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Pile Design and Construction Practice, Fifth edition

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(a) (b)<br />

Types of pile 43<br />

Figure 2.21 Types of H-section steel piles (a) Universal bearing pile (UK, European, <strong>and</strong> USA<br />

manufacture) (b) Peine pile (Hoesch).<br />

be regarded as incapable of carrying load. A further complication arises when H-piles are<br />

driven in groups to an end bearing on a dense coarse-grained soil (s<strong>and</strong> <strong>and</strong> gravel) or weak<br />

rock. If the piles bend during driving so that they converge, there may be an excessive<br />

concentration of load at the toe <strong>and</strong> a failure in end bearing when the group is loaded. The<br />

authors observed a deviation of the toes of H-piles of about 500 mm after they had been<br />

driven only 13 m through s<strong>and</strong>s <strong>and</strong> gravels to an end bearing on s<strong>and</strong>stone at Nigg Bay in<br />

Scotl<strong>and</strong>.<br />

The curvature of H-piles can be measured by welding a steel angle or channel to the web<br />

of the pile. After driving, an inclinometer is lowered down the square-shaped duct to<br />

measure the deviation from the axis of the pile. This method was used by Hanna (2.10) at<br />

Lambton Power Station, Ontario, where 305 <strong>and</strong> 355 mm H-piles that were driven through<br />

46 m of clay into shale had deviated 1.8 to 2.1 m from the vertical with a minimum radius<br />

of curvature of 52 m. The piles failed under a test load, <strong>and</strong> the failure was attributed to<br />

plastic deformation of the pile shaft in the region of maximum curvature.<br />

In the UK H-piles are rolled to BS 4 Part 1: 1993 <strong>and</strong> BS EN 10056 as universal bearing<br />

piles (Figure 2.21a). Peine piles are broad-flanged H-sections rolled by Hoesch. They are<br />

rolled with bulbs at the tips of the flanges (Figure 2.21b). Loose clutches (‘locking bars’)<br />

are used to interlock the piles into groups suitable for dolphins or fenders in marine structures.<br />

They can also be interlocked with the old Larssen sections to strengthen sheet-pile<br />

walls. The Arbed-HZ <strong>and</strong> PU (Arcelor) piles are of similar design.<br />

The Monotube pile fabricated by the Monotube <strong>Pile</strong> Corporation of USA is a uniformly<br />

tapering hollow steel tube. It is formed from steel which is cold-worked to a fluted section<br />

having a tensile yield strength of 345 N/mm 2 or more. The strength of the fluted section is<br />

adequate for the piles to be driven from the top by hammer without an internal m<strong>and</strong>rel or<br />

concrete filling. The tubes have a st<strong>and</strong>ard tip diameter of 203 mm <strong>and</strong> the shaft diameter<br />

increases to 305, 356, 406 or 457 mm at rates of taper which can be varied to suit the<br />

required pile length. An upper section of uniform diameter can be fitted (Figure 2.22), which<br />

is advantageous for marine work where the fluted section has satisfactory strength <strong>and</strong><br />

resilience for resisting wave forces <strong>and</strong> impact forces from small to medium-size ships. The<br />

tubes are fabricated in 3, 5, 7 <strong>and</strong> 9 gauge steel <strong>and</strong> taper lengths can be up to 23 m. The<br />

heavier gauges enable piles to be driven into soils containing obstructions without the tearing<br />

or buckling which can occur with thin steel shell piles.

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