This project included the construction of a new 12-story building with one cellar level in Queens, NY. GEODesign was not originally hired as the geotechnical or support of excavation engineer for this project. Rather, we were hired to perform a peer review of the support of excavation design that had been implemented, as the DOB required this as part of a stop work order that was placed on the project.
The Solutions Unearthed
- The New York City Department of Buildings (DOB) placed a stop work order on this project before the SOE was fully installed due to the adjacent building to the west experiencing movement during construction.
- GEODesign was contacted to perform a thorough peer review of the SOE system along the west side of the site to determine the cause for the reported movement. The SOE system included sheet piles with one level of bracing. The bracing included walers, rakers, and concrete footblocks.
- The peer review included reviewing the full SOE installation sequence that was performed along the west property line, optical monitoring data, SOE drawings, calculations, and field reports prepared by others. After reviewing the information, we performed our own study of the installed SOE system, which included two-dimensional finite element analyses and various shoring analyses to determine the loads in the sheet piles and bracing.
- The conclusions of the peer review showed that the measured movement of the adjacent building occurred after the sheet piles had been installed, and directly after a record rainfall event that year. It was also concluded that the design of the waler, raker and footblock bracing elements were insufficient for the design loads. We provided a supplemental design to be added to the already-installed SOE system to account for this, and to reduce the potential for any additional movement of the adjacent building.
Client: Confidential
