Brace Connection Calculator: Gusset Plate, Bolts & Welds (AISC/LRFD/ASD)
Free AISC 360-22 brace connection calculator for gusset plates, bolts, welds, Whitmore, UFM, and SCBF seismic. Instant LRFD/ASD checks and reports.
Quickly design and verify steel brace connections per AISC 360-22 (LRFD & ASD) with this comprehensive, easy-to-use calculator. It handles single diagonal, X-brace, chevron, and knee braces, performing full checks for:
- Brace tension yielding/rupture and compression buckling
- Gusset plate Whitmore yielding, Thornton buckling, shear, and block shear
- Bolt shear, bearing, and tear-out
- Fillet weld strength (directional method)
- Uniform Force Method (UFM) interface forces
- Seismic SCBF provisions (2t clearance, Ry overstrength)
Live diagram, real-time results, and professional report generation make it ideal for structural engineers performing preliminary or detailed connection design. Built for accuracy and speed. For educational and preliminary use—always verify with licensed engineering judgment.
SteelSolver.com
Brace Connection Calculator
AISC 360 (LRFD/ASD) | Gusset Plate, Bolt & Weld Design | UFM Transparency | Whitmore Section | Seismic SCBF
☍ Brace Configuration
▲ Member Sections
📊 Live Connection Diagram
ⓘ Diagram updates in real time. Shows brace angle, gusset plate, Whitmore section (30° fan), and UFM force interfaces. Not to scale.
⚡ Quick-Load Presets
⚡ Brace Axial Demand
kips
kips
°
Horizontal component = P·cosθ | Vertical component = P·sinθ
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For LRFD: enter factored (Pu) loads. For ASD: enter service (Pa) loads. The tool auto-applies appropriate resistance factors.
UFM Interface Forces
$$H_b = P_u \cos\theta - \frac{\alpha}{\alpha+\beta}\cdot P_u\sin\theta$$
$$V_c = P_u \sin\theta - \frac{\beta}{\alpha+\beta}\cdot P_u\cos\theta$$
Where α, β are UFM eccentricity parameters — AISC 360-22 Commentary C-J1
📈 Load Combinations
kips
kips
Computed UFM Forces
| Hb (Beam Horiz.) | — |
| Vb (Beam Vert.) | — |
| Hc (Col. Horiz.) | — |
| Vc (Col. Vert.) | — |
▲ Gusset Plate Geometry
Whitmore Width (30° Fan)
$$L_w = L_{bolt} + 2\,L_{conn}\,\tan 30°$$
AISC 360-22 §J4.4
◯ Effective Length & KL/r
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—
Thornton Gusset Buckling
$$r_{gp} = \frac{t_{gp}}{\sqrt{12}}, \quad \frac{KL_t}{r_{gp}} \le 25 \text{ (rec.)}$$
Thornton (1991), AISC Design Guide 29
📈 Net Area & Shear Lag
Net & Effective Areas
$$A_n = A_g - n \cdot d_h \cdot t \quad \text{(net area)}$$
$$A_e = U \cdot A_n \quad \text{(effective net area, shear lag)}$$
AISC 360-22 §D3.2, Table D3.3
🔧 Bolt Design
Bolt Properties (Per Bolt)
| Fnv | 48 ksi |
| Ab | 0.601 in² |
| φrnv | — |
| Group Capacity | — |
🔥 Weld Design
Weld Capacity
| FEXX | 70 ksi |
| Directional Factor k | — |
| φRn/L (kip/in) | — |
| Total Weld Capacity | — |
Fillet Weld Strength (Directional Method)
$$\phi R_n = \phi \cdot 0.6 F_{EXX} \cdot (0.707w) \cdot L_w \cdot (1 + 0.5\sin^{1.5}\theta_w)$$
AISC 360-22 Eq. J2-4
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Governing Limit State
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Max DCR
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Overall Status
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Connection Capacity
✅ Limit State Checks
| Limit State | Code Ref. | Demand | Capacity | DCR | Utilization | Status |
|---|---|---|---|---|---|---|
| Configure inputs and click Calculate. | ||||||
ⓘ Accuracy note: Results are based on AISC 360-22 analytical equations. For final engineering design, an independent licensed engineer should review calculations. This tool does not replace professional judgment or code-required peer review.
ƒ Brace Member Tension Checks
Tensile Yielding on Gross Area — AISC 360-22 Eq. D2-1
$$\phi_t P_n = \phi_t \cdot F_y \cdot A_g \quad (\phi_t = 0.90)$$
Tensile Rupture on Net Area — AISC 360-22 Eq. D2-2
$$\phi_t P_n = \phi_t \cdot F_u \cdot A_e \quad (\phi_t = 0.75)$$
$$A_e = U \cdot A_n, \quad A_n = A_g - \sum(d_h \cdot t)$$
Block Shear Rupture — AISC 360-22 Eq. J4-5
$$\phi R_n = \phi \bigl[0.6 F_u A_{nv} + U_{bs} F_u A_{nt}\bigr] \le \phi\bigl[0.6F_y A_{gv} + U_{bs}F_u A_{nt}\bigr]$$
$$\phi = 0.75$$
▲ Gusset Plate Checks
Whitmore Tensile Yielding — AISC 360-22 §J4.4
$$\phi R_n = \phi \cdot F_{y,gp} \cdot A_w, \quad A_w = t_{gp} \cdot L_w$$
$$L_w = L_{bolt} + 2\,L_{conn}\tan 30°$$
Thornton Gusset Compression Buckling — Thornton 1991 / AISC DG29
$$r_{gp} = \frac{t_{gp}}{\sqrt{12}}, \quad \lambda_c = \frac{KL_t}{r_{gp}\pi}\sqrt{\frac{F_{y,gp}}{E}}$$
\[\phi F_{cr} = \phi \cdot \begin{cases} (0.658^{\lambda_c^2})F_y & \lambda_c \le 1.5 \\ \frac{0.877}{\lambda_c^2}F_y & \lambda_c > 1.5 \end{cases}\]
$$\phi R_n = \phi F_{cr} \cdot A_w$$
Shear Yielding on Gusset Interface — AISC 360-22 Eq. J4-3
$$\phi R_n = \phi \cdot 0.6 F_{y,gp} \cdot A_{gv} \quad (\phi = 1.0)$$
Shear Rupture on Gusset Interface — AISC 360-22 Eq. J4-4
$$\phi R_n = \phi \cdot 0.6 F_u \cdot A_{nv} \quad (\phi = 0.75)$$
🔧 Bolt & Weld Formulas
Bolt Shear Strength — AISC 360-22 Eq. J3-1
$$\phi r_n = \phi \cdot F_{nv} \cdot A_b \quad (\phi = 0.75)$$
Bolt Bearing Strength — AISC 360-22 Eq. J3-6a
$$\phi r_n = \phi \cdot 2.4\,F_u\,d_b\,t \quad (\phi = 0.75)$$
Bolt Tear-Out (Edge Bolt) — AISC 360-22 Eq. J3-6c
$$\phi r_n = \phi \cdot 1.2\,F_u\,l_c\,t \quad l_c = e_1 - d_h/2$$
Fillet Weld Strength (Directional) — AISC 360-22 Eq. J2-4
$$k = 1 + 0.5\sin^{1.5}\theta_w$$
$$\phi R_n = \phi \cdot 0.6\,F_{EXX} \cdot 0.707\,w \cdot L_w \cdot k \quad (\phi = 0.75)$$
🌋 Compression (Brace Buckling)
Flexural Buckling — AISC 360-22 §E3
$$F_e = \frac{\pi^2 E}{(KL/r)^2} \quad \text{(Euler stress)}$$
\[\phi_c F_{cr} = \begin{cases} \phi_c(0.658^{F_y/F_e})F_y & KL/r \le 4.71\sqrt{E/F_y} \\ \phi_c \cdot 0.877 F_e & KL/r > 4.71\sqrt{E/F_y} \end{cases}\]
$$\phi_c P_n = \phi_c F_{cr} A_g \quad (\phi_c = 0.90)$$
AISC 360-22 Eqs. E3-2, E3-3
⚡ Uniform Force Method (UFM)
Force Distribution — AISC 360-22 Commentary C-J1 / AISC 15th Ed. Part 13
$$r = \sqrt{(\bar{\alpha}+e_b)^2 + (\bar{\beta}+e_c)^2}$$
$$H_b = P_u\frac{\bar{\alpha}}{r} \sin\theta, \quad V_b = P_u\frac{e_b}{r}\sin\theta$$
$$H_c = P_u\frac{e_c}{r}\cos\theta, \quad V_c = P_u\frac{\bar{\beta}}{r}\cos\theta$$
eb = beam depth/2, ec = column depth/2, α and β are work-point offsets.
🗎 Calculation Report
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This report includes all inputs, formulas, code references, and results. Copy and paste into your design package or print via browser Print (Ctrl+P).
Click "Generate Report" to create the full calculation report.
📈 Project Notes
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