Structural repair on a two-storey building due to flooding

The building next door had a pipe burst that caused Christina Tenaglia’s building to flood, causing an accumulation of 3 feet of water in the basement. The existing concrete piles of 18”x18” had begun to sink one to one and a half inches (1 to 1 ½ inches). The concrete piles were beginning to twist and buckle causing foundation instability on the building. In addition, commercial and residential tenants were residing in the building while this repair had to be mitigated and fixed. Limited access to the basement and confined space presented even more difficulty to this situation.

Year: January 2017

Dealer: Techno Metal Post Hudson Valley

Engineer in charge of the project: Geotechnical and Structural Engineers on site

Location: Beacon, New York, USA

Main contractor: Lambert et Grenier

Project objectives: Restore and support existing structure of two-storey building

Specific challenges:

1. There was only a 28” existing opening to access the basement so getting the machine into the building proposed a huge challenge.
   Solution: Proprietary R2D post installation equipment was used and modified to access the basement by removing outside wheels to reduce the size of the installation equipment. A special ramp and landing were built to lower and raise the R2D in and out of the basement.
2. Commercial and residential tenants still had to have access to their units while the foundation repair was going on.
   Solution: All work at the end of the day had to be left completely cleaned up and ready for tenants to enter the property.
3. Confined space presented a challenge for using any equipment with flammable ignition like gas or diesel.
   Solution: Use the electric hydraulic motor for the R2D so no gas emissions during equipment operation. Any welding had to be properly exhausted out the building.

Advantages: Helical Piles (Piers) were the only solution for fixing and restoring this building due to the fact of the depth required to reach shale rock without disturbing the ground. Excavating the concrete piers would have caused them to sink further and would have made the building irreparable. Helical piles were the only solution. The proprietary installation equipment due to it size became the only type of helical pier installation equipment that could be used to access the basement.

Materials used:

• P3 helical piles
• Welded 5 foot extensions
• Adjustable brackets

Type of soil: Sandy Clay to 7 feet down and at 7 feet Shale solid rock

Equipment used: R2D Electric Hydraulic Motor

Bearing Capacity: 20,000 lb and R2D reached refusal.

*******Insertion depth: Approximately 9 feet

Structural details: Two-storey, commercial/residential building with 3 residential tenants and one commercial tenant on the main floor. Building was flooded with 3 feet of water and began to sink 1 to 1 ½ inches. The building was underpinned and helical piles were installed to lift and support the building. The foundation was restored to its original height and became structurally sound.