b'THE OFFICIAL NFBA MAGAZINEbetween roof purlins at the endwalls (Figure 3),and foundations.The secondary members and componentsareasimportantastheprimary members.Alocalfailureofthesecondary members and components may create openings in the buildings envelope potentially tripling the internal building pressures (GCpi of 0.55 vs 0.18) leading to progressive failures.The secondary roof components are also part of the lateral force resisting system:once the envelope is compromised, TECHNOLOGY & RESEARCHFigure 3: Blocking transfers shear forces. so is the buildings ability to resist lateral loads. shear transfer across a continuous horizontal stripWind-borne debris is a major design consideration. of non-structural translucent wall panels (FigureASCE/SEI7provisionsstipulatethatglazed 4), design and detailing of collector members andopenings must be impact-resistant or protected by impact-resistant covering in buildings located in areas with basic wind speeds of 140 mph or greater.This requirement also applies to buildings located within 1 mile of the coastal mean high water, where the basic wind speed is 130 mph or greater. If glazing is not impact-resistant or protected by an impact-resistant system, the glazing area should be treated as an opening - potentially changing the Figure 4: Shear Transfer complication at translucent panels envelope enclosure classification from an enclosed connections in buildings with shear walls or bracedbuilding to a partially-enclosed building.State frames that are distantly spaced in the same walland local codes may also require the wall and roof (Figure 5), design of the skirt board and connectionsassemblies to be impact-resistant.The 2020 Florida to transfer shear forces from the sheathing inBuilding Code (2020 FBC), for example, provides the wall into the columns (Figure 6), and designa list of approved wall and roof assemblies and complications related to the use of knee braces inrequires testing for all other assemblies.Some the primary frames between columns and trusses.wall and roof assemblies may require thicker gauge corrugated metal panels installed over plywood or Equally important are the buildings componentsOSB panels to achieve the required impact rating. and connections resisting wind uplift forces, fromThe continued expansion of post-frame construction roof sheathing, purlins, trusses/rafters, to columnsisawelcometrendthatshouldbeembraced responsibly.Design andinstallation oversights may have highconsequences. This is especially true for buildings located inhurricane-prone regionswithhigh occupancyloads Figure 5: Collector members within shear walls Figure 6: Multiple elements transfer lateral loads14 / FRAME BUILDER - FEB2022'