> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/truss-bridge-workflow/load-rating-tb/gusset-plate-load-rating-tb.md). # Gusset Plate Load Rating (LFD) \[TB] Performs a Load Factor Rating (LFR) of one truss gusset plate following FHWA-IF-09-014, *Load Rating Guidance and Examples for Bolted and Riveted Gusset Plates in Truss Bridges*, Part B (LFD). Every member the plate connects is rated for tension yield on the Whitmore section, block shear, Whitmore column compression with its unbraced length L\_c, and the fasteners (shear and bearing); the plate itself is rated for shear on a vertical and a horizontal plane through the joint. The plate geometry, bolts and material come from the gusset plate object, the member forces from the staged analysis, and the load factors, K, Omega and rivet strength from a Gusset Plate Load Rating (LFD) template. Inventory and Operating ratings are reported for the Design (HS-20) live load of the Load Rating Combination Table (LFD). ## General **Gusset Plate:** Pick the truss gusset plate to rate. Its outline, thickness, material, plate position and bolt layout define the rated connection, and the members it connects are the rated members. The user must provide a value. **Load Rating Template:** Pick the Gusset Plate Load Rating (LFD) template that holds the shared inputs — the Load Rating Combination Table (LFD), the redundancy penalty, Omega, the Whitmore effective length factor K and the rivet shear strength Fv. **PDF Name (Export):** Name used when the load-rating report is saved as a PDF. When renaming, avoid characters that interfere with parametric equations (see the [Illegal Characters](https://docs.openbrim.org/faq/general/faq-illegal-chars) page). ## Connection **Rated Members (readonly):** The members the plate connects, in the order used by the per-member lists below. (Read-only) **Fraction of the Member Force Entering the Plates:** One value per rated member, in the order of Rated Members. The part of the member force delivered to the plates — for example 0.57 for a chord splice, 0.50 for a milled compression chord and 0.0 for a chord that runs continuously through the joint. A missing value is taken as 1.0. ## Overrides **Whitmore Width Override:** One value per rated member. Replaces the Whitmore section width solved from the bolt pattern and the plate outline. Zero, negative or missing values keep the solved width. **Whitmore Column Unbraced Length L\_c Override:** One value per rated member. Replaces the unbraced length of the Whitmore column (the average of L1, L2 and L3 measured from the Whitmore section to the adjacent fastener lines). Negative or missing values keep the solved length. **Place the Plate Shear Planes \[No/Yes]:** By default the vertical and horizontal shear planes pass through the centroid of the bolt groups. Set to *Yes* to place them. **Vertical Shear Plane, X from the Joint:** Position of the vertical shear plane along the plate, measured from the joint. Available when Place the Plate Shear Planes is *Yes*. **Horizontal Shear Plane, Y from the Joint:** Position of the horizontal shear plane across the plate, measured from the joint. Available when Place the Plate Shear Planes is *Yes*. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.openbrim.org/templates/truss-bridge-workflow/load-rating-tb/gusset-plate-load-rating-tb.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.