I had the chance to ride along with several inspectors performing
inspections on various building sites, mostly type v, light wood framing.
I saw some alarming things out there that is worth noting for those of you
who otherwise might not get the chance to see and they are as follows:
1) There is a serious problem in the shear transfer system from the roof
diaphram to the top plate by virtue of placing the freeze block almost over
an inch away from the top plate edge. Even with the use of A35 simpson
hardware, the hardwar is cantilevering over one inch.
2) I observed some trusses with over 22 feet span supported by RR hanger.
I think this is one area where the truss company leaves that to the
engineer of record to specify. " read the fine print on the truss calcs"
3) I observed lot of discontinuity between shear diaphragms and shear
walls. These elements are not detailed in some cases and in others, they
are just simply overlooked by the framer and inspectors too.
4) Shear drag collectors are often mis-installed and especially where the
top plates are discontinuous due to geometry of the building.
5) Holdown are being installed with shims over studs, plywood shims.
6) Anchor bolts are often mis aligned and offset towards the edge of the
plate, wet set anchors are nothing but problems, you must inlcude
specification for properly secured anchors or you are not going to get what
you want from the shear wall anchorage.
7) Some contractors are not setting templates to support structural steel
colums base plates, wet set is definately a no no.
8) Be ware that trusses are fabricated from spruce, not Doug Fir. Lateral
bracing is not even present on some at points of supports, in particular
where the trusses sit on a cut back wall line where the truss end is
elevated as much as 24 inches from the plate.
9) Some builders are erecting spruce on second story walls and doug fir at
lower story walls which ultimately factors into the shear and stud capacity.
10) studs are never blocked at mid height. so the effective lenght is the
full height for axially loaded studs.
11) Trusses bearing on interior wall supports do not specify headers and
framers are using the top plate to span the load to the adjacent stud and
thus use a flat 2x4 flat header on interior doors, a good deflection
demonstration for those truss spans of 20 feet or more.
Well, that's enough for now.
The whole idea is, if you want to avoid lawsuit when doing multifamily
buildings, or tract homes, please insist on structural observation or get
indemnified by the builder or face the court reality. Also, any body that
is betting their money on the inspector to find all these problems are not
Good luck to all of us.
Samir Y. Ghosn, P.E.
Harris & Associates
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