W30x99 Section Properties

The W30x99 is a wide-flange steel section weighing 99 lb/ft (147 kg/m) with a nominal depth of 30 inches. It is a heavy, deep beam section used for long-span primary girders in warehouse, industrial, and arena construction. The W30 depth group provides some of the highest Ix-per-pound ratios in the AISC inventory, making W30 sections the preferred choice when deflection governs and floor depth is not constrained.

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Complete Section Properties (Imperial)

Metric Equivalents

AISC 360 Compactness Classification

For A992 steel (Fy = 50 ksi, E = 29,000 ksi):

Flange: bf/(2tf) = 10.500 / (2 x 0.670) = 7.84. Compact limit = 9.15. Since 7.84 < 9.15, the flange is compact.

Web: h/tw. For W30x99 with k = 1.32 in: h/tw = (29.7 - 2 x 1.32) / 0.520 = 27.06 / 0.520 = 52.0. Compact limit = 90.6. Since 52.0 < 90.6, the web is compact.

Classification: Compact section -- full plastic moment Mp = Fy x Zx = 50 x 312 = 15,600 in-kips = 1,300 ft-kips (nominal).

Design Capacity Summary (AISC 360 LRFD, A992 Fy = 50 ksi)

Flexural Capacity (phi = 0.90)

Lateral bracing limits: Lp = 6.49 ft (based on ry = 2.10 in). Lr = 19.0 ft. Despite being a deep section, the W30x99 has a moderately wide flange (bf = 10.5 in) that provides reasonable lateral stability. In composite construction with metal deck, the top flange is continuously braced and the full 1,170 ft-kip capacity is available.

Shear Capacity (phi = 1.00)

phi x Vn = 1.00 x 0.6 x 50 x (29.7 x 0.520) = 463 kips

The h/tw ratio of 52.0 is well below 2.24 x sqrt(E/Fy) = 53.9, so Cv1 = 1.0 and the full plastic shear capacity applies with phi = 1.00.

Deflection Screening

For a simply supported W30x99 under uniform load (Ix = 3990 in⁴):

The W30x99 is typically used for spans of 30-50 ft. At 40 ft span with 1.5 kip/ft total service load, the live load deflection (assuming 60% of total load is live) is approximately L/380 -- within the L/360 limit.

Common Applications for W30x99

The W30x99 is a primary girder section for long-span applications:

• Long-span floor girders (35-50 ft) in warehouse, distribution center, and big-box retail construction where column-free floor space is paramount.
• Roof girders in arena, gymnasium, and convention center construction spanning 40-55 ft with moderate snow and rain loads.
• Transfer girders in multi-story buildings carrying point loads from columns above, where moments of 600-1,100 ft-kips are common.
• Industrial crane runway beams for medium-duty cranes (10-25 ton capacity) at 30-40 ft span.
• Bridge girders for short highway and pedestrian bridges per AASHTO LRFD.

The W30x99 is the lightest section in the W30 group. It competes with the W27x114 (Ix = 4,080 in⁴, Zx = 343 in³) for stiffness-controlled designs. The W30x99 provides nearly the same Ix at 13% less weight but is 3 inches deeper. For moment-controlled designs, the W33x118 (Ix = 5,900 in⁴, Zx = 415 in³) provides 48% more Ix and 33% more Zx for a 19% weight increase -- often a worthwhile trade when the span is very long.

Available Steel Grades

Note: For bridge applications, ASTM A709 is the standard specification. A709 Grade 50 has the same Fy and Fu as A992 but includes mandatory Charpy V-notch impact testing for fracture-critical and non-fracture-critical members. A709 Grade 50W adds weathering (atmospheric corrosion resistance) for unpainted applications.

Comparison with Adjacent Sections

The Ix-per-pound efficiency for these sections: W27x94 = 34.8, W30x99 = 40.3, W30x108 = 41.4, W33x118 = 50.0. The deeper sections are substantially more efficient for stiffness per unit weight, which is why deep sections dominate long-span applications where deflection controls.

Cambering Considerations

For long-span W30 beams, cambering is standard practice. The W30x99 is routinely cambered by steel fabricators using heat cambering or cold cambering (mechanical press). Typical camber values:

• Camber = 75% of dead load deflection is a common rule of thumb
• For a 40 ft span with 1.0 kip/ft dead load: dead load deflection = 5 x 1.0 x (40x12)⁴ / (384 x 29,000 x 3,990) = 1.06 in. Camber = 0.75 x 1.06 = 0.80 in, rounded to 3/4 in.
• Minimum camber for most fabricators is 3/4 in.
• Maximum camber is typically limited to span/200 or the fabricator's standard practice.

Specify camber on the structural drawings and confirm with the fabricator that the requested camber is achievable for the section and span.

Run This Calculation

Beam Capacity Calculator -- check W30x99 bending, shear, and LTB capacity per AISC 360, AS 4100, EN 1993, or CSA S16.

Beam Deflection Calculator -- calculate deflection for W30x99 under any loading pattern. Compare with camber.

Beam Span Screener -- find the lightest W-shape for your span and load.

Related Pages

• Section Properties Database
• W-Shape Beam Sizes -- Complete Table
• Steel Beam Load Tables
• Steel Beam Span Guide
• Steel Grades Reference
• Beam Formulas Reference

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