MAINLINE Final Workshop

UIC, Paris, France 30 September 2014

Degradation monitoring: gaps and

opportunities

Ujjwal Bharadwaj

TWI Ltd

WP4 context within MAINLINE

10/1/2014

WP 2

Degradation models

WP 5

LCAT Whole Life Asset Management

WP 6 Dissemination

WP 7 Management WP 8 Scientific & Technical Coordination

WP 1

Life Extension

WP 3

Repl of obsolete infra

WP 4

Monitoring and Examination (M&E)

What did we seek to achieve?

• Investigate Monitoring and Examination (M&E)

techniques/ approaches as part of an integrated

asset life cycle management system

– Investigate the interface between M&E and the

degradation assessment models with a view to

improve compatibility

– Investigate the techniques themselves for cost

effectiveness and other criteria affecting their uptake

in practical situations

• Develop Case Study applications

M&E techniques review: scope of

work

10/1/2014

– Capture current experience and research on M&E

– 5 different assets covered: cuttings, metallic bridges,

tunnels, plain line, and retaining walls

– Pros and cons of different approaches in use in the

rail sector and other relevant sectors.

– Summary tables with selected Railway Assets and

corresponding applicable M&E

– D4.1 report

M&E techniques review D4.1 report

structure

10/1/2014

• 84 pages

• 9 Chapters

• 5 asset types included

• Example: bridges

• Summary tables

(Assets/M&E)

Data compatibility gaps and

solutions: scope of work done

10/1/2014

– Examine type of data captured from M&E techniques

– Identify and propose optimal solutions to address

gaps with regard to M&E and Degradation

Assessment models

– D4.2 Report

Data compatibility gaps and

solutions: D4.2 – report structure

10/1/2014

• 106 pages

• 9 Chapters

• 5 asset types

• Example: tunnels

• Summary tables

(M&E/DMs/Gaps/Solutions)

Data compatibility gaps and potential

solutions – example: tunnels

10/1/2014

Identified Gap Potential Solutions

Lack of consistent and

reliable inspection data

across Europe

Standardisation of the inspection assessment

through a commonly accepted framework

Lack of established

models for masonry

linings

Use of field inspection data to develop empirical

models; hybrid models

High cost of continuous

monitoring and

limitations of periodic

inspection.

Monitor specific input parameters and avoid

excess amount of data

Combining monitoring

data (quantitative) with

examination

information (qualitative)

Develop appropriate decision support tools to

combine all available information in an effective

way

Case Studies – overview

10/1/2014

– Perform validation exercise on a selection of

assets

– To provide evidence on how improved

monitoring and examination can support

asset management

– To quantify the benefits of optimum M&E

systems in order to promote their uptake

– D4.3 Report on the Case Studies

Case Studies: Selection

10/1/2014

• Factors considered:

- M&E technologies reviewed

- Potential solutions to interface gaps

- Degradation mechanisms and variables to be

measured

- Assessment of traditional approach

- Expected benefit over traditional technique (cost-

effectiveness, reliability etc.)

- Potential for Case Study development

Case Studies

10/1/2014

• 3 Case Studies selected

• Bridges:

• Åby bridge (Sweden)

• Retszilas bridge (Hungary)

• Earthworks:

• Sligo Line cutting (Ireland)

Case Study on Ắby Bridge

Structure Name: Åby Bridge (Sweden)

Description of structure:

Location: Åby river, Swedish Northern mainline Type: steel truss railway bridge Year of construction: 1957 Span: 33m Width: 5.5 In 2012 the bridge was replaced by a new steel beam bridge and the old bridge was placed beside the river. It was tested to failure to study its remaining load-carrying capacity in September 2013.

Location: Åby river, Swedish Northern mainline, 50 Km W of Pitea and 80km SW of Lulea, Sweden

Photos/drawings:

View of the bridge before and after testing

Traditional M&E approaches used historically:

- visual Inspection - hammer testing - dye penetration - full scale testing

Case Study on Ắby Bridge

New Approach tested:

Photographic strain monitoring system (fatigue measurement); strain gauges, deflection gauges, temperature sensors and accelerometers were mounted on the bridge for monitoring purposes.

Monitoring in service state

Critical Sections monitored:

- Longbeam/crossbeam - Welded connection - Longbeam/crossbeam under load point

Monitoring Ắby Bridge

Figures:

• (a)The setup for photometric measurements

• (b) Cables from sensors for measurements

• (c) Optical measurements of strains in the critical riveted connection

between transverse and longitudinal beam (Blanksvard et al, 2014)

(a) (b) (c)

Monitoring Ắby Bridge

Position of sensors for global measurements, description in the Table

Monitoring Ắby Bridge

Figures:

• (a) Measurements of the horizontal deflection due to loading

• (b) Measurements of deflection at mid span and strain

• (c) Measurements of settlements and rotation at support

(a) (b) (c)

Ắby Bridge - summary

• Photographic strain measurement system used on

identified hot spots to follow failure mechanism

• Results compared with traditional methods of

determining fatigue remaining life and with Finite

Element Modelling (FEM)

• Ắby Bridge demonstrates the use of optical sensors

and photographic strain monitoring to study points

with maximum damage and make measurements to

enable calibration of fatigue models

Case Study on Sligo Line Cutting

Structure Name: 101MP Sligo Line Cutting (SMARTRAIL Cutting test site)

Description of structure:

Soil type: Boulder clay (very cohesive) Cutting height: 10-11m Slope Angle: 45-50° Slope Vegetation – none Previous failure – Evidence of some minor rainfall induced failures present.

Location:

Location:

101MP Sligo Line North West Ireland

Sligo Line Cutting

Photos/drawings:

Test cutting site on the Sligo Line

Sligo Line Cutting: Aerial view

Sligo Line Cutting - Monitoring

Traditional M&E approaches used historically:

Dependent upon location –

In many areas of Europe no planned programme of inspections is used. Cuttings maintenance is done on a reactive basis.

In the UK the SSHI visual inspection sheet is used.

Direct investigations which for example include geotechnical or geophysical monitoring techniques to investigate earthworks are used mostly in the forensic examination of failure³. Outputs from monitoring instrumentation are not commonly used for deterioration modelling and maintenance planning purposes.

New Approach used:

SKMA visual examination carried out on and results compared with NR’s SSHI assessment.

MAINLINE Input parameters for Sligo Line Cutting

(visual inspection data from desk based study)

Risk Level

Low Medium High

SRV 1 2 3 4 5 6 7 8 9 10 11 12

Sligo Line Cutting SSHI assessment

Sligo Line Cutting: Results from

MAINLINE and SSHI

Index Value Comments

Slope Risk Value (SRV) 4.9 High Risk of Failure (General)

Soil Slop Hazard Index (SSHI)

11.2 High Risk of Earthflow Failure

Marginal Risk of Rotational/Translational/Washout Failure

Low risk of Burrowing Failure

Sligo Line Cutting: concluding

remarks

• The Case Study demonstrates the use of Monitoring

and Examination techniques for inputs to Network Rail’s SSHI (Soil Slope Hazard Index) and the

MAINLINE Algorithm model (Qualitative/ Semi

quantitative models)

• Confidence in models can be improved by comparing

results from same application

• It would be useful to compare results from other

approaches

Participants

• UIC- Link to a range of asset owners

• NR – Infrastructure Manager’s perspective

• SKM- Experience of providing support to integrity management activities

• LTU- Emerging Monitoring and Examination techniques

• MAV- Infrastructure Manager’s perspective

• DAMILL – Monitoring techniques

• TWI – Monitoring and Examination; Asset integrity management

10/1/2014

Thank you for your attention

Ujjwal Bharadwaj

Asset Integrity Management Team

Principal Project Leader

TWI Ltd, Cambridge

UK

ujjwal.bharadwaj@twi.co.uk