OVERVIEW:
Earlier this year, a $92 million expansion project started at Saint Joseph’s Hospital in Syracuse, NY. Part of this project involved the conversion of an existing 7-story parking garage into space for additional patient rooms and a Women’s Services area. The parking structure required extensive renovations to make it a usable part of the facility, and these renovations increased the foundation loads. Further reinforcement of the existing foundations was needed to resist the increased loads. A foundation for a new elevator was also required. Any construction near a hospital is challenging, and installing deep foundations inside an existing structure only adds another dimension of complexity.
CHALLENGE:
Limited-access was a significant challenge for this project, as the installation needed to happen within the confines of the existing parking structure. With between 6 to 8 feet of headroom, traditional deep foundation methods were not viable options for this project. In addition to the overhead restrictions, there was also limited space for mobilizing equipment as the site was only accessible off a narrow side street. Due to the adjacent hospital and concerns about compromising the existing structure, there was also zero tolerance for vibrations.
SOLUTION:
Considering the soil conditions and concerns on this site, helical piles were the perfect solution. CMI Structural Solutions, an IDEAL Certified installer, installed over 270 piles across all phases of this project. This portion of the project consisted of 66 helical piles installed to an average depth of 20 feet. Helical piles were specified in the plans, and the IDEAL design team recommended a 5.5″ helical pile with a double helix configuration. The designed pile resisted the allowable loads of 20 tons in compression, 12.5 tons in tension, and 2.5 tons in lateral. A remote-controlled Brokk excavator was used for installation as it was the only machine that could install the 5.5″ helicals and be operated within the site’s confines. With the CMI team’s extensive experience in deep foundations and innovative solutions, they made this challenging installation look simple.
INSTALLER:
CMI Structural Solutions
LOADS:
Compression design load: 20 Tons
Tension design load: 12.5 Tons
Lateral load: 2.5 Tons
PILE DETAIL:
High Capacity Helical Pipe Pile
5.50” O.D. X 0.415” W.T. – 80 ksi
Central Shaft
12”/14” Double Helix Configuration
SOILS + EMBEDMENT DEPTH:
Fill soils from previous construction on the hospital grounds extends to about 20’ below the surface. The fill soils are comprised of gravel, sand, silt, and clayey silt with fragments of brick, concrete, and wood. The indigenous soils below the fill layer consist of silt and gravel with sand throughout the layer. The indigenous soils extend beyond 70’, becoming denser at deeper depths.
NUMBER OF PILES:
66
EMBEDMENT DEPTH:
20′
VIEW/DOWNLOAD CASE STUDY AND SOILS REPORT (PDF)