Inspection of the Saint Jean Bridge in Bordeaux – Materials appraisal

With its 474m of length crossing the Garonne River, the Saint Jean Bridge links the railway station district to the right bank of the river since 1965.

Before carrying out the repairing works, the engineering Department of Bordeaux Métrople wanted to carry out a material diagnosis of the bridge deck pre-stressed concrete. The aim was to provide entree data and specify the works program suggested by the project manager. The inspection revealed the presence of some construction defaults as well as a slight carbonation phenomenon in the concrete.

 

Tessa Guitton, Engineer at Sixense, tells us about her experience:

“It was a large-scale mission with lots of inspection tools, lots of investigation areas, particular means of access and a will to limit traffic restrictions. In the end, the mission was successfully completed thank to the efficiency of all the contributors.”

 

Even behind the masks, our teams put on their best smile to showcase the various techniques and diagnostic tools used.

 

by Francis Vigouroux
by Francis Vigouroux

One unique tool to assess the vulnerability of assets

Our design offices specialised in climate resilience, Resallience, assists the Deposit Fund Caisse des Dépôts (CDC) Habitat with its adaptation strategy to climate change. They joined forces with our experts in engineering of existing structures to develop the first DPR platform (Climate Resilience Performance Diagnosis).

It is a decision support system composed of, on one hand, a hypervisor, powered by a geographical information system, and on the other hand, an analytical spreadsheet. The DPR allows to assess the criticality level of built heritage to climate risks. It also analyses the technical and financial risks of impact of these contingencies on the components, the subsystems and the systems of the groups of buildings. The DPR applies to all the property assets of CDC Habitat, close to 500 000 housings, and will allow to power the pluri-annual plans of investments to restore this heritage, to adapt the design of the new constructions and this way, better adapt to climate change on the horizon of 2050.

This project comes within the scope of a partnership between CDC Habitat, the FFA Insurance (French Federation of Insurances and the association of natural risks mission – MNR) created in 2000 by insurers in order to contribute to a better knowledge of natural risks.

 

Discover the article from CDC Habitat for more information.

Structural monitoring of the Normandy Bridge

The Normandy Bridge, a major structure that stands up to the elements

Since 1995, the Normandy Bridge is crossing the Seine estuary and connects Le Havre and Honfleur by a 2,141-meter long prestressed concrete and steel structure. It has a cable-stayed span of 856 meters. The deck of the structure accommodates 4 vehicular traffic lanes as well as bicycle and pedestrian paths. Its 184 stays, with up to 53 strands for the largest cables, ensure that the central steel deck is maintained for no less than 654 m above the navigation channel.

The durability of this structure, a symbol of French know-how in terms of Civil Engineering but subject to the winds and tides at the Seine estuary, is ensured by regular and rigorous maintenance. This maintenace is backed by the monitoring of the structure with a set of specific sensors but also by the periodic control of the structure’s and particularily the ageing of the stay cables

 

Increased surveillance of the structure to ensure its durability

Between 2011 and 2018, Sixense installed and maintained a monitoring system composed of about a hundred sensors: displacement, inclination, force in the stay cables, temperature, vibration of the structure, weather station and even breakage of stay cable wires. This system, which measures both the external stresses and the structural responses of the structure, enables a better understanding of the structure and anticipation of maintenance operations.

Since 2011, Sixense has also carried out periodic testing of the stay cables to determine their level of aging and check their residual structural strength. The Uscan process, patented jointly with the Gustave Eiffel University, works on the principle of ultrasonic guided waves to check the health of the strand wires in the areas where the stay wires are anchored.

 

Thanks to these continuous and periodic measurements on the sensitive componentss of the structure, the CCISE* can anticipate and schedule maintenance operations that will keep this masterpiece of French Civil Engineering intact for many years to come.

 

CCISE*: Seine-Estuaire Chamber of Commerce and Industry

 

Our SHM experts working on the Normandy bridge

Environmental monitoring, modelling and assessment works on High Speed 2, Europe’s largest railway infrastructure project

A major high-speed railway project across the UK

High Speed 2 (HS2) Phase 1 is a large high-speed railway project in the United Kingdom which will link London and Birmingham, with a future second phase to reach Manchester and Leeds in Northern England.

This major project will provide increased capacity and reliability of the railway links and should help manage the rising number of passengers.

HS2 phase 1 is expected to open to passengers in 2026 and Phase 2 around 2033.

 

Sixense expertise applied to this environmentally challenging major project

Sixense is excited to embark on the significant challenge of providing noise, vibration and air quality management services on a section of Europe’s largest infrastructure project, HS2. This section of the mega engineering project, delivered by Align JV, includes the route’s flagship 3.4km-long Colne Valley Viaduct, as well as the 15.8km-long Chiltern twin-tunnels. The services to be provided by Sixense include a significant amount of monitoring, modelling and assessment work across the 10+ worksites, which will play a key role in the wider efforts to minimise environmental impacts throughout the 5-year build.

 

Sixense teams providing efficient solutions

Within the first six weeks of its involvement, Sixense already installed 22no. noise and air quality monitoring stations, which are largely powered by sustainable-energy sources.

New contract: monitoring of the construction worksite of line 18 of the Grand Paris Express

Sixense would like to thank the consortium in charge of the works for their trust on this new project of the Grand Paris Express. The forecast duration of this new contract for monitoring of the works and nearby infrastructures is of 5 years. Line 18 will be about 35 km-long from the Orly Airport railway station to the Versailles-Chantiers railway station.

 

The market, notified on May 14th of 2020 to the association of several entities of @Vinci Construction and @Spie batignolles, includes the realisation of :

 

  • a bored tunnel of about 11 800 ml, of 7,8 m of effective diameter excluding crossing of structures,
  • trenches (cut and covered) of about 850 m between the tunnel and the aerial section comprising the temporary reorganisation of the Croix de Villebois road crossing intercepted by the works,
  • structural works of the underground railway stations of Antonypole, Massy-Opéra and Massy-Palaiseau,
  • thirteen annexed works, including the connecting branches of the tunnel.

 

Sixense Monitoring was assigned the auscultations to be carried out in the framwork of the project related to the drilling of the tunnel and to the construction of the infrastructures (excluding Launching shaft and Cut & Cover and excluding inside topography of the railway stations and right-of-ways).

 

This sector comprises 2 very sensitive areas which will need to be carefully monitored : the important railways nearby the future Massy-Palaiseau railway station and the Orly Airport area.

 

A permanent Sixense team will remain on the field at the base of the worksite in order to stay as close as possible to the work teams to carry out the mission that we have been assigned to. The team will implement a diversity of auscultation measures, including:

 

  1. Automated topographic monitoring with our now well-known Cyclops and Centaurs which will examine the nearby infrastructures of the project,
  2. Measures by inclinometers of the vertical structures of the infrastructures under construction,
  3. Stresses and constraints monitoring of the infrastructures under construction or the instrumented voussoirs,
  4. The geotechnical monitoring of the 16 sections of reinforced measures of the 2 tunnels comprising inclinometers in the field, multipoints extensometers in boreholes and interstitial pressure cells.

 

Geoscope will be the management support tool for all companies to access all auscultations of the project. This tool had been designed with a multi-actors approach allowing all different parties of the same project to have access to all the useful data : intuitive visualisation of the data, management of the alarms for level exceedances, visualisation of the construction site progression and access to all reports of auscultations.

 

This project is once again an opportunity for us to implement our monitoring expertise of urban works build up throughout the years with tunnel projects in urban areas where we have been able to step in.

Ile de Ré Viaduct

Ultrasonic inspection and Acoustic Monitoring of the Ile de  Viaduct 

The Ile-de-Ré Viaduct in France experienced in 2018 a failure on one of its external prestressing tendons. The bridge owner awarded to Sixense and Freyssinet the mission to secure the structure, inspect ultrasonically the existing tendons, monitoring acoustically their potential failure and replace the broken tendon.

 

EverSense® Acoustic monitoring and cable replacement are well experienced skills of Sixense and Freyssinet. However, before Ile-de Ré Viaduct, EverScan® ultrasonic inspection of anchorages has only been done on individually sheath waxed strands of stay cables but not on grouted bare strands of prestressing tendons. On prestsressing tendons the risk of failure has clearly been identified and located in the first meter away from the tip of the strand in the anchorage zone, which is further away than stay cables application.

 

Then Sixense and Gustave Eiffel University (UGE, formerly IFSTTAR) worked on the extension of the ability of the well known ultrasonic USCAN® technology in order to apply it on grouted strand and up to 2 m away from the anchorage.

 

For this project 85 anchorages have been inspected by USCAN® and 170 acoustic sensors were installed prior to the replacement of the broken tendon. USCAN® measurement resulted in identifying 3 anchorages in bad condition with potential failure. The worst tendon has been removed for replacement. Visual inspection of removed anchorage piece confirmed the blind measurement of USCAN® and showed the ability of the technology to detect failure and corrosion in strands near anchorages.

 

This emergency job was made in less than 6 months. Today the viaduct is under high acoustic monitoring by Sixense teams for any detection of wires breaking.

Instrumentation & Monitoring Services for the Ciel Tower

Dubai is home of some of the most incredible infrastructure and is recognized worldwide for its impressive constructions. Sixense expertise was required for instrumentation and monitoring services at the Ciel Tower project, the highest hotel in the world, currently under construction.

 

A new iconic tower in the heart of Dubai Marina

 

Since 2016, an impressive project has risen in Dubai Marina, building the highest hotel in the world. This high-end hotel will include a health club, a luxury spa, a restaurant, 1042 luxury suites, rooftop infinity pools along with other facilities. The Ciel Tower is a new supertall skyscraper of over 80 floors and 365m high. Located directly across the world-famous Cayan Tower (76-floors) on the north side of the marina, the Ciel Tower will become a local memorable landmark with an estimated handover date in 2023.

 

A complex situation on site

 

The close proximity with surrounding structures and the congested urban area, including one of the main RTA Marina bridges, brought several challenges to the project. It was indispensable to set an adapted instrumentation and monitoring system during the construction phases.

Sixense provides during the construction early warnings of any excessive and undue movements of adjoining premises and structures and ensures project safety with its 24/7 monitoring system and Geoscope 7 Software, sending information about movements exceeding the expected levels to the required parties. During the excavation phase, settlement, deflection and deformation data were provided in order to verify the initial designs of the permanent structure but also the temporary works supporting the excavation. Eventually, Sixense also monitored ground movements.

Periodic monitoring data reports have been provided to the contractors, consultants and RTA throughout the project.

Zetas, contracted for Enabling Works, entrusted Sixense with the instrumentation and monitoring of the ground and the structures in and around the site. Dutch Foundation, later contracted for foundation changes, recognized Sixense’s track record of delivering success for the project.

Structural Deformation Monitoring of Hampton Roads Bridge-Tunnel Expansion Project USA

Structural Deformation Monitoring of Hampton Roads Bridge-Tunnel Expansion project using AMTS and high precision low cost GNSS.

 

The $3.8 billion Hampton Roads Bridge-Tunnel Expansion project is the biggest project in the Virginia Department of Transportation history which includes constructing twin bored tunnels west of the existing immersed-tube tunnel and bridge.

Sixense was chosen by the design-build team Hampton Roads Connector Partners (HRCP) (consists of Dragados USAFlatiron Construction, VINCI Construction Grands Projects and Dodin Campenon Bernard) to perform baseline deformation monitoring of the existing tunnel, approach walls as well as several facility buildings on the south and the north islands connected by the crossing from August 2019 to August 2020.

A robust near real-time deformation monitoring system was designed and implemented using 9 Sixense’s Cyclops automatic motorized total station (AMTS) systems, complemented by nearly 50 novel 4Dbloc, low-cost high-precision GNSS receivers and over 60 wireless tiltmeters.

In recognition of the high quality work performed by Sixense during the 1st stage baseline monitoring, a new contract for transition baseline monitoring into active construction stage monitoring was recently awarded to Sixense, in August 2020, with an expanded scope of monitoring work including a significant amount of AMTS, vibration monitors and other geotechnical instruments.

Structural Health Monitoring of the Komárom Bridge

With 500 m span and its single pylon Komárom bridge is linking Hungary and Slovakia 100 km West from Budapest. Sixense has the mission to design, fabricate and install a full EverSense® Structural Health Monitoring System (SHMS) . 

The system includes different type of sensors such as stay cable load sensors, bearing displacement, temperature, video cameras and a weather station with an integrated road surface condition sensors. 

The EverSense® SHMS will allow to follow the behavior of the structure, alert in case of abnormal activities and ensure the security of the user.  

In a few years the operator of the bridge will use the data generated by the system in order to plan its maintenance and secure the design life of the structure. 

 

Installation of the system went through during the COVID-19 lockdown period which made it more challenging. Thanks to our local entity Sixense Hungary, the installation was made possible despite lockdown with remote assistance from our SHMS experts. 

 

The bridge was inaugurated mid-september 2020. 

 

Reflectorless monitoring for Dubai’s Jebel Ali Labour City & Industrial Development

Sixense’s expertise has been requested on one of Dubai’s community development projects aiming to raise the living standards and services for labour workers with affordable housing and an innovative modern project.

 

Sixense’s contribution to a large-scale project benefiting to Dubai’s worker community

Reflectorless monitoring Dubai

Located in Dubai’s oldest and most important industrial districts, Jebel Ali Industrial development will provide quality and affordable housing to Dubai’s largest blue-collar workforce.

In the development process and in order to welcome large amounts of residents, a new sewage system had to be put in place under one of the busiest roads, Al Asayel Street. The contractor DX Contracting, hired for this project by MERAAS, opted for a Non-Destructive-Road-Crossing (NDRC) technique using a Micro-Tunnel Boring Machine. Although the machine’s drive diameter is small and used on shallow soils, there is always an existing risk of settlement that must be mitigated.

 

Sixense implements its innovative reflectorless monitoring technique

Sixense’s client requested the monitoring of the road to observe any vertical movements and mitigate the risk of settlements of this active and busy road under which the new system was being installed.

Usually, most technique consists in installing devices such as optical targets or ground settlement markers on the pavement, an invasive method interrupting traffic and needing a large site organization. Sixense was called to support the monitoring process with an innovative solution.

Sixense’s intervention brought to the project its solution consisting in the installation of a total station, an electronic optical surveying instrument on top of a nearby building, allowing a view of the whole area. From there, the influence area of the Micro-Tunnel Boring Machine could be seen with the reflectorless monitoring system to monitor the road settlements.

This innovative technique was the best solution to monitor the road safely, cost effectively whilst obtaining a density of “instrumentation” of one point every 2m² and allowing to monitor about 200 points. No installations were needed on the road and no traffic needed to be interrupted.

Sixense is aiming to put an end to conventional manual levelling techniques such as classic leveling that require specific traffic management ahead of each reading campaign and questioning safety around traffic environments.

Sixense is proud be involved in this project. Workers will now benefit as well from the area’s excellent connections to Dubai, Abu Dhabi and the northern emirates, Dubaï’s Investment park as well as the proximity to the Expo 2020 site.

Periodic inspection “on ropes” for the Zola Dam

Sixense is developing skills in areas with difficult access, including inspection of dam infrastructure.

Destination the “Provençale” region, more precisely the Saint-Victoire Massif close to Aix-en-Provence, where Sixense was called for a periodic inspection mission by the Société du Canal de Provence (SCP), who manages the Zola Dam installations.

Barrage Zola

Built in 1854 and named after the architect François Zola, father of the writer Emile Zola, the Zola Dam requires periodic inspections and recording of faults on the emerged parts of the structure to assess the state of the dam.

 

In order to inspect closely the whole surface of the dam at 36m high, our teams carried out the intervention with ropes and harness.

In 2011, a specialist rope access team carried out the inspection alongside our engineer who joined on some of the descents to observe the faults.

But on this recent occasion, and for the first time at Sixense, our engineer, who is also a qualified CQP rope access technician, could carry out a rappelling descent alone. ATOMS provided support in the form of access materials and equipment as well as know-how (anchors set up, descent supervision, presence in case of emergency).

 

Cédric Laurent, in charge of realisation, is a difficult access specialist at the BEI department:

« the walking trail on the crest of the dam stayed opened during the mission and several different strengthening works down the dam made the intervention quite sensitive. Moreover, the weather conditions and the bushfire risks in the Saint-Victoire Massif meant we could only work from 6am to 1pm. The good preparation of the mission (pre-start site visit, regular discussion with the client, evaluation of the risks…) was a key element for the success of the mission. »

Inspection corde Barrage Zola Engineering

 

This intervention method allowed us to accomplish quality recordings by an expert inspector, and to optimise the time spent on the jobsite thanks to the reduce number of rope access technician and descents needed.

With dual skills in rope access and in specialist in diagnosis,  our Sixense Engineering team can now offer a solution for future interventions on ropes such as inspections, diagnosis, and instrumentation for tall infrastructure where more typical means of access (mobile elevating work platform, scaffolding) are impossible, such as for bridges, stadiums, retaining walls, water towers and chimneys.

 

 

SHM on the Rio-Antirrio Bridge

The Rio-Antirrio Bridge in Greece is an exceptionally impressive structure built to endure extreme environmental conditions. Seismic and meteorological risks to its structural integrity must be continually monitored. Its operating concession holder Gefyra has entrusted Sixense with this task for more than 16 years.

From the construction phase onwards, the operating concession holder has needed to monitor the response of the bridge structure to its environment, and validate the assumptions made at the design stage. The ongoing monitoring of the aging structure enables decisions regarding whether the bridge can be reopened or requires maintenance closures following periods of extremely high winds or seismic events.

 

The Rio-Antirrio Bridge: a structure under the microscope 

EverSense ®, our Structural Health Monitoring System (SHM), was designed and implemented by our teams at the time of construction. Since it opened to traffic in 2004, the 1,000 data acquisition channels of this system have enabled Gefyra to record and characterize the behaviour of the structure and to detect changes in this behaviour, especially after exceptional events such as earthquakes or unusually high winds.

The monitoring system has been regularly maintained and upgraded since implementation. It now incorporates functions that enable real-time traffic management during seismic events or exceptionally high winds.

The EverSense system has made it possible to validate structural design data and coupled with the quality of data generated, has made it possible to allow traffic back safely onto the bridge promptly over 16 years of major environmental events.

 

The real-time monitoring system implemented by Sixense meant that we could analyse the huge amount of data needed to establish an overview of the structure and receive automated alerts immediately after the earthquake struck. The great advantage of the Sixense system is that it allows us to achieve significant improvements in safety, which is the most important thing from our perspective

Aris Stathopoulos, Structural Maintenance Manager at Gefyra SA/ VINCI Concessions for the Rio-Antirrio Bridge in Greece

Sensitive noise issues around a wind farm in Burgundy Franche-Comté

Controlling the acoustic impact of a wind farm while minimising the impact on its productivity: that was the challenge faced by our customer Innergex renewable energy.

In response to complaints from local residents regarding noise following commissioning of the wind farm, Innergex decided to take decisive action to ensure good ongoing relations with neighbouring communities as part of its vision to maintain long-term and responsible operational relationships with those living in residential areas around its wind farms. Innergex asked our acoustics experts to develop a methodology specific to this wind farm in order to provide an objective assessment of its acoustic impact in the context of current regulations, and to prepare an effective and optimised noise limitation plan that would deliver guaranteed outcomes.

Our teams then set to work on helping Innergex to resolve this sensitive issue of noise. For this project, our brief was to bring forward a solution that was acceptable to everyone involved, at the same time as meeting Innergex productivity goals for its wind farm. A series of conversations between Innergex and Sixense resulted in the emergence of a completely new study methodology designed to quantify residual noise levels, while maintaining almost full operation of the generators throughout the measurement campaign.

 

In estimating the overall acoustic impact of the wind farm and establishing a suitable noise reduction plan, our acoustics experts used a range of different techniques, including measurements during full-power operation of the wind turbines and noise decay measurements in close proximity to the turbines to avoid the influence of weather conditions. These measurements made close to the turbines were supplemented by measurements taken at the homes of local residents to ensure perfect calibration of measurements and calculations.

 

In this way, our engineers were able to develop an optimised noise reduction plan consistent with the current options for programming wind turbine operation. They were also able to contribute to the development of noise reduction options to reduce the intrusion perceived by some local residents. The results achieved following adoption of the noise reduction plan proved fully consistent with the results predicted by the simulations conducted by the acoustics engineers.

 

The comprehensive nature of this study has given Innergex a high level of control over the acoustic impact of its wind farm and has helped to improve the dialogue and relationship between the wind park and local residents. Based on these successful outcomes, Sixense has applied a similar methodology in a second Innergex wind farm.

 

We particularly appreciated the professionalism and responsiveness of Sixense, the reliability of the equipment used and the high quality of technical interaction at every stage of these acoustic studies, right through to the submission of reports
Vincent Remillon, Manager France Construction and Operation at Innergex

Measure the tension in the cable stays of the MOHAMMED VI bridge in Morocco

Using vibration to measure the tension in the cable stays of the MOHAMMED VI bridge in Morocco

At 950 metres in length, the Mohammed VI bridge remains the largest cable-stayed bridge on the continent of Africa. For this type of bridge, cable-stay tension must be adjusted throughout the construction phase to balance the stresses in the bridge deck; in this case, the contractors used hydraulic jacks. Following completion, an additional series of tension measurements were required. Having commissioned the structure, the Chinese contractor Cover-Mbec appointed Sixense to conduct a campaign to measure the tension in each cable-stay using vibration techniques.

 

Traditionally, hydraulic jacks would be used to take these measurements which entails expensive resources and immobilizes significant sections of the structure for extended periods. The alternate vibration method utilized by Sixense measures the vibration frequency of cable-stays, which provides a direct relationship to their static tension. In practice, accelerometers are attached to the cable-stays and oscillated for a short period.

 

For this project, the only resources required to perform the vibration measurement were a single work cradle and vibration analysis kit. As a result, only one lane of traffic needed to be closed for the work to be carried out successfully. The tension in all 160 of the bridge’s cable-stays was measured this way, and the report delivered on time.

 

This is our largest cable-stay tension measurement campaign to date, and the local team was supported by just-in-time data analysis by colleagues in France. This allowed us to optimise the measurement report delivery lead time and meet the deadlines set by our customer”

Quentin Common, Project Manager at Sixense

équipes SIXENSE SHM sur le pont Mohamed VI au Maroc
Our monitoring teams at work on the Mohamed VI bridge in Morocco

 

Need to talk with an expert ? Contact us