Preventive monitoring implemented at a Safran Power Units production site

Thanks to the preventive monitoring implemented at a Safran Power Units production site, OSMOS averted the need for the operator to carry out major, costly reinforcement work before setting up a new piece of equipment

In summer 2020, Safran Power Units, a world leader in gas turbines, planned to install a new 3D laser machine. Because that equipment weighed 10 metric tons, it was absolutely essential that the mechanical behavior of the floor slabs, beams and posts be checked, to ensure the structure would remain stable with that added load. The facility manager chose OSMOS to obtain the necessary information about the existing structures’ mechanical behavior and verify that the new machine would not cause any damage over time.

OSMOS was tasked with installing instrumentation on those parts of the building that would be the most heavily strained by the weight of the new equipment, from a preventive perspective. That instrumentation was first used to perform load testing, to assess the flooring’s real load-bearing capacity. That step consisted of weighting two separate spots, corresponding to the machine’s main contact points, and gradually reproducing the distribution of weight with continuous monitoring, until the actual equipment weight was reached. After that test, the instrumentation was left in place for two months, to track any chnages to the structure's actual mechanical behavior and identify the effects generated by installing the new machine.

 

In the long term, will the machine’s weight affect the structure’s mechanical behavior?

The data from the load test and the subsequent two months of monitoring showed that the structure was in a stable state of equilibrium. This allowed OSMOS to affirm that installation of the 3D laser machine would pose no risks to the building's integrity and that, as a result, no reinforcement work would be required. That being said, had the measurements demonstrated any insufficiencies in the floor slabs, they would have been able to pinpoint the structure’s shortfalls, in order to define the necessary consolidation measures.

Thnaks to this study, OSMOS was able to give Safran Power Units clear, precise answers about the real mechanical behavior of its existing structures, with a short turnaround time. OSMOS’s analyses enabled the industrial operator to bypass the need for additional studies and for the major work that was originally expected in order to reinforce the structure, work that would actually have been needless. The monitoring was extremely useful to the client, which was able to protect its investment and meet its delivery times.  The study also led to the creation of measurement guidelines specific to instrumented structures, for the verification of their actual behavior in response to new loads and to guarantee the machine’s operability.

Preventive monitoring is ongoing, and OSMOS is preparing to launch the next step in the project: the establishment of a forecast for the 3D laser machine’s operations.  This new phase will aim to monitor the structure’s mechanical behavior under the dynamic stress induced by the equipment’s activation.

New leaflet released!

Thanks to its expertise and innovative solutions, OSMOS gives managers of structures and engineering and construction companies the possibility of continuously monitoring changes to their structures, in real time.

OUR SOLUTIONS APPLY TO ALL KINDS OF STRUCTURES:

• Infrastructure • Ancient heritage • Industry • Buildings

  Download here

OSMOS is reinventing structural health monitoring for bridges and viaducts with WiM+D®

Infrastructure managers must contend with the widespread (and, in some cases, premature) aging of their structures, mostly caused by road traffic, especially heavy vehicles and oversize loads, passing over them. Thanks to its experience monitoring several hundred French and international sites, OSMOS has been able to push the limits of dynamic structural analysis and reinvent structural health monitoring (SHM) for bridges, thanks to its automated Weigh-in-Motion + Deformation (WiM+D®) solution.

 

Detailed dynamic analysis: One step close to the structural reality of bridges 

Multiple continuous structural monitoring solutions are currently available on the market, but none of them can calculate vehicle weights and dimensions and, at the same time, measure the effects of their crossings on the mechanical behavior of structures, despite the fact that this is one of the main factors contributing to their accelerated deterioration.

OSMOS combines weigh-in-motion techniques with dynamic analyses of structural deformation. Simply by arranging a few non-intrusive Optical Strands under the structure’s deck, the system can automatically count and weigh passing heavy goods vehicles. Based on that information, the teams at OSMOS will then determine the exact impact of those heavy vehicles on the structure’s mechanical operation.

After being piloted on multiple bridges in France and Italy since 2018, OSMOS WiM+D® is now a tried-and-tested monitoring solution, and the most economical one on the market. It costs contracting authorities less than traditional weigh-in-motion systems. This is because no major work is required for the sensors’ installation, and the bridge does not have to be shut down in order to set up the equipment. OSMOS’s WiM+D® solution also yields unique, concrete, quantifiable information about how the infrastructure is actually used and monitors its structural health.

View of the WiM+D® monitoring system, non-intrusively installed under the deck of a concrete bridge

 

Structural managers, take advantage of the support offered by the teams at OSMOS to take control of your bridge’s health and considerably cut your operating costs

OSMOS WiM+D® can monitor your bridge’s state of health in real time and calculate the exact impact of road traffic on its mechanical behavior. This allows managers whose infrastructure is traveled over by cargo vehicles to define appropriate maintenance schedules, spread the cost of upkeep over the long term and extend their bridges’ lifespans, all while guaranteeing user safety.

Thanks to precise data, our clients have access to key information about traffic on their structures. In concrete terms, they can see the speed and driving direction of each truck, total weight and weight distribution per axle, length and maximum strain caused to the infrastructure. Heavy vehicles are automatically classified by weight and by driving direction. That information can then be viewed via the online interface, SAFE WorksTM. The system also generates standardized individual records containing the information about each passing truck. The bar graph below is an example of the data collected for a bridge (client name confidential) over the course of a full month. You can see that 20 vehicles weighing more than 48 metric tons were recorded passing over the bridge during the monitoring period. This graph breaks down the number of trucks by weight.

View of SAFE WorksTM:  Heavy vehicle count and classification by weight (yellow for 40-60 MT, orange for 60-80 MT and red for > 80 MT)

As needed, video surveillance cameras can also be installed at each site and connected to our measurement system. Each heavy vehicle or oversize load can be identified by its license plate and its timestamped passage. This optional set-up can be used to confirm the conditions under which measurements are taken and to reinforce overload controls based on the total loads authorized for road freight vehicles.

Of the different weigh-in-motion solutions available on the market, OSMOS WiM+D® stands out from more conventional systems, which tend to be intrusive for the infrastructure and costly to install. Not only does the OSMOS solution offer the same functions, but it also provides real-time information about the bridge’s structural health and its evolution, as well as detecting any anomalies. With this knowledge of the structure and the exact impact of its operation, the bridge’s manager can achieve considerable savings on the budget allocated to maintenance and extend the lifespan of this vital resource. OSMOS’s teams continuously strive to further enhance the WiM+D® solution, placing special emphasis on moving research forward, namely through ongoing partnerships and new projects in France and abroad.

OSMOS GROUP and KISR implement an innovative solution for structural health monitoring and weigh-in-motion on PART’s Cairo Bridge in Kuwait

PRESS RELEASE

OSMOS GROUP and KISR implement an innovative solution for structural health monitoring and weigh-in-motion on PART’s Cairo Bridge in Kuwait

The Kuwait Public Authority for Roads & Transportation (PART) is conducting an important construction project on a Bridge supporting the Istiqlal Street over the Cairo Street in the city of Hawally.

These works consist in excavating two underpasses below the bridge, 10 meters below the original level, constructing retaining walls on both sides and near the bridge piles, reinforcing the piles with a structural support system, raising temporarily the deck of the bridge and replacing its bearing devices.

The bridge is 74 m long, on 2 spans. The deck is composed of Post-tension concrete box girders. It is part of one of the main traffic axes in the State of Kuwait, and must remain open at all times, in spite of the invasive nature of the works around.

PART has decided to implement a Structural Health Monitoring (SHM) system on this bridge in order to confirm that the structure of the bridge will not be affected by the construction works and to keep the bridge open to traffic with full safety for the users.

PART has entrusted the Kuwait Institute for Scientific Research (KISR) and OSMOS Group to perform the SHM of this bridge during the construction works.

The project is an integral part of an Agreement signed in 2019 between OSMOS and KISR for the collaborative research entitled “Real Time Structural Monitoring and Infrastructure”. Dr Jafarali Parol is the Project leader from KISR and coordinating the collaboration from Kuwait.

KISR and OSMOS have installed a set of 20 sensors called Optical StrandsTM, long-basis optical fiber deformation sensors which already equip hundreds of structures in the world. The Optical Strands measure strain variations on critical parts of the bridge and provide:

  • A confirmation of the correct structural behavior of the bridge
  • An early information in case of behavior modifications
  • An evaluation of the criticality of this modification

The instrumentation is completed by 4 accelerometers, for the vibration analysis of the deck and the determination of its dynamic characteristics.

The measurements are recorded by the sensors, transmitted to Expert Data Acquisition System Monitoring (EDAS) Stations, and from there to the OSMOS Cloud and analyzed by the OSMOS Software suite SAFE Works, permanently and continuously. The different stakeholders of this project (Client, contractor, etc.) are immediately informed in case of structural behavior modifications.

The data also provide a complete information concerning the traffic on the bridge, through the Weigh-In-Motion and Deformations (WiM+DTM) module implemented for this project. The same Optical Strands will also define the Gross Weight and the speed for all notable vehicles passing on the bridge.

The SHM system has been installed in October 2020. Since then, the results have shown that the construction works have not caused any structural damages on the bridge, with records of deformations of small amplitudes only and complete reversibility.

The contractor is able to continue the works without structural hazard, delay, with safety for the bridge users and by keeping the timetable.

 

H.E. Ambassador of France, Mrs. Anne-Claire Legendre

Successful stories of French Technology are not only those of multinational corporations. Smart SMEs such as OSMOS Group have been able to gain a worldwide footprint thanks to innovative solutions. OSMOS Solutions are remarkable because they have a clearly useful interest to public operators.

 

Mr. Patrice Pelletier, Deputy Chief Executive Officer, OSMOS Group SA

The Bridge 30 project is assuredly challenging, where the client has multiple objectives and responsibilities: Safety for everyone, Adherence to the construction schedule, and Respect of the project costs. OSMOS offers a smart suite of solutions for infrastructure owners and operators to face these challenges with success. Not only state-of-the art technologies are deployed for this project but also our latest series of algorithms to carry massive data analysis and interpretation.”

 

Dr. Hasan Ali Kamal, Member of Municipal Council, Kuwait

KISR and our research group is carrying out an applied research in the state-of-art Structural Health Monitoring (SHM) technology. The method to be implemented in the iconic civil infrastructures in Kuwait and elsewhere in the world. This is a combined technology that uses advancements in sensor technology, artificial intelligence, and IOT to assess structural performance, to ensure structural safety, and to provide maintenance strategies. This project is one of the vital steps to transform the bridges in Kuwait into a “smart bridge” and to reduce the life cycle cost of bridge systems.

 

Dr. Shaikha Al-Sanad, Program Manager, KISR

This collaborative project is the first and necessary step towards smart sustainable cities that use information and communication technology and other means to improve the efficiency of operation, maintenance and related services while ensuring that the needs of the economic and environmental aspects are met. Accordingly, the Structural health monitoring (SHM) has the potential to transform the bridge engineering industry by providing stakeholders with additional information to inform decisions about the design, operation, and management of bridges throughout the structures’ lifespans.

 

General view of the Bridge before the works

 

View of the bridge once the new lanes are excavated

 

Four Optical Strand sensors installed below the bridge deck

 

Example of deformations recorded by Optical Strands after the passage of a heavy truck: Limited strain amplitude and reversibility

 

About OSMOS

OSMOS is a subsidiary of EREN Group, the first group dedicated to the economy of natural resources founded in 2012 by Pâris Mouratoglou and David Corchia.

Established in 2006, OSMOS is a recognized specialist in the field of Structural Health Monitoring (SHM). It offers a wide range of solutions in monitoring structural assets of the building, infrastructure and industrial sectors.

OSMOS designs and manufactures innovative sensor systems based on a unique optical-fiber technology, the Optical Strand®. This technology allows the monitoring, the detection and the measurement of deformations and potential weaknesses of various types of buildings, infrastructures, and industrial equipment. OSMOS also develops with engineers, mathematicians and data scientists its proprietary algorithms for data analysis and interpretation. OSMOS’ suite of software, SAFE Works® and SAFE Analyser®, allow its customers and engineers to visualize, analyze and interpret the deformations of infrastructures. OSMOS latest WiM+DTM and SAFE Traffic® software development combined with the Optical Strands® sensors provide both structural health monitoring of bridges and overpasses and weigh-in-motion (WIM).

OSMOS structural health monitoring solutions have already been implemented with customers of the public and private sectors in more than 20 countries worldwide.

 

Media contact

OSMOS Group SA / Johanna JOUBERTEIX

Tel: +33 (0) 1 71 39 85 15

E-mail: jouberteix@osmos-group.com

Enhanced monitoring of two bridges over the Loire River

The Loire-Atlantique Departmental Council has taken a preventive approach in commissioning OSMOS to check the real-world mechanical behavior of two bridges over the river. The enhanced monitoring of those structures will maintain their service levels and ensure user safety, while awaiting major rehabilitation work.

 

Built in the late 19th century, the Grand Pont de Mauves and Haut Village Bridges are part of a group of four strategic structures that connect the banks of the Loire to the east of Nantes. Periodic detailed inspections identified multiple problems, including signs of progressive corrosion, advanced deterioration of the brick arches under the deck and differential settlement of the supports. That damage was caused by the age of the bridges, their permeability and the intensification of the traffic traveling over them.

To maintain its structures’ level of service while guaranteeing user safety, the Loire-Atlantique Department Council decided to invest several million euros in an enhanced monitoring and specialized maintenance program for its infrastructure. With those renovations in mind, the Civil Engineering Department commissioned OSMOS to monitor the behavior of the Grand Pont de Mauves, while awaiting its restoration as part of a series of rehabilitation and modernization work. The Haut Village Bridge was then monitored to assess the effects of the additional road traffic that would be diverted to it during the work performed on the bridge line at Mauves-sur-Loire. This made it possible to avoid shutting down the Grand Pont de Mauves early, a move that would have been costly and inconvenient for its users.

Monitoring of the Mauves Bridge: Ensuring optimal user safety while keeping the structure under enhanced monitoring, leading up to its restoration

The Grand Pont de Mauves had been covered by enhanced monitoring since 2002, as part of periodic monitoring and inspection procedures. In 2018, after pitting corrosion was observed in a number of floor beams, visual inspections by rappellers were arranged in parallel to the schedule of renovation work to restore the bridge. Before that project was launched, the Loire-Atlantique Departmental Council wanted to have continuous, real-time monitoring while the bridge was still in operation, to prevent its premature closure and to control any structural risks. OSMOS was asked to roll out a monitoring system seven months prior to the start of work on the bridge. The goal was to continuously check its elasticity and displacement, in real time, as well as any day-to-day deformation caused by moving loads.

After a period spent studying the Mauves Bridge’s behavior, OSMOS was able to notify the contracting authority of any significant events indicating a change in its overall stability, particularly as a result of temperature fluctuations and moving loads. On the whole, the structure displayed good stability, with a slight tendency toward tension in Span 11. Most of the dynamic strain generated by road traffic was of a low magnitude and had no harmful effects on the bridge’s mechanical behavior. Only the passage of certain heavy vehicles had an irreversible impact on the framework of the bridge. An analysis of all of the deformation amplitudes associated with moving loads revealed that the strain was substantially higher on one part of the bridge. That area appeared to be more “strained” than the others when heavy vehicles passed over it, as a result of localized deterioration of rigidity.

 

Assessing the effects of the traffic diverted to the Haut Village Bridge: Would the additional moving loads pose a threat to the state of the structure?

In anticipation of the diversion of traffic to the Haut Village Bridge during work on the Mauves Bridge, the Loire-Atlantique Department asked OSMOS to place the structure under continuous monitoring. This was because, despite the renovation work and repairs performed on it in recent years, the Haut Village Bridge’s load-bearing capacity was still limited, due to the aging of its materials and its original design. The contracting authority wanted to understand how the structure would actually behave under the “over-strain” caused by the traffic detour. The monitoring also made it possible to refine the modeling assumptions for the bridge and determine the maximum load it could bear.

The structural deformations demonstrated even amplitudes, consistent between the spans, as well as a good correlation to heat fluctuations. The statistical analysis of dynamic events, shown below, highlights the effects of the lockdown on road traffic, including a decline in the frequency of heavy vehicle crossings. Despite a rise in traffic during the 10 days following May 11, 2020, the date when the lockdown was lifted, it eventually returned to the frequency observed during the lockdown. Out of all of the dynamic events, two unusual crossings were recorded, with effects three times higher than the usual consequences of heavy vehicles on the bridge. After those first six months of monitoring, the structure’s behavior displayed long-term stability and responses that were consistent with its traffic loads, even unusual loads. The following months further enriched this analysis.

 

Placing the Mauves Bridge under enhanced structural monitoring while awaiting its renovation, and the Haut Village Bridge during that work, allowed the administrator to maintain operations with guaranteed user safety. The data obtained from OSMOS’s monitoring and statistical analyses will be extremely useful to the Loire-Atlantique Departmental Council when it comes time to recalculate its structures. That way, the contracting authority will be able to verify that their condition is still in line with the expected level of service. The management of this infrastructure can then be oriented so as to ensure their availability and control their structural integrity over time.

 

Testimonial from Thibaut Pannetier, Head of the Loire-Atlantique Civil Engineering Department

“Under our strategy of monitoring the infrastructure along the Mauves and Thouaré bridge lines, we needed to supplement our inspections with a more comprehensive structural approach. It was difficult to control structural risk through the enhanced monitoring performed on the bridges of Mauves, based solely on corrosion measurements and the losses of material observed during semiannual inspections. In particular, the 19th-century bridge design, in the form of riveted connections between plates and multiple trusses with brick arches, would have been complicated to recalculate or would have required the development of calculation models whose modeling time and methods were not in line with the short-term issues related to keeping crossings safe before shutting down the bridge for work.

That’s why we reached out to OSMOS, after sourcing providers in 2019, to install a solution using Optical Strands that would avoid the need for lengthy, complex calculations and that would provide a continuous, quantitative observational approach. It was vital for us to make sure of the bridge’s structural elasticity. Otherwise, we would have had to make the call to shut it down, in a geographic area with relatively few crossing points, making detours very costly for both users and local businesses.

In parallel, the instrumentation installed on the Haut Village Bridge for the same reasons allowed us to make sure it would continue to function correctly when traffic was diverted during work on the bridges in Mauves.

The assistance provided by OSMOS easily satisfied our needs. The team understood our approaches and our constraints, so they were able to recommend instrumentation capable of controlling the risks to people and property. Their responsiveness when rolling out the solution and setting up the support engineering was effective, making this collaboration an experience worth reproducing for contracting authorities managing an infrastructure of complex, aging bridges along strategic roadways. This successful experience is undoubtedly the start of a new orientation for instrumentation strategies, as a complement to periodic inspections and ad hoc assessments.

Finally, the instrumentation on the Haut Village Bridge also allowed the Civil Engineering Department to finalize its calculation model through various iterations, by comparing the digital results with the actual displacement measurements.”

Structural monitoring of the Mont Blanc Tunnel: A model for safety

Extending over a length of 7.2 miles (11.6 km), the Mont Blanc Tunnel is a strategic feat of engineering that offers fast travel between France and Italy. It is a major trade route that supports the local and inter-regional economy. In fact, substantial traffic travels along it daily, contributing to its wear and tear. The tunnel is operated by a Franco-Italian organization, the GEIE-TMB (Mont Blanc Tunnel European Economic Interest Group). The company is responsible for the tunnel’s structural monitoring and maintenance, as well as traffic safety and management.

Today, the Mont Blanc Tunnel is a model in terms of safety, particularly with regard to structural aspects. 117 LIRIS Optical Strands installed under the surface of the road provide for its continuous monitoring. The tunnel’s instrumentation is designed to track and analyze its mechanical behavior, particularly as a result of road traffic, and its evolution over time.

Static and dynamic measurements for a dual analysis of tunnel slab behavior

An average of 1,721 heavy vehicles pass through the tunnel, each and every day. Those crossings are dynamic stresses, of varying intensity, that contribute to the structure’s aging. The OSMOS monitoring system measures the effects of those events, which represent not only loads that cause stress to the structure, but also the associated strains on the material. Consequently, the slabs supporting the tunnel’s traffic lanes were equipped with LIRIS Optical Strands.

Over and above dynamic measurements, static analyses are an important part of this monitoring project. They involve measurements taken once an hour, to reveal slow-moving changes to the structure. Because the temperature is taken at the same time, these data can be used to study the structure’s response to fluctuations in heat. Then, OSMOS corrects for the effects of temperature, in order to identify any gradual trends caused by the aging of the structure.

As a result, the objective of the installed monitoring system, approved by the tunnel’s safety committee, consists of studying the mechanical behavior of the concerned slabs, by measuring deformation due to the bowing of the slabs’ undersides, owing to their own weight (static data) and/or to traffic loads (dynamic data).

The combination of these two types of analyses – static and dynamic – allows OSMOS to periodically calculate and assign a stability index to each sensor, as well as to the structure as a whole. The assigned score provides concrete, relevant information to the client, which can then review the structure’s state of health and any changes in its assessment over time.


Overview of the scores assigned to all of the sensors for the latest period (October 2019 to January 2020)

A preventative approach for optimized structural management

The Mont Blanc Tunnel monitoring project is, first and foremost, a preventive one. The goal is to anticipate any structural risks and adapt the level of service, if necessary. In some instances, notable changes to the structure’s behavior may lead to the implementation of protective measures or reinforcement work. By taking a proactive approach, the managers of the Mont Blanc Tunnel have secured the structure and were able to institute an optimized maintenance policy to keep it in a good state of health.

Overall, the structural behavior of the Mont Blanc Tunnel is very stable. Only one of the sensor locations has been characterized as “sensitive,” with significant changes in tension between October 2019 and January 2020. The reason for this abnormal measurement has been identified: a sliver of the reinforcing concrete cover had become detached in a ventilation shaft, causing the tensioning of the Optical Strand installed under the roadway. Since that problem was corrected, the structure’s behavior has stabilized completely and remains under continuous monitoring.

Graph of the deformation curves associated with all of the project’s sensors over the course of the past year (July 2019 to July 2020)