Airport operators face many challenges when they look to develop solutions to meet current and future facility space requirements. Having the proper knowledge in knowing how to expand capacity to meet a growing passenger demand — while also ensuring that all airport operations continue to function properly — plays a critical role in the planning process.
Because of this, modular construction has now become an increasingly popular cost-effective option for airport expansion projects due to its ability to improve the efficiency of the building process while minimizing expenses and reducing the amount of exposure to airport operations.
The evolution of modular construction also no longer suggests that the structure be void of aesthetics or have limited functionality. Whether it is for a permanent or temporary application, modular buildings can provide for a seamless and natural extension of the buildings they are adjacent or connected to. Modular construction can also meet the requirements of the Federal Aviation Administration (FAA) and all local and state building code requirements and certifications.
Temporary modular buildings can be used as swing space to meet surging passenger demand or as administrative space while permanent facilities are being remodeled or refurbished. If properly designed, they can also be repurposed, allowing them to be moved or relocated to another place on the airport field to meet customs, cargo, maintenance or other operational uses.
A Collaborative Approach
Collaborative arrangements between a modular building company, a designer and a prime contractor are optimum when using modular construction for developing airport expansion projects.
Oftentimes, the modular construction company can work in a design-assist role to aid the airport’s architect in developing the project, while also working as a subcontractor providing the manufacturing and installation of the modular building while the general contractor performs the site improvements, utility connections and close-out.
This scenario was employed when the Denver International Airport embarked on an upgrade and expansion of the airport’s Concourse A commuter terminal. Design-build modular construction firm Ramtech Building Systems of Mansfield, Texas, and its in-house design team and estimators worked closely with Denver-based Wong Strauch Architects PC and Hensel-Phelps, the prime contractor on the project. Together, the team developed an approach to construct the 38,920-square-foot Type IIB facility, which added six gates to the east side of the concourse.
The goal was to accelerate the conversations with both the architect and the general contractor to define where each company’s strengths were early in the planning process in order to develop the right roles for each team member.
In this case, the modular building company was deemed most adept in providing the core and shell manufacturing and installation of the structure, including all the structural requirements, installation of the window glazing, application of the roofing materials, and the development of the building’s foundation design. Hensel-Phelps was then tasked with executing all the site development and improvements, utility connections and the finish-out of the building.
A Temporary Structure Designed for Long-Term Use
The Denver Airport project was designed to be a temporary facility that would be used within a period of 5 to 10 years, and then eventually be removed and relocated from the site. The use of modular construction was ideal for this purpose, and together with the interim use designation, provided for specific allowances to be made with respect to the foundation design.
For this project, and other similar projects done using modular construction, bonded CMU block piers were utilized as the foundation to support the building. This required an analysis based on recognized testing values in order to substantiate the compressive strength from the loads when eccentrically applied.
The modular design approach that can achieve the large open areas required for any airport terminal requires a lateral resisting system to resist the wind and seismic design forces. The system used for the Denver Airport project used shear walls sheathed by thin steel plates fastened to cold formed steel framing. The structural elements were made up of the building’s exterior walls and select interior partitions that were in the existing architectural building plan.
The racking strength of the shear walls, along with the strength and rigidity provided by the steel roof deck, allowed for the architect’s layout to be properly maintained. Similar subfloor shear wall elements were also used to secure the building to the concrete in combination with the concrete masonry unit (CMU or cinder block) foundation system.
Developing the foundation and building envelope this way was more efficient than the site-built alternatives, which would have required more expensive, time-consuming and disruptive excavation or demolition of the existing tarmac. Another benefit to the modular design used for the project related to the utilities that came from the existing concourse area, all of which existed overhead and not under grade.
Here, too, the modular building approach with its additional height considerations allowed for a more seamless transition of the distribution of the power, data and mechanical systems without having to connect them by cutting into the existing concrete.Taken all together, this approach allowed for a much more efficient use of the existing tarmac and site infrastructure, resulting in an expedited installation and finish-out of the 65 modular sections that made up the concourse expansion.
By choosing modular construction, the airport was able to meet the passenger demand and cut the typical 3- to 4-year time frame for developing a site-built permanent project down to less than a year for the temporary modular building.
An Opportunity to Minimize Common Project Challenges
The concurrent nature of the modular construction process — where the building is being manufactured off-site while the site improvements and preparation are simultaneously taking place on-site — provides a significant benefit to airports by improving the overall construction efficiencies.
Fewer people are required to have security clearances and constant monitoring, and the entire project minimizes or eliminates the need for any airport closures or adjustments to flight schedules. The entire process reduces the amount of time spent on-site, while also minimizing the size of the construction footprint required to complete the project. This applies to both the required site construction activities as well as the installation of the building modules.
Using site-built construction methods, a laydown area equal to or larger than the building footprint must be set aside to store and stack all the wood, steel and other construction-related materials.
The sheer size of the laydown area can create logistical problems and negatively impact the airfield operations especially at smaller airports. Under the modular construction process, there is significantly less space required as there is a minimal amount of materials that must be stored since the bulk of the materials that make up the structure are used at the manufacturing plant and not dropped off at the construction site.
The disruptions to airport operations are also minimized during the installation process. Once the manufacturing of the building is complete, the modular sections that make up the structure are typically trucked and unloaded at a secure location on or close to the airport property.
Then, an allotted number of modules that can be effectively installed within each workday are individually moved via airport security escort from the staging location to an area adjacent to the building pad. From here, they are typically rolled into place using specialized equipment.
This type of process was used for a 7,168-square-foot modular building that was recently constructed by Ramtech Building Systems at Northwest Florida Beaches International Airport in Panama City Beach, Florida. The modular building was designed to connect to the airports existing terminal to provide for additional passenger seating area capacity for the two gates that serve the airports regional jet operators. The Type IIB all-steel facility was installed on formed and poured piers that extended up two feet from the existing tarmac.
This type of installation process would normally require a crane to set the modules, which is generally not feasible at an active airport location, especially at smaller airports with limited access. To set the nine modular sections that were built in three different sizes, a customized modular cribbing system was used built from pressure-treated heavy lumber in 20-foot sections. The individual modules were set onto the cribbing sections using a telehandler and then rolled into place on casters in between the piers.
Once the modules were in place, they were lowered down onto the foundation and connected to the piers using weld plates. After the entire building was set and weathered-in, the finish-out process was able to begin enabling the entire project to be completed in just under 90 days.
Overall, a design-build modular construction approach is an excellent option for meeting the requirements of a temporary
or permanent airport expansion project. This type of application can save airports time and money, facilitate reaching their goals faster, while at the same time limiting the disruptions to their operations.