The total cost of the new coastal road, Nouvelle Route du Littoral (NRL), is estimated to be $1.9 billion. It is a 12.5-km long road positioned 80-300 meters away from shore to avoid the impact of the natural hazards. The road includes three main sections, two causeways, an interchange and a causeway linking La Grande Chaloupe and La Possession and a 5.4-km-long coastal viaduct. The construction of the project began by the end of 2013 and was due to be completed by 2020 – but is now delayed due to the Covid—19 pandemic. The aim of the project is to create a faster coastal road to facilitate travel and construct the road infrastructure to reduce traffic congestion and provide users with reliability, and safety.
There were many contractors for the Nouvelle Route du Littoral (NRL) including major European contractors such as Vinci Construction, Dodin Campenon Bernard, Bougyes Travaux Publics, and Demathieu & Bard – are constructing the 5.4-km viaduct along the coastline from Saint-Denis to La Grande Chaloupe. The 3.6-km, three-lane dual causeway between the La Grande Chaloupe and La Possession is being led by a consortium led by the GTOI (a subsidiary of the French construction company – Colas) and VINCI Construction subsidiary SBTPC and VINCI Construction Terrassement. The other contractors involved in the project are HEBETEC Engineering, Mecap and APP Consultoría Powerproject & TILOS & Ecodomus.
To deal with the technical complexities and address the challenges of the natural hazards, the Topcon Positioning Group’s GPS/GNSS based technology, along with pre-fabrication tools were selected. In the initial phase of the project, approximately 35 machines, including dozers and graders, excavators were equipped with Topcon GPS devices. The technology was implemented across all the construction processes of the project, “including earthmoving, positioning embankment protection blocks and embedding the viaduct”. Further X-63 machine control, equipped with 360-degree tilt sensors were used on excavators to track their position and use GPS technology to provide precise information and help excavators work well on steep slopes. This eliminated over-excavation and costly material overruns. Topcon’s C-63 compaction system was used to pave the road offering real-time quality control to ensure consistent, accurate and efficient compaction.
Using the Sitelink 3D Enterprise package, all aspects of the projects were linked digitally, and all the GPS-equipped machines on the site were able to be controlled remotely. Real-jobsite data was shared to remotely eliminate miscommunication and improve decision making. The team collaborated to source geographic coordinates data from different topographies and collated together to solve errors and solve problems remotely. The GPS devices were used to also identify the position of materials, and underwater scenarios which helped save costs and time.
For the construction process, prefabrication was also used wherein two production sites were set up in the harbor zone to prefabricate approximately 48 piers. Seven segments – each weighing 2,400 tons — formed the deck portion and was transported using a barge and installed along with pier heads.
Real-time sharing of information enabled collaboration among the teams on the job site, and helped increase safety, accuracy, cost optimization and productivity across the entire construction workflow. The use of the Topcon’s GPS devices eliminated any miscommunication, increased both safety and productivity, and significantly reduced labour costs, material costs and timescales.