• Transport and infrastructure

Monitoring water erosion on bridge foundations

Strainstall has opened up a rich new seam of potential work across the Indian subcontinent with a series of bridge-monitoring contracts for the Indian Railway Board (IRB).  

Work has begun on installing structural health monitoring systems on a series of river and sea bridges across India. These new contracts come as part of a recent push into the Indian market by Strainstall with a local Indian partner called Tranz Rail Solutions.

The IRB, which manages around 150,000 bridges, of which 50,000 are more than 100 years old, is keen to deploy scour safety systems on its river bridges to provide real-time alerts in the event of heavy rain or flooding. Scour is the primary cause of bridge failure around the world, occurring when strong currents remove and alter the river or sea bed around a bridge pier, potentially undermining bridge foundations, and destabilising and weakening the structure.

The first installation will be on India’s second longest rail bridge; a two kilometre structure which links the Pamban island in Tamil Nadu to the mainland’s rail network. A further three bridges in Assam, two in the Mumbai area and two north of Delhi are also planned to have Strainstall’s scour monitoring system installed.

The team is installing scour sensors on each bridge to monitor river or sea bed levels, then Smart Asset Management System (SAMS) software will be used to store, analyse and report the data. This will provide bridge managers with the information to be able to effectively target resources to the bridges deemed to be at greatest risk.

Damian Griffiths, regional monitoring solutions manager at Strainstall Malaysia says:

‘We are excited to be working so closely with such a large organisation which means our bridge monitoring systems will have a positive effect on the safety of so many passengers. 

‘There have been several recent bridge collapses in India which could have been prevented through real-time monitoring,’ explains Damian, adding, ‘we aim to demonstrate our effectiveness on these first projects in the hope that we can offer further bridge monitoring solutions on the Indian railway network in the future.’

The Strainstall team is bidding on several larger bridge monitoring and testing projects on the railway network in other parts of the country.

How Strainstall’s scour monitoring works

• A solar-powered autonomous real-time river bed depth monitoring system is installed on each bridge.
• A sensor uses sonar acoustic technology (a ‘ping’) to regularly measure the river bed depth on both upstream and downstream piers. 
• This information is processed by an integrated data logging system which uses high frequency wireless transmission to send information about the varying depth of each pier and 3G/4G data transmission to take the information to Strainstall’s cloud based server. 
• Data is channelled through a dedicated and specially configured SAMS web portal which gives the customer real-time information on river or seabed depth. 
• Data can be viewed in real-time, or can be analysed to determine long term trends in order to inform planned maintenance programmes. 
• Automated alerts are also sent when significant changes in river bed levels are detected, enabling rapid inspection and emergency repair if needed.

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