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 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.