Located in the deserts of California approximately two hours north of Los Angeles, Edwards Air Force Base (AFB) is a major U.S. Air Force training and test-flight facility and an alternate landing strip for the Space Shuttle. As such, the mission-ready capabilities of the base can not be compromised, not even for the demolition and reconstruction of the installation’s only main base runway.
It is not surprising that a base known for testing the latest state-of-the-art aircraft elected to reconstruct its main runway using a design-build contract, the latest state-of-the-industry contracting method. The U.S. Army Corps of Engineers (USACE) Los Angeles District acted as the Air Force agent to award and administer the high-profile design-build contract.
Ensuring continued flight operations throughout the duration of the project necessitated a two-phased approach. First, a fully mission-capable, 12,000-ft by 200-ft temporary runway was constructed, including reconstruction of three associated taxiway intersections and four aircraft parking pads. Upon completion and operational certification of the temporary runway in May 2008, the second project phase began to reconstruct more than 85 percent of the 15,000-ft by 300-ft main runway. Each of these principal project tasks was subsequently subdivided into separate construction milestones planned specifically to keep the airfield operational at all times without impacting any flight operations.
A joint venture formed between CH2M HILL and Interstate Highway Construction Inc. (IHC) to complete the project. The joint venture took advantage of CH2M HILL’s design and construction management capabilities and IHC’s airfield construction expertise to design and build both the temporary runway and the new main base runway, which required the laying of nearly one-quarter of a million cubic yards of pavement to the highest quality standard while working in the very difficult climatic conditions of the high desert.
Typical design-build teams comprise a construction firm acting as a prime contractor and subcontracting design, with the construction firm bearing the brunt of the project risk. However, the CH2M HILL–IHC joint venture took a different approach by equally sharing project responsibilities and risks. CH2M HILL acted as the managing partner, responsible for project management and project design, while IHC took the lead in construction management, quality control and testing management, and equipment, enabling the joint venture to self-perform the majority of the construction efforts. The arrangement created a truly integrated project team equally responsible for the risks and rewards encountered during project completion.
The Design-Build Mentality
The design-build contracting method allowed the designers and construction experts to meet early and often to ensure the design met specified criteria and would be constructible as well. Alternative construction methods and techniques were fully evaluated by the designers and constructors to determine the most efficient way of building.
Both members of the joint venture team were asked to review the design as it progressed through every milestone. Construction personnel provided early input through constructability reviews, were engaged throughout the design process and were fully prepared to begin construction while the design was being finalized.
In turn, the design team provided input on aspects of the construction process. For instance, at Edwards AFB, the development of a concrete mix design capable of meeting the specified performance and constructability requirements for slipform paving proved to be problematic with the locally-available aggregates. Team members from both the design and construction sides met frequently to discuss the issues and potential solutions. After testing a total of 36 trial mix designs, one mix was selected and fine-tuned for production. The final mix produced a consistent Portland cement concrete capable of obtaining flexural strength of more than 700-psi, comfortably exceeding assumed design value of 650-psi. The mix also provided the necessary workability to slipform slabs up to 25-in-thick while meeting the strict requirements for construction tolerances.
Though a small group of CH2M HILL project construction engineers, construction managers and support staff members relocated to the California project site along with construction personnel from IHC, the CH2M HILL design team remained in its home office in Englewood, Colo., throughout the life of the project. This long- distance relationship succeeded as a result of daily conference calls and frequent trips to the site by the design staff. Once construction commenced, the design team had regular constructability meetings with field personnel to continually share lessons learned during the initial phases of construction and offer suggestions for the remaining design.
The flexibility of the design-build team was further tested when the initial construction of the temporary runway was delayed due to circumstances outside the control of the team: One of the project constraints required that two of the three connecting taxiways remain operational during the taxiway reconstruction. An expedient temporary taxiway bypass was suggested and evaluated by the joint venture team. It was concluded that the additional time and cost necessary to construct the taxiway bypass would be recouped with the increased construction productivity. Because two of the three taxiways could be brought down simultaneously for construction, significant construction schedule savings could be achieved. The design team quickly processed the design of the taxiway bypass within two weeks, and the bypass was constructed and in operation 75 days later.
The broad sense of partnership within the joint venture also spread to its relationships with primary subcontractors. The subcontractors responsible for grading and preparing the subgrade and placing rigid base and crushed aggregate base course material all utilized the latest GPS-guided equipment. The joint venture agreed to develop and provide the 3-D, digital terrain model and corresponding electronic files to the subcontractors. This allowed the subcontractors to load information into their equipment quickly and accurately to complete the nearly 500,000-yd3 of earthwork and millions of square yards of subgrade and base finishing associated with the project.
Design-build delivery allows construction to begin even while final design is being completed, significantly shortening the project schedule and allowing the design to accommodate any unique challenges that arise during construction. In addition, a united team of design and construction personnel working together under the same contract promotes improved agility and flexibility throughout project execution, as both entities are working towards a common goal—a quality project delivered on time and within budget.
A successful design-build project, such as the construction of the temporary runway and reconstruction of the main runway at Edwards AFB, begins with an integrated team willing to work together. Teamwork and communication are the cornerstones to a successful joint-venture partnership and must be established at its inception. A well-functioning design-build team will strive towards innovative ideas, maximizing the combined efficiency and strengths of the design and construction team. A positive, can-do attitude, shared by all members of the team, combined with a shared sense of responsibility for any issues that arise during the project, provides an atmosphere in which solutions are developed and endorsed by the joint venture team before being implemented. The result is a successful project and a pleased client.