Glass Guardrail to Wood Joists
Glass Guardrail to Wood Joists
(OP)
How are the forces resolved for a guardrail on wood framing?
See attached sketch from an architect. This is an interior 'lightwell', i.e. a floor opening that allows you to see down to the next floor. It's a single family residence. The lightwell is about 6ft x 3ft in plan, i.e. longest span of the header/trimmer joists is about 6ft. until something frames in. The members are 9.5" LVL on each side of the opening. On one side there are joists framing into the 6ft. header @ 16" o.c., at the other two sides where joists are parallel I can add blocking (4th side is exterior wall, no rail).
My instinct is that this works, but not sure how to calc it. It's partially built but I can still add blocking in there. If I did that do you count on the sheathing, i.e. a tension/compression couple between the sheathing and blocking? Forces still seem pretty high when I check that.
See attached sketch from an architect. This is an interior 'lightwell', i.e. a floor opening that allows you to see down to the next floor. It's a single family residence. The lightwell is about 6ft x 3ft in plan, i.e. longest span of the header/trimmer joists is about 6ft. until something frames in. The members are 9.5" LVL on each side of the opening. On one side there are joists framing into the 6ft. header @ 16" o.c., at the other two sides where joists are parallel I can add blocking (4th side is exterior wall, no rail).
My instinct is that this works, but not sure how to calc it. It's partially built but I can still add blocking in there. If I did that do you count on the sheathing, i.e. a tension/compression couple between the sheathing and blocking? Forces still seem pretty high when I check that.






RE: Glass Guardrail to Wood Joists
Mike McCann
MMC Engineering
RE: Glass Guardrail to Wood Joists
RE: Glass Guardrail to Wood Joists
This is probably one of those details that happens all the time but nobody really cares about. Well, until some engineer in a powerhouse company delegates the design responsibility of the railing to others and then complains that he doesn't like my mathematics but he can't come up with anything better.
RE: Glass Guardrail to Wood Joists
I do not see this as a difficult problem with additional blocking and strapping, plus the lateral restraint of whatever the platform diaphragm is, which I do not know the details of, yet.
Mike McCann
MMC Engineering
RE: Glass Guardrail to Wood Joists
http://www.strongtie.com/ftp/bulletins/t-grdrlpst1...
Alternatively, we wrap a coil strap around the rim @ 4'-0" to take the torsion out, similar to as described above.
RE: Glass Guardrail to Wood Joists
RE: Glass Guardrail to Wood Joists
The attached publication walks you through the calcs for the glass standoffs.
Regards,
DB
Link