Thomas J. O'Connor is a senior engineer of construction for the World Trade Center Construction Department and is responsible for managing the construction of the National September 11 Memorial & Museum.
Mr. O'Connor has nearly 30 years of experience in project management and engineering construction activities, including the restoration of the temporary World Trade Center PATH Station and major construction projects at John F. Kennedy International and LaGuardia airports.
Q. Now that we've just passed the eighth anniversary of 9/11, I'm trying to find out when work on the plaza finishes - such as the trees and waterfalls - will begin? -- Michael, Brooklyn, N.Y.
A. Michael, if you take a look at our Web site - www.wtcprogress.com - you can see the substantial progress we've made to build the Memorial in just one year. We'll keep up the aggressive pace we've set during this upcoming year. To answer your specific question, by the 9th anniversary, we'll have work underway on the Plaza finishes, beginning with stonework on the two signature reflecting pools.
Q. I am following the construction of this project and find it remarkable. So much water cascading will surely be dramatic, both the sound of falling water and the visual appearance of it. Will the falls operate year-around, day and night? How much water is required to cascade in order to give the right effect? How will they light the pools at night? In how many years will the pools be in operation? -- Victor, Scarsdale, N.Y.
A. I'm sure others who have seen the renderings of the Memorial on the Web site will agree that it will be a beautiful, contemplative public space once it is complete. Once the Memorial Plaza is open on the 10th anniversary, the waterfalls will operate 24/7, 365 days a year. Each waterfall will pour 40,000 gallons of water per minute, which could fill an Olympic-sized pool in eight minutes. Lights in the interior of the pools will illuminate the waterfalls.
Q. Is there a scheduled date to return the tridents to the site? -- Franklin, TN
A. The tridents you refer to are the signature pieces of steel that resemble tuning forks that were recovered from the remains of the Twin Towers and preserved for the past eight years. These jumbo steel columns will be returned to the site in the 4th Quarter of 2010 and will be displayed in the Memorial Pavilion.
Q. When visitors go down to the bottom of the bathtub and enter the North Pool, will they be able to see and touch the remains of the perimeter columns and core columns? -- Orlando, FL
A. The perimeter column remains from the former 1 World Trade Center are among the key artifacts we've preserved on the site. They will be visible in the Museum and visitors will be able to walk around the perimeter columns surrounding the pools.
Q. When will the south tower reflecting pool be finished? Also, when will the steel over the PATH Terminal be erected? -- Anthony, Commack, N.Y.
A. As you can see on our Web site, the south reflecting pool is already beginning to take shape and will be completed with active waterfalls by September 11, 2011. The steel over the PATH terminal will begin in the 2nd quarter of 2010.
Q. I see that the North Pool is very visible. When will the South Pool be as far along as the North Pool? -- Montana, N.Y., N.Y.
A. As I mentioned above, the south pool is already taking shape. The reason why it is being completed second to the north pool goes to the complexity of the entire project. The steel to complete the south pool is being built on top of the south mezzanine of the PATH Station, which was installed as part of the Hub project. This had to built first - all while maintaining service on an active railroad under the work area - before the street-level steel can be installed for the south pool. The Memorial steel will be installed during off-peak hours so PATH service is not disrupted.
Q. Will the long building that houses the PATH train tracks, just east of the North Pool, need to be dismantled or will you just add a level on top of it to finish the plaza level and Museum Pavilion? -- Joe, Cambridge, MA
A. The building that currently houses the PATH train tracks will be dismantled and a new station below the Memorial will replace it.
Q. I would like to know when the PATH Station, which is just beside the World Trade Center Memorial, will be covered by the new plaza? Also, I would like to know when the southwest corner of the Memorial will be built, and when Greenwich Street will be built along with Fulton Street? -- Boris, Ridgefield, CT
A. Your question clearly shows how integral seemingly unrelated projects are to the Memorial. We will complete steel installation in the southwest corner of the Memorial footprint by the 1st quarter of 2010. The current temporary PATH Station will be completely covered by the new Memorial Plaza by the 1st quarter of 2012. Portions of Greenwich Street - which will serve as the front door to the Memorial - will be accessible with interim walking surfaces by the 3rd quarter of 2011. And portions of Fulton Street adjacent to the Memorial Plaza will be accessible with interim surfaces by the 4th quarter of 2012.
Q. When is the remaining steel going to be put in place over the PATH rails? Secondly, when is the roof for the South Mezzanine going to start and why is it taking so long to put a roof on? -- Ryan, Roseville, MN
A. The majority of steel will be installed over the PATH rails by the summer of 2010. The roof for the South Mezzanine will start early next year. As I mentioned above, this section requires close coordination between the Hub and Memorial project and work cannot begin until the steel for the Hub's south mezzanine is installed first.
Q. How are you incorporating building around the operating PATH Station? -- Jason, Hoboken, N.J.
A. The PATH Station is in operation seven-days-a-week, 24-hours-a-day. To keep PATH running and get the Memorial and the other projects built at the same time, we can only work on and around the tracks during scheduled outages on the weekends and overnight by closing one of the two PATH tunnels that provide access in and out of the site. This allows the Memorial work to proceed without shutting down the entire system. This kind of logistics coordination is essential when building so much in such a confined area with literally two active subway systems running 24-hours-a-day.
