Excavation and backfilling specifications, 10th Ave Tunnel

NYC 9/11 Public Portal Document

B. The Contractor shall provide all required cooperation and assistance to the Authority's seismologist in setting up instruments, taking of readings, measuring of distances and other related operations. 3.11 RESTRICTED AREA AT EXISTING AMTRAK NORTH RIVER TUNNELS A. A 50 foot width centered on the existing Amtrak North River Tunnels and extending from the westerly right-of-way of Tenth Avenue to west of the westerly right-of-way of Eleventh Avenue shall be considered a restricted I* area. B. The Contractor shall not store equipment or materials in the restricted area unless approved by the Engineer. C. Equipment may cross the restricted area only where excavation has hot taken place or where backfill in the restricted area has been completed to the indicated finish grade, subject to limitation specified elsewhere in this , I ■ Section, on the Drawings, or as ordered by theEngineer. • J; D. Submi t a detai 1 ed pl an for al 1 work that w1 T1 be ^rformed i n the restricted area. This plan must be approved by the EngineerVprior to the start of any ; tl : work in the restricted area. The plan shall Include the type of equipment, with weights and load distribution, proposed for use' in the work.' Also included in the plan shall be the Contractor's proposed methods of protecting the existing tunnels and the proposed methods of monitoring vibrations transmitted to the tunnels. E. Nagon drills up to 14,000 pounds gross weight will be permitted to work in the restricted area when a minimum four feet of cover exists above the i n section Tine of the tunnels. The section line is shown on the ''as^' v | ■constructed"0raw1ngsof the existing Amtrak tunnel prepared by the j Pennsylvania Railroad. ; w: । F. Excavation and other equipment will not be permitted in the restrict^ area. | i } Excavation equipment shall be positioned outside the restricted area and material shall be removed by backhoe, bucket or clamshell. Other ineans of excavation must be approved by the Engineer. Excavation within the .1 restricted area shall proceed in maximum four foot lifts across the entire is width of the excavation. - r sit, ’ G. Caisson drilling equipment shall not be operated in the restricted area or in any position that the Engineer determines may cause damage to the “ existing tunnels. c. . .u-« H. Ori 11 holes in rock Shal 1 be terminated no deeper than 2 inches below the subgrade as shown on the Drawings. I. The use of mechanical rock breakers will notbe permitted in the restricted area of the Amtrak tunnel. The rock shall be excavated by means of drilling and the use of non-explosive demolition agents such as Bristar as approved by the Engineer, or by the use of approved rock splitters. Excavation within the restricted area shall proceed in maximum four foot lifts across the entire width of the excavation.

Contract 02220-11 Excavation and 1-02-21064-0-0 Backfilling

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