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Component Manufacturing dverti$er
Don’t Forget! You Saw it in the
Adverti$er
July 2017 #10216 Page #92
Protect Yourself by Understanding Design Responsibilities By Simpson Strong-TieÂŽ Staff
ANSI/TPI 1, Chapter 2 As a truss technician or component manufacturer, have you ever been asked to perform duties that fall outside of ANSI/TPI 1, Chapter 2 guidelines? We know in our previous roles as truss technicians and component manufacturers, we were often requested to perform a task that fell well outside of our scope of work. In some situations, it was not an issue and our plate and software supplier could assist us in achieving the desired results. But what happens when the Registered Design Professional (RDP) disregards the scope of work and requires you to assume responsibility for something that falls outside of the agreement and guidelines set by the building code? In many situations you can look like the villain by being unwilling to perform a task that is incorrectly perceived to be your responsibility. Take for example permanent continuous lateral restraint (CLR). As a component manufacturer, the truss design drawings you supply are responsible for specifying the webs under compression which are subject to buckling. You are not responsible for specifying the material or determining how CLRs should be permanently incorporated into the structure. It is the ultimate responsibility of the RDP, who has designed the structure, to ensure that the permanent CLR is attached to the structure in order to transfer the forces. Another scenario encountered more often today is the request for sealed placement diagrams. First and foremost, it is important to define exactly what a Truss Placement Diagram (TPD) is and what it is not. The TPD is a document to be used by the installer as a reference for locating trusses. It is not an engineering document and is not intended to supersede the Construction Documents. The confusion comes when the RDP believes their responsibility ends at the top plate. There is a common misconception by RDPs in the industry that the component manufacturer is designing trusses as a system. As manufacturers, you know all too well that you are in fact not designing systems, but rather individual components. This is important to understand because liability increases when sealed placement diagrams are provided. Although requests for providing bracing plans and stamped layouts are the most common, there are certainly other situations that force component manufacturers outside of their comfort zone. Some additional examples include requests for designing trusses to resist out of plane forces or specifying truss to plate connections.
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