By Liz Moucka
Manhattan Construction has been busy these past 18 months constructing the George W. Bush Presidential Center and grounds on a 23-acre site on the east side of the SMU campus in Dallas. President George W. and Laura Bush chose the site after much public speculation and contractors began turning dirt after a lavish groundbreaking ceremony November 16, 2010. The building topped out and reached the 50 percent milestone in October 2011. It is scheduled for completion in mid-2013.
Designed by Robert A.M. Stern in the American Georgian style of architecture as is the SMU campus, the three-story tall building is designed to achieve LEED platinum certification. Construction material has been sourced from a 500-mile radius within Texas, Oklahoma, Louisiana and Mississippi, including red brick from Columbus, MS; Texas Limestone; pecan interior wood paneling; trees and planting medium from various north and central Texas locations.
Stoutly built, the massive 226,565-square-foot structure contains 3,245 tons of rebar and 28,638
tons of concrete. Spanning the ceiling of the underground parking garage are 60-inch deep transfer girders along with 12 miles of post tension cables installed in both directions, not a normal practice. The post tension cables had to be coordinated extensively with the rebar and special measures were taken in order to be able to stress the cables after the pour, according to Manhattan engineers.
Peter Edward Arendt is the Director of Design & Construction for the George W. Bush Presidential Center. As the agent for the George W. Bush Foundation, he is charged with orchestrating the project team of architects, engineers, designers, contractors and other consultants in a mutually collaborative effort to achieve the project’s goals. Manhattan Construction Company is providing construction management services for the George W. Bush Presidential Center project.
As impressive as the building will be, the transformation of flat blackland prairie into a 23-acre Texas hill country oasis is a landscaping feat. General contractor, Manhattan Construction has employed the talents of Metheny Commercial Landscaping and a number of their subcontractors to shape the terrain with hills, outcroppings and a meandering draws in preparation for lush plantings that will be reminiscent of north-central Texas.
The world-famous landscape architectural firm of Michael Van Valkenburgh Associates designed the landscape for the Bush Center. Metheny Commercial Landscaping is the primary subcontractor for earthwork and plantings, while Environmental Design is performing actual planting and transplanting of trees.
One of the initial steps in the site preparation involved relocating 30 trees to a holding nursery until it was time for them to be replanted onsite. Excavation was able to kick into high gear thanks to the previous clearing of most of the underground utilities as part of the contract that demolished the former structures that were on the property.
Water Resources
On the south side of the building, 10 to 15-foot swales were cut into the landscape to create a rolling hills effect and help channel stormwater runoff into the wet prairie area, to be filtered into
a 260,000-gallon cistern. Excavated material was stockpiled for later use in the formation of hills and to raise the northern portion of the grounds at the front entrance to the Center by 15 to 18 feet above original grade.
The cistern, at the bottom of the wet prairie area, was designed to retain water that will be used for irrigation of the gardens and to reduce the amount of water runoff into the public water system. “It’s not like most storm water management program you would normally see on a 23 acre site,” commented Travis Maiwelmal, senior project engineer and landscaping coordinator for Manhattan Construction. “Rainwater will either be absorbed into the soil or run into the bioswales to be channeled into the cistern. It is estimated that the cistern will provide about 50 percent of the water needed for irrigation.”
The cistern, excavated to about 15 feet below grade, was constructed as an open modular system. Stacked plastic crates, resembling milk crates, but strength engineered, are wrapped in plastic and topped with sand to filter the water as it leaches down from the wet prairie area. Pumps will circulate the filtered water from the cistern into the irrigation system and back into the stream.
Earthwork
To create hills, the excavated soil was placed in 12-inch lifts, to heights of approximately 15 feet, then cut back 30 to 36 feet to resemble Hill Country terrain. Geofiber material was then placed on the hilly slopes to prevent erosion. But it was the upper three and a half feet of soil that would serve as the specified planting medium that proved to be a commodity much more difficult to locate.
“We went through numerous testings and visited many sources – probably ten different sites, taking multiple tests at each site – trying to find the base planting soil that had the correct sieve and granulation to promote drainage, yet at the same time, had the clays to hold water and promote growth,” said Travis Maiwelmal. “That process took between three and four months.”
Soil with just the correct characteristics was located on private property near Streetman, TX. “It is a sandy loam that retains moisture even in the heat of summer and allows water to percolate through to get to the subgrade,” explained Bruce Fields, Manhattan Project Executive.
Process sand is being brought in from Waco and compost with just the right maturity and “feed stock” was located at Texas Pure in Melissa, TX. The sandy loam is dug at about 23 percent moisture, and must be placed at 15 percent moisture according to specifications determined by Ted Hartsig, soil scientist for Olsson Associates of Kansas City, according to Fields. It must, therefore, go through a drying phase. The sandy loam, along with the processed sand and compost are collected at a centralized location in Hutchins, just south of Dallas for drying and mixing before being applied at the George W. Bush Presidential Center and grounds. An estimated total of 70,000 cubic yards of this special soil mix will be used as the planting medium on the grounds. In order to minimize compaction, the soil mix is placed by using a Putzmeister telebelt machine of the type normally used to place concrete.
Three layers of specially designed planting mix comprise the tree planting profile:
|
Designation |
Depth |
Material |
|
S1 |
Top 12 inches | Mixture of sandy loam from Streetman, TX and compost from Melissa, TX. |
|
S2 |
Middle 24 inches | Sandy loam from Streetman, TX. The irrigation system is also installed in this layer. |
|
S3 |
Bottom 6 inches | Primarily clay harvested from the GWBPC is used as a transitional soil. |
A Walk Though Texas
Along the north of the George W. Bush Presidential Center, BLW Concrete Contractors constructed SMU Boulevard, which was landscaped with 200 trees both curbside and in a center median. The north lawn, the front approach to the Center, will have a more formal lawn appearance to greet visitors.
Except for the replica of the White House Rose Garden adjoining the main building, the remainder of the 15-acre south grounds will provide visitors with an opportunity to experience the best of Texas’ native Hill Country, with a wildflower meadow, a wet prairie, and meandering paths along a meandering draw. Numerous native trees have been supplied by Lone Star Trees of Crawford, TX, including Live Oaks, Cedar Elm, Red Oak, Mexican White Oak and Bald Cypress. More come from locations in Oklahoma and Louisiana – approximately 900 young trees in all. The frequent and heavy rains in this Spring of 2012 have narrowed the window of opportunity for planting these trees, so that late April and early May have seen the contractors scrambling to get the trees planted before the heat of summer arrives.
On the foot paths, Stalite forms a surface that is provides a sturdy walking surface, yet allows rainwater to filter through. Stalite is a rotary kiln expanded slate lightweight aggregate. Pedestrian bridges will traverse the meandering draw, and Lueders limestone boulders will create hardscape features and enclaves perfect for congregating with friends.
About Manhattan
Tulsa-based Manhattan Construction Co. maintains offices in Dallas, Houston, Tulsa, Oklahoma City, Atlanta, Washington D.C., as well as five Florida (Tampa, Ft. Myers, Kissimmee, Naples, Sarasota ) offices. They have become widely known for building high-profile, technically difficult mega projects like the Dallas Cowboys Stadium in Arlington, Reliant Stadium in Houston, and Texas Rangers Ballpark at Arlington. Manhattan also built the George Bush Presidential Library in College Station, for which it won the Associated Builders and Contractors (ABC) of America “Excellence In Construction Award.”
Primary Subcontractors
Americal Steel………………………………………………….. Structural Steel
AVI SPL ………………………………………………………….. Audio Visual
Baker Triangle …………………………………………………. Acoustical PlasterPlaster
BLW Concrete Contractors ……………………………….. Concrete Place and Finish
Brandt Engineering …………………………………………… Electrical
Camarata Masonry Systems …………………………….. Masonry – brick and stone
Cardinal Roofing, Inc. ……………………………………….. Roofing
Chamberlin Roofing & Waterproofing………………….. Waterproofing
Dallas Door & Supply Co. ………………………………….. Doors and Hardware
DynaTen …………………………………………………………. Mechanical
Dee Brown Inc. ………………………………………………… Exterior Building Masonry
Environmental Design ………………………………………. Tree Transplanting & Installation
Haley_Greer, Inc. …………………………………………….. Glass and Glazing
John Burns ………………………………………………………. Utility installation
Johnston Products ……………………………………………. Ornamental Metals
LASCO Acoustics and Drywall, Inc. …………………… Drywall
Lone Star Trees………………………………………………… Tree Supplier
Metheny Commercial Landscaping ……………………. Landscaping
Mortensen/Latta ……………………………………………….. Interior Millwork
Naylor Commercial Interiors ……………………………… Painting
Northstar Fire Protection of Texas, Inc. ………………. Fire Protection
Siemens ………………………………………………………….. Security
Sigma Marble & Granite ……………………………………. Ceramic & Quarry Tile
Texas Stone & Tile Services ……………………………… Interior Stone
The Anchor Group ……………………………………………. Security Bollards & Barricades
Thyssen Krupp …………………………………………………. Elevators
Woodwright ……………………………………………………… Wood Flooring
This article appeared in the June 2012 issue of Texas Contractor