floor to floor connections

[TheCommish]

2015 IRC Massachusetts

Looking for code and reference material to support the need for connection of multiple stories, when using continuous sheathing for required wind wall bracing.

R301.1 Application. Buildings and structures, and parts thereof, shall be constructed to safely support all loads, including dead loads, live loads, roof loads, flood loads, snow loads, wind loads, and seismic loads as prescribed by this code. The construction of buildings and structures in accordance with the provisions of this code shall result in a system that provides a complete load path that meets the requirements for the transfer of loads from their point of origin through the load-resisting elements to the foundation. Buildings and structures constructed as prescribed by this code are deemed to comply with the requirements of this section.

Massachusetts amendments out earthquake load for 1 & 2 family, my concern is wind wall bracing from floor to floor.

All the WWB bracing methods show plate to plate construction, except for the general requirements of R301.1 the requirements for connections the second floor to the first floor seem to be lacking.

General practice has been to lay the sheathing long way on the building with sufficient overlap to the wall below and the wall above to connect the walls, the general rule is 16” of overlap above and below the walls plates is sufficient. Lacking that we have allowed nail strap on 4-foot intervals to correct the connection. or other hardware.

 

[Joe.B]

I don't have a code reference for you, and the times I've seen this style of sheathing to connect the two floors (instead of straps or other mechanical fasteners) it was done with engineering. Also the specs would call out blocking at all seems in order to preserve 6" edge nailing integrity. Of course I am in a high seismic zone...

 

[steveray]

From a former Mass****...Drove through Charlton just a couple hours ago...

R602.3.5 Braced wall panel uplift load path. Braced
wall panels located at exterior walls that support roof rafters
or trusses (including stories below top story) shall
have the framing members connected in accordance with
one of the following:
1. Fastening in accordance with Table R602.3(1) where:
1.1. The ultimate design wind speed does not
exceed 115 mph (51 m/s), the wind exposure
category is B, the roof pitch is 5:12 or greater,
and the roof span is 32 feet (9754 mm) or less.
1.2. The net uplift value at the top of a wall does
not exceed 100 plf (146 N/mm). The net uplift
value shall be determined in accordance with
Section R802.11 and shall be permitted to be
reduced by 60 plf (86 N/mm) for each full
wall above.
2. Where the net uplift value at the top of a wall
exceeds 100 plf (146 N/mm), installing approved
uplift framing connectors to provide a continuous
load path from the top of the wall to the foundation
or to a point where the uplift force is 100 plf (146 N/
mm) or less. The net uplift value shall be as determined
in Item 1.2.
3. Wall sheathing and fasteners designed to resist combined
uplift and shear forces in accordance with
accepted engineering practice.

 

[Genduct]

This is a great question because as some have pointed out, there are prescriptive instructions about how to insure that there is wind bracing (lateral /shear and uplift ) examples. The AWC info does a more complete job for the Design info and tables. Do we insist on them.

Contractors have Completed Operations/ Liability Insurance that does not allow them to pretend to be Design Professionals. This is a very thorny area with a lot of land mines.
Cross that double yellow line and you can find yourself in a head on collision

SO, the question is: the Code Reviewer is NOT THE DESIGN PROFESSIONAL so where do we draw the line?
Do we insist that a Structural Engineer "Sign Off" on the design. Who of us is 100% comfortable with the Specs that often include Proprietary Products? Does the outside inspector really APPROVE the job to withstand the structural integrity of the design or even the quality control for the proper amount of structural details, especially when the design drawings are not comprehensive enough to use as a guide, A special NICET Inspector ??

Here is where the Rubber meets the Road !!!!!

Let's see where this question takes us

 

[TheCommish]

I am shocked, this thread did not draw more comments

 

[Mark K]

If a reading of the IRC allows such an interpretation, then the IRC needs to be revised. There appear to be words regarding a load path but this is a concept that engineers are more familiar with and contractors seem not to understand. The ply layout shown would provide little resistance to uplift.

As mentioned, blocking of sheathing is needed.

An inspector can check for compliance with the construction documents but does not have the background to render an opinion on structural integrity. Further an inspector can report on the inspections but should not be the one to approve the building.

There are real limits on what you can accomplish with a proscriptive code without an engineer

 

[steveray]

As mentioned, blocking of sheathing is needed.

Actually, the IRC allows you to omit joint blocking if you provide 2X required bracing....

R602.10.10 Panel joints. Vertical joints of panel sheathing
shall occur over, and be fastened to, common studs.
Horizontal joints in braced wall panels shall occur over,
and be fastened to, common blocking of a minimum 11/2
inch (38 mm) thickness.
Exceptions:
1. Vertical joints of panel sheathing shall be permitted
to occur over double studs, where adjoining
panel edges are attached to separate studs with the
required panel edge fastening schedule, and the
adjacent studs are attached together with two rows
of 10d box nails [3 inches by 0.128 inch (76.2 mm
by 3.25 mm)] at 10 inches o.c. (254 mm).
2. Blocking at horizontal joints shall not be required
in wall segments that are not counted as braced
wall panels.
3. Where the bracing length provided is not less
than twice the minimum length required by
Tables R602.10.3(1) and R602.10.3(3), blocking
at horizontal joints shall not be required in braced
wall panels constructed using Methods WSP,
SFB, GB, PBS or HPS.

DISCLAIMER: I am not an engineer, but I do know how to read a code book....

 

[Genduct]

Actually, the IRC allows you to omit joint blocking if you provide 2X required bracing....

R602.10.10 Panel joints. Vertical joints of panel sheathing
shall occur over, and be fastened to, common studs.
Horizontal joints in braced wall panels shall occur over,
and be fastened to, common blocking of a minimum 11/2
inch (38 mm) thickness.
Exceptions:
1. Vertical joints of panel sheathing shall be permitted
to occur over double studs, where adjoining
panel edges are attached to separate studs with the
required panel edge fastening schedule, and the
adjacent studs are attached together with two rows
of 10d box nails [3 inches by 0.128 inch (76.2 mm
by 3.25 mm)] at 10 inches o.c. (254 mm).
2. Blocking at horizontal joints shall not be required
in wall segments that are not counted as braced
wall panels.
3. Where the bracing length provided is not less
than twice the minimum length required by
Tables R602.10.3(1) and R602.10.3(3), blocking
at horizontal joints shall not be required in braced
wall panels constructed using Methods WSP,
SFB, GB, PBS or HPS.

DISCLAIMER: I am not an engineer, but I do know how to read a code book....

The info that you and Mark K pointed out suggests we need the Drawings to CLEARLY show the DETAILS OR have a spec that and drawings/ details that make clear the How this is to be Built.

The text you both used is OK but as we know A PICTURE IS WORTH A THOUSAND WORDS

IMHO Mike B