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RC Beam Design

Singly-reinforced rectangular concrete beam — ACI 318 / NSCP 2015. Get required steel area, ρ vs ρmin/ρmax check, suggested bar combination and φMn.

Inputs

Code

Units

Width bmm

Total Depth hmm

Effective dmm

f'cMPa

fyMPa (Grade 60 ≈ 420)

φ (flexure)

Factored Moment MukN·m

Clear Covermm

Notes & assumptions

Singly-reinforced rectangular section, tension-controlled (ε_t ≥ 0.005).
Whitney equivalent rectangular stress block, β₁ per ACI 318 22.2.2.4.3.
ρ_min = max(1.4/f_y, √f'c/(4·f_y)) (MPa form).
ρ_max for tension-controlled: ε_cu=0.003, ε_t=0.005 → c/d=0.375.
Bar suggestions assume ASTM/PNS standard sizes; verify spacing & cover.

Design

StatusOK

R_n = M_u/(φbd²)—

ρ required—

ρ_min / ρ_max—

A_s,req—

a (stress block)—

c (neutral axis)—

ε_t (tension steel)—

φM_n provided—

Suggested Bar Combinations

Combination	A_s provided	Status