Laser Scanning of the underwater roadway tunnel from The Saint Petersburg Flood Prevention Facility Complex

 St. Petersburg Flood Protection Barrier. Point cloud is a result of laser scanning.In May 2011, Trimetari Consulting LLC performed a laser scanning of the Russian underwater tunnel, which is part of St. Petersburg Flood Protection Barrier (FPB). The construction of the unique hydraulic structure including eleven dams, six culverts, two navigation openings and six-lane highway that runs along the crest of the dams and makes out 25 km with bridges, tunnels and interchanges, was launched in 1979. In August 2011, the FPB was put in commission. The tunnel is considered to be the longest underwater tunnel in Russia.

Tunnel in the image of St. Petersburg. Image from portal Google Maps.During the installation of the fire-retardant coating and engineering systems in the transport tunnel, which is not only part of the FPB, but also a part of St. Petersburg ring road, a local mismatch of concrete structures with the project documentation had been identified. In this regard, the need for tunnel measurement had arisen in order to add operational adjustments to the execution work.

The underwater transport tunnel passes under the sea channel and navigation openings «C1». The tunnel length is 1961 m, including two open ramp area 386 m long. There are two transport corridors in the tunnel, 5.5 m height and 15,25 m width each. The middle compartment for systems maintenance and evacuation is designed between transport corridors. There are two cable compartments along the outer sides of the tunnel. The level of the roadway in the deepest section of the tunnel (under the Sea Canal) is minus 24,3 m.

Laser scanning of the tunnel. Field stage.The field stage of the laser scanning of the transport corridors took three days, one week was required for the data processing. The cross-sections of the transport compartments were built on the basis of the point clouds. Trimetary Consulting LLC provided the point cloud together with the sections to the customer, an engineering company. The point cloud was imported into Autodesk AutoCAD. AutoCAD is able to work with a point cloud directly, which is a huge advantage. Now designers have an opportunity to compare the tunnel project data and the survey data to make quick changes and adjustments in the documentation.

Point cloud of the tunnel. Inside view.Mikhail Anikushkin, CEO of Trimetari Consulting LLC comments: «The peculiarity of the project is a very dense work with the customer who never used laser scanning data before. We provided the designers with not only measurements of the tunnel, but also the consultation on the development process. The consultations were given on the basis of the analysis of existing processes of the enterprise. Our experts analysed the fact that the organization uses actively Autodesk products (more than a hundred licenses) in its project activities, and has no resources for a long-term training, and advised the organization to integrate a three-dimensional survey technology into the existing cycle of engineering with the use of AutoCAD. This low cost approach is characterized by a minimal change of the production cycle and a high speed. No need to buy an expensive third-party software and take a long training course. Efficiency was the key point of this project. As a result, the designers were able to import laser scanning data in a familiar AutoCAD environment and continue their work, using a familiar interface. Consulting is one of the directions of our activity. With a team of professionals, experienced in laser scanning, we not only carry out work on scanning and 3D modeling, but also give advice on the effective use of our survey. We are pleased that this feature is highly appreciated by our customers. In addition, this approach differentiates us from other companies on the market of laser scanning in Russia and the CIS.» 

Cross-sections of the tunnel, created from point cloud.You have an opportunity to see a part of the laser scanning data of Saint-Petersburg Flood Protection Barrier. To view the scan data on your computer, you should have:
— Internet Explorer version 6.0 or higher;
— TruView software from Leica Geosystems.

If you have the programs above installed, please view the laser scanning data. The laser scanning data in Leica TruView are displayed from the position of the scanner. TruView allows you to make measurements, notes, get the three-dimensional coordinates of the points. All changes can be saved and transferred to other users over the network. 

Trimetari Consulting LLC is a provider of laser scanning services, including rental of laser scanners in Russia and the CIS countries. Variuos 3D laser scanners are available for hire on a daily and weekly basis.