Evaluation and benchmarking of the SENSKIN system
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09/11/2017
Evaluation and benchmarking of
the SENSKIN system
Panagiotis Panetsos
Head of Inspection & Maintenance of Technical
Works
EGNATIA ODOS AE
Project co-funded
by the EU under H2020
1st SENSKIN Workshop, 8 Nov. 2017, Brussels
WP7 – Objectives and Major steps
• To field evaluate and benchmark the SENSKIN monitoring system and
integrated package on two actual and in service bridges in terms of:
▫ the technical performance of the SESNKIN sensoring system
▫ the operational performance of the SENSKIN sensoring system.
▫ the performance of the structural assessment tool.
(Results of the evaluation and benchmarking in this WP will provide
input to the final exploitation plan (D9.2).
Project co-funded
by the EU under H2020
KoM meeting, Athens, Greece
2
2-3/6/2015
1
09/11/2017
WP7 – Objectives and Major steps
The field evaluation and benchmarking of the SENSKIN monitoring system
and integrated package will be carried out in two actual bridges in terms of:
•the operational performance of the sensor/acquisition unit .
•The operational performance of the communication/data transmission
system. Its ability and robustness, its autonomy under catastrophic
conditions.
•The interpretability of the sensors’ data to support engineering assessment.
•The successfulness of the integrated structural assessment to detect the real
structural condition of the monitored bridge
•The predictability of the integrated LCCAnalysis module to predict the life
expectancy and the damage initiation of the monitored bridge.
Project co-funded
by the EU under H2020
KoM meeting, Athens, Greece
3
2-3/6/2015
WP7 – Major steps
In month no 36 (March 2018) the SENSKIN Monitoring system will be
installed in parts of the Bosporus 1 suspension bridge in Istanbul.
The SENSKIN sensors will be installed in combination with the
installation of a small array of conventional sensors in order to compare
the performance of these two types of sensors.
Based on the results, in month no 40 (July 2018) a refined version of the
monitoring system as part of the integrated SENSKIN package will be
installed in Egnatia G4 ravine bridge. This system will stay there indefinitely
in order to assess its predictive ability and life expectancy.
Project co-funded
by the EU under H2020
KoM meeting, Athens, Greece 2-3/6/2015
4
2
09/11/2017
WP7 – Field Evaluation Planning
1. Field Evaluation and Benchmarking in Turkey
5 SENSKIN and 5 conventional strain sensors is finally planned to be
installed on various positions on the bridge and directly compare the two
sensing systems at the bridge environment by a portable interrogation
system and conventional sensors that MGH will bring to the site.
Instead of a full pilot, the consortium will execute reference tests for the
sensing units, execute the connectivity tests (node-node and node-
gateway), networking topologies, other integration
aspects (with the DSS)
Project co-funded
by the EU under H2020
(a) General view (b) underview of the Bosphorous I suspension bridge in Istanbul, Turkey.
2. Field Evaluation and Benchmarking in Greece
Bridge
G4
The integrated package will be installed in the Egnatia Motorway ravine
bridge G4 at the west sector of Egnatia Motorway section, in Krystalopigi.
The bridge is built over a steep ravine.
There are three spans of steel beams and a concrete deck on top. The
spans are 54.75 m, 65.00 m and 68.00 m. The superstructure is supported
through circular elastomeric bearings on two centre concrete piers (70 m
Project co-funded
high) and on the abutments. The main bridge superstructure
by the EU underelements
H2020 are
steel beams while trusses provide transverse restrains to the beams.
3
09/11/2017
Launching of G4 bridge on its two central beams
(steel nose/steel beams and truss
traverses/preslabs)
Field Evaluation and Benchmarking in G4 ravine bridge in
Project co-funded
by the EU under H2020
Egnatia Motorway, Greece
Support of the launching steel nose at pier M2
Launching of the steel superstructure
Span arrangement : 54.75 m - 65.00 m - 68.00m Project co-funded
Reinforced concrete hollow piers, 70m high by the EU under H2020
4
09/11/2017
Construction info of G4 bridge
4 main steel beams continuous over the 2 piers
Precast preslabs as formworks for the concreting of the
deck slab
Final composite superstructure (steel main bridge
elements with a top r/c slab)
Project co-funded
by the EU under H2020
Long/typical cross section of G4 bridge
A1
A0 M1 M2
54,39 65,23 68,27
3,5
47,82
65,05
0,55
3,7
Project co-funded
by the EU under H2020
509/11/2017
A general view of the bridge high piers, built by reinforced concrete B35
Peak ground acceleration A=0,24g
Factor considering the vicinity of active seismic fault = 1,25
Maximum Spectral design acceleration =2,5* (0,6/2,5)*1,25*0,24~0,20g
Maximum Spectral design displacement =0,20*9,81/2,52~ 32cm
Seismic isolation of the deck by the use of hydraulic absorbers
View of the deck underside, built by Steel GradeProject
S355 .
co-funded
by the EU under H2020
Deck slab built by reinforced concrete B35
The superstructure is supported on the piers through
24 very thick elastomeric bearings, type 4 (anchored)
Hydraulic absorbers are installed under the end diaphragm beams
Project co-funded
by the EU under H2020
609/11/2017
Traffic moving load analysis of the G4 ravine bridge, by SAP
2000NL to define positions of sensors
Maximum M (A1M1 1st span) for extreme traffic loads
of the G4 ravine bridge, by SAP 2000NL
Project co-funded
by the EU under H2020
Minimum M for extreme traffic loads of the G4 ravine bridge(pier M1)
Final sensor arrangement for G4 bridge
60 orthogonal sensors
25cmx5cm
9 positions/sections for installation: Project co-funded
by the EU under H2020
7 on superstructure/ 2 on piers basement (TECNIC/EOAE)
709/11/2017
18 sensors in midspan locations (2, 4, 6)
2x3 sensors in midspan on 3 steel beams (bottom flange/ web)
6 sensors in supports on abutments A1, A4
Project co-funded
3 diagonal by the EU under H2020
sensors/abutment
12 sensors at the basement of r/c piers P1, P2
A1
A0 M1 M2
187,88
54,43 65,23 68,27
34,13
22,75
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P1 ( 4 sensors) P2 (8 sensors) at the basement
Project co-funded
by the EU under H2020
809/11/2017
24 sensors at 3 beams (2 external, 1 internal) at
their supports on piers P1, P2
Project co-funded
by the EU under H2020
WP7 Field test- Basic Evaluation Tasks
The following will be performed:
• Assessment of the validity of the orthogonal strain sensor
measurements will be accomplished through direct comparison
between the performance of these sensors
and collocated strain gauges to detect shear and tension/compression.
• Strain measurements from the monitored bridge will be transmitted to
the offices of EOAE, TECNIC, KGM, DNDI and MGH once a month
during the last six months of the project where it will be evaluated
according to accepted behaviour.
• Field test measurements of the wireless communication system will be
undertaken. For this, inter alia, while installing the sensors an
electrical signal which resembles an earthquake vibration will be
applied into the circuitry of the strain sensors and DUTH will study to
see how it has been transmitted.
• Assessment and evaluation of the reliability of the network
communications and availability of the data will be undertaken. A
number of test scenarios will be performed to cover the events of
communication failures of the nodes, as well as, the adProject
hocco-funded
and DTN
functionality. by the EU under H2020
909/11/2017
WP7 Field test- Basic Evaluation Tasks
To assess the structural models in the DSS, bridge structural assessment
will be performed from the offices of the end users using the programme
developed in WP5 and input from measurements of the monitored
bridge. The above at EOAE will continue indefinitely after the end of the
project.
In addition, EOAE from its premises will evaluate the Rehabilitation
Module in terms of trustworthiness, user friendliness and ease of
application (including whether it clashes with the agency’s procedures)
Moreover, a quantitative costs/benefit analysis of the
proposed package will be carried out by EOAE. This cost will include the
cost to buy the proposed package, including customisation and training
costs, the cost to install it, the cost to operate it and the cost to maintain
The benefits will include reduced inspection and maintenance costs,
reduced or deferred capital expenditure by increasing the operational
uptime of the bridge, increased safety, less disruption of traffic, and
decreased fuel consumption and CO2 emissions.
Project co-funded
by the EU under H2020
The outcome of the LCA and LCC of the rehabilitation solutions will be
included in the above cost/benefit analysis.
Testing /validation scenarios
Three operational scenarios are prepared and described herein such as to
represent basic requirements of motorway bridge operators, in our case EGNATIA
ODOS AE, regarding the long term monitoring of the evolution of the natural
mechanical properties of a characteristic ravine bridge and the short term
monitoring based assessment under both a static and a dynamic load test.
1st Scenario. Static monitoring based assessment of the traffic load carrying
capacity of the bridge, during a supplementary static load test
2nd Scenario. Bridge model calibration based on the strain monitoring data in combination
with the ambient vibration data, during a static/dynamic load test.
3rd Scenario. Long term monitoring based assessment of the life expectancy and the safety
under fatigue.
Project co-funded
by the EU under H2020
1009/11/2017
1st Scenario. Static monitoring based assessment of the traffic load carrying
capacity of the bridge, during a supplementary static proof load test
The application of defined traffic loads, here by the use of 45tons loaded trucks, on pre-
defined locations of the bridge deck to verify the load carrying capacity is a strong tool
for assessing the bridge of Egnatia motorway. The proposed type of proof load regards to
the investigation of serviceability limit states of the bridge
The static load effects will be measured by both the SENSKIN and the conventional
strain sensors.
1st scenario
RIGHT BRANCH
45 tons 5 axes pre-weighted loaded trucks will be installed for 4-6 hours in the mid
section of the intermediate – second span of the bridge, in two or more steps. In the first
12.76
step one truck and in the second step two trucks will be installed, such as their resultant
10.95
load to act eccentrically on the bridge deck section
5.82 5.13 1.25
LL ML EL
0.75 3.75 3.50 2.95
Project co-funded
by the EU under H2020
Cross-section of 1st scenario with one truck (first step) and two trucks (second step)
1.58 3.20 3.20 3.20 1.58
1st Scenario. Static monitoring based assessment of the traffic load carrying
capacity of the bridge, during a supplementary static proof load test
• During this test both SENSKIN and conventional sensors it is expected to measure strains of a
magnitude of hundreds of μstrain.
• A sampling frequency of 1Hz is adequate, to measure the effects from the load test which will
be static.
• The measured strains will be directly compared with:
• The strains predicted by a proper analytical 3dimensional structural bridge model under the
static loads of the load test
• The strains of the design serviceability limit states
• Although the SENSKIN can operate under extensively large strains, it is not expected these
sensors to perform under ultimate operation states, during the static load test steps,
described herein. Nonetheless, their linearity, accuracy, resolution under large strains is
expected to be properly checked.
• The temperature effect on the measurements of the SENSKIN sensors will be also well tested
under steady/stable load conditions.
Project co-funded
by the EU under H2020
1109/11/2017
2nd Scenario. Bridge model calibration based on the strain monitoring data in
combination with the ambient vibration data, during a static/dynamic load test.
The big advantage of the load test is that gives the necessary data to calibrate the
structural assessment and the life cycle prediction modules, as its strain output, from both
SENSKIN and conventional sensors, that will be used as the static/dynamic response
input for the accurate calibration of the structural static models of the bridge.
Therefore more representative models of the real structural conditions of the bridge, will
be based on measured strains under well-known static load conditions.
Ambient vibration time histories will be measured for 10 minutes before, during and after
the supplementary load test, in order to calibrate the dynamic model of the bridge and
investigate the dynamic changes in terms of the changes that will be detected on the
identified Eigen frequencies/periods, damping ratios and mode shapes
In the frame of the supplementary load test, before the installation and after the de-
installation of the loaded trucks on the bridge deck, a dynamic load test will be carried out
using the same trucks. Crossings with different velocities from one and two pre-weighted
5axles 45tons loaded trucks will be implemented.
The strain induced on the bridge superstructure by the fast crossing of a single and of two
45tons trucks, with various velocities, will be measured from both SENSKIN and
conventional strain gauge/sensors.
The ability of the SENSKIN sensors to measure the dynamic strain of the structural
elements of the bridge will be checked, by the sensors installed on the webs of the steel
beams of the steel superstructure. Project co-funded
by the EU under H2020
• 3rd Scenario. Long term monitoring based assessment of the life expectancy
and the safety under fatigue.
After the installation of the SENSKIN sensors and their corresponding
conventional sensors on the G4 bridge, a continuous monitoring will be
carried out up to the end of the research project. This continuous
monitoring will combine strain measurements affected by temperature
variations, induced by traffic loads, wind loads and other ambient loads.
This scenario will help to test SENSKIN sensor under log term monitoring
conditions. The nonlinearity constraints, the durability, strength and
adhesive bonding sufficiency in the long term reversible loading, the energy
consumption, the autonomy and the data acquisition long term operability
will be tested as well as the interpretation of the long term thermal effects.
Project co-funded
by the EU under H2020
1209/11/2017
THANK YOU! ANY QUESTIONS?
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Panagiotis Panetsos
Head of Inspection & Maintenance of
Technical Works
EGNATIA ODOS AE
Project co-funded
by the EU under H2020
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