Professional concrete shear design calculator based on ACI 318. Compute nominal and design shear strength (Vc, Vs, φVn) for reinforced concrete beams, verify Vu ≤ φVn, and optimize shear reinforcement.
Compute Vc, Vs, Vn, and φVn per ACI 318 and verify Vu ≤ φVn in US or SI units.
Calculator
The width of the web (web thickness) of the beam section resisting shear. Use consistent units with depth d.
in
Distance from extreme compression fiber to centroid of tensile reinforcement. Use consistent units with b_w.
in
Specified compressive strength of concrete at 28 days. Enter in psi (US) or MPa (SI).
psi
λ accounts for lightweight concrete. Use 1.0 for normalweight concrete; lower values apply for lightweight per ACI 318.
—
The factored design shear at the section under consideration (strength design). Enter in kips (US) or kN (SI).
kips
Total cross-sectional area of all vertical legs of stirrups within spacing s, crossing a potential shear crack.
in²
Longitudinal spacing of stirrups along the member length.
in
Yield strength of shear reinforcement. Typical values are 60,000 psi (US) or 420 MPa (SI).
psi
Resistance factor for shear. For nonprestressed members, ACI 318 commonly uses φ = 0.75. Confirm for your case.
—
Results
Outputs shown in kips (US) or kN (SI).
Concrete shear Vc
—
—
Stirrup shear Vs
—
—
Nominal shear Vn = Vc + Vs
—
—
Design shear φVn
—
—
Demand/capacity Vu / (φVn)
—
Vu: —
Status: —
Note: Detailing limits (e.g., minimum shear reinforcement, maximum spacing, and special members) are not checked by this tool and must be verified per ACI 318.
Data Source and Methodology
Authoritative Source: ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary,” 2019.
Direct link: ACI 318-19 Product Page.
All calculations are strictly based on the formulas and data provided by this source.
The Formula Explained
Concrete contribution (US customary):
$$V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}$$
Concrete contribution (SI):
$$V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}$$
Check: φV_n (63.38) < V_u (85) → NG (increase stirrups or adjust design)
By decreasing s (closer spacing) or increasing A_v (larger bar/legs), Vs increases and the design may pass.
Frequently Asked Questions (FAQ)
Does this calculator automatically enforce all ACI 318 detailing provisions?
No. It focuses on strength equations (Vc, Vs, Vn, φVn) and the Vu ≤ φVn check. Verify minimum shear reinforcement, maximum spacing, member geometry limits, and any special provisions separately.
What λ value should I use?
Use λ = 1.0 for normalweight concrete. For lightweight concrete, use the value specified by ACI 318 per concrete type.
What φ factor should I select?
For shear in nonprestressed members, φ is commonly 0.75. Confirm with the latest ACI edition and the specific member classification.
Can I enter Av as “per leg” area?
Enter the total area within spacing s of all vertical legs crossing a potential shear crack. If your stirrup has multiple legs, multiply the area per leg by the number of legs.
Are deep beams or transfer girders covered?
No. Those members are governed by special provisions and strut-and-tie methods not covered by these equations.
What units are used in the results?
Results are shown in kips for US and kN for SI. A secondary line shows the alternate unit for quick reference.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}\]
V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}
Formula (extracted LaTeX)
\[V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}\]
V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}
Compute Vc, Vs, Vn, and φVn per ACI 318 and verify Vu ≤ φVn in US or SI units.
Calculator
The width of the web (web thickness) of the beam section resisting shear. Use consistent units with depth d.
in
Distance from extreme compression fiber to centroid of tensile reinforcement. Use consistent units with b_w.
in
Specified compressive strength of concrete at 28 days. Enter in psi (US) or MPa (SI).
psi
λ accounts for lightweight concrete. Use 1.0 for normalweight concrete; lower values apply for lightweight per ACI 318.
—
The factored design shear at the section under consideration (strength design). Enter in kips (US) or kN (SI).
kips
Total cross-sectional area of all vertical legs of stirrups within spacing s, crossing a potential shear crack.
in²
Longitudinal spacing of stirrups along the member length.
in
Yield strength of shear reinforcement. Typical values are 60,000 psi (US) or 420 MPa (SI).
psi
Resistance factor for shear. For nonprestressed members, ACI 318 commonly uses φ = 0.75. Confirm for your case.
—
Results
Outputs shown in kips (US) or kN (SI).
Concrete shear Vc
—
—
Stirrup shear Vs
—
—
Nominal shear Vn = Vc + Vs
—
—
Design shear φVn
—
—
Demand/capacity Vu / (φVn)
—
Vu: —
Status: —
Note: Detailing limits (e.g., minimum shear reinforcement, maximum spacing, and special members) are not checked by this tool and must be verified per ACI 318.
Data Source and Methodology
Authoritative Source: ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary,” 2019.
Direct link: ACI 318-19 Product Page.
All calculations are strictly based on the formulas and data provided by this source.
The Formula Explained
Concrete contribution (US customary):
$$V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}$$
Concrete contribution (SI):
$$V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}$$
Check: φV_n (63.38) < V_u (85) → NG (increase stirrups or adjust design)
By decreasing s (closer spacing) or increasing A_v (larger bar/legs), Vs increases and the design may pass.
Frequently Asked Questions (FAQ)
Does this calculator automatically enforce all ACI 318 detailing provisions?
No. It focuses on strength equations (Vc, Vs, Vn, φVn) and the Vu ≤ φVn check. Verify minimum shear reinforcement, maximum spacing, member geometry limits, and any special provisions separately.
What λ value should I use?
Use λ = 1.0 for normalweight concrete. For lightweight concrete, use the value specified by ACI 318 per concrete type.
What φ factor should I select?
For shear in nonprestressed members, φ is commonly 0.75. Confirm with the latest ACI edition and the specific member classification.
Can I enter Av as “per leg” area?
Enter the total area within spacing s of all vertical legs crossing a potential shear crack. If your stirrup has multiple legs, multiply the area per leg by the number of legs.
Are deep beams or transfer girders covered?
No. Those members are governed by special provisions and strut-and-tie methods not covered by these equations.
What units are used in the results?
Results are shown in kips for US and kN for SI. A secondary line shows the alternate unit for quick reference.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}\]
V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}
Formula (extracted LaTeX)
\[V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}\]
V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}
Compute Vc, Vs, Vn, and φVn per ACI 318 and verify Vu ≤ φVn in US or SI units.
Calculator
The width of the web (web thickness) of the beam section resisting shear. Use consistent units with depth d.
in
Distance from extreme compression fiber to centroid of tensile reinforcement. Use consistent units with b_w.
in
Specified compressive strength of concrete at 28 days. Enter in psi (US) or MPa (SI).
psi
λ accounts for lightweight concrete. Use 1.0 for normalweight concrete; lower values apply for lightweight per ACI 318.
—
The factored design shear at the section under consideration (strength design). Enter in kips (US) or kN (SI).
kips
Total cross-sectional area of all vertical legs of stirrups within spacing s, crossing a potential shear crack.
in²
Longitudinal spacing of stirrups along the member length.
in
Yield strength of shear reinforcement. Typical values are 60,000 psi (US) or 420 MPa (SI).
psi
Resistance factor for shear. For nonprestressed members, ACI 318 commonly uses φ = 0.75. Confirm for your case.
—
Results
Outputs shown in kips (US) or kN (SI).
Concrete shear Vc
—
—
Stirrup shear Vs
—
—
Nominal shear Vn = Vc + Vs
—
—
Design shear φVn
—
—
Demand/capacity Vu / (φVn)
—
Vu: —
Status: —
Note: Detailing limits (e.g., minimum shear reinforcement, maximum spacing, and special members) are not checked by this tool and must be verified per ACI 318.
Data Source and Methodology
Authoritative Source: ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary,” 2019.
Direct link: ACI 318-19 Product Page.
All calculations are strictly based on the formulas and data provided by this source.
The Formula Explained
Concrete contribution (US customary):
$$V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}$$
Concrete contribution (SI):
$$V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}$$
Check: φV_n (63.38) < V_u (85) → NG (increase stirrups or adjust design)
By decreasing s (closer spacing) or increasing A_v (larger bar/legs), Vs increases and the design may pass.
Frequently Asked Questions (FAQ)
Does this calculator automatically enforce all ACI 318 detailing provisions?
No. It focuses on strength equations (Vc, Vs, Vn, φVn) and the Vu ≤ φVn check. Verify minimum shear reinforcement, maximum spacing, member geometry limits, and any special provisions separately.
What λ value should I use?
Use λ = 1.0 for normalweight concrete. For lightweight concrete, use the value specified by ACI 318 per concrete type.
What φ factor should I select?
For shear in nonprestressed members, φ is commonly 0.75. Confirm with the latest ACI edition and the specific member classification.
Can I enter Av as “per leg” area?
Enter the total area within spacing s of all vertical legs crossing a potential shear crack. If your stirrup has multiple legs, multiply the area per leg by the number of legs.
Are deep beams or transfer girders covered?
No. Those members are governed by special provisions and strut-and-tie methods not covered by these equations.
What units are used in the results?
Results are shown in kips for US and kN for SI. A secondary line shows the alternate unit for quick reference.
Audit: CompleteFormula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}\]
V_c = 2\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(lb; f'c in psi, b_w and d in in)}
Formula (extracted LaTeX)
\[V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}\]
V_c = 0.17\,\lambda\,\sqrt{f'_c}\,b_w\,d \quad \text{(N; f'c in MPa, b_w and d in mm)}