The subject new construction activities are located within the Gansevoort Market Historic District (a.k.a. Meat Packing District), which was designated on September 9th, 2003 by the NY City Landmark Preservation. The district is bounded by the High Line to the west and Greenwich Village Historic district to the south.
NY City Department of Buildings Technical Policy & Procedures Notice # 10/88 dated June 6, 1988, requires that for any structure designated a NY City Landmark or located within an historic district and is contiguous to or within a lateral distance of 90 feet from a lot under development or alteration shall institute a monitoring program. The structures of interest shall be monitored for vibrations; the maximum peak particle velocity (PPV) triggering event shall be set at 0.5 inches/second. The monitoring standard also limits the vertical and horizontal movement of the subject landmark structures to 0.25 inches (6 mm).
E2PM was contracted by 402-04 West 13th LLC to inspect the structures adjacent to the proposed reconstruction of a commercial building located at 402 West 13th Street (Block 645 Lot 38). The property is owned by the Romanoff Equities Inc. Based on architectural plans prepared by PKSB Architects, PC, New York, NY, a five story commercial building with a one level basement is proposed for the property. Shoring and underpinning is proposed for the adjoining existing structures, along the common lot lines at the east, south, and west property line. The services conducted by E2PM were:
- Conducted a Pre-Construction assessment report.
- Installation of 5 seismographs (Instantel Minimate Plus advanced vibration).
- Conducted a week of baseline vibration monitoring readings.
- Installed survey targets and optical readings are taken to an accuracy of +/- 0.01 ft (3 mm).
- Measurement of the crack gauges are done bi-weekly and recorded. Tracking the cracks was necessary to ensure no movement was occurring during construction/underpinning activities.
- Created and implemented a Monitoring Protocol in the event of a triggered event.
- A final inspection report was conducted at end of activities.