Infrastructure projects are increasingly using sophisticated digital technology to improve long-term asset management. Stephen Cousins examines the emerging technologies at the forefront of ‘smart infrastructure’.
Rapid urban migration means that, by 2030, roughly 5 billion people will live in cities worldwide. Concerns over the associated demands on utilities, water and transport infrastructure have resulted in a drive to “smartify” cities, by installing networks of sensors able to monitor and manage the performance of assets.
Embedding sensors into infrastructure such as bridges, tunnels, roads and utilities can give these assets the ability to sense, or even respond to, problems as they develop, directing their own maintenance to reduce downtime and provide greater operational efficiency.
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This nascent technology has incredible potential, says James Abdool, head of digital experience at infrastructure consultancy Arcadis: “In future there will be increased monitoring of assets like roads or bridges: using data from sensors makes maintenance more predictive and intelligent and less reactive. If you have the knowledge well ahead of time you can plan maintenance works for a time that causes least disruption.”
Through trial installations at four Crossrail sites, the Cambridge Centre for Smart Infrastructure and Construction (CCSI) has been experimenting with using fibre-optic sensors to monitor the health of concrete structures.
Fibre-optic sensors in cable were fixed into diaphragm wall reinforcement cages as they were lowered into deep trenches in the ground. The cables effectively act as a continuous strain gauge, able to measure microstrain over lengths of up to 10km.
Data from the sensors has provided completely new insights into the behaviour of shaft linings and retaining walls during construction, according to CCSI. The technology will continue to provide information on the performance of the structures throughout their design life.
Sensors on pavers can record details about the quality of the installation, from the materials to the weather conditions
A similar monitoring technology, using a “sensing skin” of metal paint connected to electrodes in concrete, has been developed by researchers from North Carolina State University and the University of Eastern Finland (see below).
Connecting sensors, or other devices, to a communications backbone, such as the internet, can enable real-time data analysis and intercommunication between previously siloed systems.
Internet of Things (IoT) networks typically incorporate groups of nodes that integrate sensing capabilities with wireless communication chips, data processing and a power supply. The technology offers significant benefits – particularly the speed of deployment due to the lack of cabling.
Tech giant Siemens has developed an IoT-based system that uses streetlight-mounted radar to detect when vehicles are parked illegally and automatically alert the authorities over the internet. The same technology, paired with a smartphone app, can tell drivers where parking spaces are available, even sensing the size of the gap to check it is big enough.
Other technologies promise to improve the efficiency of how cities are run. Dutch waste management firm Rova has implemented a platform that integrates IoT data, GPS data, smart devices and radio-frequency identification (RFID) tags to predict when waste bins are ready to be picked up. The software is able to calculate, in real time, the best possible route to drive through the city, resulting in a more efficient service and reduced CO2 emissions.
Sensor technologies are capable of producing vast amounts of data which, when combined and interrogated in different ways, can provide a greater understanding of infrastructure, opening up new options to streamline operation and maintenance.
A pioneer of the so-called “big data” approach is the Milton Keynes smart city testbed MK:Smart. Here the central MK Data Hub, created by the Open University and BT, collects and integrates data from energy, transport and water networks, along with weather and pollution data and crowd-sourced data from social media and mobile applications.
The analytics hub “mashes up” different data points and runs “use cases” to identify potential new applications. One application already developed is the Community Action Platform for Energy (CAPE), which combines satellite data and high-resolution satellite imagery, mapped against other sources, such as buildings’ energy performance certificates (EPCs), to identify properties that are thermally inefficient or those with the potential to generate solar energy.
Tarmac’s highways employees work with the firm’s bespoke data capture system
MK:Smart is also exploring the use of data from sensors that measure water saturation in soil for flood prevention or flood management.
Big data has not yet fully entered the highways sector’s lexicon, but there is great scope to embrace its principles, says Neil Pattinson, head of optimisation at Tarmac Contracting. “There is the possibility to collect and analyse data, not just on the condition and material composition of our roads, but also on the regular ‘interventions’ highways contractors make to the local and strategic road networks,” he explains.
“Traffic flow information can be drawn from satnav applications and even from sensors built into the road surface to add extra granularity.”
"In future there will be increased monitoring of assets like roads or bridges: using data from sensors makes maintenance more predictive and intelligent."
James Abdool, Arcadis
Tarmac has developed a bespoke process combining data capture and advanced analysis during its road surfacing projects. Sensors on paving and compaction equipment collect data on the laying process, including the quality of installation, materials used and ambient weather conditions. This is combined with GPS location data, and material and ticket data from its SAP business management system, to generate an electronic laying and compaction record for every load.
This dataset is uploaded to a system that gives clients real-time access to the laying and compaction record for each location and job. Analytical tools enable them to monitor and interrogate this data to inform their asset management plan.
“It’s an exciting and evolving development that can not only improve laying quality but, critically, help clients develop evidence-based asset management plans based on a detailed understanding of their roads,” says Pattinson.
If big data analysis and smart sensors are set to become the enablers of smart infrastructure then several barriers must first be overcome. “The technologies currently tend to come into play during the construction phase, but involving consultants earlier in design could help identify more applications for construction and operation,” says Arcadis’ Abdool. Many smart infrastructure technologies focus on new build, but retrofitting systems to existing assets is more sustainable and could help the sector evolve much faster.
In addition, the cost of smart communications such as fibre optics and wireless IoT nodes must come down if they are to become a viable alternative to traditional connectivity solutions. If these obstacles can be overcome, the smart city of the future might not be far away.
Smart skin protection
An innovative ‘sensing skin’ can monitor concrete defects in vital infrastructure such as nuclear power plants.
A smart “sensing skin” for concrete could one day be used as an early warning system to spot defects in vital infrastructure such as nuclear power plants and bridges.
Developed by a team of researchers at North Carolina State University and the University of Eastern Finland, the electrically conductive paint is applied over electrodes embedded in concrete around the perimeter of structures.
A computer monitors the skin’s conductivity when small currents are passed through pairs of electrodes, cycling through a number of possible electrode combinations. Any decrease in conductivity indicates the structure has been cracked or damaged.
Dr Mohammad Pour-Ghaz, an assistant professor of civil, construction and environmental engineering at North Carolina State and co-author of a paper describing the work, tells CM: “We ‘image’ the skin’s conductivity distribution – very similar to x-ray imaging, but instead of x-ray we use a very small electric current, in the order of a few micro to milliamps. When the cracks happen, the conductivity goes to zero and we can capture them. The method is called electrical impedance tomography (EIT).”
According to researchers, the sensing skin can be used for a range of structures, but the impetus for the work was to help ensure the integrity of critical infrastructure such as nuclear waste storage facilities. The idea is to identify problems early so they can be addressed before they deteriorate – allowing public safety measures to be implemented.
The paint could be applied to new or existing structures and incorporate any number of conductive materials, making it relatively inexpensive, say researchers. A set of algorithms have been developed to register damage and determine where it has occurred.
Plans are afoot to prove the lab-based technology will work on real-world structures, and a new multi-modal sensing technology is being developed.
“We are very excited about this research,” says Dr Pour-Ghaz. “We have received very good reviews for it and hoping to receive acceptance and publication in an international journal in the next couple of months.”
The company behind a smart paving tile that captures energy from footfall has added data functionality so it can track location and perform heat mapping.
Pavegen became a crowdfunding success story last year when it won more than £2m of investment, through the website Crowdcube, to develop its product, which has already been installed in around
100 projects worldwide.
The money was channelled into R&D to develop a more efficient tile, known as V3. The new design is triangular in shape, rather than square, and can capture up to 20 times more kinetic energy from footsteps than its predecessor. It also collects real-time data on factors such as heat, footfall traffic and energy.
The technology can connect to smartphones and allocate steps to consumer “accounts” so in the future businesses will be able to reward pedestrians for helping provide power, perhaps by giving money off purchases, or by donating to third world countries.
Pavegen’s founder, entrepreneur Laurence Kemball-Cook, tells CM: “We have a data and energy proposition we are really excited about. We can provide a granular look at how people move, which is really important for the smart city of the future, because every footstep has a unique ID.
“Link it to people’s smartphones – with their permission – and it gets really exciting because you can know who a person is and where and when they are going somewhere.”
Pavegen tiles have historically been used to provide power for lighting, and the new tile connects to a bespoke high-spec LED matrix, using 90% efficient drivers, to ensure footfall can be relied on as the only source of renewable energy.
One of the first installations of V3 will be at the Westfield shopping centre in Stratford, east London. Contracts are also in place for installations at Dupont Circle in Washington DC and Oxford Street in London, where 200 generators will be installed for clients including Transport for London.