North Carolina Construction News special feature
In February, Carolinas AGC bestowed the 2014 Pinnacle Award to Winston-Salem based New Atlantic Contracting for the Railroad Underpass project at the University of North Carolina Greensboro (UNCG). “There are few occasions when a contractor is fortunate enough to win a project that is so unique, complex, challenging, and also great fun,” said New Atlantic Contracting president Ricky Adkins.
The same project also has received recognition through CPN of NC Star Award for projects under $20 million.
“Throughout the project, stakeholders, design team, subcontractors and vendors remained focused and together on delivering the project as efficiently as possible. Without this, the project would have never been a success,” added New Atlantic senior project manager Michael Hardman.
The UNCG Railroad Pedestrian Underpass provides safe passage through the railroad property for students, faculty, and local residents. It also serves as link for UNCG to the upcoming mixed-use development initiatives along the Lee St. corridor.
The 30,619-sq. ft. pedestrian underpass project consists of three major sections. They include a North Plaza located on the existing core side of campus, a tunnel beneath Oakland Ave. and three active railroad tracks, and a South Plaza that opens to the Lee St. corridor.
The North Plaza includes a new ramp from Forest Street down to the tunnel. The ramp is flanked by new cast-in-place walls with brick veneer and precast caps that structurally supports Forest St. on the east side and a new parking lot on the west side.
The tunnel itself is a cast-in-place concrete structure; 170-linear-feet, 17-feet wide, and 15-feet tall. Concrete form liners were used to create a pyramid texture on the curved roof of the structure, and a horizontal wave texture on the walls separated by vertical pilasters.
A complex five-color, hand painted scheme was developed for the tunnel walls and ceilings by Fred Patrick, the director of facilities design and construction at UNCG. The walls are painted in rich, earth tones in order that the pedestrians feel “grounded” as they walk through the tunnel. The curved top is painted with a base white tone and it is accented by the school colors of deep blue and gold.
The 16,000-sq. ft. South Plaza connects the tunnel to Lee St.. “It is semi-circular in shape with cast-in-place concrete walls with brick veneer structurally supporting Lee Street, cast-in-place concrete Spanish Steps, a bike ramp, and a gently sloping grade to the tunnel,” said Patrick. This also serves as an area for the students and community to congregate and allows for local events, such as concerts or movie nights.
The project’s innovative and creative qualities
The Railroad Pedestrian Underpass provides students entering from the south edge of the campus along Lee St. unimpeded access to the university under the rail line. It was the university’s intention for this connection to be an iconic gateway feature.
Architect David Wagner, principal-in-charge of Charlotte-based Wagner Murray Architects said the scope of the project included a program to provide a significant entry plaza on W. Lee Street to compliment and integrate the streetscape and connector to the campus. “This gateway serves as a visual and physical connection to the Glenwood Ave. intersection. The design is further enhanced and integrates the future plans for campus building construction along this corridor, as well as a connection to the historiic Glenwood community,” said Wagner.
Cast-in-place concrete tunnel
The cast-in-place concrete tunnel was given texture through the use of two styles of concrete form liners. The walls were constructed using a regularly repeated
pattern of smooth vertical pilasters, and smooth top and bottom rails, surrounding a three dimensional “wave” pattern form liner.
The “wave” involves a series of horizontal ribs spaced approximately ½-inch on center, and an overall vertical plane that gently oscillates approximately one-inch toward the interior of the tunnel and back again. The curved top section was constructed using a three dimensional “pyramid” form liner. There are no breaks in the pattern for the entire length of the tunnel, despite having two construction joints in the tunnel top.
New Atlantic’s senior project manager Michael Hardman said “extreme care was taken to ensure the pyramid pattern was matched up, and is continuous through the three separate tunnel top sections.” In addition, the form liners were installed with precision so that the sloping section of the north end of the tunnel could be mitered to the horizontal. This allowed the pyramids to taper evenly and be uniform.
The complex, five color, hand painted scheme was conceived for the tunnel walls and ceilings by UNCG’s Fred Patrick, who is also an associate member of the International Association of Color Consultants North America.
“The curved top is painted with a base white tone representing the sky, and it is accented by the school colors of deep blue and gold,” said Patrick. “Gold paint was applied to two adjacent sides of the concrete pyramids facing the tunnel opening, symbolizing the light from outside of the tunnel,” he said.
Adjacent pyramids were painted with the gold paint, such that gold bands were created, which appear to spiral over the tunnel top. A gold band is repeated every fifth pyramid through the tunnel. The back sides of the pyramids are painted in a similar manner with deep navy blue paint, symbolizing the shadow created by the pyramids to the inside of the tunnel.
North and south icons
A 26-foot tall icon stands on the North Plaza and a 34-foot tall icon stands at the South Plaza. Located at the northern most and southern most extremes of the project, these icons serve as focal points of the plazas, and welcome pedestrians as they walk towards the tunnel.
Hardman said “the North and South plaza towers are comprised of concrete footings and walls, precast concrete veneer and cap, vertical brick masonry walls, and a galvanized structural steel frame covered by translucent glass panels that are backlit with fluorescent lights and topped with aluminum panels. The UNCG Minerva graphic is etched into a circular translucent panel at the top of each icon, and backlit to illuminate at night.”
Changes in the original schedule
The project schedule was very fluid and dynamic. “Significant schedule events, such as tunnel concrete pours were scheduled 30 days in advance,” Hardman said. “Our team had to remain flexible to coordinate the construction activities without impacting freight movement on the tracks,” he said.
Hardman said “the construction team worked to develop the North and South Plazas from the furthest extents of the construction limits, working towards the tunnel, while still maintaining access for materials, labor, and equipment to construct the tunnel. This allowed for all three sections to be built concurrent and minimized construction cost,” said Hardman.
The project was built beneath three active railroad tracks that serve 34 trains per day. “We had to ensure the safety of the construction workers onsite, as well as the safety of the passengers and crew on the trains,” said Hardman. “All persons who stepped onto the jobsite, regardless of their role on the project, were required to participate in a specific railroad safety training program at the start of the project,” he added.
“In addition, Norfolk Southern Corporation provided a flagman dedicated to the project during construction,” Hardman said. “The flagman was a valuable asset at our regular safety meetings attended by members of the university, design team, construction management and trade contractors,” he added. “The focus on safety paid off resulting in an accident-free project.”
Value to the community
From a community perspective, this project serves to create the first pedestrian link between UNCG’s core campus, the Lee Street corridor and adjacent Historic Glenwood community. Patrick noted the railroad tracks have historically been a boundary to the growth of the campus, and the tracks have separated UNCG from Lee Street and the Glenwood community.
“The new Railroad Pedestrian Underpass creates a link for UNCG to upcoming mixed-use development initiatives along the W. Lee Street. corridor,” said Patrick. In addition, the South Plaza adjacent to Lee Street serves as a place for students and the public to congregate.
Construction industry benefits
The project benefited the construction industry by broadening the railroad specification for concrete. Hardman said “the initial railroad specifications required the use of 4,300 psi concrete with air entrainment, and a slump of two-inches to four-inches.”
“The Railroad is typically unwavering with their specification,” said Hardman. “This concrete would have been extremely difficult to cast into the ornate form liners that were selected for use in the project, and there was concern that it would not consolidate properly into the points of the pyramid texture in the tunnel ceiling, and the fins of the wave texture in the tunnel walls,” Hardman noted.
As such, the team worked to develop a compromise that met the structural and aesthetic needs of the project, while still maintaining the original intent of the railroad specification. The concrete was batched to the site in accordance with the railroad specification, and was tested at each truck. The railroad then allowed super-plasticizer to be added to the concrete, so long as it was tested again at the end of the pump truck, immediately before being placed into the forms.
“The railroad allowed for slump at the end of the pump truck to be six-inches to eight-inches,” Hardman added, “which significantly enhanced the workability of the mix.”
The Railroad Pedestrian Underpass was Tim Norman’s final project before retirement as State Construction Office project monitor. He made his feelings known on the success of the project in a reference letter. “This was a very challenging project, but it has been a very positive experience. In short, it has been one of the best State Construction Office projects that I have been a part of,” wrote Norman.