Pier Drilling – The Basics

bay area pier drilling

Pier drilling is one of several deep foundation methods which can be used to bypass surface-level ground, which is usually relatively soft and unstable, instead of the favorable solid ground that would be found deeper down. Bedrock is the ideal layer sought by deep foundation drilling because it provides the best support for a structure for passive as well as dynamic conditions.

To reach the harder ground further down, it is usually necessary to use an auguring tool, which can bore into the ground to create space for a vertical column. This dug out column would then be filled with concrete and reinforced steel to create an extension from the foundation to the bedrock. The size and number of these columns will depend on the size and load of the foundation.

How Pier Drilling Works

The process for pier drilling works something like this:

augur drilling – an augur, or spiral drilling tool, is attached to a motorized shaft and is forced into the ground under rotation. When it becomes entirely filled with soil it has loosened, it must be brought to the surface to have the soil removed. This process is repeated until the column depth is reached.

bell pier drilling – when the soil is considered too soft for normal support systems, the augur might be replaced by a bell tool which can dig out a ‘bell pier’, i.e. a shaft wider at the bottom to provide additional support.

concrete insertion – once the hole has been dug to the desired depth, all water if present, is pumped out from the bottom of the shaft. A reinforcement cage is placed in the shaft, then concrete is poured in and allowed to settle.

Pier drilling offers one big advantages over ordinary pile driving in that pile driving creates a lot of noise and ground vibration. In most conditions, especially those near other buildings, piers may be a much better option.

The Bay Area Pier Drilling Experts

If you need any kind of deep foundation drilling or excavation for your construction project, the company to call in the Bay Area is Lassiter Excavating Inc., a family-owned business which has provided expert excavation services to people of the region since 1989.

If you’re not thinking of installing a whole new building, but just want to implement some deck piers or footing piers as a preliminary step toward a follow-on project, we can do that too. Whatever your project consists of, contact us at Lassiter Excavating, Inc. for a free estimate, or to have any of your questions answered courteously and professionally. Our phone number is (925) 490-2037