Description
Three adjoining historic structures (111, 113, & 115 West Main Street) in Louisville, KY was to be redeveloped to include a restaurant, retail, office, entertainment spaces, and loft-style apartments. Each building had plan dimensions on the order of 29 feet x 200 feet.The existing structures consisted of masonry facades (front walls) along West Main Street and brick masonry party walls that reportedly were built in the 19th century. The existing walls typically have narrow, corbelled brick or thin limestone block foundations estimated to have been subjected to high soil bearing pressures (5,000 to 8,000

The existing structures consisted of masonry facades (front walls) along West Main Street and brick masonry party walls that reportedly were built in the 19th century. The existing walls typically have narrow, corbelled brick or thin limestone block foundations estimated to have been subjected to high soil bearing pressures (5,000 to 8,000 psf or more).The original buildings had four above ground floor levels with a basement along the south (West Main

The original buildings had four above ground floor levels with a basement along the south (West Main
Street) side. The lower north (West Washington Street) side had three above-ground levels. Two new floor
levels will be added to the north end as part of the new construction. Three elevators would be added: two near the northwest corner of the west building (115 West Main Street) and one near the southeast corner (111 West Main Street). Stairways also would be constructed at each of these two locations. Plans for the redevelopment were complicated by a fire that took place in July 2015 causing significant damage to the wood floor and roof systems.

Requirements & Challenges

Micropiles were chosen as the recommended

Micropiles were chosen as the recommended foundation system based on the encountered subsurface conditions, the expected new foundation loads, and the anticipated sensitive nature of the existing adjacent walls and buildings.

It was also recommended that the final design documents allow for the piles to be a design-build type, with details of the individual pile configuration determined by the specialty contractor. Our designers had to be aware that the installation of micropiles systems may be encumbered at this site due to overhead clearance restrictions and the presence of brick, remnant structures, existing foundations, utilities, cobbles, boulder, and other subgrade obstructions / conditions that may be located at specific pile locations.In addition, there were access and space restrictions,

In addition, there were access and space restrictions, along with the sensitive, fragile nature of the adjacent buildings that will impact equipment and material selection and installation activities. Final design values were determined by Helitech and reviewed by the project structural engineer and geotechnical engineer. The submitted design had hollow bar micropiles being installed to 65-feet deep with eight-inch grout columns that would be embedded in sand. The submitted design was for 120 micropiles capable of holding a 120kip load.

Solution

During the load test, Helitech was able to reduce the piles by 30 feet for the owner. This new design allowed Helitech to install 120 piles at 35-feet deep.

Results

Helitech Civil Construction was able to save the owner time and money. The project was completed on time and offered opportunity for additional projects in the area.

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