Concrete Tension Tie Mech. Splices? ACI 318 12.5

[Gebau]

I am designing a metal building foundation with a concrete "grade" beam at each column to resist the Outward Thrust forces imposed by the columns.
Just noticed ACI318-05 sect 12.5 requires Mechanical Splices for Tension Tie beams, but cannot find any definition of what constitutes a tie beam.
In this case, I have 2x the Area of Steel required and initially designed with staggered Class A Splices. Do I have to go to Mechanical Splices?

 

[slickdeals]

A tension tie is a member that is subject to net tension. I would think a grade beam that acts as a tension tie would constitute a member requiring mechanical splices. That's how I would interpret the code.

If you provided 2 times the reinforcing, then are you required to have mechanical splices? By code , unfortunately yes.

 

[msquared48]

If this "grade beam" is in line with the mainframes to take the kick, for the larger forces that hairpins cannot take, I use a welded angle splice, with the area of the angle equal to or greater than the rebar being welded. I also stagger the splices and provide an even number of bars to avoid any eccentricity in the tension resistance.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[joeHSE]

Dayton Superior (and others) make good couplers and they are easy to install. Then you don't have to mess with spec'ing A706 for the rebar and deal with the contractor getting A615 "by mistake". Plus worrying about weld quality. If you are dealing with high loads and it sounds like you are then I'd go with the coupler.