What is the shear capacity of concrete alone?

ACI 318 simplified: V_c = 0.17λ√f_c·b_w·d (MPa units). For f_c = 28 MPa, b_w = 300mm, d = 500mm: V_c = 0.17×1.0×√28×300×500 = 135 kN. Detailed equation accounts for N_u, A_s, V_u, M_u.

When are stirrups required by ACI 318?

ACI 318 requires minimum shear reinforcement when V_u > 0.5φV_c, except for slabs, footings, and shallow beams. Minimum A_v = 0.062√f_c·b_w·s/f_yt or 0.35b_ws/f_yt (whichever is greater).

How do I determine stirrup spacing?

V_s = V_u/φ - V_c (required stirrup contribution). Spacing s = A_v·f_yt·d/V_s. Maximum spacing: min(d/2, 600mm) if V_s ≤ 0.33√f_c·b_w·d; min(d/4, 300mm) if V_s > this threshold (high shear zones).

Beam Shear Design Calculator (Stirrups)

Design shear reinforcement in RC beams per ACI 318: V_n = V_c + V_s. Concrete shear V_c = 0.17λ√f_c·b_w·d. Stirrup spacing s = A_v·f_yt·d/V_s. Maximum spacing min(d/2, 600mm). Torsion plus shear interaction.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Design shear reinforcement in RC beams per ACI 318: V_n = V_c + V_s. Concrete shear V_c = 0.17λ√f_c·b_w·d. Stirrup spacing s = A_v·f_yt·d/V_s. Maximum spacing min(d/2, 600mm). Torsion plus shear interaction. Use the shear stirrups result to inform your clinical assessment.

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Beam Shear Design Calculator (Stirrups)

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Frequently Asked Questions

What is the shear capacity of concrete alone?

When are stirrups required by ACI 318?

How do I determine stirrup spacing?