Excavation and backfilling specifications, 10th Ave Tunnel

NYC 9/11 Public Portal Document

I. No blasting will be permitted closer than 50 feet from the existing operating railroad tunnels when there is a train or trains in the section of tunnel adjacent to the blast. The Contractor shall provide, maintain and operate a telephone or other electric communications system between the work site and the Railroad's operating tower so that . blasting operations can be safely coordinated with the Railroad's train operations in the tunnels. The communications system shall be of a type that will not affect the detonating devices used for blasting. 2. No blasting will be permitted above the existing Amtrak tunnels within the restricted area defined in paragraph 3.11 of this Section. 3. Comply with provisions of paragraph 3.11 of this Section. C. Tenth Avenue Bridge Area: 1. No blasting will be permitted for rock excavation east of the broach line lying on the easterly property line of the 10th Avenue Bridge. 2. Blasting east of the centerline of 10th Avenue shall proceed only after underpinning of the West Yard Building has been completed, and prior to excavation of rock east of the broach line lying on the easterly property line of the 10th Avenue Bridge. Explosive charges for this excavation shall be designed so that peak particle velocities measured at underpinning columns do not exceed 0.5 inch’ per second. Coordinate the work with underpinning work specified in Section 02150. No blasting will be permitted within 400 feet of the underpinning work during the ac actual load transfer operation. 0. Existing Evacuation Shaft of Amtrak North River Tunnels: No blasting will be permitted in the vicinity of the existing Evacuation Shaft as shown on Drawing No. S-E2. E. Eleventh Avenue Viaduct: No blasting will be permitted in the area indicated on the Drawings adjacent to the existing Eleventh Avenue viaduct column. F. North Access Tunnel: No blasting will be permitted in the area of the jacked section of the North Access Tunnel as shown on Drawing No. ST-Nla. G. Existing 32nd Street Demolition: Blasting may be utilized in the demolition of the existing 32nd Street structures provided that the requirements of paragraph 3.08 F of this section are complied with. H. Line Drilling: Line drilling shall be completed before blasting operations are conducted closer than 50 feet from these lines, except in the area of the Tenth Avenue Bridge where line drilling and broaching shall be performed as specified in Section 01030. 3.10 SEISMOLOGIC MONITORING A. During all blasting operations, the work will be subject to sei sinolog ic monitoring by a seismologist engaged by the Authority at the expense of the Authority. Coordinate blasting operations and schedules with the Engineer give advance of each blast as required and as directed.

Contract 02220-10 Excavation and 1-02-21064-0-0 Backfilling

NYC-WTC_000165817