Bending moment, shear, and deflection for simply supported and continuous beams. AISC 360 / ACI 318.
Max Moment Mu
284.5kip·ft
↓ 22% below ϕMn
Max Shear Vu
57.0kips
↓ 41% below ϕVn
Live Load Deflection
0.89in
↑ 89% of L/360 limit
D/C Ratio (Moment)
0.78
↓ Capacity OK
Diagrams
Beam
Moment
Shear
Deflection
Limit State Summary
Limit State
Demand
Capacity (ϕR)
D/C
Status
Flexure (Mn)
284.5 kip·ft
367.5 kip·ft
0.77
OK
Shear (Vn)
57.0 kips
232.8 kips
0.24
OK
Deflection (L/360)
0.89 in
0.80 in
1.11
Near Limit
Web Local Buckling
—
Compact
—
OK
Why deflection controls this designLearn
For longer spans with lighter loads, serviceability (deflection) often governs over strength. At L = 24 ft, the L/360 limit for live load deflection is 0.80 in. The computed δ = 0.89 in exceeds this by 11%.
Options: increase Ix by upsizing to W21×68 (Ix = 1,600 in⁴), reduce the live load, or increase the span depth ratio. The W18×97 provides adequate strength but insufficient stiffness at this span.