This call for ideas closes on the 26th of February 2021. Members from Industry and Academia are invited to reply. Any submissions need only be at an initial outline stage. There is potential, although not guaranteed, for direct funding from Highways England for ideas with great promise, or at least strong backing from them when approaching other funding agencies.
Introduction
The Highways England Asset Management Transformation Programme is looking for improved and novel methods for assessing and continually monitoring the integrity of Post-Tensioned Bridges within their asset network.
The greatest threat to the integrity of the UKs existing road and rail bridge infrastructure is the corrosion of their steel elements. This corrosion affects steel bridges and concrete structures (reinforced with embedded tensioned or untensioned steel bars and wires) alike. Corrosion of embedded steel in concrete is usually caused by the ingress of water and oxygen to the steel surface, exacerbated by the presence of contaminants such as chlorides in the water and the gradual carbonation of the concrete due to the exposure to atmospheric CO2 which removes the passivating effect of the alkaline concrete which initially protects the steel.
Surface signs of corrosion, such as cracking, delamination and spalling of the concrete cover, are typically observable when corrosion is usually well advanced and the opportunity to prevent it has been missed. The design of these bridges includes many internal steel elements which generally means that there is no external warning-signs of failure; any critical defects being hidden within the structure and only detectable by invasive site-investigations leading to road closures and traffic restrictions. The corrosion damage may lead to reduced load-carrying capability, the need for repair and strengthening or, complete replacement of the bridge.
Key Research Questions
Highways England is therefore seeking suggestions for new research ideas with the potential to transform the way they detect and measure corrosion in steel structural elements buried in concrete. The aim is to make this a reliable and automated process such that data on corrosion of all buried steel elements in a bridge can be captured, stored and used to facilitate timely maintenance decisions. The intention therefore is to surface fresh ideas that are likely to necessitate new lines of research, rather than looking for incremental improvements to existing techniques. There is potential, although not guaranteed, for direct funding from Highways England for ideas with great promise, or at least strong backing from them when approaching other funding agencies. The call is not limited to UK institutions, and technologies from outside of traditional engineering circles would be most welcome if applicable and transferrable – indeed a primary goal of this call for ideas is to look outside of our usual ‘box’ and see what exists in other fields and institutions.
The key research questions for this project are:
1. Identifying if the conditions for corrosion exist and how severe they are:
-Look for visible signs of water ingress
-Identify high chloride levels in the concrete, carbonation of concrete near the reinforcement, acidic conditions via pH metres
-Identify areas of poor corrosion protection
2. Identifying if corrosion is actually occurring:
-Look for delamination, spalling or rust staining of concrete
-Use corrosion probes to identify electrical activity associated with corrosion
-Intrusive investigation to remove concrete to look at the embedded steel
-Acoustic emission monitoring – mainly to listen for wire and bar breaks
3. Identifying how much corrosion has occurred:
-Intrusive investigation to remove concrete to look at the embedded steel
-Use established scanning techniques, all of which have limited applicability e.g. X-ray
-Use less developed scanning techniques e.g. magnetic flux leakage
Successful ideas may involve: hyperspectral imaging of assets using remote sensing and drones; innovations involving digital-twin modelling; proven advanced and reliable long-life sensing devices; remote detection of water-ingress into voids; indirect geophysical and geochemical detection and mapping of chloride corrosion; methods of exploiting large real time datasets.
Submissions
Please use the online form for submissions: https://bit.ly/2YeB8cr by the 26th of February 2021. Further details are available in the Highways England Call Document. Responses will be reviewed by a Highways England panel led by Vlad Palan and Chris Hendy.
If you have any questions related directly to this call please contact Dr Chris Mundell at: chris.mundell@atkinsglobal.com
If you would like any further information from the Institute on this please email the Hon. Secretary (Andrew Dobrzanski) at: ad2021@cam.ac.uk
When submitting ideas the Institute would appreciate you mentioning our involvement with this. If your idea is successful then please do get in touch with us to let us know. The Institute would be interested in setting up a Civil Engineering working group to be able to impartially respond to future research calls of this nature, please contact Andrew Dobrzanski(ad2021@cam.ac.uk) if you are interested in taking part in this.
Call Documents and Further Resources:
Highways England – Call for Research Ideas for Post-Tensioned Bridge Management
Highways England – Asset Management Working Group Post-Tensioned Structures Presentation
Post-Tensioned Structures Literature Review
Summary of Current Methods of Assessing the Integrity of Post-tensioned Bridges (C Mundell, Consultancy Report)
