Can a Fabricator Mix or Substitute Connector Plates from Different Manufacturers?

Back to Library

Issue #13260 - March 2021 | Page #39
By Glenn Traylor

The simple answer is no, not normally, but the reasoning behind that answer merits discussion. It should come as no surprise that truss connector plates are tied to design software and ultimately engineering design.

The problem is one plate manufacture is not equivalent to another plate manufacture. None of them have exactly equal or equivalent properties. Software values can be adjusted to account for plate inventories, but they must consider tooth holding, section, orientation, and tensile strength to name just a few items. Connectors strengths vary by orientation. Reference ANSI/TPI 1 Figure 5.2-3 Test Specimen Fabrication for Gross Area Method, Figure 5.2-4 Test Specimen Fabrication for Net Area Method, and Figures 5.3-2, 3, 4 & 5, Orientation configurations. The strengths and applications of connectors in relation to orientation vary from plate manufacturer to manufacturer.

Trusses require a design. The design is based on values. Lumber might be a varying element that is accounted for carefully by the design software or engineer, but connectors are almost always tied to the design. In the case of an individual engineer, they might take this course of action, but it is not recommended due to the increased complexity of the design.  

There are situations where a manufacturer might migrate from one plate supplier to another, creating a period when production mixes connectors, but this is an incredibly unique and limited situation that requires special considerations. Your new supplier needs to provide a process for using your existing inventory.

Sometimes trusses manufactured years ago using a connector that no longer exists might be repaired using a modern connector. These situations must be evaluated by a qualified engineer knowledgeable of truss design and who should design per ANSI/TPI 1 requirements.

In the history of the connector industry, consolidations have been made by connector manufacturers. These marriages have created situations where connectors were mixed in designs. An example would be MiTek’s mergers with TeeLok and Robbins or Alpine’s mergers with Clary, Lumbermate, and Truswal. These situations were addressed by the manufacturers for a specific period. Documentation should be retained as long as the business is in business.

So, what is the bottom line? The component manufacturer must follow a design. They are in partnership with their plate supplier. Mixing and matching connectors is playing Russian Roulette. Once the fabricator steps out of their agreements and obligations with their supplier, they risk a great deal of responsibility previously borne by the plate supplier. It is perilous. It is possible the fabricator can tempt fate, but in a litigation it will be impossible for the fabricator to justify the mixing of connectors unless he had someone covering this situation, namely his new supplier or an engineer that can provide and qualify the designs. ANSI/TPI 1-compliant third-party quality assurance audits require a review of the truss design. If plates are not installed per the design, there must be something that clearly resolves any issues. Doing business otherwise is reckless.

The reason one should not mix connectors is simple. Mixing without a design is senseless and irrational, and it poses unnecessary liabilities and risks.

 

An ANSI/TPI 1 3rd Party Quality Assurance Authorized Agent covering the Southeastern United States, Glenn Traylor is an independent consultant with almost four decades of experience in the structural building components industry. Glenn serves as a trainer-evaluator-auditor covering sales, design, PM, QA, customer service, and production elements of the truss industry. He also provides project management specifically pertaining to structural building components, including on-site inspections and ANSI/TPI 1 compliance assessments. Glenn provides new plant and retrofit designs, equipment evaluations, ROI, capacity analysis, and CPM analysis.

Glenn Traylor

Author: Glenn Traylor

Structural Building Components Industry Consultant

You're reading an article from the March 2021 issue.

Search By Keyword

Issues

Book icon Issuu Bookshelf