Whether you’re designing and building a one- or two-story single-family residence, or doing the same for a multifamily, mid-rise wood-frame structure, fire and smoke protection features must be considered, and in most cases are required. When a fire starts, time is of the essence and the longer the flame and gases can be contained and the spread of the fire to adjacent spaces is kept in check, the greater the chance firefighters and first responders will have to defeat the blaze. Though many building jurisdictions have slightly different requirements and provisions, the three primary modes of fire rating that codes consider are an F-rating (flame), a T-rating (temperature rise), and an L-rating (air or gas leakage). The F and T ratings are gauged on a resistance per hour basis and the L rating is based on a rating of air leakage in cubic feet per minute per square foot of opening, or CFM/sq.ft. These ratings and provisions are in place to help safeguard against the spread of fire and smoke within the immediate structure as well as to contain the spread of fire to other structures.
Author: Scott Fischer
Scott Fischer is a Senior R&D Engineer for Simpson Strong-Tie working out of our home office in Pleasanton, CA. He has a bachelor’s degree in Architectural Engineering from Cal Poly San Luis Obispo and is also a licensed professional engineer in the state of California. Since joining Simpson Strong-Tie in 2006, Scott has worked on cast-in-place connectors to concrete, helped develop the current testing criteria for these products as well as performed the testing needed for these cast-in-place product lines. Beginning in 2016, Scott took over the roll of lead engineer for the Strong-Rod Systems product line and has helped develop several new products and provided technical product support for this growing product line. Prior to joining Simpson Strong-Tie, he worked for nine years as a consulting engineer while gaining experience in the design and analysis of concrete structures, including post-tensioned slab design, design of lateral systems and foundations.
Rod-to-Steel-Beam Connections for Anchor Tiedown Systems: Rod Welding, Brittle Failure, and Alternative Connections
Continuous rod tiedowns are a common way to restrain shearwall overturning in light-frame structures. Anchoring the rod run in a steel beam can be challenging, however, because the holdown typically aligns with the beam’s web and thus cannot pass through the beam. Welding, on the other hand, can cause brittleness and fracture of the rod or coupler at the location of the weld, especially in high-strength steel rods and couplers. An effective alternative also using high-strength rods is provided by the Simpson Strong-Tie® ATS-SBC steel-beam connector, which comes with a steel plate whose flat edges can be fillet welded to the steel beam or embed plate without brittle failure. Scott Fischer, P.E., of Simpson Strong-Tie explains the results of our lab testing in the following post.
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