Masonry Lap Splices

[CTSeng]

Curious as to who is using the ACI530-05 rebar lap-splice calculations. They increase laps dramatically for bars larger than #5 to the point that #6 and larger are uneconomical.

We've been noticing few people using them and no building departments aware of this change. Everyone is sticking to the 48 bar diameters.

 

[jike]

This change happened with the adoption of IBC 2000 and we changed our practice to exclude #6 bars and larger as you indicate. ACI 350 was still debating this and was in the process of review. I was not aware that ACI 350-05 adopted it.

 

[Lutfi]

ACI made the change in the previous edition as well. Florida Building Code has similar lap splice formals. I agree the length gets ridiculous large for bars #6 and larger.

I am old school; I do not see anything wrong with the old rule of 48 times bar diameter or something similar to it would have done nicely.

In my humble opinion, some PhD researcher (All PhDs please forgive for saying so) got a hold of that portion of the code and decided to add more complexity!


Regards,
Lutfi

 

[haynewp]

Don't confuse 350 with 530. And it may be ridiculous, but unfortunately it is not optional under the new codes.


The ideal engineer is a composite ... He is not a scientist, he is not a mathematician, he is not a sociologist or a writer; but he may use the knowledge and techniques of any or all of these disciplines in solving engineering problems.
-N. W. Dougherty

 

[jike]

The 350 is a typo, I meant 530!

I have been around for a number of years and agree with Lufti's comments

 

[haynewp]

It would seem that this could be easily tested and shown if the 48 dia works or not. What happened? They must have changed it to a more strict fractile percentage working than previous. But I am not sure what is causing the large gap at the >#5 bar sizes.


The ideal engineer is a composite ... He is not a scientist, he is not a mathematician, he is not a sociologist or a writer; but he may use the knowledge and techniques of any or all of these disciplines in solving engineering problems.
-N. W. Dougherty

 

[rt06]

The new code requirement is based on review of available test data. But the problem is the test data is not enough and masonry material itself is so variable. I believe ACI 530 committee is aware of this and they are working to improve it. Hopefully the improvement will show up in the next edition of code.