ASTM A709 Gr HPS 100W — Yield Strength, Tensile Strength and Applications

ASTM A709 Grade HPS 100W: Fy 100 ksi min, Fu 110–130 ksi (range). The bridge umbrella spec. A709-26 lists twelve grades that parallel A36, A992, A588, A913 and stainless A1010, with bridge-specific toughness and quality requirements. Use where American Association of State Highway and Transportation Officials (AASHTO) or a Department of Transportation (DOT) invokes it.

Strength

GradeFy (ksi)Fu (ksi)Note
HPS 100W100110–130Plate ≤ 2.5 in. Over 2.5 to 4 in.: Fy 90 ksi. Design uses Fu = 110 ksi.

Fy and Fu are specification minimums. Verify the grade on the Mill Test Report (MTR); dual-certified material is common.

Applicable members

Plates and shapes (grade-dependent); shape grades cover W, S, M, HP, C, MC, L, WT, MT, ST

Applicable is not the same as stocked. Confirm availability with the supplier.

Common applications

Highway and rail bridges, fracture-critical members, DOT-governed structures.

Field notes

  • The value is the toughness and quality requirements, not the base strength.
  • Charpy V-Notch (CVN) and testing requirements depend on grade, member category and project provisions. They are invoked on the order by the T (non-fracture-critical) or F (fracture-critical) suffix and temperature zone 1–3, e.g. A709 Grade 50W T2.
  • Never swap in a building-grade equivalent on a bridge without carrying the toughness requirements.
  • High-Performance Steel (HPS) grades are plate only; they cut weight and improve field weldability on long-span girders. Quenched and Self-Tempered (QST) grades are shapes only.

Material constants

  • Modulus of elasticity E: 29,000 ksi
  • Shear modulus G: 11,200 ksi
  • Density: 490 lb/ft³ (0.284 lb/in³)
  • Poisson's ratio: 0.30
  • Thermal expansion: 6.5 × 10⁻⁶ in/in/°F

These are the same for every structural steel grade. Strength changes with the specification; stiffness does not.

Related

The full specification

Chemistry, tolerances, coatings, galvanizing, weldability, availability and substitutions for every spec: ASTM 101 (STL+).

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