CRSI Retaining Wall Tables

[tw]

What are the "D" bars in the CRSI retaining wall tables for? I assume shear but there is little info given about them and they aren't included in any of the past tables.

tw

 

[mrengineer]

I have the 2002 CRSI Design Handbook. Per page
14-11, ""D" bars in the stem/base were designed for shear at the base of the stem and at the face of the heel". They also show calculations in manual exampples on pages 14-17 and 14-20.

 

[vincentpa]

Shear friction bars. If you are using a shear key at the base of the wall, D bars are unnecessary.

 

[Galambos]

vincentpa, i think D bars are for shear on the concrete section and are sized as such, whereas the shear key is designed to resist the sliding force on the foundation as a whole.

 

[WillisV]

Galambos - no, vincentpa was referring to an actual keyway between the bottom of the wall step and the top of the footing to resist shear between the stem and footing, not the concrete key down into the soil to resist sliding.

This key is commonly made with a 2x4 or 2x6, however IMHO roughing the surface appropriately is just as good or better. The CRSI D bars are used for shear friction at the stem to foundation interface however many people (including myself) use the vertical reinforcing dowels for shear friction without the additional D-bars if possible.