Roof angle connection to block wall
Roof angle connection to block wall
(OP)
I need some clarification regarding roof perimeter connection to masonry block wall.
I have a 8" block shear wall. The roof is metal deck on steel joists(5' c/c spacing) acting as diaphragm . The metal deck is connected to roof angle around perimeter and the angle is welded to joists at every 5' c/c. The joists are normal to the block wall.
My question is "Do we need to attach roof angle to the block wall with hilti/anchors or not?". According to me it should be as that's how the shear will be transfered to block wall. But most of the details (done by others) I have seen, does not show this attachement. Am I missing something?
Also, in case of joists parallel to wall, normally the detail is a cont. plate on top of wall that transfer the shear to wall below.
Thanks
I have a 8" block shear wall. The roof is metal deck on steel joists(5' c/c spacing) acting as diaphragm . The metal deck is connected to roof angle around perimeter and the angle is welded to joists at every 5' c/c. The joists are normal to the block wall.
My question is "Do we need to attach roof angle to the block wall with hilti/anchors or not?". According to me it should be as that's how the shear will be transfered to block wall. But most of the details (done by others) I have seen, does not show this attachement. Am I missing something?
Also, in case of joists parallel to wall, normally the detail is a cont. plate on top of wall that transfer the shear to wall below.
Thanks






RE: Roof angle connection to block wall
RE: Roof angle connection to block wall
I agree with haynewp. You don't want to go through the joist seat because they typically aren't attached very well.
Also, make sure you call out the metal deck fastening pattern on your plans. This is often omitted (guilty).
You also want to stay away from 24 gauge deck, even if it easily handles the loads. Attachment of 24 gauge requires weld washers, increasing the construction cost.
RE: Roof angle connection to block wall
RE: Roof angle connection to block wall
RE: Roof angle connection to block wall
Dik
RE: Roof angle connection to block wall
None of the joist manufacturers I know have any provision for taking lateral shear across the joist seat. Most seats are comprised of a built-up section of angles forming what looks like a pair of small channels back to back with a gap between them.
With a perpendicular horizontal shear force, there's really no direct, stiff load path.
For the masonry wall condition described in this post, the previous ideas are the way to go: bolt the angle to the wall.
For conditions where you have braced frames or moment frames the challenge is getting the deck shear down the 2 1/2" (or whatever the seat depth is) to the supporting beam top flange below. We've in the past used the continuous edge angle as a deck collector and then inserted small tube shapes between the deck angle and the beam (like a 2 1/2" tube) at intermittent spacings to achieve this transfer.
RE: Roof angle connection to block wall
RE: Roof angle connection to block wall
I usually don't have roof joists at a small enough spacing to meet the cmu anchorage to diaphragm requirements anyway. I have also used the HSS 2.5x2.5 tube between the joists to transfer the shear when there was no parapet. This is common at the rear of retail tilt-up buildings.