Structural health monitoring of masonry structures

  • Application end date: 11th February 2018
  • Funding Availability: Funded PhD project (EU/UK students only)
  • Department: School of Civil Engineering and Surveying
  • PhD Supervisor: Dr Nikos Nanos, Dr Gareth Swift, Dr David Begg

Project code: TBC

Project description

Masonry arch structures are integral to the UK transport infrastructure, whether in the form of bridges carrying road or rail traffic, or historic masonry-lined tunnels, extensively used as part of the UK rail and road network. They are therefore assets that are essential for human life in terms of economy, mobility, environment and the integration and development of communities. In addition, these structures have significant heritage value, being in many cases well in excess of 100 years old. Although considered in general to be long-lived structures, due to significant changes in mechanical loading (eg. faster, larger vehicles) and time-dependent, degradation effects, there is now a real and significant concern over their long-term resilience. Two specific research areas have been identified as requiring urgent investigation:

· global structural capacity (ultimate limit state) and how this might be evaluated, and;

· quantitative assessment of the changing condition of the structure (structural health) under complex loading regimes (serviceability limit state).

This project aims to address the second of these issues, primarily, but will also contribute to the first. The proposed programme of research builds on previous experimental and numerical modelling work centred mainly on the behaviour of brick arches, but this will be extended now to consider tunnel lining behaviour.

In order to ensure a robust monitoring and maintenance mechanisms for these structure, it is essential that a quantitative assessment of the changing condition of masonry/brick structures is undertaken, however, such assessments are difficult, as assessing engineers generally only have access to the external surface of the structure. As such, assessment is usually based on visual observation, supplemented with measurements of change in geometry. The fundamental thesis to be explored in this research is whether such visual evidence provides any useful indicator of the changing internal condition of this complex soil-structure system and, whether this could be informed by additional targeted monitoring using external acoustic emissions (AE) sensors, and by Ground Penetrating Radar (GPR).

From an assessment point of view, it is essential that the engineer recognises when the structure has entered a state that may lead to failure and require some form of intervention (bridge/tunnel closure, remediation etc). Developing an understanding of the behaviour of masonry arch structures when loaded will ensure that the assessment identifies key indicators of critical changes in state. What this research programme will develop is a means by which these indicators can be identified in the first instance, with significantly reduced uncertainty, leading to more effective management decisions regarding maintenance and repair/replacement.

The intention is that the AE data will inform engineers of the changing internal condition of the arch barrel/tunnel lining system, whilst the GPR data will provide information relating to the changing condition of the wider soil-structure system (condition of fill materials, presence of voids (whether in the backfill, or the structure), migration of moisture etc).

AE monitoring data already exists for a series of full-scale tests, and this data will be used to develop a fundamental understanding of the relationship between the change in internal condition (what cannot be seen) of a masonry structure and the applied load. By understanding fully what the monitoring data tells us about the changing condition, we will be able to identify what needs to be monitored, how this could most effectively be done, and where monitoring could be focussed.

The proposed research programme has three strands:

 1. Laboratory scale experimental work to explore the application of acoustic emissions (AE) techniques to the changing condition of masonry units, using small-scale samples (e.g. triplets);

2. Analysis of existing full-scale experimental data including AE datasets (for background see Augustus-Nelson et al (2017), EP/I014357/1 and EP/I014489/1); and

3. Field application using full-scale ‘real’ arch structures

The first strand will be undertaken at the University using carefully prepared samples to explore issues such as crack initiation (CI), strain profiles across brick units and mortar joints, and distance between sensors and CI location; this latter issue is of critical concern as arch spans maybe large, and knowing where to locate sensors will be essential to success. The second strand requires the student to interrogate existing test data collected during a previous research programme and will attempt to gain insights into the potential use of AE on real structures. The final strand will utilise in part the findings from the first two strands, in conjunction with two ‘real’ arch structures located on the Isle of Wight (now abandoned bridges).

Supervisor profiles

Dr Nikos Nanos

Dr Gareth Swift

Dr David Begg

Admissions criteria

You’ll need a good first degree from an internationally recognised university (depending upon chosen course, minimum second class or equivalent) or a Master’s degree in an appropriate subject. Exceptionally, equivalent professional experience and/or qualifications will be considered. English language proficiency at a minimum of IELTS band 6.5 with no component score below 6.0.

Specific candidate requirements

This laboratory-based project would be suitable for a bioscience graduate e.g. biomedical science, biochemistry, pharmacology or similar.

Enquiries

Informal enquiries are encouraged and can be made to Dr Nikos Nanos at nikos.nanos@port.ac.uk (02392 842947) or Dr Gareth Swift at gareth.swift@port.ac.uk (02392 842280).

For administrative and admissions enquiries please contact tech-enquiries@port.ac.uk.

How to Apply

You can apply online at www.port.ac.uk/applyonline. You are required to create an account which gives you the flexibility to save the form, log out and return to it at any time convenient to you.

A link to the online application form and comprehensive guidance notes can be found at www.port.ac.uk/pgapply.

When applying, please quote project code: TBC.

Interview date: TBC

Start date: October 2018.

Funding notes

UK/EU students -  The fully-funded, full-time three-year studentship provides a stipend that is in line with that offered by Research Councils UK of £14,553 per annum.

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