Reinforced Concrete Beam Design

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

Code:
US flagACI 318-19
ϕ

Resistance factor

Constraints
min: 0step: 0.01
ϕ_v

Resistance factor for shear

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: 0.5
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: 0.5
b=12b=12h=24h=24d=21.6d=21.6 c=4.1c=4.1 εu=-0.003 εs=0.0128 FsFsFcFcf=α1*f'caa

Calculation Steps:

    Determine the flexural capacity
    ϕMn = 212k-ft (287 kNm)
    • d

      Depth to primary reinforcing

      in
    • A_s

      Area of reinforcing steel

      in²
    • A_smin

      Minimum flexural steel area

      in²
    • β_1

      Modification factor for neutral axis location

    • a

      Equivalent compression block depth

      in
    • c

      Neutral axis depth

      in
    • ε_y

      Yield strain of reinforcement (fy/Es)

    • ε_t

      Tensile strain in extreme layer of longitudinal tension reinforcement

    Determine the shear capacity
    ϕVn = 46k (205 kN)
    • A_v

      Area of transverse reinforcing

      in²
    • A_vmin

      Minimum shear reinforcement area

      in²
    • V_c

      Nominal concrete shear strength

      kip
    • ϕV_c

      Factored concrete shear strength

      kip
    • V_s

      Nominal steel shear strength

      kip
    • V_smax

      Maximum permitted shear resistance to avoid concrete crushing

      kip
    • ϕV_s

      Factored steel shear strength

      kip
    • smax

      Maximum stirrup spacing along member length

      in
    • s_b

      Transverse spacing of stirrup legs across member width

      in
    • s_bmax

      Maximum transverse spacing of stirrup legs across member width

      in
    • ϕV_n

      Factored shear strength

      kip
    User Notes: