Challenge

The Thames Tideway Tunnel will provide capture, storage and movement of almost all the sewage and rainwater discharges that currently overflow into the river Thames from central London. The Rotherhithe Tunnel sits in close proximity to the Tideway East shaft site.

CVB (Costain, VINCI Construction Grands Projets and Bachy Soletanche), along with Sixense as their appointed monitoring contractor, required a monitoring system 12 months ahead of impacting works, to provide a sufficient period of baseline monitoring and continuing until any movements associated with the works have ceased.

Access was only allowed during night-time engineering closures that took take place once per week. Another challenge was that the majority of the tunnel lining is tiled and is very delicate and as such, TfL were reluctant to allow fixings into it. Every two weeks a machine, which combines a spinning brush and high pressure hot water jet, runs through the tunnel in order to clean this tunnel lining. Therefore, any system had to be robust enough to survive the twice monthly tunnel cleaning.

Challenge

The Blyth Offshore Demonstrator Project is an ambitious project delivered by EDF Energy Renewables, showcasing groundbreaking and experimental construction techniques. It consists of 5 wind turbines with a combined generation capacity of 41.5MW, enough low carbon energy to power 34,000 homes, whilst cutting annual CO2 emissions by 57,600 tonnes.

The turbines make use of a concrete Gravity Based Foundation (GBF) for support, which were constructed by BAM using a technique called Float & Submerge, where they were constructed on land, floated down a river and submerged to the sea floor.

BAM performed inclination tests to define the exact centre of buoyancy for the GBFs to confirm the stability during tow and installation. A reliable inclination system was needed to demonstrate that they were as stable as the design had predicted they would be during the towing and final submersion. Based upon other successful deployments for BAM, and a reputation for being world leaders in wireless remote condition monitoring, Senceive was asked to provide a solution.

Solution

Two high precision triaxial tilt nodes were positioned around steel platforms on top of each of the GBF’s steel shafted masts, complete with waterproof straight antennae. Senceive’s patented magnetic mounting system allowed the tilt nodes to be quickly installed in any orientation, with each unit having a magnetic pull force of 100Kgs. The BAM team responsible for monitoring the GBFs asked for the two triaxial tilt nodes to be installed at a right angle to each other, which served two purposes: To provide redundancy in the unlikely event of failure or node disturbance and corroboration of the readings.

The nodes were all set to an initial reporting rate of 1 minute for the dry dock testing period (increased to 1 second later on) and trigger levels were preset to alert users via SMS text message. Data was then relayed through each mast’s own Solar 3G Gateway and wirelessly communicated through the FlatMesh network to the Senceive WebMonitor visualisation software, which can be accessed by registered users on any tablet, smart phone or computer worldwide.

Outcome

BAM needed to demonstrate that the built GBFs were as stable as the design had predicted it would be during the towing and final submersion, so monitoring was extended a further month and BAM also requested that the reporting rate be increased to a real-time level of 1 Hz.

The innovative Float & Submerge method used proved highly successful with the only movement shown in the dynamic data being that of the tides. The system had the advantage of swift easy installation and proved its reputation for robustness and reliability in harsh and challenging environments.

Challenge

June 2018 marked the start of an exciting redevelopment of the prestigious Royal College of Music (RCM) campus, which was first opened in 1882. The large courtyard will be dug out and a new basement and building is planned to go in its place.

Due to the total mass of the building and the depth required to excavate a basement, substantial shoring equipment was required to protect the existing building and ensure the safety of site workers from potential collapse.

Groundforce Shorco’s, one of the world’s leading supplier of trenching and shoring equipment, provided their MP150 and MP250 hydraulic struts which weighed five tonnes. The two MP150 struts and one MP250 strut had load pins which required monitoring to ensure that the correct hydraulic force was exerted to counter balance the pressure from the surrounding soil.

Solution

Senceive provided three wireless Millivolt per Volt nodes, which allowed Load Sensors to be integrated into the FlatMesh™ platform. These, now wireless, sensors measure the pressure exerted on the struts’ load pins during building works.

Data from the nodes is received by a solar 3G gateway, which was mounted on a crane using standard Jubilee clips. The wireless nodes were mounted using our patented magnetic mounts in a matter of minutes.

Image courtesy of Groundforce Shorco

Challenge

Balfour Beatty on behalf of their client, Norfolk County Council, were contracted to construct £147 million, 20km of dual carriageway called the Norwich Northern Distributor Road (NNDR). This route went very close to Norwich International Airport and joined the Fakenham Road/A1067, north west of Norwich.

As part of the carriageway construction a large structure at Rackheath had to span Network Rail’s line regularly carrying passenger and freight trains between Norwich and Cromer. Due to the close proximity of the construction works to the rail, it was deemed necessary to carry out monitoring of the track bed to ensure no deformation was taking place.

Based upon several successful deployments elsewhere for Balfour Beatty and a pedigree in monitoring many other track bed environments for Network Rail, Senceive were approached to provide their high precision wireless tilt sensors as a monitoring solution. The project started January 2016 and is expected to complete April 2018.

Solution

Senceive proposed monitoring the two rail tracks using 106 wireless triaxial tilt nodes split equally between both the UP line, where sleepers were made from steel, and DOWN line, where the sleepers are mostly made from wood with a few being concrete. The nodes were installed using sacrificial track bed mounting plates on the area of the sleeper immediately off the ballast shoulder, known as the cess, to measure cant and twist of the track bed.

The flat terrain provided ideal conditions for the FlatMesh™ system and data from the wireless mesh network was easily transmitted to two solar 3G gateways. The gateways then used the mobile GSM network to transmit data to a secure cloud server, which could then be viewed by registered users of Senceive’s WebMonitor software.

Movements were detected very early on during monitoring and triggered SMS messages at certain alert levels, which were preconfigured by the customer.

Challenge

In order to obtain reliable information about the structural health of important Italian rail infrastructure, ETS srl and Microgeo srl have been using wireless sensors for the monitoring of a multi span Masonry Arch Bridge located on the Roma – Formia railway line.

Retrofitting works were designed by ETS’ engineers, who proposed sewing cracks and reinforcing the entire surface of the barrels with a reinforced concrete shell joined to the existing masonry arches through connection steel bars. In order to obtain appropriate information about the efficacy and functionality of the retrofit design, a precise and reliable monitoring system was required. Due to the particular geometry and monitoring requirements, several methods of monitoring architecture were evaluated.

Over all other instrumental solutions, a wireless one was selected on a trial basis to assess a section of the bridge. This offered a high cost savings, allowed control of thresholds safe values of monitored parameters and provided alerts in case of excessive deformations or displacements.

Solution

Senceive proposed the monitoring using wireless triaxial tilt nodes, as well as Optical Displacement Sensors (ODS), mounted on 1000mm beams. ODS nodes were easily fitted to beams using swivel mounts, then beams were quickly installed using self-tapping screws. Initial deployment consisted of 8 tilt sensors, measuring the rotation and 2 ODS installed on the underside of the bridge, at 12 o’clock positions, measuring rotational movement as well as the change in distance to the ground.

The wireless mesh network, formed by these sensors then transferred data to a solar powered 3G gateway. It used the mobile cellular network to relay data to a secure cloud server, which can be viewed and analysed by registered users of Senceive’s WebMonitor software.

Outcome

Sensors were extremely precise and the accuracy of ODS distance measurements showed a repeatability of ±0.15mm which also detected the natural “breathing” of the bridge to sub-mm precision.

The scalability of the FlatMesh® system allows it to be expanded easily and it gives the client control of changing; reporting rates, text alert trigger levels and the option for real-time monitoring if necessary. With a battery life of up to 15 years, the nodes are completely autonomous and monitoring duration can be increased if required. Eliminating any kind of intervention or maintenance also reduces the risk to site workers. Precise and reliable data continues to be received 24/7 and is supported by Senceive’s dedicated customer support and technical team.