University of Kentucky College of Agriculture Alumni Plaza

Challenge

While the deterioration of the 40-year-old concrete plaza surface was apparent, the drainage had also ceased to function properly, resulting in ponding after rain events and icy patches in the winter. The university also needed to replace the underlying roof membrane, roof drains, and all of the existing drainage fill material. Construction would be another challenge. While site access was at-grade, the occupied classrooms and lab space below the plaza meant that crews would need to take extreme caution in the use of construction equipment and employ creative techniques.

Solution

The new plaza was designed using permeable pavers set directly over new roof drainage stone to shed rainwater continuously. Because construction occurred during the school year, staging of work had to be moved frequently to allow for continuous pedestrian access through the plaza. A detailed phasing schedule and pedestrian access plan were developed to balance construction work, circulation demands, and user safety.

• Nearly every surface in the 21,000-sf plaza was designed to be permeable, allowing stormwater to percolate down through a layer of drainage stone to the roof deck drains below.
• The plaza consists of 12,000 sf of permeable concrete pavers. Two styles of pavers were used in alternating bands to visually break up the space and help define smaller conversation areas.
• A 1,500-sf dining deck was constructed from composite decking made of 95% recycled wood and plastic film. The framing was constructed over new concrete piers poured directly on the roof.
• 7,500 sf of planting beds more than doubled the amount of vegetated area on the site. There are 15 species of native vegetation and agricultural crops, including purple lovegrass, red switch grass, buffalo grass, sideouts grama, northern sea oats, liriope ‘Royal Purple’, sedum kamscaticum, chia, sunflowers, Little Henry itea, cherry laurel, cotton, and black gum.
• An experimental row of chestnut trees was planted with 13 potentially blight-resistant sapling American chestnut trees and pure American chestnuts.
• A drip irrigation system reduces water use while helping plants to flourish in the challenging rooftop conditions.
• 6 benches made of local Kentucky limestone slabs provide seating in social spaces and smaller study nooks. 
• Large native limestone slab benches provide seating in the smaller study nooks, while tables and chairs with umbrellas provide sheltered dining and study space on the sun deck. 
• A new 52-ft blue steel arch sculpture creates a gateway to the college.
• 14 30W LED light fixtures are used throughout the plaza. The fixtures make use of downlighting to illuminate that plaza while reducing light pollution.

For this project, the material cost of composite decking ($7 per sf) was an estimated $3,750 more than traditional wood decking ($4.50 per sf). However, the estimated maintenance costs to clean, stain, and, seal wood decking annually are $1,200 per year, while composite decking requires minimal maintenance.

• During the winter months, maintenance staff began to remove the excess snow and ice from the plaza by using leaf blowers. While efficient for snow removal, the technique blew the rock infill from between the permeable pavers to the edges and against the planter beds. To avoid disturbing the rock infill, an alternative snow removal technique should be used.
• The Alumni Plaza design has been an important catalyst for further improvements in the vicinity of the plaza. Plans are underway to replace over 9,000 sf of the main ground-level sidewalks surrounding the Garrigus Building with pervious paving. In the past, use of innovative “green” construction practices like this would not have been suggested or considered.

Plaza Lighting and Pole Fixture: Invue “Slide” medium LED
Light Column: Ligman Lighting USA “Ottowa Light Column” LED
Uplights: Invue “Vision” small LED
Drip Irrigation System: Rainbird
Permeable Pavers: Reading Rock “EcoFlo” and “HydraBric”
Tables and Shade Structures: Landscape Forms “Plexus” and “Solstice”
Trash Receptacles: Landscape Forms “Scarborough”
Composite Decking: Trex “Transcend”
Fiberglass Planters: The Chandler Company “Monica Rectangle”

Project Team

Landscape Architecture, Civil Engineering, Planning: Element Design
Structural Engineering: Brown + Kubican  
Construction Team: Marrillia Design and Construction

Role of the Landscape Architect

Thought originally conceived as a repair project, the University of Kentucky’s College of Agriculture, Food and Environment (CAFE) decided to seek a broader solution for Garrigus Plaza due to its deteriorating materials and low functionality. The landscape architects responded to the university’s solicitation of design proposals, submitting a plan based on a bold concept of agricultural patterns and greening the roof deck to create a plaza worthy of the college it serves. The landscape architect was selected and designed, produced construction documents, and oversaw the construction of the new Alumni Plaza.