The International Information Center for Structural Engineers

Wednesday, 18 October 2017 11:55cat

Hayward Baker micropiles in South California Featured

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Hayward Baker is helping to preserve and restore a historic US Government facility in Southern California.

Company's crews are installing micropiles to underpin the foundations & prevent further settlement of the structure. Micropiles were chosen due to the difficult subsurface drilling conditions, the tight site access, and the concern that vibration may damage the structure

Micropiles are also known as minipiles, pin piles, needle piles, and root piles. The micropile casing generally has a diameter in the range of 3 to 10 inches. Typically, the casing is advanced to the design depth using a drilling technique. Reinforcing steel, typically an all-thread bar, is inserted into the micropile casing. High-strength cement grout is then pumped into the casing. The casing may extend to the full depth or end above the bond zone with the reinforcing bar extending to the full depth. The finished micropile (minipile) resists compressive, uplift/tension, and lateral loads and is typically load tested in accordance with ASTM D 1143 (compressive), ASTM D 3689 (uplift/tension), and ASTM D 3966 (lateral). Capacities vary depending on the micropile size and subsurface profile. Allowable micropile compressive capacities of more than 500 tons have been achieved.

This technique has been used to support most types of structures. Hayward Baker’s micropile drill rigs allow installation in restricted access and low headroom interiors, allowing facility upgrades with minimal disruption to normal operations.

Click here for more information on micropiles.

Source: Hayward Baker

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