Residential Girder Truss Holdowns
Residential Girder Truss Holdowns
(OP)
In my high wind area I usually see a net uplift on girder trusses (.6D + .6W) for most residential roofs that I look at. For girder truss bearing points I will usually have a triple 2x6 post for the gravity loads or larger depending on the numbers. To counteract the net uplift on the girder truss my go to has typically been a Simpson LGT2 or LGT3 series girder tiedown.
This may be a matter of preference but I'm wondering if others are finding other straps/tiedowns are a better solution in this application. The problem I am having as a newbie is that the Simpson catalog is so large with so many options I sometimes find myself calling out products that "can work" but for whatever reason are not the most practical solution (ie. price, habit, trade knowledge...) for certain applications.
Also where the net uplift on the girder is quite larger I will typically call out a holdown to attach the girder truss post to the stemwall below. However, I'm wondering in some instances if this method may be a bit too conservative and if the uplift force may not spread out into the wall below and be redistributed into some of the nearby anchor bolts.
In general I've had some trouble trying to determine how to assign distributed loads to point holdowns or vice versa.
This may be a matter of preference but I'm wondering if others are finding other straps/tiedowns are a better solution in this application. The problem I am having as a newbie is that the Simpson catalog is so large with so many options I sometimes find myself calling out products that "can work" but for whatever reason are not the most practical solution (ie. price, habit, trade knowledge...) for certain applications.
Also where the net uplift on the girder is quite larger I will typically call out a holdown to attach the girder truss post to the stemwall below. However, I'm wondering in some instances if this method may be a bit too conservative and if the uplift force may not spread out into the wall below and be redistributed into some of the nearby anchor bolts.
In general I've had some trouble trying to determine how to assign distributed loads to point holdowns or vice versa.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com





