When would you use a drilled shaft?
Drilled shafts, also referred to as drilled piers, caissons or bored piles, are deep foundation solutions used to support structures with large axial and lateral loads by excavating cylindrical shafts into the ground and filling them with concrete.
What is shaft drilling?
A drilled shaft is a type of deep foundation that is constructed in place by drilling a hole into the soil, often to bedrock or a hard stratum, and subsequently placing concrete in the hole. A drilled pier is constructed by drilling a cylindrical hole of the required depth and subsequently filling it with concrete.
What is a drilled shaft rock socket?
Drilled shafts are used to resist relatively high lateral loads. The rock socket is usually 6 inches smaller in diameter than the shaft portion to form a ledge on which to better seal the casing. For shafts at known dry-socket locations, the 6-inch step can be eliminated.
How much does a drilled pier cost?
There are many factors that go into the pricing including access, reinforcement design and the actual material that is being drilled into. However, average costs for drilled concrete piers on residential homes range from $4K-$7K per pier.
Are driven piles Displacement piles?
Driven piles displace and compact the soil. Other deep foundation options can require the removal of soil and considerable subsidence, which can undermine the support of adjacent structures and cause excessive deformations, both of which can result in structural problems.
What are drilled piers designed to carry?
In the most common design condition, a drilled shaft is designed to carry load by side friction in a rock socket. The rock socket should have a diameter 6 inches less than the shaft diameter and may be grooved or smooth depending on the type of rock encountered.
What drilled piles?
Bored piles are reinforced concrete elements that are executed in loco, in holes excavated using proper machinery. The execution method for this type of piles is simple and can be applied to the most types of soils, including in the presence of the water table.