The Earthbound Seismic Holdown System features the use of the Impasse Device. The patented Impasse Device is an engineered fastener that addresses the need for a self-adjusting mechanical fastening device that enables axial travel along a bolted or sliding connection and yet withstands significant tension forces in the opposite direction.
The Impasse Device is used at specified locations by the Structural Engineer on every floor (the load application of the Impasse Device can skip floors depending upon the load requirements) to connect the rod sections and allow for shrinkage and deflections due to wood compression in the structure. The view shown at right is a fourth floor application.
At the top of each threaded rod is an Impasse Device which serves as the top nut effectively creating a continuous steel rod connection through the structure.
Each Impasse Device is designed and proven through testing to always be stronger than the attached rod and helps maintains a constant tension on the rod. The Impasse Device is available for threaded rod sizes ranging from size R3 (3/8-inch) through R8HS (1 inch-high strength) with our maximum capacity nearing 42,000 pounds.
There is no additional labor required for retightening.
This is a common practice with existing holdown systems as the wood shrinks. Once the
Impasse Device is installed, you do not have to go back to retighten. This yields
significant labor savings.
