Retaining Wall Reinforcing

[Eng_Girl]

Hi Everyone,

I've never quite understood the concept of skin reinforcing. I understand it's purpose is to prevent surface cracks but I'm wondering if I need to supply skin reinforcing as well as flexural reinforcing. For context, I'm designing a retaining wall which has 25M @150 both ways each face. That'd be 6 bars per meter each way so actually 12 bars with a total area of 6000 mm2 (each face). My required skin reinforcing is 4300 mm2 so I thought I didn't need skin reinforcing as well. Is this correct?

 

[GeorgeTheCivilEngineer]

That would be my take on it.

 

[BridgeSmith]

Not sure about other codes/specifications, but my understanding of AASHTO skin reinforcement is that it's required in the side faces of flexural members in the tension region. IOW, along the bottom half of the sides of a simple span beam or the entire side faces of a continuous beam. It would theoretically be applied to the ends of a retaining wall, but the wall would have to be more than 30" thick to actually require it.

 

[Eng_Girl]

Thanks for the replies!

Yes A23.3 has that as well. So where my wall only 18" thick I wouldn't require skin reinforcing.

 

[BridgeSmith]

Yes, for a 'beam' less than 30" 'deep', skin reinforcement would not be required, per AASHTO. Even for a wall greater than 30" thick, it would theoretically only be required for the back half of ends of the wall, not the front face. That's assuming the ends of the stem were exposed, which they typically would not be.