CMU Partition Top Anchors - Constructability
CMU Partition Top Anchors - Constructability
(OP)
There are several variants on top anchors for CMU walls to the underside of slabs above (talking about non load bearing walls here). Although I have specified and/or approved these I am not clear on how easy it is to actually build this. The pictures on the product info look neat - but how do you get the last blocks in and grouted with the anchor in place?
A more logical detail uses angles or similar at the sides of the wall, but this isn't always possible - in particular at edge conditions. For example a brick veneer wall with CMU backup in a concrete building, what's the best top anchor to ensure that it actually gets installed/built correctly?
Do they knock out face shells to slide the block in around the anchor?
For example
Top Anchor Type 1
Type 2
A more logical detail uses angles or similar at the sides of the wall, but this isn't always possible - in particular at edge conditions. For example a brick veneer wall with CMU backup in a concrete building, what's the best top anchor to ensure that it actually gets installed/built correctly?
Do they knock out face shells to slide the block in around the anchor?
For example
Top Anchor Type 1
Type 2






RE: CMU Partition Top Anchors - Constructability
RE: CMU Partition Top Anchors - Constructability
Hokie, Building the walls first creates other constructability issues: It may inhibit productive formwork & shoring methods, and; Ensuring there is movement space over the top of the CMU wall is only as good as the workers ability to remember to install a low density foam to provide said space.
What I often see in my little corner of the globe is post-installed angles on both sides of the CMU, with no connection to the CMU.
Ralph
Structures Consulting
Northeast USA
RE: CMU Partition Top Anchors - Constructability
Hokie - Definitely couldn't build the walls first in this area, the concrete goes up fast and the walls come ages later.
These anchors are pretty typical - I wonder if they're just not getting installed properly or am I missing something?
RE: CMU Partition Top Anchors - Constructability
I have typically used one of three methods: 1) angle tight to wall on both sides 2) angle tight to wall on one side with bolts into CMU in vertical slots or 3) Dowels similar to PTA 420.
The bond beams are usually placed at the 2nd course below the slab for partition walls. The course above the bond beam (directly below the slab) should be solid to receive anchors. At each vertical dowel, the blocks are either end blocks with an open end or two half wythe blocks. Grout or mortar can be put in from the end.
RE: CMU Partition Top Anchors - Constructability
RE: CMU Partition Top Anchors - Constructability
Fastened to overhead concrete just prior to mason getting to required height, and placed to approx match courses/perpends.
RE: CMU Partition Top Anchors - Constructability
curious if anyone has had fire-rating issues because of the angle connections.... many 2-hour walls are called out U-905 in the code summary section and the angle isn't on that UL material list.
i will say that running a beam next to the wall close enough to weld clips to has made lots of fireproofing headaches to spray the wall-side of the beam. the masons on the other hand love that detail, because the beam height drops the anchor point down the wall to an area easier to grout solid.
RE: CMU Partition Top Anchors - Constructability
The dowels have a "slip sleeve" as you stated.
For the PTA 422, I would try to space them at 16" or 32" to align with vertical joints at the ends of each block.