OVERVIEW:
The Highland Hospital Patient Tower Project will take three years to complete and will open in the spring of 2023. The project will add five additional stories to the existing 2-story southeast wing and join the south and southeast wings with a 7-story structure. The $70 million project will add 58 patient rooms allowing nearly every patient to have a private room. The expansion will also allow space for advancing clinical programs and the mechanics required to run the new facilities.
The 2-story annex between the south and southeast wings had to be demolished to allow the two structures to join. A foundation needed to be installed for a 157′ tall tower crane with 267’ of horizontal reach. A support of excavation (SOE) wall also needed to be put in place.
CHALLENGE:
This project’s most significant challenge was the zero-tolerance policy for vibrations and noise. Due to the proximity of the installation area to patient rooms and the critical nature of the hospital’s medical procedures, disruptions were not allowed. A residential neighborhood also surrounds the hospital. Wherever possible, noise, mess, and large machinery had to be kept to a minimum.
Limited access on the hospital grounds presented another challenge. Most of the piles had to be installed in the 15 feet wide area between the south and southeast wings of the hospital. With barely enough room to fit an excavator between the two wings, any pile types relying on bulky installation equipment could not be used.
SOLUTION:
CMI Structural Solutions, the installer for this project, submitted STELCOR DDMs as a value-engineered option. STELCOR can be installed relatively quietly compared to other piling methods. STELCOR piles are driven into the ground using an excavator and hydraulic powered rotary drive head, making STELCOR a perfect fit for this project. As part of the test program for the STELCOR pile, vibrations were monitored during installation. The results showed that any vibrations recorded were extremely low and would not be disruptive to the hospital or the nearby residential community.
The largest piece of equipment needed to install the foundation was a 25-ton excavator. The colloidal grout mixer was kept in a remote location, out of the way of the main install area, and pile sections were brought as needed using a track loader. The CMI team commented that installing the piles with compact machinery allowed them to save thousands of dollars and make the best use of the limited site space.
In total, 93 STELCOR DDMs were installed to support the new 7-story structure and the tower crane required for construction. The allowable pile loads were 180k in compression, 116k in tension, and 8k lateral.
STELCOR wasn’t the end of time and money savings on this project. With the same equipment used to install STELCOR, CMI also constructed the SOE wall quickly and efficiently using 7” diameter helical pipe piles from IDEAL. By value engineering this project and using the same installation equipment for all the foundations, all parties involved saved time and money. Isn’t that Ideal?
INSTALLER:
CMI Structural Solutions
LOADS:
Compression design load: 180 kips
Tension design load: 116 kips
Lateral load: 8 kips
PILE DETAIL:
STELCOR 1600
16” Tip or Drive Plate
14” Corrugated Grout Column
11” Solid Grout Column
8” Reverse Grout Auger
5.5” O.D. X 0.361″ W.T. – 80 ksi central shaft
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:
93
EMBEDMENT DEPTH:
45′-50′
VIEW/DOWNLOAD CASE STUDY AND SOILS REPORT (PDF)
