Part 1 — Load Definition (Checks 1-3)

Check 1: Confirm design loads

Verify that all loads applied to the beam are correct and complete:

• Dead load (D): Self-weight of beam, concrete slab, metal deck, finishes, mechanical, ceiling, partitions. Tabulate each component.
• Live load (L): Per building code occupancy table. Include live load reduction per ASCE 7 4.7 where applicable.
• Roof live (Lr), snow (S), wind (W), seismic (E): As applicable. Snow drift loads at parapets and roof steps are commonly missed.
• Construction loads: Before the deck is composite, the bare steel beam carries the wet concrete weight. Construction load typically governs for composite beams at spans over 30 ft.

Red flag: If your beam load diagram shows only one uniform load number without itemization, you probably missed something. List every component.

Check 2: Confirm load combinations

Verify LRFD and ASD combinations per the governing code:

For beams: 1.2D + 1.6L typically governs gravity beams. 1.2D + 1.0W + 0.5L may govern for uplift on cantilevers or wind girders.

Check 3: Verify load application point

Is the load applied through the shear center? If not (eccentric loading such as a spandrel beam supporting a brick veneer or a crane runway girder), the beam experiences torsion in addition to bending. Torsion requires additional checks per AISC Design Guide 9:

• St. Venant (pure) torsion
• Warping torsion (restrained at ends)
• Combined bending + torsion interaction including warping normal stresses

Part 2 — Section Classification (Checks 4-5)

Check 4: Classify the section per Table B4.1b

Determine whether the section is compact, noncompact, or slender for flexure:

For Fy = 50 ksi (A992 steel): Most standard W-shapes are compact. Exceptions: W6x8.5, W8x10, W12x14, W14x22 (flange noncompact for Fy = 50 ksi). If the section is noncompact, use AISC F3 (flange) or F4 (web) procedures instead of F2.

Check 5: Confirm flange and web are continuously connected

For built-up sections (plate girders): The flange-to-web welds must develop the horizontal shear flow: q = V * Q / I. Intermittent welds are acceptable for stiffened webs. For rolled shapes, this check is satisfied by the rolled fillet. For coped beams, verify the reduced section at the cope satisfies the compactness criteria.

Part 3 — Flexural Strength (Checks 6-8)

Check 6: Confirm unbraced length Lb

Lb is the distance between lateral bracing points along the compression flange:

• For simply supported beams under gravity: the top flange is in compression. Deck attached with puddle welds at <= 12 in. spacing braces the top flange.
• For continuous beams near supports (negative moment): the bottom flange is in compression. The unbraced length for the bottom flange is the distance between cross-frames or bottom-flange kickers.
• During construction (before deck attachment): Lb = full span unless temporary bracing is provided.

Check 7: Calculate Lp and Lr

Lp = 1.76 _ ry _ sqrt(E / Fy) Lr computed per AISC Eq. F2-6 using rts, J, Sx, ho, and c.

For A992 (Fy = 50 ksi): Lp typically ranges from 4-10 ft for common W-shapes. Lr ranges from 10-25 ft. Values for every W-shape are tabulated in AISC Table 3-2.

Check 8: Calculate available flexural strength phi*Mn

Based on the relationship between Lb, Lp, and Lr:

Case 1 (Lb <= Lp): phi*Mn = 0.90 * Fy * Zx (full plastic capacity) Case 2 (Lp < Lb <= Lr): Inelastic LTB with linear transition from Mp to 0.7*Fy*Sx, multiplied by Cb Case 3 (Lb > Lr): Elastic LTB with Fcr from AISC Eq. F2-4

The moment gradient factor Cb is calculated per AISC Eq. F1-1 at each unbraced segment using quarter-point moments.

Part 4 — Shear Strength (Check 9)

Check 9: Verify shear capacity

Per AISC 360 Chapter G: phi*Vn = 1.00 * 0.6 _ Fy _ Aw * Cv1

For most rolled W-shapes with h/tw <= 53.9 (A992): Cv1 = 1.0 and shear almost never governs. When shear does govern: very short heavily loaded beams, plate girders with thin webs, beams with large web openings, or coped beams.

Check block shear at coped beam ends per AISC J4.3: phiRn = 0.75 * (0.6FuAnv + UbsFuAnt) <= 0.75 * (0.6FyAgv + UbsFu*Ant).

Part 5 — Deflection Serviceability (Checks 10-11)

Check 10: Calculate deflection under service loads

Use unfactored (ASD) service loads, NOT LRFD factored loads:

• Simply supported, uniform load: delta = 5 _ w _ L^4 / (384 _ E _ Ix)
• Simply supported, midspan point load: delta = P _ L^3 / (48 _ E * Ix)
• Cantilever, uniform load: delta = w _ L^4 / (8 _ E * Ix)

For composite beams, use the effective moment of inertia I_eff that accounts for partial composite action.

Check 11: Compare to deflection limits

Deflection is often the governing check for beams with spans over 30 ft. A beam that passes all strength checks may still need upsizing for deflection compliance.

Part 6 — Web Local Checks (Checks 12-14)

Check 12: Web local yielding at concentrated forces

Per AISC J10.2: phiRn = 1.00 * Fy _ tw _ (N + 5k) [interior] phiRn = 1.00 _ Fy _ tw * (N + 2.5k) [end]

Check 13: Web crippling

Per AISC J10.3: phiRn = 0.75 * 0.80 _ tw^2 _ [1 + 3(N/d)(tw/tf)^1.5] * sqrt(EFy*tf/tw) [interior]

Check 14: Sidesway web buckling

Per AISC J10.4, when a concentrated compressive force is applied to one flange and the other flange is not restrained against lateral movement. If any of checks 12-14 fail, either increase the bearing length, select a heavier section, or add transverse stiffeners.

Part 7 — Bracing Requirements (Checks 15-17)

Check 15: Lateral bracing at supports

Per AISC 360 App. 6: Beam ends must be restrained against twist. Nodal bracing locations must have adequate strength and stiffness per App. 6.3. Brace strength requirement: P_br = 0.01 * Mr / ho.

Check 16: Bracing of the compression flange

Metal deck qualifies as lateral bracing when: deck attached at <= 12 in. spacing, deck-to-beam connections made, and diaphragm has adequate stiffness. For negative moment regions: bottom flange must be braced by cross-frames or kickers.

Check 17: Intermediate bracing stiffness

Per AISC 360 App. 6.3.1b: Required brace stiffness beta_br = (1/phi) * (4Mrn/(Lb*ho)) for nodal bracing. The provided stiffness from the brace must exceed the required stiffness.

Part 8 — Special Conditions (Check 18)

Check 18: Coped beams, openings, and non-standard conditions

Coped beam ends: Check flexural yielding of reduced section, LTB of coped tee, and block shear. Web openings: Check Vierendeel bending, web post buckling. Opening depth <= 50-70% of beam depth per AISC DG 2. **Sloped beams:** For slopes > 1:12, check combined bending + axial per AISC Ch. H. Crane runway beams: Additional checks for fatigue, lateral forces, and vertical impact.

Part 9 — Documentation (Checks 19-20)

Check 19: Verify all calculations are traceable

Each check references the specific AISC section. Section properties from AISC Table 1-1. Load values include source. Intermediate results shown. Governing load combination identified for each limit state.

Check 20: Final capacity summary

Create a summary table showing every limit state check with demand, capacity, and ratio:

Beam Design Checklist — Quick Reference Card

Related References

• Beam Design Guide
• AISC 360 Beam Design — Worked Example
• Lateral-Torsional Buckling Guide
• Deflection Limits per IBC
• Bracing Design Guide
• Beam Capacity Calculator

Disclaimer

This page is for educational and reference use only. It does not constitute professional engineering advice. All beam designs must be verified against the applicable standard and project specifications by a licensed Professional Engineer (PE) or Structural Engineer (SE).