Geologic follow ups of excavation works: the Pika solution

Whilst tunnelling using traditional method, the geologists usually carries out regular “manuals” cutting face mappings using a combination of field observation and pictures. But this method is not optimised as the pictures are not “at scale” and the images are often distorted and therefore, not representative of the actual geometry of the cutting face.

 

The new photogrammetric solution Pika allows a true and instant 3D reconstruction model of the tunnel faces. The geologist simply takes a few pictures of the tunnel face, then drops off the images on the Sixense Mapping BeMap online platform. A Few minutes later, an ortho-image, a 3D map, a point cloud and a mesh are all made available through beMap. All those files are a true representation of the reality, for both the geometry and the texture.

 

With Pika, the geologist therefore has access to:

  • The lithology and/or the mineralized veins, with real appearance, size and thicknesses
  • The location and the orientation of the fractures and cracks
  • The visualizations (2D and 3D) of all successive tunnel face, one after another
  • The exact measurement of size, distance and surfaces, of anything on the models

Precision, time saving, data storage, Pika facilitates geologic follow ups of excavation works.

 

Pika is a solution from Sixense Mapping.

 

More information : mapping@sixense-group.com & natacha.robert@sixense-group.com

 

Greetings from Sixense teams

All the Sixense teams wish you a happy new year! We would like to take this opportunity to thank our customers for their loyalty throughout the past year.

After an atypical year in 2020, we close this chapter on a positive note by sharing with you a quick report of the year, which was nevertheless rich in projects for Sixense.

Follow the highlights of 2020 in the video below from building to underground construction projects, power plant site, bridge digitalisation to the roof of a stadium in the USA.

For more information about Sixense challenges, come and follow throughout the year the projects and highlights of Sixense on our LinkedIn page.

 

Monitoring standards

Sixense takes part in writing international monitoring standards

A group of about ten European experts has been working since 2010 on writing international monitoring standards.

Sixense is involved in the project via Martin Beth, director of our Monitoring Division France, by representing France among monitoring specialists from all over Europe, in charge of elaborating European and worldwide standards (CEN and ISO).

Their aim is to help sharing best practices in monitoring, by coordinating and writing them collectively.

 

Our expert explains :

Each standard takes between 2 and 3 years work in average and we will prepare about ten of them in the following years. The basic standard on general rules was published in 2015, followed by the standards on extensometers, inclinometers, piezometers and pore pressure cells. Our group is currently working on standards for liquid level settlement sensors, strain gauges and load cells and will start working shortly on geodetic monitoring instruments (automatic theodolites for example).

Martin Beth, director of Monitoring Division France, Sixense

 

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.

Sixense Mapping’s partnership with Topcon Positioning Group for Africa

Sixense Mapping’s partnership with Topcon positioning Group to expand in africa          

 

As a reference in 3D digitisation of existing assets, Sixense Mapping signs today a partnership with Topcon positioning Group to develop their activity in Africa. The common ambition is to fulfil the needs for digital transformation in the African markets of construction, infrastructures, mines and agriculture.

 

As an international Group, Topcon is a reference in technologic solutions for constructions such as 3D guidance for jobsite machinery. Topcon is present in Africa through a dense network of reseller, ensuring a busy activity for clients, their projects and local jobsites.

 

Sixense Mapping just broaden its services offers on one hand, its acquisition solutions by drone, LiDAR on board helicopter or even Mobile Scan already carried out in France and Europe, and on the other hand its data management solutions for a better operational performance:

  • Change detection: remotely monitor engineered structures, natural areas (cliffs, vegetation…);
  • Exploitation follow up: surfacing project optimisation, monitoring of earthworks, monitoring of quarries & mines.

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.

 

 

Helimap has joined the Sixense Group

Helimap is specialised in precision helicopter-borne LIDAR mapping, with a solid international reputation. The Swiss company, based near Lausanne, established itself on the market thanks to its innovative LIDAR system, adapted to complex terrains and tailor-made applications.  

With the acquisition of Helimap, SIXENSE Group is strengthening its position in 3D capture and modelling technologies for existing assets, a strategic entry point into the digitisation of construction and infrastructure operations. As a result, SIXENSE is now a leading global player in 3D digitising technologies. 

New CIRIA guidelines on Earth Observation and InSAR technology in civil infrastructure

We are delighted to announce that a consortium led by Sixense and Imperial College London (with support from experts at Royal Holloway, Crossrail and Thames Tideway) has been selected to produce a CIRIA (Construction Industry Research and Information Association) guidance report on the application of ‘Earth Observation and InSAR technology in civil infrastructure’. This report will draw on the extensive experience of the consortium members and will detail current practices, illustrated with case study examples, and outline respective advantages and limitations of the various techniques to assist all users and, in particular, those involved in asset management and construction. A separate online database of case studies will also be developed in parallel by CIRIA to support the guidance document. We understand that this document will form an important review, of current practices and ongoing developments, to inform newcomers to Earth Observation as well as those already using such technologies.

Civil engineering and infrastructure (construction, maintenance and monitoring) are activities which demand high spatiotemporal accuracy, precision and detail of observations and measurements. Satellite borne remote sensing techniques are now able to produce data and information of a quality which satisfies such requirements. Yet there are few standards and regulations for best practice in the production and use of Earth Observation products. CIRIA has therefore recognised a need to inform stakeholders, to realise the full potential of Earth Observation techniques in both research and commercial operations; hence this guidance report will form a much needed and important step towards establishing the employment of Earth Observation techniques as a matter of ongoing best practice for asset management in all infrastructure projects.

 

The guidance document will be published in 2021. For more information, please contact satellite@https://www.sixense-group.com

2019 Soletanche Freyssinet Activity report

 

Check out our 2019 annual activity report in PDF here.

You can also discover the gloabl Soletanche Freyssinet’s 2019 annual report here.

Monitoring the Alaskan Way Viaduct end-of-life cycle

Providing risk management and control throughout the Alaskan Way Viaduct end-of-life cycle

Having suffered earthquake damage, Seattle’s Alaskan Way Viaduct was replaced by the State Route 99 Tunnel. To provide the level of risk control required to carry out this project safely, our local teams installed a total monitoring system for the full 3.2  kilometres of this tunnel beneath the city centre. Four years later, it was joined by another system to monitor demolition of the old viaduct.

 

Completed on 4 April 1953, the Alaskan Way Viaduct was an elevated double-deck section that carried the State Route 99 above Seattle city centre via the waterfront at Elliott Bay and the city industrial heartland.
The viaduct suffered minor damage in the 2001 Nisqually earthquake, and the following structural inspections persuaded the state and national governments to replace much of the structure with a tunnel beneath the heart of the city.
With a working diameter of 17.5 metres, the world’s largest tunnel boring machine began work on the new State Route 99 tunnel in 2013. The progress made by this super-machine beneath the main landmarks of the city, including Pioneer Square and the Pike Place market, demands an equally impressive risk management and mitigation system.

 

The highly urbanised environment of this project demanded some very special attention to detail, since existing buildings, engineered structures and utility networks were all exposed to the risks inherent in tunnel excavation.

 

Controlling these structural and geotechnical risks demanded a wide range of  monitoring solutions, including 37 Cyclops (automated monitoring total stations) installed on building roofs and walls, internal geotechnical instrumentation, underground measurement instruments, real-time monitoring managed directly from the TBM control room, and satellite radar interferometry measurements.

 

All the data gathered are centralised and managed using the BEYOND Monitoring decision-support platform. Special attention was paid to converting this data into ready-to-use information for individual project contributors. The scale and environment of this project make its monitoring program the most comprehensive ever implemented in the USA.

 

As an important member of the Alaskan Way Bored Tunnel team, Sixense has provided outstanding technical support, delivered innovative solutions to complex challenges and maintained an unwavering positive attitude.

David Sowers, Deputy Program Director at WSDOT (Washington State Department of Transportation)

 

Alaskan Way photo
The Alaskan Way Viaduct in Seattle, USA

SHM on the Rion-Antirion Bridge

The Rion-Antirion 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 Rion-Antirion 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 Rion-Antirion Bridge in Greece

COVID-19 Update

The world is facing a health crisis of unprecedented scale.

We have the responsibility to protect ourselves and collectively curb the spread of the Covid-19 virus.

Therefore, SIXENSE teams strictly observe the recommendations of public authorities. In all our activities, we apply the principle of precaution to guarantee the health and safety of our employees, our customers and our partners.

SIXENSE is a key player in construction services and infrastructure operations. SIXENSE teams work on infrastructures of strategic importance such as health, energy, personal safety, water, telecoms and transport.

Furthermore, SIXENSE is committed to serving its customers by providing crucial security services for their sites.  We want to reassure all our customers and partners that we are fully mobilized to maintain continuous service within the bounds of what is feasible given the constraints of the current situation.

Our 3 primary concerns / objectives in the countries where we operate are to:

  • Guarantee the necessary level of service on all projects required to maintain core infrastructure operations;
  • Protect our employees and participate in the collective effort to contain the Covid-19 pandemic;
  • Meet our customers and partners expectations by maintaining our services wherever possible.

Our teams remain mobilized to maintain activities. All staff who are able to work remotely have been placed on home office. Your usual contacts at SIXENSE remain available and ready to listen. In addition, we continue to engage in all daily actions necessary to ensure the proper advancement of our joint projects.

In response to the trust you have placed in us, rest assured of our total commitment and solidarity with you to overcome this extraordinary crisis impacting us all.

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

Development phase support for wind power projects

We have supported Nordex wind farm development projects since 2003 through our involvement in developing the noise component of the environmental impact assessment package for its projects. This long-term partnership has developed throughout our collaboration on more than 50 projects all over france. Now is a great opportunity to look back on this special relationship and the way we operate.

All wind farm projects in France must meet particularly strict regulatory criteria, including the environmental impact study that acts as the basis for consideration of all applications to operate a wind power generating facility. The study is required to demonstrate that the project can be integrated sensitively into its environment, and that the potential impacts of the future wind farm are both managed and controlled.

Noise pollution is a major element of such an impact study. France has some of the most restrictive regulations in the world, requiring wind power projects to comply with a noise emission criterion based on residual noise: the base noise level prior to construction of the project, as measured at the dwellings closest to the future wind farm. A predictive acoustic impact study is then prepared as the basis for estimating the emergence levels (the difference in noise levels with and without wind generators in operation) and providing local authorities and communities with guarantees that the project will comply fully with all applicable rules once it becomes operational.

As acoustic engineers, our priority is to provide an objective and robust study that will enable the wind farm developer to prepare its operating strategy and strike precisely the right balance between power generation and regulatory compliance.

A standard study therefore includes pre-construction residual noise level measurements taken over several weeks, which will serve as the current benchmark level. There then follows the use of a predictive model to forecast the level of noise generated by the future wind turbines. Operating scenarios prepared in consultation with Nordex on the basis of reducing turbine noise levels in different weather conditions are then studied to ensure that the project complies fully with all regulations.

As these projects have advanced, so we have been able to develop our techniques in a number of ways: examples include systematic preliminary visits to all study areas before beginning any campaign to measure the initial noise landscape. The purpose of such visits is to identify the most representative measurement locations and to agree arrangements with local residents before installing our sensors.

The relationship between Nordex and Sixense is much more of a partnership than simply a customer/supplier relationship. The long-term involvement of Sixense in our projects and its excellent understanding of wind farm noise gained from practical experience in the industry mean that Nordex can be certain that the acoustic studies it includes in the impact assessments for its development projects are both robust and comprehensive. The primary goal of the acoustic study is its acceptance by the regulatory authorities, and the feedback we have received from these authorities tells us that the studies produced by Sixense are appreciated not only for their technical and scientific content, but also for their clarity.

As a wind farm developer rather than an operator, it’s important that Nordex obtains the most reliable acoustic measurement results in order to estimate how wind farms should be operated to maximum advantage. So we have to anticipate the possible noise reduction measures to be applied prior to their commissioning. In practice, these noise emission reductions impact the generating output of the project. These issues are relevant, because it is important that the customer ultimately responsible for operating the wind farm has no nasty surprises as a result of underestimating the impacts of the project, at the same time as avoiding the pitfall of devaluing a project by overestimating the risks involved and recommending excessively stringent constraints that will negatively affect the forecast generating output.

From our prospective as a wind turbine manufacturer, the expertise and involvement of Sixense helps us to develop our wind turbines in ways that can take maximum advantage of the operating conditions recommended by Sixense. The issues around the specific impact of wind parks during the particularly sensitive evening period can now be effectively addressed by the wind turbines we produce. In return, our special expertise as a turbine and wind farm developer undoubtedly helps Sixense to continuously improve its knowledge of wind energy technology and related issues.

Quentin Crespel, Acoustics Expert at Nordex France SAS

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

 

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