Innovative technology keeps surveyors safer in Dutch highway reconstruction project

The complex ‘Ring Zuid’ highway project in the Dutch city of Groningen illustrates the crucial role of advanced geospatial techniques in the infrastructure sector for design efficiency, execution accuracy and sustainable development.

Advanced surveying techniques are indispenable in the infrastructure sector, where geospatial data holds the key to more efficient design, more accurate execution and more sustainable development. The recently completed ‘Ring Zuid’ highway project in Groningen, the biggest city in the north of the Netherlands, is a prime example of this. The aim was to reconstruct the southern ring road to improve accessibility, traffic flow, quality of life and safety in and around the city. Surveyors and site engineers from Geomaat were closely involved in the preparation, execution and completion of this project, which was one of the nation’s most complex infrastructure projects in recent years.

Partly due to increasing traffic levels, the aim of the ‘Ring Zuid’ project (2019-2024, €927 million) was to reconstruct the southern ring road (the N7) on the outskirts of the Dutch city of Groningen to improve capacity and traffic flow. The existing road featured lots of traffic lights and junctions, which frequently resulted in congestion. Key components of the project were the conversion of the two biggest bottlenecks to grade-separated intersections, and the lowering and partial tunnelling of the N7.

Specifically, the project included altering the trajectory of the road, constructing three tunnels and adapting a number of crossroads. This would reduce congestion and improve the accessibility of the city and surrounding area. At the same time, lowering the road and creating more green spaces would reduce noise pollution and improve the attractiveness of the urban landscape, thus improving the quality of life in the nearby neighbourhoods.

Additionally, new infrastructural elements were developed for the local community. These included a tunnel for pedestrians and cyclists, and a safe cycle route that enabled cyclists to pass beneath the ring road without having to navigate busy junctions. These changes would not only improve road safety, but also enhance the immediate surroundings for local residents and businesses.

The role of surveying

The surveyors and site engineers were crucial to the success of the ‘Ring Zuid’ project, from design to completion. Thanks to their adaptability, they played a big part in helping to solve complex challenges. Meanwhile, their proactive monitoring directly contributed to the quality, safety and efficiency of the project in a number of areas, including:

1. Tunnel geometry precision: optimal concrete layer thanks to digital accuracy

Surveyors were constantly involved in the various phases of constructing the tunnels. For example, they provided detailed 3D models of the tunnels, allowing engineers to determine the exact thickness of the concrete backfill layer before pouring. This accuracy was essential to correct deviations stemming from previous construction phases. In the dynamic environment, the surveyors used total stations to gather hundreds of reference points quickly, efficiently and error-free. This was essential to capture the unique tunnel shapes. It would not have been possible to complete the project on time and cost-efficiently without that data.

2. Flexibility in the field: the right tool for every situation

In each case, the surveyors selected the tools that suited the situation and the required level of accuracy. Whereas GPS was sufficient for general terrain measurements, total stations were the right choice for restricted tunnel environments. Whenever possible, the Streetmapper – Geomaat’s mobile 3D scanner solution – was used to acquire large volumes of data efficiently. However, traditional methods also came in useful, mainly in areas with no GPS signal or where poor access made it difficult to place scanners.

3. Proactive monitoring: a safer environment

The surveyors went beyond merely taking traditional measurements by also continuously monitoring environmental risks using innovative techniques. For instance, they kept track of:

• Compaction (using precision levelling and hundreds of facade anchors)
• Groundwater levels (using monitoring wells)
• Vibrations (using vibration sensors)
• Drainage (using measuring poles)

This real-time data prevented surrounding buildings from becoming damaged and ensured that the construction work progressed safely. For example, the rapid detection of even the slightest subsidence allowed countermeasures to be taken immediately.

Technologies for safer working

During the 'Ring Zuid' project, specific protocols and methodologies were followed to ensure that the surveyors could collect data safely as well as efficiently. The Robotplotter and the Streetmapper were two technologies that played an important role in this.

Robotplotter

The Robotplotter, which can be operated remotely, allowed the surveyors to apply road markings without having to put themselves in the direct vicinity of the traffic. The Robotplotter can autonomously operate in a straight line guided by a global positioning system (GPS) or terrestrial positioning system (TPS), thus reducing the number of potentially dangerous situations.

Streetmapper

The Streetmapper-IV is an advanced mobile 3D mapping system capable of scanning up to two million points per second with an accuracy of up to 5mm without interrupting the traffic flow. Thanks to Geomaat’s self-developed and continuously evolving artificial intelligence (AI) system, the Streetmapper not only automatically detects objects such as road markings, light poles, signs and guide rails, but also conducts a deeper layer of logical checks. The system then filters out moving objects (e.g. cars, cyclists and pedestrians), leaving only the static infrastructure, resulting in the near real-time transformation from point cloud to classified objects.

Both these technologies improve the work of surveyors and site engineers by allowing them to capture more data more accurately, more efficiently and, above all, more safely. Additionally, the resulting data is reliable enough to be used as the basis for future analysis and comparisons. As a result, this approach not only shortens the amount of time spent in the field, but also reduces the need for return visits to conduct repeat measurements.

Conclusion

Tackling Groningen’s southern ring road was a far-reaching infrastructure project. The aim was to have a lasting positive impact on both the city’s development and life in the local community by improving accessibility, traffic flow, liveability and safety in and around Groningen. These objectives were definitely achieved. Geomaat’s land surveyors and site engineers played a crucial role in the preparation, execution and completion of the project. Innovative technologies such as the Robotplotter and Streetmapper improved the efficiency and safety of the work.

Major projects such as ‘Ring Zuid’ illustrate the growing need to not only build new infrastructure, but also to replace, renovate and reconstruct existing infrastructure. In future large-scale projects over the coming years, the lessons learned during ‘Ring Zuid’ will provide valuable knowledge in the areas of efficiency, safety and the added value of combining traditional land surveying with state-of-the-art mapping techniques.

Objectives of the ‘Ring Zuid’ project

1. Improving accessibility: Widening the ring road and modernizing the infrastructure to make it easier for motorists to reach their destinations.
2. Traffic flow: Reducing the number of traffic lights and improving traffic conditions to ensure a smoother traffic flow, which also reduces journey times.
3. Liveability: Reducing noise and air pollution in the vicinity of the ring road to improve liveability in the nearby neighbourhoods.
4. Safety: To increase safety for both motorists and pedestrians with better infrastructure and fewer traffic lights.

Richard Kainama, leader of the surveying team at Geomaat, led a team of up to ten surveyors and three work planners. The team’s tasks ranged from placing markers and mapping the environment using GPS, spirit levels and total stations, to performing both static scans and mobile ones using the Streetmapper. Geomaat took care that the design was a true representation of the environment and worked in close collaboration with MUG Ingenieursbureau (which has recently been acquired by Movares and will soon be known as Movares Smart Urban Engineering). Multiple engineering design firms were involved in the preparation and execution phases of the ‘Ring Zuid’ project. Among other things, Geomaat’s role was to perform checks and verify that the geometry of the designs was in line with the real-life situation. 

Further reading (in Dutch)

www.geomaat.nl/artificial-intelligence-ai-in-puntenwolk/

https://www.geomaat.nl/expertise/mobile-mapping/

https://www.geomaat.nl/nieuwe-camera-streetmapper/

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