pålar

Pålar are long, slender structural members used in foundations to transfer loads from structures to deeper, more stable soils or rock. They are driven or drilled into the ground to provide support for buildings, bridges, and offshore structures, especially where surface soils are weak or prone to excessive settlement.

There are several types of pålar. End-bearing piles transfer most of their load through a bearing surface at the pile tip, while friction piles rely on skin friction along their length. Materials include timber, reinforced concrete, steel, and composite piles. In practice, concrete and steel piles are common in modern construction, while timber piles have historical use in soft soils but limited durability in damp ground.

Installation methods differ. Driven piles are installed with hammers or vibro tools and compact the soil around them. Drilled or bored piles are cast in place after drilling a borehole; continuous flight auger (CFA) piles are formed by drilling and pumping concrete through a hollow drill.

Design and assessment follow geotechnical standards. The capacity of a påle comes from end bearing and skin friction, and is verified by soils data, load tests (static or dynamic), and, in many regions, Eurocode 7 or national annexes. Pile design must account for settlement, horizontal forces, corrosion, and scour protection.

Applications include foundations for low- to high-rise buildings, bridges, piers, and offshore platforms, particularly where stratified soils, soft layers, or variable groundwater conditions require deep foundations. In addition to cost and noise considerations, installation can affect nearby structures and habitats, so environmental measures are often required.