For the $493-million upgrade to the Newtown Creek Water Pollution Control Plant (WPCP) in Brooklyn, NY, for the New York City Department of Environmental Protection, heavy construction equipment has been facilitating work on the project since it began in September 2003.
According to Ali M. Catik, a project executive of Slattery Skanska Inc. of Whitestone, NY, the lead partner in the general contracting joint venture of Slattery, Picone, McCullough and Perini Corp. (SPMP), the project called for the upgrading and expansion of the plant, which is New York City’s largest wastewater treatment facility and one of the largest WPCPs in the nation.
“The new construction and upgrade to the existing facility will incorporate unique process developments,” he said.
Catik added that it also will feature a modern grit removal system that is intended to eliminate the need for primary settling tanks. There also will be a full floor coverage air diffuser system in the aeration tanks that will enhance the biological process.
“The introduction of polymer and a flocculation zone in the sedimentation tanks are intended to reduce the suspended solids in the effluent,” Catik said.
“The objective of the project,” he continued, “is to increase the capacity of the plant while keeping its operations within federal guidelines.”
Included in the project will be 145,000 cu. yds. (110,860 cu m) of concrete, 24 million lbs. (10.8 million kg) of reinforcing steel, 1.7 million sq. ft. (157,935 sq m) of formwork, 100,000 linear ft. (30,480 m) of pipe, 200,000 cu. yds. (152,911 cu m) of excavation, 300,000 sq. ft. (27,871 sq m) of New North Battery Tanks to treat 100 million gal. (378 million L) per day during normal operations, and nine new 2,000 hp. (1,491 kW) Process Air Blowers with a 96-in. (244 cm) diameter stainless steel distribution system.
At any given time, Catik noted, the project’s peak work force exceeded 450 employees.
“The project presented many safety challenges,” he said. “The work force regularly exceeds 400 people working adjacent to and within the existing sewage treatment plant. SPMP assigned a full-time safety manager to administer the general contractor’s job-site safety program. Construction plans are used extensively to plan work and identify and mitigate hazards. Training, both general awareness and specific to work activities and hazards is given the highest priority.”
Catik also said “The joint venture’s re-engineering capabilities have contributed to the success of the project. In accordance with the contract documents, rakers, struts and reaction slabs were required throughout the project. Slattery Skanska’s engineering group in conjunction with field staff successfully eliminated all of the rakers from the project. The elimination of the rakers was accomplished by increasing sheeting size, modifying bracing, incorporating king piles and re-evaluating and studying the hydrostatic loads on the support of excavation.”
In addition, he said, custom designed wall, elevated slab and haunch formwork from several manufacturers has been utilized on the project to overcome challenging geometry and logistics of the project.
And, “Challenging site conditions,” Catik said, “have forced us to use a variety of different cranes to access work areas. We have used hydraulic and rough-terrain truck cranes from 35 tons to 600 tons, 150-ton and 200-ton lattice boom truck cranes, and a Liebherr LR-1160 lattice boom crawler crane and a Manitowoc 888 were both used on the ground and mounted on a barge.”
The Liebherr LR-1160, which is owned by Slattery Skanska, Catik said, is lightweight for travel on newly constructed slabs and has a high capacity for a small footprint in limited space, was used to service the concrete slab and wall construction, place concrete, erect structural steel and set piping and mechanical equipment.
Slattery Skanska also owns the Manitowoc 888. This crane, Catik noted, has a long reach and high capacity. It also can be assembled and disassembled quickly in tight areas. This crane was used to set the structural steel towers in the tanks, hoist the process air blowers and set the mini-pile rigs in the tanks.
The project also required the use of four Slattery Skanska-owned Tadano 450XL cranes, which offer heavy steel gang forms that require a hook with each carpenter crew, to facilitate operations throughout the job site, he added.
A Liebherr TM 1500 600-ton (544 t) hydraulic crane, rented from Bay Crane in New York City, was used to specifically set a 100-ton (91 t) steel truss at a 60-ft. (18.3 m) radius, while a Demag AC-40 crane, which also was rented from Bay Crane, was used to operate inside the existing building to set the 96-in. diameter stainless steel pipe required for the project, Catik explained.
The project also required the use of several excavators and loaders. They included a Slattery-Skanska-owned Hitachi 750 track excavator, which was used for its extended boom for deep and high volume excavations; a Komatsu PC-400 track excavator, which was rented from CAP of New York City, which was used to demolish existing concrete structures; a Volvo EC-460-B track excavator, which was rented from Penn-Jersey Machinery, was used for major excavation and demolition work; and a Caterpillar 345 track excavator, which was leased from H.O. Penn of New York City, was used for “difficult, high-volume excavations” and, with the help of a hammer attachment, for concrete demolition.
A Slattery Skanska-owned Caterpillar 320 track excavator, which, Catik said, provided “good traction on bad soil,” was used to maneuver in tight spaces and for breaking; and a Slattery-Skanska-owned Caterpillar 966G rubber-tired loader, was used as a utility vehicle, for loading soil and for general cleanup tasks. A Caterpillar 322M rubber-tired excavator, leased from H.O. Penn of New York, was used for trenching and exaction in tight spaces and to service mechanical trades in the trenches.
Catik said pile and sheet driving equipment included three Slattery-Skanska-owned Junttans, one a PM-40, which handled the 130-ft. (39.6 m) long, 24-in. (61 cm) diameter pipe piles and 115-ft.-long (35 m) piles that were barged in and was used to drive these piles; the PM-23. which was used to drive steel sheeting and timber piles in tight work areas and because they were able to be maneuvered inside existing tanks; and the PM-20L, a custom-made lightweight rig for working in existing tanks that was used to drive H-piles inside the existing tanks.
According to Catik, four additional Slattery-Skanska-owned pile and sheet driving rigs also were used. They included the Davey Kent DK 525, which was used to install 8.5-in. (21.5 cm) diameter mini piles in the existing tanks; a Bauer BG-22, which was used to auger 24-in. (61 cm) pipe piles; a Caterpillar 966F, which was used to unload and transport piles and sheeting; and a Manitowoc 3900, which was used to drive sheeting from the land into the water.
Completion of this contract for the upgrading and expansion of the Newtown Creek WPCP is scheduled for February 2008. CEG