don't have a solid handle on the reinforcing drawings.

 

[canwesteng]

Never seen anything like that myself. Are there any acronyms near the bar callouts?

 

[BadgerPE]

Here are the sheets I am looking at with the specific area highlighted in yellow.

 

[DaveAtkins]

The drawing says there is top steel in both directions, and bottom steel in both directions.

DaveAtkins

 

[BadgerPE]

I agree with that, but it doesn't appear that the schedule does....unless it is saying use the designated bar in each direction.

 

[hokie66]

1, 2, 3, 4. Looks clear to me. In fact, a much better drawing than we see nowadays.

 

[BadgerPE]

I agree hokie. Would you interpret the schedule to mean that the bar listed (i.e. CB3) should be placed in both directions?

 

[hokie66]

No, the CB3 bars are North-South. For the East-West bars, go to that schedule.

 

[BadgerPE]

Right, but CB3 also says "bottom bars" so it is only indicating bars in 1 direction. See my confusion?

Unless "North-South Column Bands" is indicative of the physical orientation of the strip and not the orientation of the bars. Therefore, the CB3 bars would be the "bottom bars" in both directions and the TB25 would be the "top bars" in both directions.

 

[hokie66]

No, you need to spend a bit of time learning how to read these plans, which were typical of the time, and in my opinion, much clearer than some plans today.

In the yellowed in area, the East-West bottom bars are the ends of MB31 and MB39 bars. See the typical placement details for how they are curtailed.

The North-South top bars in that area are TB2 from the bottom, and TB7 from the top. In the East-West direction, you have the middle strip top reinforcing, which are TB25 bars.

Looks like all the bars are #6. In the 60's, they could be Grade 40 or 60, most likely 60.

 

[DaveAtkins]

I see north-south bottom, for column strip and middle strip, then east-west bottom for column strip and middle strip, then north-south top, for column strip and middle strip, then east-west top, for column strip and middle strip.

DaveAtkins

 

[BadgerPE]

Will do. Thanks hokie for the help...haven't seen shop drawings like this before (or any 2-way for that matter).

 

[Ingenuity]

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