Three different scenario settings based on noise mapping became the solution when the Danish Road Directorate and the Danish State Railway wanted to provide politicians with the best possible options to choose from at a public hearing about the construction of Storstrømsbroen.
While the majority would focus on the project itself - that is, the new bridge, which is replacing the existing worn down bridge - people living close by the construction site will focus on other bothering factors such as noise nuisance and vibrations.
In the future, cars and freight trains will be able to cross the new bridge at full speed compared with the reduced speed today. However, full speed means more noise and vibrations. Add to this, the nuisance from the heavily increased freight traffic, which in the future might be a result of the Femern Connection.
Citizens have an actual influence
Noise mapping and simulations from the different scenarios provided the Danish Road Directorate and the Danish State Railway with optimized opportunities to have a forthcoming and varied dialogue with the citizens affected by the environmental impact of the construction. The hearing was part of a EIA, which is a comprehensive analysis of environmental impacts. The scenarios gave the citizens an actual opportunity to influence the construction of the land connection.
The new bridge will enable cars and freight trains to cross the bridge at full speed
Influence on bridge connection
While the construction plan of the bridge was established, there were three different options to choose from as regards to the connection points on land.
In each case, the objective was to reduce the noise with various noise screens, noise-deflecting walls and other parts of a 500 meter long connection point, focusing on both noise from the motorway and railroad. The specific constructions and mitigation measures were in each single case drawn up differently and would affect the citizens on different levels.
The bridge hearing ended in 2015, after which the Danish Parliament passed the construction of the bridge in spring 2016. The construction will go through regardless what happens with the Femern connection. The Storstrømsbro will be completed in 2022 and involves a cost of 2.4 billion Danish Kroner.
Ten computers work for a whole week to complete one noise mapping
Today, noise mapping is solely conducted by the use of sophisticated models, simulations and calculations. Prior to this kind of technology readings were often to random and inaccurate. Noise mapping involves massive computer power, and though ten connected computers from NIRAS’ server room in Copenhagen and Aarhus work at the same time, it can take weeks to conduct a single calculation.
That is also why noise mapping is carried out at an early stage. Just the slightest miscalculation or inaccuracy and the entire mapping process must start over.