The project is one of the most prestigious investments built in the heart of Poland’s capital. Museum of Modern Art is a structure with unique design, built close to existing infrastructure. Foundations include deep large-diameter piles equipped with EpsilonRebars for safety reasons. Measurements were done during load tests and allowed for detailed analysis of piles structural performance and force transfer to the surrounding ground.

EpsilonRebars had been chosen for this project as the best solution dedicated to crack detection and estimation of their width changes. Four sensors were installed in the pylon’s horizontal beam, supporting the deck slab. In this case, a near-to-surface installation method was applied (grooves) to provide appropriate integration of EpsilonRebars with the existing concrete and to create natural protection against the environmental impacts.

Die weltweit einzigartige Lösung war der Einsatz der intelligenten EpsilonRebar-Sensoren (DFOS-Technologie) mit einer Länge von jeweils 17 m zur Überwachung des Verhaltens der Gründungspfähle. Durch der quasikontinuierlichen Messungen über die gesamte Länge der Sensoren ist es möglich, die in das Fundament eingeleitete Kräfte, welche bei der Errichtung der nachfolgenden Stockwerke des Wolkenkratzers entstehen, zu analysieren. Die EpsilonRebar Sensoren ermöglichen auch die Identifizierung der schwächsten Querschnitte und der aufgetretenen Risse. Vier faseroptische Sensoren, die auf der Skyliner-Baustelleinstalliert sind, liefern Daten, die 13 600 herkömmlichen punktuellen Dehnungsmessstreifen entsprechen.

EpsilonRebars and EpsilonSensors were integrated (embedded) inside the steel-concrete bridge, which is the first such type of smart bridge in Germany. The DFOS-based monitoring system was designed to provide the possibility of analysing strains in concrete, in steel reinforcing bars, as well as to detect all the microcracks and calculate vertical displacements (deflections). Also, additional distributed temperature measurements were applied for appropriate thermal compensation.

EpsilonRebars and EpsilonSensors were integrated (embedded) inside the steel-concrete bridge, which is the first such type of smart bridge in Germany. The DFOS-based monitoring system was designed to provide the possibility of analysing strains in concrete, in steel reinforcing bars, as well as to detect all the microcracks and calculate vertical displacements (deflections). Also, additional distributed temperature measurements were applied for appropriate thermal compensation.

Żelazny Most Reservoir is the largest reservoir for copper mining tailings in Europe, owned by KGHM Polska Miedź. It was put into exploitation on February 12, 1977. There are four industrial overflow towers on the site. One of them in 2018, was equipped with vertical 3DSensors to monitor temperatures and horizontal displacements. One of the reasons for DFOS-based monitoring system installation was the construction of the tower’s new floors.

The concrete sewage collector was constructed in 1964 and is now reinforced with Glass-fiber Reinforcement Plastic (GRP) panels. EpsilonRebars (ER) and the EpsilonSensor (ES) from the Nerve-Sensors family were installed inside the near-to-surface grooves to verify the strengthening process. ERs were placed longitudinally over the entire 150 m long section, while ES was installed in selected key circumferences. The system allowed for detailed analysis of strains, cracks, displacements and temperatures.

Three 24 m long prestressed concrete girders were quipped with EpsilonRebars embedded inside. The sensors were delivered on-site in coils and tightened to the existing reinforcement. This fast and easy installation process allowed the creation of smart elements able to self-diagnose during all stages: concrete hardening, prestressing, mounting in the structure, as well as during the load tests. Currently, the girders are under continuous operation in one of Polish production halls.

DFOS-Sensoren in Form von Faserverbundstäben, die gleichzeitig als Bewehrung für das Betonfahrbahn dienen, wurden entlang der gesamten Spannweite von fast 80 m angebracht. Durch der Anwendung der verteilten faseroptischen Technologie war es möglich, Messungen von Dehnungen, Verformungen (Durchbiegungen) und Temperaturänderungen in einer quasi-kontinuierlichen Weise entlang der gesamten Länge der Fußgängerbrücke durchzuführen. Die in die Fahrbahn integrierten Sensoren wurden zur Messung ausgewählter Größen während der Hydratation des Betons (Dehnungen infolge Temperatur und Schwinden) sowie während der Belastungstests eingesetzt

3DSensoren wurden neben einen Fundamentfuß installiert, der dann während des Herausziehens aus dem Boden, d.h. unter extrem großer Verformungen, untersucht wurde. Die Einzigartigkeit dieser Installation basiert vor allem auf der Tatsache, dass keine andere Messtechnik in der Lage ist, die während des Versuchs auftretenden Phänomene zu identifizieren. Keiner der auf dem Markt erhältlichen Verformungssensoren könnte ohne erhebliche Interferenzen in den untersuchten Boden eingebaut werden, was zu einer Störung der analysierten Phänomene und der Möglichkeit ihrer Fehlinterpretation führen würde.

Within this project, two 3DSensors were installed along a road embankment to measure its vertical displacements. Two independent lines of 3DSensors, each 48 m long, were provided, together with multiple reference measurement techniques: longitudinal and transverse inclinometers, spot tiltmeters and geodetic benchmarks. Vertical displacements were measured in a distributed way with 3DSensors and compared with the results of reference methods.

The steel cable-stayed bridge in Przemyśl was put into the service in 2012. At the time of construction, it was the fourth highest bridge in Poland. It is supported by two 61.5 meter high pylons, and its total length (inc. overpasses) is equal to 530 m. In 2017, the bridge was equipped with distributed fibre optic sensors (DFOS) dedicated for strain and temperature measurements. Two measurement sections were installed in collaboration with university graduate students.

The road embankment was designed above the substrate, strengthened with concrete columns. The transmission layer between the columns and earth body of the structure was equipped with Nerve-Sensors: EpsilonRebars (ER) and 3DSensors for measuring strains and vertical displacements respectively. A total number of 16 sensors were installed both in longitudinal and transverse directions. Furthermore, the sensors were used for simultaneous measurements of temperatures.

In the present case study, the base of the road embankment was reinforced by composite rebars in two directions. This solution is favourable in the context of durability due to the high resistance of composites to corrosion. Some of the bars were replaced with EpsilonRebars, which now have a double function in the structure: both sensing and reinforcing. Two measurement layers also allowed for the calculation of vertical displacement profiles.

To monitor the structural behaviour of the largest road embankments in Poland, we applied three independent measurement solutions: Inclify, SHMProfiler and EpsilonRebars from Nerve-Sensors. The latter were used to measure temperature distributions at the base along the entire width of the structure. Temperature results were used, among other things, to compensate for data from the two other measurement techniques.

The composite (steel-concrete) bridge in Dąbrowa Górnicza was designed according to a new approach and put into the service in 2019. This is why verification of its structural performance under real operating conditions was of significant importance. The bridge was equipped with DFOS strain sensors, installed both on the concrete and steel surfaces. The measurements during load tests allowed for detailed analysis of the deformation state, including the detection of all microcracks.

This project involved two types of road surface structures equipped with Nerve-Sensors, measuring both strains (EpsilonRebars) and displacements (3DSensor). All of them were embedded into the road layers during its construction, providing the possibility of analyzing its internal structural behaviour under static proof load tests. Our nervous system, supplemented by spot temperature sensors, was used successfully also in terms of long-term structural health monitoring (SHM).

This project involves two types of road surface structures equipped with Nerve-Sensors, measuring both strains (EpsilonRebars) and displacements (3DSensor). All of them were embedded into the road layers during its construction allowing for analysis of its internal behaviour under dynamic load tests (truck’s runs). Our system was successfully applied for analysing the structural response in real time, including all dynamic effects registered using high-frequency mode.

The subject of the project was the slurry wall made of a new type of material: fibre-reinforced concrete mixed with the ground. As this technology must be carefully checked before use, the EpsilonRebars were used for this purpose. The structural performance of the wall was monitored during deepening of the excavation area as well as load tests. Thanks to Nerve-Sensors, it was possible to detect cracks and fractures invisible to other techniques.

The subject of the project was a slurry wall made of a new type of material: fibre-reinforced concrete mixed with the ground. As this technology must be carefully checked before use, EpsilonRebars were used for this purpose. The structural performance of the wall was monitored during the deepening of the excavation as well as during the mechanical load tests. Thanks to Nerve-Sensors, it was possible to detect cracks but also to calculate horizontal displacements.

The performance of a full-scale concrete structure was investigated during the simulation of column failure. EpsilonSensors were installed inside the slab by tightening to the existing reinforcement. The main aim was to observe the crack morphology. Additional optical fibres were glued to the steel reinforcement to analyse its behaviour during the yielding process. The Nerve-Sensor system measured strains successfully during the entire research until the planned structural failure.

The very challenging experiment was a concrete cube equipped with embedded optical sensors in three directions XYZ. The total number of 75 sections for strain and 25 sections for temperature measurements were created without disturbing the structural performance of the concrete. The research aimed to analyse the spatial behaviour of the massive element during the hydration and shrinkage process, including temperatures and heat transfer.

The reinforced concrete slabs were investigated in laboratory conditions in mechanical four point bending tests. Some were strengthened with FRP material to analyse this solution’s effectiveness. However, the application of FRP prevented visual inspection of cracks. That is why all the slabs were equipped with distributed optical fibre strain sensors placed in-between the concrete and the strengthening material, which allowed for the detection of all cracks invisible to the naked eye.

A number of steel girders designed for bridge applications were investigated in laboratory conditions during mechanical tests. The research includes MCL girders as well as I- and H-beams. The challenge in this project was to measure extremely high strains, exceeding the range of elastic behaviour significantly. Thanks to DFOS strain sensors, it was possible to analyse the yielding process up to 20 000 µε in tension and 10 000 µε in compression.

Nerve-Sensors provide new tools for structural analysis of small-size laboratory specimens made of concrete. In this case, 20 standard cylinders were investigated in mechanical axial compression tests up to their failure. DFOS strain sensors allowed for measurements of both compression (longitudinal) and tension (circumferential) strains at the same time. Thanks to the unique data, advanced structural analysis was possible.

Three 8 m long prestressed concrete truck scale platforms were quipped with EpsilonRebars embedded along the main tendons both in the lower and the upper part. DFOS strain sensors were installed on both surfaces after concrete hardening. The structural performance of the slabs was investigated during all critical stages, including thermal-shrinkage strains of early-age concrete, prestressing & activation of dead weight and finally, during mechanical bending tests.

The subject of the project was to analyse strain distributions in CFA concrete columns during their hydration (early-age concrete) as well as during mechanical load tests. EpsilonRebars were used for this purpose. Because there was no reinforcement inside the columns, a special mounting process had to be designed and implemented. Nerve-Sensors allowed for detailed assessment of columns’ technical conditions along their entire depth.

In this unique project, it was possible to create a smart element capable of self-diagnosis. Nerve-Sensors, including full integration of optical fibre with composite core, as well as displacement (shape) calculation, was implemented in a single bridge panel dedicated for smart bridge engineering. Many laboratory tests with both strain and displacement measurements were performed under the control of independent reference techniques.

Ageing infrastructure is a growing problem in many countries, making it a challenge to take optimal decisions for their further safe operation. Therefore, effective diagnostic solutions are being sought, enabling reliable technical condition assessments. The case study presents the results of static and dynamic DFOS strain measurements of a 57-year-old girder dismantled from one of the production halls. Nerve-Sensors were successfully applied for this purpose.

After seven years of operation, University Bridge in Bydgoszcz became famous because of its structural failure. Significant deformations of the steel anchorage plates beyond the elastic range were identified. All the cables were relieved and then prestressed again after strengthening. Nerve-Sensors were used to monitor this process and identify the safety-critical areas most probable to yield. Now, this unique and essential to the city bridge came back to regular operation.

The Gdański Bridge is a six-span steel truss bridge, 406.5 m long and 17 m wide, across the Vistula River in Warsaw. It was opened in 1959 after three years of construction. Its characteristic features are two decks: the upper for road traffic and the lower for trams. EpsilonSensors from the Nerve-Sensors family were selected and installed on the bridge (surface installation with an appropriate adhesive) to monitor the structural performance of safety-critical steel elements.

Prestressed concrete beams, equipped with EpsilonSensors, were investigated during prestressing and mechanical load tests. Twelve beams were made to provide statistical confidence about the obtained results. One EpsilonSensor was arranged in such a way to create four measurement sections at different beam heights. Thanks to that approach, it was possible to detect cracks and calculate their widths, but also to assess the crack depths depending on the load step.

This experimental project involved a road structure equipped with EpsilonRebars for strain measurements. Our sensors provided the unique possibility of analysing the internal behaviour of asphalt layers under dynamic truck’s runs. The measurements were done in real-time with extremely high spatial resolution and extreme accuracy. This was due to the high elastic composite core, monolithic design and perfect bonding of the sensors with surrounding asphalt.

This experimental project involved a new type of road with a foam-concrete substructure. EpsilonRebars were used to monitor structural response on mechanical load tests. Thanks to the appropriate installation methods, it was possible to provide measurements not only along the horizontal sections but also along with the vertical ones. It’s worth noting that there was no reinforcement facilitating the installation within the entire structure.

EpsilonRebars were integrated (embedded) inside the asphalt layer of a real road structure running in mining areas, i.e. where very large deformations are expected. A new road's structural performance was first investigated during shot-term mechanical load tests. They were performed a few times over the year analyse temperature influence. However, the DFOS-based nervous system will also be a useful diagnostic system for long-term monitoring.

EpsilonRebars with lengths of 60 m and 90 m were installed within two similar steel truss bridges, crossing the Noteć River in Poland. Nerve-Sensors were embedded inside the concrete slabs over their entire length. They were delivered on-site in coils and secured to the existing reinforcement along the main prestressing tendons. The designed and implemented nervous system of the structure is a perfect solution for both short-term load tests and long-tem monitoring.

Composite collectors and pipelines were investigated in collaboration with the Warsaw University of Technology. The specimens were equipped with surface-mounted optical fibres for internal and external strain measurements. Thanks to that approach, 3DSensor could be utilised to calculate displacements (shape changes) expressed directly in millimetres. The research included pipe specimens with different geometry of the cross-section.

This unique research was performed at the Cracow University of Technology. Even though it was a laboratory test, the lessons learned will be beneficial during the monitoring and maintaining the real brick masonry walls of the barracks located in Auschwitz Birkenau camp. Thus, the project is of significant historical meaning. DFOS strain sensors were used to monitor the wall response (built with all imperfections corresponding to the actual state) during mechanical load tests.

EpsilonSensors and 3DSensors were used to create embedded nervous systems in a test environment, simulating the structural behaviour of the actual road substructure. Both longitudinal and transverse sections were investigated at two levels. Despite many sensors installed inside the box, they were not acting as reinforcement and thus, they did not influence the response of the substructure. Strains and displacements were measured at the same time during mechanical loading.

The innovative foot deck was designed and implemented within an existing bridge in Rzeszów. DFOS fibres were integrated within the composite panels during their production (infusion), so sensors became an integral part of the entire structure. Appropriate fibres arrangement and their full integration inside the composite panels allowed us to utilise the idea of both strain sensing with the EpsilonSensor and vertical displacement sensing with 3DSensor. The ready-to-use smart panels were delivered on-site.

The innovative DFOS-based monitoring system was applied within the first Polish full composite bridge (composite girders + composite slabs). DFOS strain fibres were installed on the surface in the production hall, and then pre-prepared smart elements were delivered on-site. The system’s design, including the appropriate arrangement of the fibres, allowed us to utilise the idea of both strain sensing with the EpsilonSensor and vertical displacement sensing with the 3DSensor.

The T. Mazowiecki cable-stayed bridge in Rzeszów was put into service in 2015. The bridge is 482 m long, with two traffic lanes in each direction. The structure is supported by a 107-m long A-shaped pylon with 64 cables. In 2018, the bridge was equipped with distributed fibre optic sensors for strain and temperature measurements. One of the main aims was to create the displacement 3DSensor from the steel girder itself along the 150-metre long river span.

Die Messungen mit der DFOS-Technologie (Distributed Fibre Optic Sensing) wurden im Labor der Fakultät für Bauingenieurwesen an der Technischen Universität Wrocław durchgeführt. Die Ergebnisse der Dehnungsmessungen, die auf quasikontinuierliche Weise über entworfene Messstrecken durchgeführt wurden, werden von den Doktoranden dieser Fakultät für ihre Dissertationen verwendet.