Helicopter Squadron One Opens Mammoth Maintenance Hangar

Author: 
Greg Gerber
Published in: 
March-April
2011

The U.S. Marine Corps Helicopter Squadron One (HMX-1) has one of the most critical missions in America: It shuttles President Barack Obama and other high-level government leaders throughout the Washington, D.C., area and beyond. The elite unit also tests assault support helicopters and related equipment for the Corps.

As such, its aircraft must be maintained in tiptop shape, so they're ready to fly on a moment's notice. But unlike most everything else connected to the presidential detail, the hangar facilities that house HMX-1's aircraft and maintenance operations were considerably outdated.

Constructed around 1935 and updated multiple times since, the facilities were trustworthy, but antiquated, explains Maj. Brian Leich, logistics officer for Marine Corps Air Facility Quantico, located just outside the D.C. area in Virginia.




factsfigures

Project: Maintenance Hangar

Location: U.S. Marine Corps Air Facility Quantico (VA)

Size: 65,000 sq. ft.

Project Management:
RW Armstrong

Architect/Engineer:
RW Armstrong

Structural Engineer:
Thornton Tomasetti

General Contractor: Archer Western

Structural Steel Fabricator: Postel Industries

Design Challenges: Soft existing soil conditions; adding solar panels mid-construction

Unique Strategy: The structural engineer and structural steel fabricator integrated the fabrication and connection preferences along with shipping and erection to reduce the original construction schedule by several months.

"The facilities were seriously outdated," relates Leich. "When you apply modern safety policy to the facility and factor in the equipment we are using now, it was very difficult and challenging to accommodate the mission-essential activities we are tasked to perform in 2011."

So last May, the base launched an ambitious $38.9 million project to replace the three aging hangars and construct modern multi-purpose facilities that would better accommodate the Marine Corps' modern inventory of rotor wing aircraft. The project also included 540,000 square feet of new airfield taxiway/apron pavement and construction of an adjacent multi-story maintenance shop with administrative, medical, storage and support areas.

The recently completed maintenance building - designed by RW Armstrong and constructed by Archer Western Contractors - measures 65,000 square feet. A nearby administrative support building houses classified mission briefings, but the care and service of the squadron's aircraft takes place in the new facility.

RW Armstrong senior project manager Mark Vilem found it "very rewarding" to earn the contract for the third hangar, because the firm that built the first two hangars also competed for the project.

"We always look for innovative approaches to distinguish ourselves," explains Vilem. "The design team worked closely with Archer Western Contractors to offer a solution that was very appealing to the government - including a considerably shorter project duration."

Dan Petno, director of federal programs for RW Armstrong, is very familiar with the HMX-1 squadron. As a former naval officer in the Civil Engineering Corps, Petno previously served as the public works officer at the U.S. Naval Observatory, which is also home to the vice president's residence. Petno was a member of the team that developed a new building to house HMX-1 aircraft that flew into and out of the facility to transport the vice president. "It was an honor to support the HMX-1 squadron back when I managed the landing zone at the Naval Observatory," he notes. "It's an honor to support it again in a different capacity."

After years of heavy involvement in commercial aviation design, RW Armstrong recently turned its attention to military airfields, because many have a commercial component as well, Petno explains.

"We teamed with a contractor to build a Navy fighter runway at Norfolk Naval Air Station in Virginia," he relates. "Through that entry into the military market, we expanded our airside design service to include hangars, general buildings, Navy piers and other projects. Today, we are very heavily involved in military defense projects across the globe."

Designed to Accommodate

The new maintenance facility was designed to improve safety and provide more flexibility for storing aircraft. The former facility allowed only three or four to be put in use, notes Richard Rabak, facilities manager at the Quantico complex. The new 65,000-square-foot building allows more aircraft to be stored and ready to launch.

"The sheer size of the hangar is impressive in itself," he remarks, noting that they've considerably raised the bar within the rotor wing community. "The length of the facility often catches people by surprise."

The larger building allows crews to open hangar doors and remove aircraft with few impediments. The old facility required staff to open five hangar doors to extract just one helicopter. Today, the crew can access almost any aircraft in the facility by opening just two bay doors.

The fire suppression system is one of the most welcome additions for Leich - and something completely lacking in the 1935 hangar. Heat sensors and an automatic sprinkler system now protect equipment and personnel in the event of an accident or other emergency.

His other favorite addition is the hoist and crane system that allows crew members to better service helicopters without moving them. In the past, a helicopter had to be towed outside to remove an engine or rotor. Now, such repairs can be made in the same facility that houses the necessary tools and equipment.

Mired in Muck

One of the biggest challenges designers faced was the site's existing soil conditions. Situated very close to the Potomac River, the site had 10 feet of good soil and 80 feet of muck or very soft clay - material that isn't strong enough to support the heavy, concentrated loads of a long-span hangar.

"Really soft clay can settle beyond what a building is designed to tolerate," notes Thomas Poulos, principal with structural engineer Thornton Tomasetti.

Because the existing hangar was only inches from the proposed hangar, engineers were unable to use driven steel piles, the preferred deep foundation system. Vibrations caused by driving the steel piles would have damaged the nearby structure. So engineers opted to use soil improvement methods that ultimately allowed for a shallow foundation system with spread footings - a less expensive and faster alternative.

Augers were used to displace the soil laterally, which made the surrounding soil denser. The resulting void was then filled with cast-in-place concrete. The piles were closely spaced underneath each of the spread footings and in a ten-foot-on-center grid under the slab-on-grade. A buffer layer of granular fill was used between the bottom of the footings and the top of the piles to distribute the loads to the piles. The piles and the shallow foundations are not tied together by any means, stresses Poulos. The piles and surrounding soil transfer the vertical loads down to a soil stratum that is capable of supporting the loads.

"Being able to utilize the soil enhancement methods which allowed the use of shallow foundations for this project saved time and money - and met the performance requirements for the allowable long-term settlements of the building," explains Poulos.

Collaboration Was Key

Collaboration between the structural engineer (Thornton Tomasetti) and structural steel fabricator (Postel Industries) helped condense the project's timeline. "Instead of providing a design without input from the construction team on connections and the proposed erection scheme, we discussed several design schemes with the contractor and structural steel fabricator right from the start," explains Poulos. "We sought their thoughts and philosophies and looked at their proposed erection procedure before we even began the design process."


In addition to acting as structural engineer on the project, Thornton Tomasetti also designed the steel connections and produced the shop drawings.

"We were able to develop a fully integrated process - one that blended a well-thought-out design with the capabilities and preferences of the steel fabricator. The design allowed the fabricator to assemble the steel trusses in his shop, easily ship them to the site and accommodate the planned erection scheme without the use of costly shoring towers," adds Poulos.

The collaboration enabled the structural steel to be delivered much earlier than conventional procurement processes allow, clipping months from the original construction schedule.

"Once the design was approved by the government, we were able to jump right into the production of shop drawings and proceed directly into fabrication," says Petno.

Thornton Tomasetti and Postel used Tekla software, which provided three-dimensional modeling and the ability to prepare technical drawings and develop fabrication models. According to Poulos, it alone saved the team three months. "Turnaround time for the review of the structural steel shop drawings was accomplished in three days instead of the industry average of two weeks," he remarks, noting that the same process could be incorporated into any construction project.

According to Brian Volpe, senior associate at Thornton Tomasetti, Tekla also helped the structural engineer manage its deliverables and reduce submittal congestion.

Once the fabrication drawings were complete, they were sent electronically to the steel fabricator in Texas. Because the fabricator had been involved from the beginning, issues regarding how items would be sized and connected to the structure had already been resolved. The design even took into consideration the fabricator's preferred methods for bolting or welding certain shapes.

"In a design/bid/build project we would come up with a design and it would go out for pricing," describes Volpe. "Design/build offers us the opportunity to collaborate with the general contractor and the prime steel contractor to develop the most economical approach."

"With three-dimensional modeling, it is much easier and faster to see the effects a change has on the building and the process," agrees Vilem. "And with the steel fabricator using the same program, he could modify the process accordingly much more quickly than with traditional processes."

Typically, a designer creates a concept which, when approved, is sent to a fabricator, applies its preferences and sends it back for the designer to rework.

"We saw a tremendous advantage to the project approach," comments Vilem. "When the designers and construction crew work together as one team, they can get input and give feedback throughout the process, which allows both teams to do their jobs much more efficiently. That, in turn, saves the client a lot of money and shaves a lot of time off the construction schedule."

"The integrated design phase set the stage for the construction to proceed very smoothly," he adds.

Energy Enhancements

HMX-1's new hangars were constructed to attain Leadership in Energy and Environmental Design silver certification. "We were committed to that from the beginning," reports Petno. "As we progressed in the design process (under budget), we identified new technology to build in additional energy-saving opportunities."

For example, the roof was modified to accommodate an array of solar panels that now produce 3% of the facility's total energy needs. Retrofitting the solar panel system into the building structure added almost $1 million to the project budget, because the steel was modified and beam and roof trusses were reinforced to handle the added weight of the solar panels. Snow load also had to be taken into consideration because snow tends to build up against the panels rather than blowing off the roof, explains Vilem. In addition, the electrical system also had to be modified to convert the DC power collected from the sun into AC power that could be used in the facility.

Project of Honor

"It was exciting working with the HMX-1 squadron," relates Petno. "When you see the white-topped helicopters departing on a mission, or even sitting on the apron, you realize how special a place it is, and you're glad to have been able to play a part in making it successful."

The hangar has since become a signature project for RW Armstrong. "We are an Indianapolis-based firm. But through this military contract, we were able to design a facility that not only serves the military, but supports the White House as well," explains Petno. "It was very rewarding to be able to play an important role in supporting the day-to-day operations of the highest level of the U.S. government."

Subcategory: 
Hangars

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