Award of Merit - Transit

1/9 Subway Ventilation Plants

Constructing two new vent plants for the 1 and 9 subway line in Lower Manhattan echoed other jobs that took on massive underground infrastructure improvements.

"These were extraordinary insertions in an environment that was very difficult to work in," one judge said. "They had to build that the same way they built the Big Dig up in Boston."

The $59 million project involved replacing two fan plants destroyed by the Sept. 11 terrorist attacks. Located north of the World Trade Center site, the Park Place Fan Plant consists of three 150 HP fans producing a total of 300,000 CFM. The Albany Street Fan Plant, located south of the trade center site, consists of two 200 HP fans and also produces 300,000 CFM.

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A project of this scale usually takes four years to complete, but the 1and 9 job took 22 months. Crews built the two plants simultaneously, working extended hours, six days a week.

The project team could not begin work until after Jan. 1, 2002, because of a local requirement halting such work until after the holiday season. New York City Transit granted the project team one year to keep Albany Street closed, but the project team reopened the street in 10 months.

The construction involved installing a sheeting bathtub approximately 50 ft. deep by 200 ft. long at each site. Since both plants are completely below the city streets and surrounded by commercial and residential buildings, stability of the existing subsurface was a concern. To address this, the team used steel sheeting, bracing, roadway decking, and chemical grouting to control the groundwater and soil.

The team had to safeguard streets, surrounding buildings, and groundwater levels, while also monitoring water, sewer, gas, steam, telecommunications, and electrical utility lines, all which ran through the site's footprint. The team had to ensure continued operation for all utilities during the entire construction period. The team accomplished it by providing temporary utility service outside the main cuts or by hanging existing utilities from below the decking system.

"The project team really executed it well, to dig underneath the infrastructure and create the environment they needed to insert the steel," said one judge.

With 30 subcontractors on the job, the project required detailed planning and scheduling to allow multiple trades to work at the same time. The team coordinated with local unions, subcontractors, and vendors to limit crews on site to essential staffers.

A limited staging area also presented challenges. The team staged deliveries to limit materials around the worksite. It also engaged in meticulous planning to ensure workers had the necessary materials to complete programmed tasks, while keeping unnecessary material deliveries away.

The proximity to numerous residential buildings also limited the loudest work activities to certain hours. Work impacting subway service or vehicular traffic took place during night and weekend hours. The project team also had to update New York City Transit daily so that the agency could post bulletins on its Web site to keep the public informed about upcoming construction activities.

"I don't know how they ever did it," said one judge.