Steel Piles

- Support heavy loads.

- Can be driven to great depth without damage.

- Are easily cut and spliced.

- Sections as H-Piles and Pipe Piles are common.

- Pipes are filled with concrete for additional strength.

- Principal disadvantage is its high cost.

- Bearing is the principal load transfer mechanism, but the small area

   of the tip limits the load capacity of steel piles.

Steel piles generally are either pipe piles or rolled steel section H-section piles. Pipe piles can be driven into the ground with their ends open or closed. Wide–flange and I section steel beams can also be used as pile. However, H section piles are usually preferred because their web flange thicknesses are equal. In the wide-flange and I section beams, the web thickness are smaller than the thickness of the flange. When necessary, steel piles are splice by welding or by riveting.

Rolled steel H-section piles:

 – 40 ft to 100 ft in length,

 – 40 tons to 120 tons capacity.

Steel Pipe piles:

– 50 ft to 150 ft in length,

– 50 tons to 150 tons capacity.

Composite Piles

- Made up of two or more different materials (for example, steel and concrete).

- For a timber-concrete pile, the lower section of the pile might be timber, while upper section might be a concrete or even a steel shell pile. The timber part is installed below ground water due to its vulnerability to insect attack and decay above ground. The concrete or steel pile is then used above the ground water level.

The upper and lower portions of composite piles are made up of different material. For example, composite piles may be made of steel and concrete or timber and concrete. Steel and concrete piles consist of a lower portion of steel and upper portion of cast-in-place concrete. This type of piles is the one used when the length of the pile required for adequate bearing exceeds the capacity of simple cast-in-place concrete piles. Timber and concrete piles usually consist of a lower portion of timber pile below the permanent water table and an upper portion of concrete in any case, forming proper joints between two dissimilar materials is difficult and, for that reason composite piles are not widely used.

Pre-stressed concrete with steel H-section:

 – 60 ft to 200 ft in length,

– 30 tons to 100 tons capacity.

Concrete filled steel pipe:

– 50ft to 150 ft in length,

– Capacity varies.

PIER of BRIDGE

A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars. The lighter structure of a pier allows tides and currents to flow almost unhindered, whereas the more solid foundations of a quay or the closely spaced piles of a wharf can act as a breakwater, and are consequently more liable to silting. Piers can range in size and complexity from a simple lightweight wooden structure to major structures extended over a mile out to sea. In American English, pier may be synonymous with dock.

Piers have been built for several purposes, and because these different purposes have distinct regional variances, the term pier tends to have different nuances of meaning in different parts of the world. Thus in North America and Australia, where many ports were, until recently, built on the multiple pier model, the term tends to imply a current or former cargo-handling facility. In Europe in contrast, where ports more often use basins and river-side quays than piers, the term is principally associated with the image of a Victorian cast iron pleasure pier. However, the earliest piers pre-date the Victorian age.

Piers can be categorized into different groupings according to the principal purpose. However there is considerable overlap between these categories. For example, pleasure piers often also allow for the docking of pleasure steamers and other similar craft, whilst working piers have often been converted to leisure use after being rendered obsolete by advanced developments in cargo-handling technology.