The owner of a 24′ X 40′ prefab modular building wanted to add a 2nd story to maximize water views in a beach town. However, the structure lacked a footer and was supported on Sono tubes above grade. The structural engineer required a deep foundation system in this sandy soil environment to reach a suitable bearing stratum and to support the additional load.
Project Summary:
- Helical Pile Type: IDEAL 2 7/8″ pipe pile (.203 wall)
- # of Helical Piles: 16
- Location: Sailsbury, MA
- Installation Depth: 15′ to 20′
- Equipment Used: Pro Dig 7K low-profile Drivehead with special fabricated 10′ Boom.
- Challenge/Unique Aspect: Access was a major issue. The building was 2′ above grade with little room to get the piles up under the structure. The contractor installed the 5′ lead section at a slight angle as you would in an underpinning application and then used extensions to install the helical piles. He then used the long boom to muscle the piling up under the support beam under the house. The engineer insisted the beam be reinforced with a continuous 3/8″ thick, 10″ high steel plates behind the beam attached with 2 bolts every 8″. This innovative install, terminating with walkway beam seat brackets, prevented the owner from a costly house lift to create a foundation that could safely support the additional load.
- Danbro Installer: Carpentier Construction
- Engineer/Architect: Structural Engineers – THC
