Reinforced Concrete Beam Design

This calculation provides the moment and shear capacity of a rectangular concrete beam.

Code:
CA flagCSA A23.3
ϕ_c

Resistance factor for concrete

Constraints
min: 0step: 0.01
ϕ_s

Resistance factor for reinforcing steel

Constraints
min: 0step: 0.01
λ

Concrete density modification factor; 1.0 for normal density concrete

Constraints
min: 0step: 0.01
b(in)

Effective width of cross section

Constraints
min: 0step: 1
h(in)

Overall depth of cross section

Constraints
min: 0step: 1
cc(in)

Concrete clear cover to reinforcing

Constraints
min: 0step: 0.125
f_c(ksi)

Specified concrete strength

Constraints
min: 0step: 1
f_y(ksi)

Specified reinforcing steel yield strength

Constraints
min: 0step: 1
Lbar/nb

Quantity of reinforcing bars

Constraints
min: 1
Tbar/nl
Constraints
min: 0
s(in)

Spacing of rebar

Constraints
min: 0step: 0.1
θ(deg)

Assumed shear crack inclination

Constraints
min: 0max: 90step: 1
b=12b=12h=24h=24d=22.1d=22.1 c=4.2c=4.2 εu=-0.0035 εs=0.0151 FsFsFcFcf=α1*f'caa

Calculation Steps:

    Determine the flexural capacity
    Mr = 194k-ft (263 kNm)
    • d

      Depth to primary reinforcing

      in
    • A_s

      Area of reinforcing steel

      in²
    • A_smin

      Minimum flexural steel area

      in²
    • α_1

      Stress modification factor for equivalent stress block

    • β_1

      Modification factor for neutral axis location

    • a

      Equivalent compression block depth

      in
    • c

      Neutral axis depth

      in
    • cdratio

      Strain compatibility check

    • M_r

      Factored flexural resistance

      kip-ft
    Determine the shear capacity
    Vr = 60k (267 kN)
    • A_v

      Area of transverse reinforcing

      in²
    • A_vmin

      Minimum shear reinforcement area

      in²
    • d_v

      Shear depth, normally taken as 0.9d

      in
    • smax

      Maximum stirrup spacing

      in
    • β

      Cracked concrete shear factor

    • V_c

      Concrete contribution to shear strength

      kip
    • V_s

      Reinforcing steel contribution to shear strength

      kip
    • V_rmax

      Maximum permitted shear resistance to avoid concrete crushing

      kip
    • V_r

      Factored shear resistance

      kip
    User Notes: