Jacked in piles or piers are constructed using small-diameter steel pipes advanced to bearing depth by hydraulic jacks that are secured to the existing structure being underpinned.

Jacked in piles technique illustration

Common uses

Underpin existing foundations
Increase the load-carrying capacity of existing foundation elements

Process

Using the structure as the reaction load, a hydraulic ram is used to push a 3.5 ft section of steel casing into the ground. This method essentially load tests each pile, as we are monitoring the pressure/resistance needed to install the casing. This installation resistance directly correlates to the pile capacity. After reaching bearing depth, the tops of the pipes are bracketed to the structure’s footing, filled with grout and locked-off to a specified percentage of the design load.

Advantages

Can be used in low-headroom environments (as low as 6 feet) with tight access
Each pier is essentially load tested ensuring a high level of confidence
Installed by a smooth, controlled stroke of the hydraulic cylinder ie no hammering or vibration
No spoil requiring handling and disposal

Quality assurance

Keller's extensive jacked in pile installation and design experience allows for custom connections to the existing structure based on the site specific logistics eg grade beams, pile caps, structural slabs.