Hillside presents engineering challenge for parking deck construction
Forced to transport members from off-site parking lots, a Northwest Arkansas church has built a parking deck into a hillside to overcome its landlocked campus.
Central United Methodist Church (CUMC) in Fayetteville, Ark. averages 1,500 weekly worshipers. Unable to support the traffic at its location, and unable to expand because of surrounding streets and a steep hill, church officials sought a better solution to busing in its congregation. The solution? To build up.
CUMC hired Garver to provide professional and lead-design services for a four-level parking deck, including structural, mechanical and electrical features. Don Kimble Architects provided architectural services.
Opened last August, the post-tensioned cast-in-place structure cuts into the side of a 30-foot hill. It rises three stories above the campus' main parking lot and only one story above adjacent Lafayette Street. Prior to any site work, the hill sloped down from Lafayette Street to the pavement below.
"Because of its unique location, the 215-space, four-level structure offers entrances and exits from two different levels," said Garver Project Leader John Watkins. "Church members have the option of entering the parking deck's ground level from the main campus and exiting to St. Charles Avenue, or entering and exiting from the third level to Lafayette Street."
Extensive excavation and retaining wall construction were required to ready the hill and property for construction.
"Due to the column loads and unsuitable near-surface soils, excavation to sound rock was required at various locations across the site," Watkins said. "The conventional spread footing foundations are supported on flowable fill or concrete pedestals that extend from the bottom of the footing elevation to the top of rock."
As an "open deck," Garver designed the structure without including a dedicated ventilation system for the bottom two floors built into the side of the hill. To meet the requirements of an open deck, retaining walls were constructed in strategic locations to allow openings in the exterior walls for ventilation. Without the addition of the retaining walls, the bottom two levels would have required a complete ventilation system.
Garver's electrical design included light fixtures that utilize pulse-start metal halide fixtures, which provide white light, better color rendering and longer life. The design provides emergency lighting at stairwells, elevator areas and paths of egress. Additional electrical design responsibilities included power service and distribution, interior and exterior lighting to Illuminating Engineering Society of North America requirements, elevator power and controls, and special electrical systems including fire alarm and telephone.
During design and construction, CUMC deferred the installation of revenue control and security systems. However, Garver designed the facility to ease their future incorporation. This included installing empty conduit from a central electrical room to the likely location of ticket dispensers, pay-on-foot stations and security cameras. Recently, the church positioned security cameras at all entry/exit points, elevators and stairwells.
Mechanical systems design included 30,000 square feet of roof parking drainage, 100,000 square feet of covered parking area drainage, domestic water plumbing, elevator sumps and equipment room HVAC components.
Garver's structural design also included the possible future addition of two levels if needed. To aid patrons, the parking deck is equipped with an exterior vehicle-counting sign that monitors available space within the facility.
Although built to serve the church, the $4.2 million parking deck is also meeting the needs of its community. Last October, a section of concrete fell from the nearby Washington County Courthouse parking deck. At the time, early voting for local and national elections was underway, daily bringing more visitors to the courthouse. CUMC stepped in and allowed the public to use its parking deck for free. The church now has an agreement in place with Washington County that provides parking for employees and patrons during the construction cycle for a new county parking deck. The deck also has been added to the University of Arkansas' bus route, and students park free of charge.
"We are extremely pleased with the design concept for our new parking structure and believe it will serve our church and community well for many decades to come," said Brian Swain, CUMC administrator. "Garver did an excellent job of working with a challenging construction area to design a user-friendly facility that blends well with existing campus buildings."
This project received a 2009 Engineering Excellence Award from the American Council of Engineering Companies of Arkansas.
Share this article