Bolts thru grouted masonry wall
Bolts thru grouted masonry wall
(OP)
Referring to the attached drawing, I have several questions. The situation is as follows:
The client desires to remove a section of bearing wall which is around 18' high and supports approx. 35' of steel bar joist/deck roof system. Although I've done this before, I've wondered what others think of certain aspects:
1. Would you take the grout bearing as 0.7(0.85f'c)?
2. Being that it is 12 wide block I feel I should consider bolt bending. What would you use for that value? 0.6Fy?
3. It occurs to me that the amount of grout in the cells above (where there is a bolt) needs to "grip" the masonry, which I know it does assuming an 8-10" slump but what kind of friction value would you use here. To take it to the ridiculous, if I covered the bolt with 1" of grout, it might not hold.
4. Lastly (sorry), I'm curious what you guys think about the order of bolt installation relative to grouting. Grout around an installed bolt or grout first, then drill in to install bolt?
Anyway, I'd appreciate any and thoughts on this matter.
Thanks!
The client desires to remove a section of bearing wall which is around 18' high and supports approx. 35' of steel bar joist/deck roof system. Although I've done this before, I've wondered what others think of certain aspects:
1. Would you take the grout bearing as 0.7(0.85f'c)?
2. Being that it is 12 wide block I feel I should consider bolt bending. What would you use for that value? 0.6Fy?
3. It occurs to me that the amount of grout in the cells above (where there is a bolt) needs to "grip" the masonry, which I know it does assuming an 8-10" slump but what kind of friction value would you use here. To take it to the ridiculous, if I covered the bolt with 1" of grout, it might not hold.
4. Lastly (sorry), I'm curious what you guys think about the order of bolt installation relative to grouting. Grout around an installed bolt or grout first, then drill in to install bolt?
Anyway, I'd appreciate any and thoughts on this matter.
Thanks!






RE: Bolts thru grouted masonry wall
RE: Bolts thru grouted masonry wall
With that condition I would check to see if bearing on the width of the masonry face shell works. If so then I would check bending in the bolt.
If it doesn't work then, similar to shobroco, I would add plates thru the masonry, grouted tight to the underside of the masonry and welded to steel channels. Then add bolts to hold everything together and keep loose block from falling out the bottom of the opening. This is much more predictable and easy to build.
RE: Bolts thru grouted masonry wall
So the order of installation would be:
1. Drill two holes - one at each end the the channels - through the wall.
2. Install the two channels with two bolts (again - one at each end).
3. If necessary - install vertical jamb channels on each side to serve as columns to the floor if necessary.
4. Through previously pre-drilled holes in the channels - drill through the masonry and install through bolts. (sometimes we've used Hilti HY20's).
5. Sequentially remove 24" wide sections of wall under the channels. The masonry is held up temporarily by the wall through-bolts.
6. For each section removed, install and weld on a cross plate.
7. Alternatively - use pre-welded clip angles with legs installed into mortar joint slots cut in the wall.
Cover plates on the vertical channel jambs can be installed as well to provide a complete steel opening edge surface.