A continuous load path is essential to a building’s structural performance. Directing the diaphragm loads from roofs, floors and walls to the foundation in a prescribed continuous path is a widely accepted method to prevent shearwall overturning. The installation of continuous rod systems has grown in popularity with the increase in mid‑rise wood (3- to 6-story) construction. Specifying a Strong‑Rod Anchor Tiedown System (ATS) for shearwall overturning restraint from Simpson Strong‑Tie offers several advantages for specifiers and installers alike:

• An ATS restraint provides the high load capacities required for mid-rise wood construction
• System components provide low deflection to help limit shearwall drift
• Steel tension elements of the structural lateral force resisting system can be designed for the Specifier by Simpson Strong-Tie Engineering Services
• Wood compression components of the shearwall system can be designed for the specifier by Simpson Strong-Tie Engineering Services
• Simpson Strong-Tie Engineering Services can perform checks to ensure that your plans have the optimally designed system
• Our knowledge of rod system performance through years of testing ensures that all system design considerations have been met

Beyond the tension and compression aspects of a continuous rod tiedown system, wood shrinkage must also be addressed. In these types of structures, shrinkage and settlement can cause a gap to develop between the steel nut and bearing plate on the wood sole or top plate (see photo below), as the shrinkage increases cumulatively up the building and is the greatest at the uppermost floor. This can cause the system not to perform as designed and can add to system deflection. As a result, take-up devices must be used with most wood structures greater than two stories tall as is noted in the 2018 IBC Section 2304.3.3 at each level to mitigate any gap creation and therefore ensure optimum system performance.