H/TSP Seismic and Hurricane Ties
Simpson Strong-Tie® hurricane ties provide a positive connection between the truss/rafter and the wall of the structure to resist wind and seismic forces.
- See table
- Galvanized. H7Z and H11Z — ZMAX® coating. Some models available in stainless steel or ZMAX. See Corrosion Information.
- Use all specified fasteners; see General Notes.
- H1 can be installed with flanges facing inward (reverse of "H1 Installation" drawing; see image gallery).
- H2.5T, H3 and H6 ties are shipped in equal quantities of right and left versions (right versions shown).
- Hurricane ties do not replace solid blocking.
- When installing ties on plated trusses (on the side opposite the truss plate), do not fasten through the truss plate from behind. This can force the truss plate off of the truss and compromise truss performance.
- H10A optional nailing to connect shear blocking: use 8d nails. Slots allow maximum field bending up to a pitch of 6:12; use H10A sloped loads for field-bent installation.
Considerations for Hurricane Tie Selection
- What is the uplift load?
- What is the parallel-to-plate load?
- What is the perpendicular-to-plate load?
- What is the species of wood used for the rafter and the top plates?
(Select the load table based on the lowest-performing species of wood.)
- Will the hurricane tie be nailed into both top plates or the upper top plate only?
- What load or loads will the hurricane tie be taking?*
- Select hurricane tie based on performance, application, installed cost and ease of installation.
* When a connector is loaded simultaneously in more than one direction, the allowable load must be evaluated using option 1 or 2.
Option 1: Unity Equation
For all connectors use the following equation:
Design Uplift/Allowable Uplift + Design Lateral Parallel to Plate /
Allowable Lateral Parallel to Plate + Design Lateral Perpendicular
to Plate / Allowable Lateral Perpendicular to Plate < 1.0.
The three terms in the unity equation are due to the possible directions that exist to generate force on a connector. The number of terms that must be considered for simultaneous loading is at the sole discretion of the Designer and is dependent on their method of calculating wind forces and the utilization of the connector within the structural system.
Option 2: 75% Rule
As an alternative, certain roof-to-wall connectors (embedded truss anchors, seismic and hurricane ties [on this page], and twist straps) can be evaluated using the following: The design load in each direction shall not exceed the published allowable load in that direction multiplied by 0.75.