Collapsible Double-Barrel Box Culvert Formwork System

Samut Prakan, Thailand

Bangkok International Airport

Suvarnabhumi Airport, commonly called Bangkok International Airport, is the largest hub in Thailand. Covering an expansive area of 3,240 hectares (8,006 acres), it is one of the largest airports in Southeast Asia and the 17th busiest airport in the world, with the 11th most active airport in Asia.

New Airport Runway Under Construction

Suvarnabhumi Airport has two operational runways that can handle 68 flights per hour. However, construction of a third runway, measuring 60 m wide x 4,000 m long (197 ft x 13,125 ft), is underway west of the airport. Upon the project’s completion, the airport’s capacity will increase to 94 flights per hour.

Construction of a Double-Barrel Box Culvert Drainage Tunnel

The construction of a double-barrel box culvert drainage tunnel is an essential part of the expansion of the third runway, allowing the airport to function to its full potential. This structure is necessary, because it is in a low-lying area which is more prone to flooding. The box culvert is designed to handle a large quantity of water, ensuring that flooding does not disrupt the airport’s operations during the rainy season in Thailand.

No Custom Formwork Needed | Standard Formwork Used

TN-Joint Venture (Nawarat Patanakarn PCL and Thanomwongse Service Co. Ltd.), the contractor chosen for the construction project, was experienced in using custom-made steel formwork. The EFCO Thailand team provided a solution tailored to this application to reduce cost and eliminate the need for custom formwork. EFCO’s solution was a combination of standard off-the-shelf HAND-E-FORM® all-steel formwork panels, EFCO SUPER STUD® modular beams, and accessories. Using this combination allowed the contractor to adjust the widths and heights of the box culvert as needed.

Collapsible Box Culvert Traveler System

The EFCO engineers designed a collapsible box traveler system that operates with SUPER STUD®. Horizontal SUPER STUD beams were used to accommodate the different widths of the box. SUPER STUDS were also assembled vertically to act as a support, increasing the formwork’s stability. The system was converted into a traveling platform with the addition of roller casters.

Flexible and Adjustable Formwork System

To meet the customer’s needs, EFCO developed a formwork setup that was flexible and adjustable horizontally and vertically. Based on this requirement, the EFCO design featured an adjustable header beam, stiffback, and special corners using a double channel and splice plate. This design enabled the contractor to quickly strip the formwork and move the box down the tunnel to the next cast while avoiding contact with the wall and slab.

Reducing Cycle Time = Significant Cost Savings

EFCO’s solution drastically cut the customer’s cycle time to only three days for stripping, moving, rebar fixing, and preparing the area for casting concrete. As a result, the contractor appreciated the cost savings and value of using EFCO products, achieving the lowest in-place concrete cost.

Why Choose Anyone Else?

EFCO delivers innovative solutions to contractors seeking efficiency and cost savings in concrete construction. Through our commitment to quality, productivity, and safety, we can support projects of all sizes. We appreciate the opportunity to work with TN-Joint Venture and look forward to continued future success together.

Construction of a Double-Barrel Box Culvert Drainage Tunnel


Box Culvert Traveler

Contact our Thailand office today

242/2 Moo6 Ladwhai-Sukhumvit Road Bangprieng, Bang Boa,
Samutprakarn, 10560, Thailand

Phone: (66) 2077-8446


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TN-Joint Venture TEAM

Kongpak Rungwitayawutthikul, Project Manager



Thanapol Saithong, Territory Manager

Rakchat Nimpila, Field Supervisor

Kevin Khor, Engineer