jdgengineer
Structural
- Dec 1, 2011
- 754
I am working on a project where the architect wants to put in a fairly large slap opening parallel to an existing concrete basement retaining wall (approximately 18').
The basement wall is a daylighting condition (1 story one side, 2 stories on the other side). The opening would be on the retaining side. The building consists of concrete exterior walls, one-way concrete elevated 1st floor slab, and wood framed hipped roof. The structure was built ~1910. I will be reinforcing the 1st floor slab as part of the project, but my main concern is with the concrete wall. We are in a high seismic area, relatively low wind area. It is likely that the basement wall was originally designed as pin-pin between the basement level and the elevated first floor slab.
One option I have been kicking around is the use of FRP. I was envisioning putting in horizontal strips of FRP on the inside of the concrete basement wall and designing the basement wall at the penetration as pin-pin spanning horizontally across the opening. I was then thinking of putting in vertical strips either side of the opening to reinforce the wall to transfer a higher load back to the slab. I would need to check the slab connection and extend the horizontal strips far enough as necessary to engage a large enough section of vertical wall area that is in contact with the slab. As an alternate, a similar approach could be done utilizing steel channels or tubes.
Above grade, I have not completely thought out my approach. It may be similar but it is a higher value area so eliminating the FRP would be ideal. Possibly, I could use the horizontal strips just near the first floor intersection to form a beam to span the opening. Still thinking about the approach.
Just wanted to get some opinions on this approach, and if you all have used another solution for similar penetrations in floor slabs supporting concrete walls.
The basement wall is a daylighting condition (1 story one side, 2 stories on the other side). The opening would be on the retaining side. The building consists of concrete exterior walls, one-way concrete elevated 1st floor slab, and wood framed hipped roof. The structure was built ~1910. I will be reinforcing the 1st floor slab as part of the project, but my main concern is with the concrete wall. We are in a high seismic area, relatively low wind area. It is likely that the basement wall was originally designed as pin-pin between the basement level and the elevated first floor slab.
One option I have been kicking around is the use of FRP. I was envisioning putting in horizontal strips of FRP on the inside of the concrete basement wall and designing the basement wall at the penetration as pin-pin spanning horizontally across the opening. I was then thinking of putting in vertical strips either side of the opening to reinforce the wall to transfer a higher load back to the slab. I would need to check the slab connection and extend the horizontal strips far enough as necessary to engage a large enough section of vertical wall area that is in contact with the slab. As an alternate, a similar approach could be done utilizing steel channels or tubes.
Above grade, I have not completely thought out my approach. It may be similar but it is a higher value area so eliminating the FRP would be ideal. Possibly, I could use the horizontal strips just near the first floor intersection to form a beam to span the opening. Still thinking about the approach.
Just wanted to get some opinions on this approach, and if you all have used another solution for similar penetrations in floor slabs supporting concrete walls.
