Ledge Removal Continues in Vermont Before More Rocks Tumble on Highway

Contractor Achieves Solid Foundation at Air Force Base

Thu April 05, 2007 - West Edition
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For approximately 75 years, Brooks Air Force Base was a leading aviation training, education and research facility. Formally established as Brooks Field in 1918 in San Antonio, Texas, this location was one of the first flight training schools in the country.

In 1926, it became the home of the School of Aerospace Medicine, supporting the flying school by performing medical examinations for all cadets and allowing flight surgeons to conduct research in aviation medicine. Since that time, the base has been the location of numerous laboratories and scientific facilities, which have provided significant data to aerospace medicine.

In 1995, however, military planners from the Base Realignment and Closure (BRAC) committee recommended closure of Brooks Air Force Base. The base was later saved in the eleventh hour, but the writing was clearly on the wall. One day in the not-so-distant future, the base would once again be recommended for closure — and this time it might not be so lucky. Instead of sitting on their hands waiting for the inevitable, losing thousand of jobs and millions of dollars in the process, San Antonio officials took action and the Brooks City-Base concept was born.

A completely new concept, the brilliance of the City-Base plan was its simplicity. The base would transition from a military installation to a civilian-owned property with benefits to both parties: the Air Force would save money and San Antonio would receive land for new development.

The Department of Defense approved the gradual transition in ownership of the base from the U.S. Air Force to the City of San Antonio, and in 2002, Brooks City-Base was created as the first of its kind. Once strictly an Air Force base, the newly formed City-Base plan included the addition of a large commercial development as well as research and education facilities.

Under a 20-year, rent-free lease from the city, the Air Force and its facilities operate as tenants of the base, free from the responsibility and cost of managing its infrastructure.

According to the United States Department of Defense, the Air Force expects to save approximately $10 million annually by its partnership with San Antonio. For the city, it means retaining thousands of existing jobs already in place at the base, plus the potential to create thousands of new private-sector positions at well-known companies. This development will generate an estimated $560 million per year for the San Antonio economy.

Two of the larger businesses planned on the Brooks City-Base include DPT Laboratories, a large pharmaceutical company, and Wal-Mart Super Center. Before these buildings could be constructed, a strong soil sub-base had to be created. The DPT Laboratory building would be located on 100,000 cu. yds. (76,500 cu m) of soil, while the Wal-Mart Super Center site was planned over 75,000 cu. yds. (57,300 cu m). G.T. Sirizzotti Ltd., a large commercial contractor based in San Antonio, was hired to complete the soil conditioning and compaction, with the mission of making the ground suitable for these large buildings.

Founded in 1985, G.T. Sirizzotti Ltd. is a commercial contractor that focuses on site prep projects including shopping centers, roads and streets, sub-divisions and schools in and around the San Antonio area. Owner and president Gene Sirizzotti knew this project would be a unique undertaking due to the building site’s soil conditions.

In dry climates like Texas, soil consisting of clay or other cohesive material is difficult to compact. The moisture content of the soil is so low that load-bearing compaction densities are hard to achieve. The soil specifications on the DPT Laboratory and Wal-Mart Super Center sites required Sirizzotti and his crew to take the soil through an extreme moisture conditioning process to reach the required load-bearing density.

This process begins with a water truck saturating the soil. A soil stabilization machine follows behind the truck, mixing the water into the soil. As the soil particles absorb the water, the particles expand and separate. When the water evaporates, the soil dries into a more pliable state that allows for proper compaction to occur.

The plans for the Wal-Mart and DPT sites required that the soil be mixed with water until a moisture content of 6 to 8 percent over the normal moisture content was achieved, literally creating mud. When the soil dried, it would seal to the ground and, after compaction, create an exceptionally solid base to help reduce potential building shifts and prevent future structural damage.

Because the soil would be liquefied, Sirizzotti needed a machine that could work in such a demanding environment.

“The soil conditioning process the developers wanted to implement was very aggressive,” said Sirizzotti. “We knew that we would have to use a machine that could hold up to the constant stress of the project and continue to be productive at the same time. It sounds crazy, but we’ve had some equipment sink into the soils when working in such a vigorous environment.”

For four years, Sirizzotti employed the use of a Bomag MPH100 recycler/stabilizer when he performed soil conditioning jobs. However, because of the difficult nature of the project, he needed to find a bigger machine that would function properly in the job-site conditions.

“That [MPH]100 was a great machine, but we literally had to turn dirt into mud,” said Sirizzotti. “The actual specs on this job were so aggressive that the [MPH]100 would get stuck and couldn’t handle it. It was just time to get a more suitable machine, especially with the difficult nature of the soil conditioning.”

Sirizzotti worked with Waukesha-Pearce, the local Bomag distributor, to trade in his MPH100 for a new soil stabilizer that would work better in the mud. Numerous machines were brought in for trial runs, but they sank into the ground, and Sirizzotti and his crew could not accept delays that a machine stuck in the mud would bring to the City-Base project. Sirizzotti found his solution in the Bomag MPH122, a larger, four-wheel drive recycler/stabilizer with a mid-mount loader design.

The soil conditioning process began with numerous water trucks flooding the soil in front of the MPH122. As the machine mixed the soil and water, it introduced moisture into all of the material without leaving large chunks of dirt behind. After the soil was conditioned, rollers were used to compact the soil to achieve the required load-bearing density. Sirizzotti and his crew conditioned and compacted 175,000 cu. yds. (133,797 cu m) of soil in approximately six weeks. He credits the MPH122 for allowing him to finish the project so quickly.

“The MPH122 is a four-wheel drive machine, a lot bigger and more powerful [than the MPH100]. The MPH122 can actually till the mud and really leave the moisture in there without getting stuck,” said Sirizzotti. “I like the way that the unit tilts with its articulated steering. This in combination with rear wheel steering gives high maneuverability, which increases flexibility on restrictive sites and allows it to function better on difficult terrain. It really fit the bill.”

Sirizzotti and his crew are currently working on other base projects, including infrastructure jobs like streets. The investment in the MPH122 has already paid off, allowing him to complete a job that may not have been possible without the four-wheel drive machine.

“We had a large amount of soil to condition on the Wal-Mart and DPT Laboratories sites,” Sirizzotti said. “Since the terrain was so difficult to work in, it definitely worked out pretty well to have a four-wheel drive machine on hand.”

Even though the Brooks City-Base project will continue to evolve over the next 5 to 10 years, it is starting to take shape. A nine-hole golf course with a driving range and pro shop recently opened, and plans include a community recreation center to be located on the base, complete with soccer and baseball fields. The Wal-Mart Super Center and a Sam’s Club are expected to open soon, along with numerous restaurants and other retail stores. A research and technology park is beginning to lease its space, while the residential village is starting to fill up with occupants.

With the BRAC committee currently making headlines once again, the Brooks City-Base may be the model that other cities use to save their bases. Because the city of San Antonio was proactive in its approach to revitalizing the base, it will save thousands of jobs and millions of dollars in revenue. As work continues on the project, the city and Air Force, not to mention G.T. Sirizzotti Ltd., know they took the right steps to achieve a solid base for growth and success.