The Pennsylvania Convention Center, which opened in 1993 in the heart of City Center Philadelphia, lived up to its promise of attracting more convention business to the city and prompting economic growth.

The additional convention business in turn prompted hotel construction and economic development projects in the surrounding region and made the area surrounding the Pennsylvania Convention Center its own activity hub.

However, demand soon outgrew the convention space in the 1.3 million-sq-ft facility, and city officials wanted that convention center hub to connect to the rest of the city. So in 2008, the Pennsylvania Convention Center Authority undertook an expansion project that has become the largest single public works project in Pennsylvania history.

�The building needed to remain competitive within the market,� says Joseph Resta, project executive for the Pennsylvania Convention Center Authority. �A lot of the conventions we hold needed to have more space or they wouldn�t come back.�

The 960,000-sq-ft, $786-million expansion will give them that space to keep current convention customers, attract new ones and prompt more hotel construction.

The project, which began in June 2008, is slated for a spring 2011 completion, says Pierce Keating, chairman and CEO of the Daniel J. Keating Co. of Narberth, Pa.

His company is working in a joint venture with Keating Building Corp. of Philadelphia (Pierce Keating and Keating Building Corp. CEO Daniel J. Keating are brothers). Vitetta of Philadelphia is the architect.

The brothers decided to work in a joint venture because of the sheer size of the project, says Pierce Keating.

The expansion will bring the total square footage of the Pennsylvania Convention Center up to 2.3 million sq ft, making it the 14th largest convention center in the country.

The expansion will add 376,000 sq ft of salable meeting space, raising the total to over 1 million sq ft and allowing the convention authority to hold two major conventions at once. It will also expand the second-story main exhibit hall to 540,000 sq ft, making it the largest contiguous exhibit space in the Northeast.

The expansion will include what will be the largest convention center ballroom on the East Coast at 60,000 sq ft, with the capacity to hold 6,000 people. The project will renovate parts of the existing convention space and add three additional halls, 17 new truck berths, 23 new meeting rooms, a new lobby, offices, kitchen and mechanical room.

The space will have new fiber-optics systems built into the walls, allowing Webcasting, teleconferencing, audience response polling systems and wireless capabilities.

The expansion will seek LEED certification. It includes energy-efficient HVAC systems and water-saving toilets, as well as stormwater collection tanks installed underground.

�They will receive all watershed from the roof down into the tanks, which will then trickle into the city�s stormwater system at a rate it can handle,� Resta says.

A major challenge was the initial demolition and concrete pours on the eight-acre expansion site in a crowded section of Center City Philadelphia. The center is also over an underground transit center and the above-ground Reading Terminal Market, a 1892 building on the National Historic Registrar and a major tourist draw.

The building team worked closely? with its subcontractors in the timing of the demolition and pours.

�Whatever we needed that day, we needed to have onsite,� Resta says. �It was a large-scale exercise in �just-in-time� scheduling.�

Once construction started, that issue of laydown space became manageable because of the sheer square footage of the project.

�We could actually drive up through a ramp to different portions of the building, which helps because you could bring things right to the job and minimize laydown,� Keating says. �We left certain parts of the building off of the fa�ade so we could feed the job directly from the street.�

The coordination forged during the demolition process was key throughout construction, too, because the project team was not allowed to shut down the existing Pennsylvania Convention Center for construction, nor create noise that would affect meetings and conventions held in the space.

One goal on the exterior of the building was to give the new and old portions of the building a unified look. �Architecturally, the expansion was predominately a repetition of the existing facility, which harkened back to the residential architectures of the area,� Resta says.

The only exception to that architectural design is a new Grand Entrance being built on Broad Street, which is one of the city�s main thoroughfares. It will feature a 100- by 400-ft glass curtain-wall fa�ade that will create a new entranceway and second-story pedestrian access to the building.

�North Broad Street has really been a lagging area of Center City in terms of investment and the occupancy level in buildings, but putting a major front door on North Broad street has the effect of drawing people from the convention center,� says Paul Levy, CEO of the Center City District, an economic development agency. �I think this will drive new investment in the area.�

Many hotel projects slated for the Pennsylvania Convention Center area were put on hold during the recession, but Levy estimates that once the convention center opens, the city will have a shortage of about 2,000 rooms, which will re-start some of those stalled hotel projects and add more.