Ductile Iron Piles
Ductile Iron Piles (DIPs) are the newest edition to Chris-Hill's foundation arsenal. Typically stronger than helicals and micropiles, DIPs are also useful in limited access situations that call for limited vibration.
DIPs are relatively new to the North American foundation scene. These piles can be installed quickly and in any type of soil or weathered rock.
Ductile Iron Piles can be selected as the foundation option for any new construction. Since installation is performed with an excavator, DIPs can be installed in places inaccessible to cranes, such as sites with steep slopes, below grade footings, limited headroom applications, areas with limited access and hard to reach places.
How it's done
DIPs are installed using an excavator, concrete breaking hammer, and specialty driving bits. The piles consist of ~15 ft sections of belled-end ductile iron pipes of various diameters and wall thicknesses. Pile members are belled together during installation and driven to a desired depth or refusal. The impact of the driving hammer on the DIP fuses the bell and spigot connection together so that the connected pipe sections form one continuous member structurally. The inside of the DIP is then filled with grout and a 48 inch long threaded bar is left projecting from the DIP for connection to the structure. DIPs are either installed as end bearing piles (capacity derived from pile driven into hard pan) or friction piles (capacity generated with grout bond to surrounding soil). End bearing piles are simply driven to refusal (where the pile will drive no further) into competent bedrock. Friction piles are driven with an oversized drill bit and grout is pressurized through the DIPs and out of the drill bit to encapsulate the DIP in neat grout and form a bond with the surrounding soil. End bearing piles typically provide higher capacities but friction piles can generate upwards of 200 kips in competent soils.
DIPs provide high loading capacities with easy and convenient installation. Simplicity of installation equipment prevents costly maintenance and constant breakdowns and repairs. Since the soil is merely displaced during pile installation, there are no spoils to account for.
We recently added DIPs to our repertoire in 2021. Working closely with our DIP supplier DuroTerra, we successfully completed one project in 2021 and have a number of projects on the horizon for 2022.