Contact vs. Non COntact Splices

[johnnybeltway]

I have a question about contact splices. I understand that non-contact splices are allowed, if they are designed as non-contact splices. My question is if you have a designed contact splice, is there any tolerance for the bars to be not in full contact. I have been back and forth with a few people and I have done a bunch of searches, but I cant seem to find an answer.

Thanks,

 

[UcfSE]

Try ACI 318-05 12.14.2.3.

 

[dukem]

12.14.2.3 isn't very clear. The contact/noncontact distinction makes it sound like there should be different procedures for the design of each. Is a noncontact lap splice designed with the same procedure as a contact lap splice as long as the gap between the lapped bars is within the limits in 12.14.2.3?

 

[TXStructural]

There is no difference in contact or non-contact lap splices. Wiring the bars together is the best way to assure that the bars are not displaced during placement of concrete, but other methods which secure the bars is permitted under the code. Bars must be secured into position before and during concrete placement.

CRSI publication Reinforcing Bars: Anchorage and Splices paragraph 3.1.1 describes the contact/non-contact issue.

ACI 318 7.5.1 requires securing reinforcement prior to concrete placement.

John Turner CSP PE
CRSI Greater Southwestern Regional Manager

 

[henri2]

"ACI 318 7.5.1 requires securing reinforcement prior to concrete placement."--John Turner

This is what the code states, but in reality this rule is regularly flouted. A lot of dowels intended to anchor walls to footings are simply "wet-set"; unless of course, the RDP is present during installation and concrete placement and puts his/her foot down.

 

[TXStructural]

Wet setting dowels is a good way to get bad connections. It is prohibited because, unless they are vibrated in before initial concrete set, there will likely be little or no structural bond development. Vibrating them (which requires liquifaction of the concrete) prevents them from staying in place. Once the concrete is stiff enough to hold, it is too stiff to consolidate properly around the bar.