Vibration Measurement during the Expansion of Railway

Vibration measurements are underway at the expansion of a railway in Southern Sweden

The engineering company Efterklang is conducting extensive vibration measurements and risk mitigation efforts as Trafikverket expands the railway from two to four tracks between Malmö and Lund in southern Sweden.

The daily commute between Malmö and Lund in southern Sweden has seen significant growth in recent years, with tens of thousands of people traveling back and forth on this route. The railway is being expanded to four tracks to increase capacity and reduce sensitivity to disruptions. The project was started in 2017, and the new tracks are expected to be fully operational by the end of 2023.

Railway construction can generate vibrations that travel through the ground and into nearby buildings. Madelene Persson, an acoustician and engineer at Efterklang, and her colleagues play a crucial role in measuring vibration levels along the construction of the new tracks to ensure that they do not exceed established standards. Detailed measurements and risk assessments assist the contractor (a collaboration between NCC and the Spanish company OHLA) in maintaining the lowest possible vibration levels to avoid impacting people or structures.

– By measuring vibration levels, we check for a risk of damaging nearby buildings due to construction work like piling, foundation work, and excavation. Trafikverket and NCC/OHLA are performing continuous measurements, and, along with others, Efterklang has conducted pre-inspections and post-inspections of properties, says Madelene.

The measurement work is comprehensive and has been conducted along the entire route for an extended period. During construction, Efterklang has primarily focused on vibration measurements and, in some cases, noise measurements.

Robust Measurement Systems with Long Battery Life

Advanced measurement systems from Sigicom are used to measure vibrations. Both wired and wireless measurement instruments are in use along the route where the new railway is being built. Efterklang has had about fifteen measurement systems in operation along the route.

We’ve used the instruments available in our company because they last a long time and can be used across multiple projects. We’ve used the wireless INFRA C20 and INFRA C22, as well as a lot of wired systems with INFRA V10 and INFRA V12, along with corresponding data loggers because they are robust and have worked very well, Madelene explains.

The instruments are installed on the building foundations, and measurement data is registered and transmitted directly via built-in modems to the web-based program INFRA Net. The program provides a comprehensive overview of all projects and measurement points.

– INFRA Net makes it easy to generate reports with vibration levels for all measurement points and listen to recorded vibration signals above the threshold. Since a large number of people are working on the project, it’s convenient that everyone has access to INFRA Net so that we can collaborate easily, says Madelene.

Before construction began, risk assessments were conducted for nearby buildings where measurements would be carried out to determine the baseline vibration levels they need to adhere to. If a measurement instrument registers values above the set trigger level, immediate alarms are sent via SMS and email. In INFRA Net, it’s easy to see whether registered alarms result from natural building movements or vibrations from construction work. Identifying high measurement values allows Madelene and her team to notify the contractor and assist in taking measures to reduce vibrations. These measures may include using smaller machinery that generates lower vibration levels.

Sigicom released the first version of INFRA Net in 2011, and since then, it has been a reliable system that constantly evolves to simplify project management for contractors and consultants. Thanks to remote monitoring and alarm functions via INFRA Net, Madelene and her team often only need to visit the construction site to retrieve instruments for annual calibration or battery replacement. The wireless vibration meter INFRA C20 from Sigicom is used in the project and has a battery life of up to six months.

– The work has gone well despite handling many measurement points simultaneously. The advantages of using INFRA Net include having an excellent visual overview of all active measurement points. It’s also easy to generate lists of those receiving alarms, check sensor battery levels, and create summaries of vibration levels during a specific period,” Madelene adds.

Work Continues after Commissioning

Despite the new tracks being put into operation in late 2023, the measurement work in the area doesn’t cease. Post-construction activities, such as dismantling temporary tracks and restoring areas near the railway, will also require inspection and vibration measurements.

This project isn’t just a new railway enhancing communication in southern Sweden; it’s also an example of how advanced measurement techniques and thorough analyses can ensure the quality and safety of existing structures and communities during significant infrastructure projects. Madelene Persson and Efterklang demonstrate how vibration measurements play a crucial role in building the railways and communities of the future.

About Efterklang

Efterklang is part of the AFRY group and consists of 140 employees. They have offices in Sweden, Denmark, Finland, Norway and the Netherlands. Efterklang has extensive knowledge of vibration, structural dynamics, and the reaction of people, buildings, and products exposed to vibration. Do you want to know more? Read more about Efterklang and their exciting project in vibration measurement here.

Instruments and sensors for vibration monitoring used in this project:

 

 

 

 

 

 

 

 

 

 

 

 

 

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