Abstract:
The re-development of the historical Brooklyn Rapid Transit Powerhouse Building involved preservation of the building exterior while re-framing the inside for its future use as an artist workshop. The existing foundation for the building consists of a 6-foot-thick concrete raft supported on a timber pile field. It quickly became apparent that the most economical foundation solution was to re-use the existing foundations as opposed to replacing them. However, voids under the raft were identified during the subsurface exploration program, and the conditions of the piles were unconfirmed. To justify re-use of the existing foundations to the local building officials, a supplemental exploration program was executed to better understand void limits, pile conditions, and existing foundation capacity. A chemical injection program was implemented to fill voids, an extensive test pit program was performed, and two full-scale soil stockpile load tests were performed to evaluate the behavior of the raft. This paper will discuss the approaches taken to load testing of a unique historical structure, allowing for adaptive re-use of an existing foundation in contaminated soils. The load testing resulted in acceptable movement under the proposed design loads, ultimately providing financial and schedule benefits to the project.