This document discusses the structural health monitoring system installed on the Barddhaman cable-stayed bridge in India. The system monitors cable forces using electromagnetic sensors installed on 6 cables subjected to maximum loads. Data is acquired and presented in real-time on a web-based interface, allowing monitoring of forces and issuing alarms if thresholds are exceeded. A load test was also conducted on the bridge to measure deflections at various loading stages and confirm the design performed as expected.

1. By
Rajesh Prasad, IRSE
Chief Project Manager (M) & Group General Manager
RVNL, Kolkata
07.102016 at IRICEN Pune
Bridge Structural Health Monitoring System
(BSHM) for live Monitoring of the Cable Forces
at Barddhaman ROB

2. SCOPE
• Why Bridge Structural Health Monitoring
(BSHM) required?
• How Bridge Structural Health Monitoring
(BSHM) function in this case?
• Methodology and Monitoring
• Output and Report generation

3. WHY BSHM?
• New concept and New Technology
• Health Assessment for change of load
pattern
• Condition Assessment with the passage of
time
• Life Extension Beyond Design life
• Experimental Verification of Design
Procedure/Criteria

4. BSHM Consists of :-
• Design, Installation, Commissioning of
BSHMS
• Operation, Maintenance, Data Recording,
Analysing and Reporting
• Sensors to measure environmental and
structural response factors (F&T).
• Signal acquisition solution, signal verification
and temperature adjustment, conversion of
signal to digital format etc.

5. 4 –LANE CABLE STAYED BRIDGE, BARDDHAMAN
(During Construction)

6. 4 –LANE CABLE STAYED BRIDGE, BARDDHAMAN
(After Construction)

7. 4 –LANE CABLE STAYED BRIDGE, BARDDHAMAN
(After Construction)

8.  RVNL Kolkata PIU is Implementing Agency
 M/s GPT-RANHILL(JV) are main Contractor
 M/s Freyssinet are specialized subcontractor
 M/s Consulting Engineering Services(India) Pvt. Ltd
(JACOB) are the DDC and PMC
 IIT Roorkee is the proof consultant
 Wind Tunnel Test Being Executed By CRRI
 STUP Consultant for Geometry Control
 Experts like Dr. Prem Krishna and Shri R.R.Jaruhar
 Railways and CRS for blocks and approval
AGENCIES INVOLVED

9.  Clear Span(ABT to ABT): 184.429m
 Main span length : 124.163 m
 Back span length : 64.265 m
 No of cable planes : 3
 Type of cable in main span : harp pattern
 No. of cables in main span : 9 per plane
 No. of cable per side span : 9 per plane
 Spacing between cables in main span : 12 m
 Spacing between the cables in side span : 6.881 m
 Height of centre pylon : 53.798 m
 Clearance above rail track: 6500mm
 Maximum height of road surface from rail track level:
7500MM
 (Road surface to bottommost part of superstructure =
1000mm)
BARDDHAMAN CABLE STAYED BRIDGE DETAILS

10. • Engineering Challenge confronted…
• Superstructure carries 7.5m carriageway and 1.5 m wide
footpath on each side.
• DECK Geometry:
Total Length of the Bridge : 188.431 m
CP1 to P1 (Steel composite deck) : 124.163 m
P1 to CP2 (RCC Deck) : 64.265 m
Number of Lanes in each Direction : 2
Cross Slope : 2 %
GEOMETRY OF THE CABLE STAY BRIDGE
Barddhaman yard is one of the busiest yard of Eastern Railway and
Rajdhani route over Barddhaman station spanning across 8 platforms and
10 tracks.

11. Cable Stayed Bridge Construction at Barddhaman

12. Online Video link :
https://www.youtube.com/watch?v=aApXrEmwq5U
Cable Stayed Bridge Construction at Barddhaman
Handbook cum Coffee Table Book titled Staying
with Cables - A modern construction in new era
is at:
http://www.slideshare.net/slideshow/embed_code/key/

13. • LARSA 4D model for design
• Wind tunnel test
• Use of precast RCC slabs to avoid scaffolding on deck
• Composite structures for easier construction
• Monolithic Back Span
• Durable painting by epoxy based paint of Akzonobel
• Erection scheme
• LUSAS model for Construction Stage Analysis
• Geometry Control during execution.
• ROBO Control (Monitoring System) by M/s Mageba
FEATURES

14. • For monitoring of the structural health of the bridge during its service
life, 6 nos. of sensors have been installed on the stay cables
subjected to maximum loads.
• The structural monitoring system issues alarm notification based on
measurements by the on-structure instrumentation when pre-
defined threshold values of structural loads are passed. Alarm criteria
can be configured based on the structural design of the bridge
MONITORING SYSTEM (ROBO-CONTROL)

15. • Long term monitoring system.
• Measurement of forces on stay cables.
• Compact Monitoring System.
• System sustenance to extreme conditions.
• Graphical data output in web interface
with redundant data storage.
MAJOR COMPONENTS OF THE MONITORING SYSTEM

16. DESIGN
The sensors are placed to measure the various physical
performance parameters with the following general requirements
Solution was designed for bridge monitoring application and all
components is of such design as to sustain severe environmental
conditions and stand for several years of operation.
Hardware and sensors are available on open markets.
Alternatively any proprietary components is replaceable with
components available on open markets with reasonable
modifications to the overall configuration.
Software operating system is based on Windows.
Software application packages is an open source or code
available based programs in case vendor unavailability to support
the solution at any time in the future

17. DESIGN
 User interface is very easy to operate and very much user
friendly.
 User interface is Standard Web Browser based to ensure
compatibility to any future operating environment.
 Bridge Structural Health Monitoring System (BSHMS) is
designed to sustain partial damage and the undamaged parts
remain operational and not lose real time and stored data.
 Manual has been made in electronic format (PDF) and paper
copy.
 Mageba has on-line auto diagnostic, trouble shooting and
support services for hardware and software.
 Archived data has on-line controlled access.

18. SENSOR SCHEME
6(six) Nos. of sensors have been provided on the central pylon and
extreme cables to monitor the forces on these critical cables which are
subjected to maximum load. (10% of the total Cables need to be
instrumented)

19. Sensors Used
SENSOR SCHEME
Electromagnetic Sensors

20. FUNCTIONAL PRINCIPAL
Electromagnetic measures magnetolastic characteristics (magnetic flux) of
the ferromagnetic materials which are in relation with the mechanical
stress. Accuracy: + 0.5%
(Comparator)

21. Data Acquisition Unit
DATA ACQUISITION SYSTEM

22. Key Features
•Lockable Box
•Compact Design
•Redundant Data Storage
•PC Based System
CONSOLE USED

23. Monitoring Cockpit -Monitoring Cockpit -
All measured dataAll measured data
presented in real timepresented in real time
Min / Max Values
System overview
Actual values of each sensor
Alarm values
DATA PRESENTATION IN WEB FORMAT

24. INDIVIDUAL GRAPHS

25. CABLE SCHEME

26. CABLE SCHEME

27. CABLE SCHEME

28. • Placed inside
protected box
• Round the clock
running
• Data redundancy
• Internet connection
required
• Uninterrupted power
supply required
SYSTEM INSIDE THE PYLON

29. Sensor tied up on the required strand Sensor on strand inside the AV tube
INSTALLATION
Onsite calibration Cabling left inside for future connections

30. Installation of strands & Stressing
 Freyssinet’s Parallel Strand System (PSS) stay cables - which
has a design life of 100 years and is the most advanced
and durable stay cable system in the world today. There
are 3 planes of stay cables with 18 cables each. Vibration
control dampers have been installed in long stay cables (>
80m) as per CIP recommendations. Sensors for permanent
monitoring of forces during service condition, have also been
installed in 6 stays subjected to heavy loads. An inspection
and maintenance manual for the stay cables has been
prepared. 15.7mm 7 wire strand. Erected and tensioned
individually, easier to inspect, repair, replace.
 Isotension® Method

31. PARALLEL STRAND SYSTEM
High Fatigue
Resistant Wedges

32. CORROSION PROTECION

33. Cable
No.
No. strands Pop up cable
force
(kN)
After
wearing
course
(kN)
Maximum
Cable force
(kN)
Minimum
Cable
force
(kN)
Maximum
per strand
force
(kN)
Minimum
per strand
force
(kN)
7001 73 3854 3974 5642 2438
77.285
33.399
7002 73 6102 6575 8245 5272
112.949
72.221
7003 73 5898 6561 7989 5089
109.437
69.714
7016 73 6993 7438 8542 6203
117.015
84.975
7017 85 6162 6314 7753 4332
91.214
50.967
7018 85 5601 5736 6992 3544
82.257
41.697
Cable Threshold Values
Derived from Larsa 4 D Model

34. LOAD TEST
Cable
No.
Observed Value Reference range
Reading during
load test on
30.08.2016 (KN)
Lower limit
(KN)
Upper limit
(KN)
7001 55.7 33.39 77.28
7002 89.4 72.22 112.95
7003 75.4 69.71 109.44
7016 99.8 84.97 117.01
7017 78.1 50.99 91.21
7018 75.8 41.70 82.26

35. LIVE MONITORING
Cable
No.
Observed Value Reference range
Reading on
06.10.2016 (KN)
Lower limit
(KN)
Upper limit
(KN)
7001 56.1 33.39 77.28
7002 84.7 72.22 112.95
7003 73.5 69.71 109.44
7016 96.6 84.97 117.01
7017 74.0 50.99 91.21
7018 68.6 41.70 82.26

36. Main benefits of Structural
Health Monitoring:
• Design Confirmation.
• Safety of the structure.
• Understanding behaviour
of structures at certain
environmental
conditions.
• Load Validation
CONCLUSION

37. THANK YOUTHANK YOU

41.  It was done at the location where maximum stresses in bridge girder
assumed
 Loading on footpath for live load @300 kg/sqm
 Test load of 160 MT was given for Vehicular Live Load on both the carriage
way
 Vehicular live load is increased and decreased in four stages i.e. at 50%, 75%,
90% & 100% of test load
 Initial survey to measure deflection was carried out at pre-determined
location as marked on deck/girder before loading.
 After loading on foot path (live load) survey was carried out and deflection
are measured
 Incremental loading of vehicular live load was carried out as per stages as
mentioned above.
FEATURES OF LOAD TEST
LOAD TEST WAS CARRIED OUT IN MAIN SPAN AT CH. 12.163 TO
25.563M AS PER IRC:SP:51.
Loading on Bridge Deck conducted in following sequences :

42. FEATURES OF LOAD TEST
 Deflection are measured after stabilization of the load applied,
normally after one hour period
 The final load maintained for 24 hours and hourly reading of
deflection was recorded with full load
 Unloading was carried out at two stages: (1) vehicular live load and
(2) footpath live load.
 The removal of vehicular live load has been done at the same
sequences as adopted during loading
 Reading of Deflection was taken at the end of every sequential stages
 Net deflection was recorded after removal of full load and the same
was compared with original profile (before loading) of the deck
 It is found that after unloading of entire loads, the recovery of
structure deflection is above 90% (as per guideline mentioned in
IRC:SP:51, Cl. 6.8.2 for steel composite structure minimum recovery
shall be 75%)

43. VEHICULAR LIVE LOAD IN CARRIAGEWAY
Axle No.
Dimension of supporting block
Block Load on
Each (Tonne)
B (mm) W (mm)
1 265 860
27.2
2 265 860
3 265 860
27.2
4 265 860
5 265 860
19.2
6 265 860
7 265 860 6.4

44. SKETCH OF SURVEY POINTS

45. SKETCH OF LOADING POINTS

46. Instrument Used : Automatic Level
Description Date
Time
(Hrs)
Ambient
Temp (o
C)
Reading at Survey Point (Reduced Level)
A B C D E F G H I J K L
Location (Chainage in m): 12.163 (A) 12.163 (C) 12.163 (H) 16.163 (A) 16.163 (C) 16.163 (H) 58.163 (A) 58.163 (C) 58.163 (H) 94.163 (A) 94.163 (C) 94.163 (H)
Reading initial 20.08.16 16.00 30.0 39.555 40.112 39.530 39.588 40.149 39.573 39.935 40.378 39.895 39.804 40.315 39.780
After loading on Foot
Path (both Side)
25.08.16 11.00 32.0 39.540 40.093 39.512 39.567 40.127 39.550 39.909 40.354 39.868 39.796 40.308 39.773
Reading during Loading : Reading taken after 1 hour of loading (After Stabilization)
After 50% loading 29.08.16 12.10 38.5 39.513 40.065 39.487 39.536 40.092 39.518 39.890 40.337 39.849 39.791 40.306 39.766
After 75% loading 30.08.16 8.00 32.0 39.515 40.060 39.488 39.538 40.085 39.519 39.907 40.347 39.864 39.800 40.309 39.774
After 90% loading 30.08.16 13.20 38.0 39.500 40.049 39.474 39.519 40.071 39.503 39.883 40.329 39.841 39.791 40.304 39.767
After 100% loading 30.08.16 18.20 30.0 39.501 40.048 39.478 39.52 40.072 39.508 39.897 40.338 39.857 39.797 40.308 39.772

47. Description Date
Time
(Hrs)
Ambient
Temp (o
C)
Reading at Survey Point (Reduced Level)
A B C D E F G H I J K L
Location (Chainage in m): 12.163 (A) 12.163 (C) 12.163 (H) 16.163 (A) 16.163 (C) 16.163 (H) 58.163 (A) 58.163 (C) 58.163 (H) 94.163 (A) 94.163 (C) 94.163 (H)
Reading during Unloading : Reading during Loading : Reading taken after 1 hour of Unloading (After Stabilization)
After 90% loading31.08.16 19.00 28.0 39.507 40.052 39.481 39.528 40.078 39.512 39.902 40.345 39.864 39.799 40.309 39.773
After 75% loading31.08.16 22.20 27.0 39.516 40.061 39.491 39.537 40.088 39.525 39.913 40.353 39.873 39.801 40.312 39.777
After 50% loading01.09.16 11.30 34.0 39.516 40.066 39.490 39.541 40.095 39.524 39.899 40.342 39.857 39.795 40.306 39.769
After 0% loading03.09.16 13.00 34.0 39.534 40.089 39.510 39.559 40.120 39.545 39.903 40.348 39.863 39.793 40.304 39.768
After unloading from
Foot Path (both side)
05.09.16 15.55 33.0 39.554 40.108 39.528 39.587 40.145 39.570 39.934 40.377 39.894 39.803 40.313 39.779
Difference between initial and after
100% Loading (Deflection measured)
(mm) (-) 54 (-) 64 (-) 52 (-) 68 (-) 77 (-) 65 (-) 38 (-) 40 (-) 38 (-) 7 (-) 7 (-) 8
Expected Deflection (By Designer) (mm) (-) 87 (-) 92 (-) 87 (-) 106 (-) 111 (-) 106 (-) 67 (-) 66 (-) 67 (-) 19 (-) 18 (-) 19

48. Sl. No. CHAINAGE
REF.
POINT
INITIAL
READING
OBSERVATION AFTER 50% LOADING OBSERVATION AFTER 75% LOADING OBSERVATION AFTER 90% LOADING
OBSERVATION AFTER 100%
LOADING
READING
DEFLECTION (IN MM)
READING
DEFLECTION (IN MM)
READING
DEFLECTION (IN MM)
READING
DEFLECTION (IN MM)
ACTUAL THEOR ACTUAL THEOR ACTUAL THEOR ACTUAL THEOR
1 12.163 A 39.555 39.513 42.0 33.0 39.515 40.0 49.0 39.500 55 59 39.554 1 0
2 12.163 B 40.112 40.065 47.0 36.0 40.060 52.0 54.0 40.049 63 64 40.108 4 0
3 12.163 C 39.530 39.487 43.0 33.0 39.488 42.0 49.0 39.474 56 59 39.528 2 0
4 16.163 D 39.588 39.536 52.0 39.0 39.538 50.0 59.0 39.519 69 71 39.587 1 0
5 16.163 E 40.149 40.092 57.0 43.0 40.085 64.0 65.0 40.071 78 78 40.145 4 0
6 16.163 F 39.573 39.518 55.0 39.0 39.519 54.0 59.0 39.503 70 71 39.570 3 0
7 58.163 G 39.935 39.890 45.0 16.0 39.907 28.0 23.0 39.883 52 28 39.934 1 0
8 58.163 H 40.378 40.337 41.0 16.0 40.347 31.0 24.0 40.329 49 29 40.377 1 0
9 58.163 I 39.895 39.849 46.0 16.0 39.864 31.0 23.0 39.841 54 28 39.894 1 0
10 94.163 J 39.804 39.791 13.0 3.0 39.800 4.0 4.0 39.791 13 5 39.803 1 0
11 94.163 K 40.315 40.306 9.0 3.0 40.309 6.0 4.0 40.304 11 5 40.313 2 0
12 94.163 L 39.780 39.766 14.0 3.0 39.774 6.0 4.0 39.767 13 5 39.779 1 0

49. • In order to reduce the effect of fatigue on the stay cables due to
oscillations induced by wind or other external phenomena, stay cables
of more than 80m length have been provided with Internal Radial
Dampers (IRD). 15 such dampers have been installed on the stays
• IRD is composed of three hydraulic pistons placed at 120° angle
around the cable. The inner end of the pistons is fixed with a pin joint
on a collar compacting the strand bundle. Their outer end is fixed with
pin joints to a metallic tube called the guide tube. The damper is fixed
rigidly to the guide tube.
• The available stroke for the transverse displacements is +/- 40mm.
INTERNAL RADIAL DAMPERS

50. Tension
Compression
CABLE STAYED BRIDGE
Basic Principle :- Pylon
Stay Cables

51. In Larsa 4D these construction stages are simulated so as
to get more realistic analysis. As cable elements have been
used which are nonlinear in nature, nonlinear analysis is
carried out at each stage. The initial structure has been
kept with a pre-camber such that after complete
construction, the deflection brings the structure to desired
finish level.
Fundamental period of vibration of the structure is
calculated by creating a 3D model of the structure and
carrying out its modal analysis in STAAD Pro V8i/ Midas
Civil/ Larsa4D.
DESIGN SIMULATION BY LARSA 4D
Transverse section showing components of Back Span (124.163m)
65mm WEARING COAT

52. Stage 16
•Max moment in Pylon. Utilization ratio
<1
Bending Moment diagram
Stage 16
•Max moment in Pylon. Utilization ratio
<1 Max. deflection is 208 mm (with lane
reduction it will become 166mm)
(Dead Load + SIDL) (Two Tracks of 70R wheeled)

53. Construction Stage Analysis using LUSAS model
• Analysis has been done using finite element analysis software LUSAS.
• Deck is modeled as grillage of longitudinal and transverse members.
• Deck is integral at P1 and CP2. At CP1 pin support with longitudinal
free movement is used representing the Guided PTFE bearings.
• At P1 and CP2, elastic spring supports representing the pile stiffness
are used.
• Load Cases : 67