Bucks County Judicial Parking Facility
Structural Precast Elements:
• Shear walls
Architectural Precast Elements:
The County of Bucks in southeastern Pennsylvania is modernizing and expanding its judicial facilities located in historic Doylestown, the county seat. Designed by the Washington, D.C. office of HOK Architects, the $140 million, three-phase project is the county’s single largest such undertaking. Phase 1 involved the construction of a new $22 million, 1,200-space parking garage, which was completed in summer 2010. Subsequent phases will focus on demolition of an older garage and construction of an administrative building and the justice center itself.
“We chose the precast parking garage system based on a 30-year cost projection,” says Kevin Carrigan, director of engineering for the project’s parking consultant Timothy Haahs and Associates of Blue Bell, Pa. “Precast was lower in initial and long-term maintenance cost than cast in place post-tensioned and steel systems. The one cost concern was sealant joints,” says Carrigan, “but the lower initial cost easily overcame this.” Haahs designed the garage to comprise mainly 15’-wide double tees, which reduced the number of sealant joints by approximately 20 percent versus conventional 12’-wide double tees.
“We were also concerned about quality control, which we knew would be better with precast,” he says. “Not all areas of the country have reliable cast in place contractors.”
Situated in a residential area of downtown Doylestown, the new 276,600 sq. ft. parking facility serves the justice center by day and accommodates visitors to downtown arts and cultural attractions during off-peak hours. The garage takes advantage of a slope to conceal a large part of its mass. The elevations present a friendly, understated image that blends well with surrounding homes and light commercial buildings.
Challenges — Integrating a precast garage below grade
The garage was built on a sloping site so that the east end is tucked into the ground, with the garage roof at street level. Progressing 400’ down the slope, the brick-veneered façade gradually emerges to a tower four stories in height. To facilitate the use of precast, expansion joints around the perimeter separate the precast elements from the cast in place foundation. Area ways around the perimeter provide natural light and ventilation to areas below grade through natural convection.
Eight “K”-frames were used for lateral bracing. “The ‘K’-frames are much better for visibility and safety when you’re standing or driving within the garage,” says Carrigan. “Because of the very flat footprint of the building, solid shear walls would not have permitted a clear line of sight at the ends of the drive lanes.” Shear walls were used at the perimeter, as well as walls with punched openings.
Steel-reinforced double tee flanges with 4-3/4” thickness ensure a two-hour fire rating. Stems are 26” in depth to optimize headroom and floor-to-ceiling heights while keeping the cambered driving surfaces solid and with a minimum of bounce. The broom-finished 15’-wide and 12’-wide double tees were sealed with a silane sealer.
Three bays in width, with a fourth bay on the back half, the new garage has easy-to-navigate 26’-wide two-way drive aisles, and traditional 90-degree front-in parking with 9’ x 18’ spaces. There are three entrances/exits on each of three sides of the building to help move cars in and out easily onto the adjoining city streets. Visitors have their choice of glass elevator and switchback stair towers at the three main corners.
Inside, entryways and waiting areas have steel trowel-finished wall surfaces painted with graffiti-proof paint to match the architectural buff of the exterior. Lighting is accomplished with energy efficient fluorescent fixtures. With a nod to the not-so-distant future, provisions were made for future electric vehicle charging.
Aesthetics — Upscale facade is sensitive to neighbors
The façade of the parking structure was driven by the borough’s effort to combine the traditional architecture of Doylestown with a contemporary style. To achieve the appropriate style, Haahs used a combination of traditional materials, geometry, and architectural patterns to create a building that blends with its neighbors in terms of height, materials, and fenestrations, while adding contemporary detailing to give the building a warm and intimate feeling.
The parking garage is situated at the northwest corner of the judicial complex, surrounded by a mix of brick duplexes, townhomes and several light commercial buildings. To play well with its neighbors, the garage is finished in a traditional red thin brick veneer in a running bond pattern with rake joints. The thin brick cast into the precast using a snap system formliner. Precast surfaces received a medium sandblast. Buff-colored lintels and horizontal banding break up the scale of the façade. Details including copper spouting, decorative grillwork and fencing demonstrate attention to detail.
Topped with a green metal standing seam roof, the main entrance/exit greets visitors with the courthouse name and county seal cast into a buff-colored precast marquee. A residentially-styled stair/elevator tower repeats the roofing theme, and merges easily with surrounding brick and frame duplexes and townhomes. From here it is a short walk through surface parking to the future judicial center plaza.
Secondary entrance/exists face Broad Street to the north, and Doyle Street to the west, and are also covered by green standing seam canopies with inscribed precast marquees. The northwest stair tower serves as a prime architectural element and is located on Broad Street, a main corridor into town from the Route 611 bypass. Using a clock tower as a focal point for design, the building creates a visual entryway to the downtown district. With ornate hands and Roman numerals, the image recalls the clock tower of the town’s first courthouse that had to be demolished in the 1960s.
Set backs, towers and notch corners create a variety of surfaces that further breaks up the building’s mass. Colonial-style windows and tall spandrels downplay the function of the building while allowing daylight to penetrate. Generous plantings and trees further soften the façade and help create a visual separation from adjacent properties.
Although natural light is abundant throughout the facility due to design elements, lighting also will be controlled by a computer-based system utilizing photo cell light sensors, timers and manual switches. Energy efficient pendant lighting suspended between the double tee legs keeps the garage safely lit at night without light trespassing. Simple sconces uplight the façade, and Victorian-style streetlamps create a nighttime image that is walkable and secure.
The new Bucks County parking facility will provide the essential infrastructure needed to support the exciting new development in downtown Doylestown, including the upcoming Bucks County Judicial facility. The facility is a key component to the continued growth and development of the Borough of Doylestown now and into the future.