107 B8 Toe-Nailed Connections Are three toe-nails enough?
108 B8 1- Proper Toenail Installation
109 B8 2- Top Plate Lumber Grade and species
110 B8 3- Type of Nails 0.162″ x 3.5″
B8 Is Toe-Nailing Enough? Toe-nail values must exceed expected uplift For example: A 16d common in a Southern Pine top plate offers 72 pounds of uplift resistance. If there are three toe-nails, the total uplift resistance Is 3x72=216 pounds 72
112 B8 Load Duration Factors For wind uplift resistance use the factor of 1.6. Therefore, 216x1.6 = 346 pounds
113 B8 Alternatives to Toe-Nailing Check published uplift capacities of mechanical connectors
114 R Truss to wall connection Trusses shall be connected to wall plates by the use of approved connectors having a resistance to uplift of not less than 175 pounds (79.45 kg.) and shall be installed in accordance with the manufacturer's specifications. For roof assemblies subject to wind uplift pressures of 20 pounds per square foot (0.958 kN/m2) or greater, as established in Table R301.2(2), adjusted for height and exposure per Table R301.2(3), see section R
115 IRC R The code requirement was added in the IRC 2003 in a perhaps well-intentioned effort to address a perceived issue from the proponent's point of view. Now that it is in the code, it is proving difficult to remove. A number of code jurisdictions have amended the language or struck the language out of their code adoption. The 175 lb value is unrelated to any real design parameters or linked to any truss length. It arbitrarily discriminates against one well respected construction method. No specific evidence was or can be provided to justify this requirement.
116 IRC R TPI 1 requires that a Truss Design Drawing include reaction forces and directions, which would include a value for uplift based upon the structure's design parameters for wind. There is no valid reason for not using this calculated value in the consideration of the uplift connection requirements.
IRC R Much of the US is in the 90 mph basic wind speed zone. The resistance for uplift, beyond the prescriptive fastening requirements of Table R602.3(1) is really seldom an issue, especially for structures categorized as Exposure B and with a Mean Roof Height of less than 30 feet. IRC Table R301.2(2) is used to trigger the need for special connection requirements per Table R Only high wind speed areas, highly exposed structures or extremely tall structures ever qualify for the special requirements. When the calculated uplift requires a connection of a specific value, WTCA supports providing resistance in a manner acceptable to the EOR or building code official, not based upon an arbitrary requirement.
118 B9 Multi-ply Girders
B9 Girders Designed to carry extra loads Max. 6 plies, fastened together to act as one 4-ply 5-ply