F & M BANK - Belmont Shores, California

selects micropiles for the foundation.

The DK525 micropile drill rig in the background installing 8" diameter pipe into predrilled holesl.  The 8" diameter tar epoxy pipe is shown in foreground.

     Bremco Construction, the general contractor, was directed by the client to savethe roof and columns of an old structure in the heart of Belmont Shores.  This posed a construction challenge due to low overhead clearance on a portion of the site.  After a review of numerous competing foundation systems, including augercast piles, chance anchors and stone columns, micropiles were selected as the most cost effective, while still providing the required 60 foot depth penetration and capacity. Part of the challenge in the design was the lateral loading, as well potential liquifaction in the top 30 fee. In the micropile design this,  which was accomplished using 30' long cold tar epoxy coated 8" diameter standard pipe around the tendon .  The pipe was easily installed using a mobilram with a vibrator, but under the building, the pipe had to be but welded using two 15 foot sections. 

     Due to ground water being near the surface, the Titan hollow stem all-thread rod was used for drilling/ grouting, and left in place.  During the drill grout was injected through the hollow rod (Titan 40/20), displacing the clay soil to the surface. Once 300 psi was achieved (and only neat cement was evacuating at the surface), the pile was complete, and the drill rod/ tendon was left in place. A nut and bearing plate was installed at the top and encapsulated into the pile cap. 

     Two micropiles were tested for the system for Howard McMasters, the consultant for the soils company.