An HP bearing pile is a heavy wide-flange section whose flange and web thicknesses are nearly equal, and whose depth roughly equals its flange width, giving it a near-square cross-section built to take driving stress and axial compression, not to act as a flexural member [S3]. A W-shape is a parallel-flange wide-flange beam whose inner and outer flange faces are parallel, whose web is comparatively thin, and whose section modulus is optimized for bending about its strong axis [S2][S4].
The practical consequence is that HP and W sections live in different parts of the AISC manual, are stocked in different size families, and answer different design questions: an HP series runs from HP8x36 (8.02 in deep, 36 lb/ft) up to HP18x204 (18.3 in deep, 204 lb/ft), 22 sections in total per the AISC Shapes Database v16.0 [S3], while a typical W-shape series for floor framing is chosen for Sx (elastic section modulus) and Ix (moment of inertia) about its strong axis rather than for driving survivability.
Geometry: Why HP and W Are Not Interchangeable
HP-shapes are proportioned for piling, with flange and web thicknesses that are more nearly equal than a comparable W-shape, and the flange width is essentially equal to the overall depth, e.g. an HP16x183 has d=16.5 in, bf=16.3 in, tw=tf=1.13 in, and a cross-sectional area of 54.1 in² [S3]. The HP16x88 at the lighter end of the same nominal family still has matching tw and tf of 0.54 in with d=15.3 in and bf=15.7 in, a 25.8 in² area, and an Ix of 1,110 in⁴, showing how the section keeps axial symmetry even at low mass [S3].
W-shapes keep the same parallel-flange topology, but they trade that symmetry for a slimmer web: a W36x231, named by its 36 in nominal depth and 231 lb/ft, has a parallel-flange design optimized for bending strength and long-span deflection control, not for driving [S4]. Because the W flange-to-web thickness ratio is much larger than the HP ratio, the W-shape's radius of gyration is far higher about its strong axis than about its weak axis; HP shapes intentionally flatten that ratio so the section resists buckling in any direction a pile is loaded [S4].
Mechanical Properties and Driving Loads
An HP18x204 has Ix=3,480 in⁴, Sx=380 in³, and Zx=433 in³ on a 60.2 in² cross-section weighing 204 lb/ft, giving it a mass-per-area that absorbs hammer impact without local flange buckling [S3]. Drop to HP18x135 in the same depth group and you keep d=17.5 in and bf=17.8 in, but area falls to 39.9 in² and Ix drops to 2,200 in⁴ [S3].
The H-pile equal-dimensional design delivers uniform radius of gyration about both main axes, which translates to superior buckling resistance during driving and under combined axial-plus-lateral seismic load compared to a W-shape of equal depth [S4]. For a 14 in series, HP14x117 has d=14.2 in, bf=14.9 in, tw=tf=0.805 in, and Ix=1,220 in⁴ on a 34.4 in² area; that same 14 in depth in an equivalent W14x series would show a thinner web (typically 0.30–0.50 in) and a much weaker weak-axis Ix, which is why substituting "a W for an HP" is a known mis-spec in foundation packages [S3][S4].
Selection Matrix: When to Pick HP, W, or Neither
Pick HP when the design problem is a driven foundation or a column subject to axial load from multiple directions, and the controlling criteria are: (a) near-equal flange and web thickness, (b) depth ≈ flange width, (c) high mass per foot for driving energy, and (d) low weak-to-strong axis stiffness ratio. The 22-section AISC HP table from HP8x36 (8.02 in, 36 lb/ft, A=10.6 in²) through HP18x204 covers the standard driven-pile range, with HP12x53 and HP12x63 (A=15.5 and 18.4 in²) the most common choices for mid-capacity building foundations [S3].
Pick W when the design problem is flexural: floor beams, crane girders, bridge stringers, or any member where Sx and Ix about the strong axis govern deflection, and where bolted or welded end-plate connections benefit from parallel inner flange faces [S2][S4]. Pick neither when the load path is torsion-dominant, since I and H families both underperform hollow structural sections (HSS) for pure torsion, or when corrosion allowance dominates the wall-thickness choice, which is a different problem altogether. The steel section category page covers the full wide-flange taxonomy; for foundations specifically, the pile driver page maps the hammer-side criteria that the receiving HP section has to survive.
Connection Detailing and Fabrication Differences
Parallel inner flange faces on both W and HP shapes simplify moment-plate and end-plate connection detailing, but HP shapes' thicker webs force welded moment connections to use partial-joint-penetration (PJP) or complete-joint-penetration (CJP) welds sized to the heavier flange, increasing weld volume and ultrasonic-testing scope per AWS D1.1 [S4]. Bolted bearing-type connections on HP sections typically need the same AISC 360 J3 bolt-bearing checks as a W-shape, but with tw higher, shear-yielding of the web rarely governs, and block-shear on the connection plate is the typical limit state instead.
For column splices, the HP equal-axis geometry lets the engineer orient the upper and lower sections on either strong or weak axis without re-checking the splice plate for direction-dependent prying, a small but real fabrication advantage when piles are driven slightly off-column line and the splice has to absorb eccentricity [S4]. The same is harder to do with a W-shape because the weak-axis splice geometry is much stiffer against rotation, and any misalignment shows up as a bending moment in the splice plates.
Comparison Pass: HP12 Series vs Typical W12 of Equal Depth
Within the 12 in nominal family, HP12x53 (d=11.8 in, bf=12.0 in, tw=tf=0.435 in, A=15.5 in², Ix=393 in⁴, Sx=66.7 in³) and HP12x89 (d=12.4 in, bf=12.3 in, tw=tf=0.72 in, A=25.9 in², Ix=693 in⁴, Sx=112 in³) bracket the practical HP12 range, with mass stepping from 53 to 89 lb/ft as area grows ~67% [S3]. A typical W12x53 in the same weight class has the same nominal 53 lb/ft but a thinner web (about 0.345 in) and a flange only about 0.575 in thick on a 10.0 in flange width, giving it a higher Sx about the strong axis but a much weaker weak-axis performance than HP12x53.
On a per-pound basis the HP carries less bending capacity (Sx) than the W of the same weight, which is the point: HP strength is paid for in axial and symmetric buckling capacity, not in flexural section modulus. Engineers who treat the AISC Steel Construction Manual as their reference should read HP tables under "Piles" and W tables under "W-Shapes" precisely because the optimizing objectives differ [S3][S4].
Standards, Sourcing, and Stated Limitations
HP-shape dimensions and section properties in this article come from the AISC Shapes Database v16.0 with 2,299 sections catalogued, of which 22 are HP-shapes across HP8, HP10, HP12, HP14, HP16, and HP18 series [S3]. Material specifications default to ASTM A572 Grade 50 for HP bearing piles in most North-American projects, with ASTM A690 marine-grade steel specified for saltwater exposure; both designations should be confirmed against the project's geotechnical report, not assumed from the section name alone.
Two stated limits from the source material. First, HP-shapes are "intended for foundation and pile applications" and "geometry suits driving and axial load paths more than typical floor-beam framing, so compare HP candidates on tabulated properties and project pile criteria rather than treating them as ordinary W-beams" [S3]. Second, beam nomenclature is country-dependent: in US practice W = wide flange and HP = bearing pile, but the same letters map to different cross-sections in some European and Asian catalogues, and a quote package that does not specify the producing standard risks the wrong section being shipped [S5].
Trackable Signals for the Next Procurement Cycle
Two signals to watch: the AISC Shapes Database revision number (currently v16.0) is published on a multi-year cycle and any new HP-shape addition would land there first [S3]; and any project-specific addenda that move HP material from A572 to A690 or to A913 high-strength should be tracked because the heavier HP18x204 (204 lb/ft) in particular benefits from a 65 ksi yield upgrade in long-pile driving [S4]. For related specification work, the bearing pile and steel section encyclopedia pages cross-reference AISC and ASTM material grades used in driven-foundation design.
The underlying component specifications are covered under ball bearing.
For related coverage, see Film vs Digital Radiography: Per-Exposure Cost and Chemistry Stack.