Paalulaattoja

Paalulaattoja, often translated as "pile slabs" or "pile caps," are structural elements used in civil engineering and construction. They are typically concrete slabs designed to distribute the load from a superstructure to a group of underlying piles. Piles are long, slender columns driven or bored into the ground to transfer loads to deeper, more stable soil or rock layers. When multiple piles are used together to support a single structural element, a paalulaatta connects the tops of these piles.

The primary function of a paalulaatta is to unify the load-bearing capacity of the pile group. Instead of each pile carrying an equal share of the load, the slab ensures that the load from the structure above is distributed among all the piles in the group, even if some piles have slightly different capacities due to soil variations. This prevents differential settlement, where some parts of the structure sink more than others, which can lead to structural damage. The slab also provides a stable base for the columns or walls of the superstructure to rest upon.

Paalulaattoja are commonly found in foundations for buildings, bridges, and other large structures, especially in areas with weak or compressible soil near the surface. The design of a paalulaatta considers the number, spacing, and capacity of the piles, as well as the magnitude and type of loads it will need to support. Reinforcement, typically steel rebar, is incorporated into the concrete slab to handle tensile stresses and bending moments that arise from the load distribution.