mainline final workshop · ujjwal bharadwaj twi ltd . wp4 context within mainline 10/1/2014 wp 2...
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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