Slurry Walls as shear wall 1

[InDepth]

Does anyone have any guidance or experience with the use of reinforced slurry walls (diaphragm wall) as shear walls (seismic zone)?

Here are the concerns:
1) The diaphrgam wall is multiple segmented walls with no reinforcement continuity between panels and a waterstop joint. Any concerns about seismic?

2) How does the slurry wall transfer load to the foundation system? Is it typically designed with the tip of wall bearing and side friction against the diaphrahm wall below bottom of excavation used....or do you dowel the matt foundation into the slurry wall?

 

[ishvaaag]

For ordinary buildings the tip resistance can be more than enough. Side friction you may count at the diminished friction bentonite presence allows. And yes, it is almost standard practice to dowel the mat foundation to the walls; it makes sense seeing the same thing is made with the basement floors above.

Respect behaviour, you can model the walls as multistory vierendeels, with wall segments being vertical members and some fraction of the basement floors and mat the horizontal ones. Stiffness of the walls will be highly benefited by strong connections atop and bottom to some rigid termination top beam and the mat, for the basement floors are proportionally weaker. To better see the actual behaviour better the FEM line elements take shear deformation into account.

 

[hokie66]

Slurry diaphragm walls are generally end bearing. Some side wall capacity is sometimes used. Ask the geotech.

I don't think the presence of a waterstop between the panels significantly affects the shear resistance of the wall. The walls are normally at least 400 thick, and there is still plenty of concrete bearing area.

The floors, including the mat, if that is the system used, are typically keyed into the wall with pull out reinforcing. But I don't think it is usual to add the capacity of the wall and the mat edge for gravity loading.