Seismic Braced Frame Calculator, AISC 341-16

What it checks

The module designs steel braced frame members for Special Concentrically Braced Frames (SCBF), Buckling-Restrained Braced Frames (BRBF), and Eccentrically Braced Frames (EBF). It applies strength-based design methods using factored demand quantities supplied by the caller, typically from a separate frame analysis. The sequence of checks evaluates brace slenderness and compactness, verifies expected capacities against amplified forces, and assesses link rotation for the eccentric case.

Inputs

Geometry - Brace work-point length (ft), minor-axis moment of inertia (in^4), and radii of gyration about strong and weak axes (in).
Material - Modulus of elasticity (ksi) and core yield stress (ksi).
Effective Length - Effective length factor K, with typical values of 0.5 for X-braces and 0.65 for chevron braces.
Demands - Factored axial demand (kips), factored shear demand (kips), and factored moment demand (kip-ft).
BRBF Specifics - Steel core area (in^2), compression adjustment factor beta, and strain-hardening adjustment factor omega.
EBF Specifics - Link length (in) and optional link rotation from frame analysis (rad).
Seismic Parameters - Design spectral acceleration parameter SDS (g) and expected/yield ratio Ry.

What it reports

Slenderness Verdict - Checks if KL/r exceeds 200 for SCBF braces, failing if the limit is exceeded.
Compression Capacity - Reports phi_c * Pn, the design compression capacity in kips.
Tension Capacity - Reports phi_t * Py, the design tension capacity in kips.
Shear Demand Ratio - Compares factored shear demand Vu against plastic shear capacity Vp to determine failure.
Link Rotation Limit - Evaluates link rotation against a limit of 0.08 rad for short EBF links where e is less than or equal to 1.6 Mp/Vp.
DCR Values - Provides Demand-to-Capacity Ratios for compression and tension checks in BRBF systems.

Code references

The engine cites AISC 341-16 for SCBF, BRBF, and EBF design checks, specifically referencing sections F2, F4, and F3. It also cites ASCE 7-22 Table 12.2-1 for system factors. Column compressive critical stress calculations reference AISC 360 section E3.

Limits

The module is a pure check module with no Tauri imports or FEM capabilities. Demand quantities are supplied by the caller and are not calculated internally. Link rotation is optional; if set to zero, the module operates in trace-only mode. Results are engineering aids; the engineer of record is responsible for the design.

This module ships in the desktop app

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