taking out eccentricity from precast wall to capping beam
taking out eccentricity from precast wall to capping beam
(OP)
Hi all,
can someone remind me how to draw and calculate the correct strut and tie model/ (force through the reinforcement bar) to show how the ground floor slab helps take out the eccentricity from precast wall landing eccentric from the supporting capping beam?
i know it works but i just cant seem to recall how to draw one properly.
alternatively, ive justify that if the moment induced in the capping beam is this much, i will create a push and pull free body diagram in the ground floor slab to calculate how much reinforcement i need.
Thanks all!
can someone remind me how to draw and calculate the correct strut and tie model/ (force through the reinforcement bar) to show how the ground floor slab helps take out the eccentricity from precast wall landing eccentric from the supporting capping beam?
i know it works but i just cant seem to recall how to draw one properly.
alternatively, ive justify that if the moment induced in the capping beam is this much, i will create a push and pull free body diagram in the ground floor slab to calculate how much reinforcement i need.
Thanks all!






RE: taking out eccentricity from precast wall to capping beam
RE: taking out eccentricity from precast wall to capping beam
thanks
RE: taking out eccentricity from precast wall to capping beam
RE: taking out eccentricity from precast wall to capping beam
I'd like to think that BowlingDanish and I are on the same page here regarding the z-bars but, at the same time, I don't want to risk putting words in his mouth.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: taking out eccentricity from precast wall to capping beam
sorry for the late reply. Thank you for the detailed sketch. That STM made a lot of sense. I was trying to draw one up myself but did not achieve a result as clear as yours.
Just to clarify that the C compression and T tension is supposed to be the other way around in your sketch..top of slab is in tension after all.
Couldn't the strut that changed from sketch 1 and 2 run straight to the pile? wouldn't that be more direct pathway?
Also, i would expect a high shear area just before the slab sits on the capping beam. Should there be another tie in this area?
Thanks.
RE: taking out eccentricity from precast wall to capping beam
Quite right.
I don't see how it could do that and also provide anchorage for the tie holding the left end of the slab down. Perhaps there are other STM's possible that could be set up to facilitate that. I was gunning for a reinforcement layout that would be as simple as possible.
You'll need to assess shear along the length of the slab and provide shear capacity as required. That may or may not require reinforcement (hopefully not). I'd expect the highest slab shear to occur over top of the capping beam.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: taking out eccentricity from precast wall to capping beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: taking out eccentricity from precast wall to capping beam
RE: taking out eccentricity from precast wall to capping beam
RE: taking out eccentricity from precast wall to capping beam
It would be great if you could post a plan view sketch. We've been exploring models that imply that all of your eccentricity is resolved by the slab at the pile. My suspicion is that the capping beams span between discretely located piles and that the eccentricity is mostly transferred to the slab continuously between piles.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: taking out eccentricity from precast wall to capping beam
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: taking out eccentricity from precast wall to capping beam
Just to beat this dead horse - It might make sense to put the slab and cap into the same pour.