Works on the Başiskele Corridor Project, implemented by Kocaeli Metropolitan Municipality, have reached the final stages of construction. All 9 bridges included in the project have now been opened to traffic, while the remaining works on the D-130 Highway main carriageway and the northern and southern side roads are continuing.
Approximately 113,000 m³ of geofoam blocks have been installed to date in the world’s largest interchange project constructed using geofoam block lightweight fill. As Geotech Soil and Foundation Engineering, we are pleased to be involved in the design, field implementation and supervision of the geofoam block lightweight fill applications for this major transportation infrastructure project.
113,000 m³ of Geofoam Block Lightweight Fill Installed
One of the key engineering solutions adopted in the Başiskele Corridor Project is the use of geofoam block lightweight fill in high embankment sections. The total volume of geofoam installed across the project has reached approximately 113,000 m³.
Due to their extremely low unit weight, geofoam blocks significantly limit the additional stresses transferred to the underlying ground, providing an effective solution for the construction of high roadway embankments under weak ground conditions. Their rapid installation has also provided major advantages in site logistics and construction time by eliminating the need for the high-volume material transportation and layer-by-layer placement and compaction operations associated with conventional fill construction.
Construction Continued While Maintaining Traffic Flow
One of the notable aspects of the project has been the ability to carry out extensive road, bridge and interchange construction while maintaining existing traffic flow as much as possible. Similar to an “open-heart surgery” analogy, the process required critical infrastructure works to be carried out while the transportation system remained operational.
Geofoam block lightweight fill contributed to managing this challenging construction process through rapid installation, reduced site logistics requirements and shorter construction durations compared with conventional fill methods. This enabled controlled and phased construction to proceed without completely interrupting traffic flow.
Integrated Geotechnical Solutions for Challenging Ground Conditions
A combination of geotechnical methods was implemented along the approximately 16-kilometer transportation corridor to address variable and challenging ground conditions. Approximately 22,000 meters of bored piles and 18,000 meters of DSM (Deep Soil Mixing) have been constructed within the project.
Project-specific solutions were developed for a range of engineering challenges, from roadway embankments to bridge approach areas, using geofoam block lightweight fill, DSM, plastic piles, and geogrid- and geocomposite-reinforced engineered fills according to the requirements of each section.
All 9 Bridges Opened to Traffic
With the completion of all 9 bridges, another major structural component of the transportation corridor has been fully commissioned. The bridges, incorporating a total of 155 precast girders, are now in service, while construction of the remaining structures along the route has also been substantially completed.
The phased opening of bridges and connection roads throughout the project has helped maintain existing traffic flow as much as possible, while the remaining main carriageway and side-road works continue.
Final Works Along the 16-Kilometer Transportation Corridor
The project, which will reorganize transportation between Başiskele and İzmit, comprises an approximately 16-kilometer road network together with 9 bridges, 7 culverts, pedestrian overpasses, connection ramps and side roads, forming a comprehensive transportation infrastructure system.
The scale of the project is reflected in the approximately 113,000 m³ of geofoam block lightweight fill, 22,000 meters of bored piles, 18,000 meters of DSM, 80,000 m³ of excavation and 30,000 tonnes of asphalt completed to date.
Başiskele Corridor Project Nears Completion
At the current stage, construction activities are focused on the final works along the D-130 Highway main carriageway and the northern and southern side roads. Once these works and the remaining connection ramps are completed, the transportation system developed within the scope of the project is expected to become fully operational.
Upon completion of the Başiskele Corridor Project, the aim is to provide a more controlled separation of transit and local traffic, reduce congestion at intersections along the D-130 Highway and establish a safer, more continuous and comfortable transportation infrastructure along the Başiskele–İzmit corridor.
