Publication Abstract

Proceedings of the 45th Annual Conference on Deep Foundations, 2020 - ONLINE , (DFI)

Using Rigid Inclusions, Helical Piles and Micropiles to Revitalize 1600 Smallman Street
Nina F. Carney, PE, Zachary T. Smith, E.I.T., Melinda J. Hummel, MSc, PE, Nathaniel Witter, PE

The revitalization of Pittsburgh's historic Strip District has led to the redevelopment of existing properties and the development of new properties. At one time, the Strip was home to wholesale market products. Now, the historical warehouse buildings are being converted to multi-use residential and commercial properties. One such property, 1600 Smallman Street, consisted of 1 to 6-story connected buildings that housed night clubs, retail shops, and office space. The lower story portion of the building, on the southwest side of the property, was torn down to make room for a new 5-story- parking garage with street level retail space. The remaining 6-story-building, on the northeast, was gutted to be renovated into high-end condominiums, keeping the exterior historical building facade. A CMC Rigid inclusion ground improvement solution was designed by the specialty contractor to support the new parking garage and retail space on the southwest portion of the site. Once on site, the contractor, asked the ground improvement contractor for a cost-effective solution to support two stairwells and two elevator shafts within the 6-story-building. Due to the low-overhead restrictions, the ground improvement contractor proposed the use of helical piles for those additional areas. A system of helical piles was designed by the pile supplier and installed by the specialty geotechnical contractor. Together the two companies developed a cost-effective solution to meet the client's needs. However, during the installation of helical piles in the stairwells, the special geotechnical contractor encountered boulders from approximately 3 feet to 10 feet deep. To meet the project requirements, a low-overhead solution that could penetrate the boulders was needed. As such, the special geotechnical contractor reached out to their sister company to complete the stairwell support with micropiles. The following paper presents a brief history of the job site, the background of the rigid inclusion design, rigid inclusion load tests, the helical pile design, helical pile load test, the micropile design and the remedial design actions taken during both the rigid inclusion and helical pile installations due to unforeseen construction conditions. We will compare the design with load test results for both the CMCs and the helical piles.

 article #3661; publication #1073 (AM-2020)