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A Guide on Structural Health Monitoring (SHM)

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Humans have built large structures like dams, tunnels, skyscrapers, power plants etc. to make their life easier. Let’s discuss more on structural health monitoring, geotechnical instrumentation, and how it makes the world a safer place to live. – PowerPoint PPT presentation

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Title: A Guide on Structural Health Monitoring (SHM)


1
A Guide on
Structural Health Monitoring(SHM)
2
1
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
INTRODUCTION
2
7
WHAT IS MEANT BY STRUCTURAL HEALTH MONITORING?
STRUCTURAL HEALTH MONITORING OF TUNNELS
TABLE OF CONTENT
3
8
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
STRUCTURAL HEALTH MONITORING OF DAMS
4
9
ADVANTAGES OF STRUCTURAL HEALTH MONITORING
STRUCTURAL HEALTH MONITORING OF BUILDINGS
5
10
HOW DOES STRUCTURAL HEALTH MONITORING WORK?
STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
3
1
INTRODUCTION
With technological advancements in the field of
civil engineering and geotechnical engineering,
the magnificent structures like Burj Khalifa and
Gotthard Base Tunnel have been made
possible. Humans have built large structures
like dams, tunnels, skyscrapers, power plants
etc. to make their life easier. But even a minor
failure in these structures can cause loss of
property as well as human life. Hence, regular
structural health monitoring is a must. Let's
discuss more on structural health monitoring,
geotechnical instrumentation, and how it makes
the world a safer place to live.
4
2
WHAT IS MEANT BY STRUCTURAL HEALTH MONITORING?
Structural health monitoring is vital to avoid
sudden failures and accidents. Before proceeding
with any construction activity, it's necessary to
carry out the monitoring of the construction
site as well as the nearby assets.
5
2
WHAT IS MEANT BY STRUCTURAL HEALTH MONITORING?
Geotechnical instrumentation and monitoring
supply quantitative data on the struc- ture's
performance to aid in evaluating its safety and
detecting problems at an early
stage. Structures can fail due to several
reasons like design error, geological
instability, poor maintenance, deterioration of
construction material, etc. Structural health
monitoring is a process to keep an eye on all the
structures and generate early warnings to avoid
mishaps. Encardio-rite is geotechnical
instrumentation and monitoring company that
provides various monitoring services along with
state-of-the-art geotechnical instruments.
6
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
Site investigation Site investigation is crucial
before carrying out any construction activity.
7
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
It is important to check if the land is strong
enough to bear the structure. Apart from this,
it's essential to check for the safety of other
assets in the vicinity of the con- struction
land. Several geotechnical Instruments are used
to characterize and determine initial site
conditions. The most common parameters of
interest in a site investigation are pore
pressure, the permeability of the soil, slope
stability etc.
8
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
Design verification It's quite important to
verify the design of the structure. Improper
designing may lead to its failure.
9
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
Geotechnical instruments are used to verify
design assumptions. Instrumentation data from
the initial stage of a project may show the need
or provide the opportunity to modify the design
in later stages. For example, data obtained from
reinforcement bar strain meters installed by
Encar- dio-rite at Teesta Barrage in the left
embankment led the project authorities to revise
their estimates of the requirement of steel in
the right embankment.
10
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
Construction control Structural monitoring is
necessary to help the engineer in determining how
fast con- struction can proceed without adverse
effects on the foundation soil and construc-
tion materials used.
11
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
The instruments are installed to monitor the
effects of construction. For example, the
temperature rise in concrete due to the heat of
hydration was moni- tored at Sardar Sarovar Dam
on the Narmada River with Encardio-rites
temperature meters to determine the pouring
temperature of mass concrete. By mixing ice
flakes, the temperature of the concrete to be
poured was brought down to around 15C. This
resulted in the temperature of the setting
concrete not exceeding the critical 29C, as
specified and required by the Central Water and
Power Research Station (CWPRS), Pune.
12
3
WHY IS GEOTECHNICAL MONITORING IMPORTANT?
Safety Instruments can provide early warning of
impending failure.
Safety monitoring requires quick retrieval,
processing, and presentation of instrument data
so that analyses and decisions can be made
promptly. An effective action plan for
implementing corrective measures can then be
prepared.
13
4
ADVANTAGES OF STRUCTURAL HEALTH MONITORING
Structural health monitoring (SHM) is critical
because
  • It can provide early warning to the concerned
    authorities so that they can take actions well
    before any casualties.
  • It keeps a regular check on the health of
    structures so that sudden failures can be
    avoided.
  • It safeguards human life as well as the loss of
    property. It also protects the surrounding
    structures in the vicinity. It increases the
    life span of the structures.
  • It reduces the long-term and short-term costs
    related to structural maintenance. It monitors
    the performance for safety during the life of the
    structure.
  • It evaluates the effect of the operation of the
    structure on parameters like stress, strain,
    water, pressure, inclination, deflection and
    water seepage.
  • It compares the observed data with design
    assumptions.
  • It helps with the data to plan and schedule
    predictive and preventive maintenance programs
    for the structure.




14
4
ADVANTAGES OF STRUCTURAL HEALTH MONITORING
  • It provides data to determine the effects of
    natural calamities such as earthquake, flooding
    etc. on the structure.
  • Compilation of long-term and reliable data on the
    various elements of the plant especially
    foundations, anchoring systems and containment
    structures.


15
5
HOW DOES STRUCTURAL HEALTH MONITORING WORK?
Structural health monitoring requires several
geotechnical instruments installation. The
instruments like strain gauges, piezometers, tilt
meters, temperature sensors, pressure cells,
load cells etc. measure the crucial parameters
affecting the struc- tures. These instruments
are installed on dams, tunnels, nuclear power
plants, buildings, monuments to measure the
important parameters. The measured data is
logged in real-time through data loggers and
displayed via a PC/laptop/mobile device at any
remote location. The data loggers are capable of
generating early warnings such that the concerned
person can take actions accordingly.
16
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
There are numerous rail and road bridges built
across the globe. They are an essen- tial
component of transportation networks and, hence,
structural health monitoring of bridges is
crucial.
17
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Any damage or collapse of bridges due to their
deteriorating performance disrupts
transportation systems and may result in the loss
of life as well as property. The railway bridges
are well documented and have a laid down system
for checking and maintenance. Bridges must
function safely at all times. A large number of
bridges are quite old and not designed for the
heavier and faster-moving vehicular loads that
they are cur- rently subjected to.
18
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Online cloud-based web data monitoring
service Encardio-rite offers public cloud-based
online web data monitoring services for the
safety of existing rail and road bridges. The
heart of the online structural monitoring
instrumentation system is a web data monitoring
service (WDMS) offered by Encardio-rite. The
service forms an important part of the Bridge
Management System. It is a web-based
data-management and presentation tool for
retrieving data from the sensors through
Encardio-rite range of automatic data
loggers. WDMS consists of Drishti, data
management software that acts as a data
collection agent, a database server and a web
server hosted on a high-reliability server
computer.
19
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
The host computer periodically collects data from
the remote data logger over cell phone
networks. Users interact with the software using
their web-browser when connected to the
Internet. The only requirement is that the data
logger site is covered by a cell phone service
provider who can provide reliable GSM/GPRS
enabled cellular data connection
locally. Multiple authorized users at different
locations assigned with an individual password
are allowed to view any data or report from the
structure simultaneously. Graphs reports can
be viewed using popular web browsers like
Microsoft internet explorer or Mozilla Firefox
amongst others.
20
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Details like sensor identification tag, last
recorded sensor reading and values of pro-
grammed alert levels can be viewed on the first
page of the site that shows the loca- tion of
installation. If anyone of the alarm level
exceeds, the sensor location turns to a red
dot. Clicking the pop-up table brings up an
associated data window where the sensor data can
be seen either as a table or as a graph. Site
administrators can set alarm limits which are
generally considered as alert level and
action level. WDMS can also be programmed to
send SMS alert messages or e-mail to selected
users as soon as any sensor data crosses its
predefined alarm levels, either while going
above or going below the alarm level.
21
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Bridge Monitoring Instrumentation Scheme There
are two types of instrumentation schemes to
monitor the health of the bridges.
The figure above shows online web based
monitoring of surface parameters like tilt,
crack, load, strain, vibrations and subsurface
parameters like lateral movement, set- tlement
and piezometric pressure.
22
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
The above figure shows online web based
monitoring of lateral movement and settlement
using robotic total stations and prism targets.
23
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
The picture on the left is a typical installation
of a robotic total station installed to
automatically gather data from prism targets
installed on the structure of a bridge. The
picture in the middle is that of a mini prism
target. The figure on the right shows points at
which prism targets may be installed on a
typical bridge. More than one robotic total
station may be required for proper moni- toring
of a structure.
24
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Screenshots of some sample long term monitoring
data
The figure above shows structural crack
monitoring over a period of one year using
Encardio-rite Model EDJ-40V crack meter. Crack
opening is in blue and variation in temperature
is in red. The initial opening of the crack
gauge was set at 5.12 mm
25
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
The above image shows the structural tilt
monitoring of the bridge from September 12, 2015
to December 8, 2016 using Encardio-rite Model
EAN-92M biaxial tilt meter. Tilt variation in
the two directions is shown by the blue and black
lines. The maxi- mum change in tilt recording
during this period is 0.04 deg. The two
horizontal red lines at the top and bottom are
the alarm limits set at 0.1 deg. The red line
gives the temperature variation during this
period.
26
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
The above image shows monitoring of ground water
level along with daily rainfall for a period of
five years.
27
6
STRUCTURAL HEALTH MONITORING OF BRIDGES
Piezometric pressure is in blue and daily
rainfall is in purple. Maximum rainfall re-
corded on any day during this period is 157
mm. Ground water table variation during this
period has been between 34 and 43 m of water
column. Sensors used are Encardio-rite
piezometer Model EPP-30V and Rain Gauge model
ERG-200 tipping bucket type.
28
7
STRUCTURAL HEALTH MONITORING OF TUNNELS
Encardio-rite offers a comprehensive web-based
monitoring solution for the long-term safety
monitoring of tunnels.
29
7
STRUCTURAL HEALTH MONITORING OF TUNNELS
It manufactures a wide range of sensors which
have a proven track record for reli- ability and
long-term performance under harsh conditions. It
also offers advanced monitoring technologies such
as automatic 3D deformation monitoring using
ATS, laser scanning and aerial survey using
drones for keeping a tab on the structural
health of tunnels and appurtenant
structures. Structural monitoring solution for
tunnels WDMS Web-based Data Monitoring
Solution Web-based data monitoring solution for
any type of tunnel construction such as NATM,
TBM tunnelling, cut cover, micro-TBM/pipe
jacking, etc. essentially com- prises of the
following
30
7
STRUCTURAL HEALTH MONITORING OF TUNNELS
  • Model EAN-52M vertical in-place inclinometer
    system with several biaxial probes with SDI-12
    output mounted vertically in a borehole.
  • These are connected in a daisy chain manner with
    a single output cable for continuously
    monitoring sub-surface lateral movements.
  • Model EPP-30V vibrating wire piezometer with
    model ESVI-01-01 or ESVI-10VB SDI12 interface
    box for monitoring pore pressure variations.
  • Model EDS-70V vibrating wire type multiple point
    borehole extensometer (with ESVI-01-04 SDI-12
    interface box) for monitoring sub-surface
    settlement and lateral movement at specified
    depths.
  • Model EAN-92M-B or EAN-93M-B biaxial tilt meter
    with SDI-12 output mounted at one or more
    locations on the structures within the zone of
    influence to record changes in tilt.
  • Model EDJ-40V vibrating wire crack meter (with
    ESVI-01-01 SDI-12 interface box) for monitoring
    displacement/opening of existing cracks in
    structures within the zone of influence.





31
7
STRUCTURAL HEALTH MONITORING OF TUNNELS
  • Model ELC-30S/ELC-30SH resistive strain gage type
    centre hole load cell (with ES BI-10 SDI-12
    interface box) for monitoring tension in anchors
    and rock bolts.
  • Model ESC-30V vibrating wire shotcrete pressure
    cell or model EPS-30V vibrating wire concrete
    pressure cell (with ESVI-01-01 SDI-12 interface
    box) for monitoring radial and tangential stress
    in shotcrete lining or concrete pre-cast
    segments.
  • Model EDS-20V-E/EDS-20V-AW vibrating wire strain
    gauges (with ESVI-01-01 SDI12 interface box) for
    monitoring strains in tunnel linings and concrete
    pre-cast segments.
  • Model EBS-16 building settlement points for
    monitoring settlement of structures using a
    digital level.
  • Model ESMP-10C2 or EPS-12-60 surface settlement
    points for monitoring settlement of ground above
    the tunnel.
  • Encardio-rite Model EAN-26-MV manual inclinometer
    system comprising of a bi-axial digital
    inclinometer probe, operating cable on a reel
    with Bluetooth transceiver and a smartphone data
    logger with inclinometer application






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STRUCTURAL HEALTH MONITORING OF TUNNELS
  • These could be single multichannel. RF Gateways
    with integrated GSM/GPRS modem for enabling
    cable-free wireless transmission of data. Refer
    to the figure below showing installed sensors in
    a typical tunnel section with RF data
    transmission.
  • Encardio-rite Model ESDL-30 data logger for the
    SDI-12 output sensors, with integral GSM/GPRS
    for wireless data transmission.
  • Encardio-rite Online Web Data Monitoring Service
    (WDMS) that provides data access (with alarms)
    to authorized users at different geographical
    locations, on their computer/laptops.



33
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Laser Scanning Laser scanning is an advanced
method of surveying and conducting geometric doc-
umentation of buildings, architectural and
archaeological monuments, engineering projects
or other construction works and objects which
require a high degree of analysis, are difficult
to reach or gain access to, or are not to be
touched.
34
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Recent developments, especially in the software,
have made it a very convenient and
cost-effective tool to accurately monitor
structural deformations in 3D. Accuracy of up to
2-3 mm is possible using the method. Due to the
lighter nature of the new software, it takes
significantly lesser time to pro- cess the
results and make the same available online,
almost in real-time. It is based on
exceptionally dense mapping of 3D coordinates of
the points on the surface that is to be
surveyed, taken at speeds ranging from a few
thousand up to a million points per
second. Depending on the object (size, shape,
desired accuracy), laser scanning may be air-
borne or terrestrial, static or mobile,
autonomous or in combination with other stan-
dard topographic methods.
35
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Completion of the fieldwork results in a
geo-referenced point cloud which, due to its
great density and its ability to bear information
on the reflectivity and/or the colour of each
point, comes close to the term, virtual
reality. Depending on the case and on the
users needs, horizontal, vertical or diagonal
sec- tions, aspects, images, videos,
ortho-photographs, surface expansions, interval
curves, 3D models, determination of distortion as
well as a number of other analysis derived from
the scanners operations in the non-visible
spectrum, can be produced.
36
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STRUCTURAL HEALTH MONITORING OF TUNNELS
  • The results of laser scanning give us
  • Surveying of current state or as constructed
    state
  • Virtual reality creations Virtual tour videos
  • Geometric documentation of the structure
  • Quantitative calculation
  • Inspection of free passage space determination
    of bottlenecks
  • Creation of 2D 3D products (sections, facets,
    3D models, etc.)
  • Identification of deformations discrepancies

37
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Aerial Mapping using Unmanned Aerial Vehicles
(UAV/Drone) Inspection of huge and complex
structures like tunnel construction sites
requires a high degree of analysis but at times
is difficult to reach or gain access to.
Use of Unmanned Aerial Vehicles (UAV)/Drones is
best suited for such applications. UAVs/Drones
are unmanned and remotely-piloted aircraft that
follow a pre-pro- grammed path for takeoff,
flight and landing.
38
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STRUCTURAL HEALTH MONITORING OF TUNNELS
These aircraft are equipped with HD/IR/Thermal
cameras that compute aerial images and videos
over a defined area at a specified height. Using
UAVs/drones to video, model and scan for cracks,
erosion, corrosion and defects in areas, that
would otherwise require the inspector to use a
rope/harness or erect access scaffolding, is a
safer, faster and smarter choice. Large sites
with complex structures necessitate aerial
photogrammetry avoiding ex- pensive ground-based
surveys. This technology is useful during the
construction process also- as the development
occurs, managers have difficulty maintaining a
true picture of the site.
39
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Automatic 3D deformation monitoring system The
real-time 3D deformation monitoring system is a
systematic tracking of any al- teration that may
take place in the shape or dimension of the
tunnel as a result of stress, load, ageing etc.
or of any structure located within the zone of
influence of the tunnel construction.
The above deformation monitoring system consists
of a high accuracy automated total stations
(ATS) that have the ability of auto-target
recognition (without any human interference).
40
7
STRUCTURAL HEALTH MONITORING OF TUNNELS
Each ATS has a dedicated control box that
includes a computer running special
software. This control box manages the total
station and schedules the frequency of the
measurements, the addition or subtraction of
monitor benchmarks, the filters of acceptance or
repetition of each measurement, the atmospheric
corrections in distance measurements, the
calculation and repositioning of the total
station etc. The whole system can be
controlled/re-configured remotely after
installation at site. The on-site system
transmits the collected raw data to a remote
server/computer via GSM/GPRS. Raw data is
processed into meaningful results and presented
in the WDMS. The system has the facility of
alert notifications through SMS and (or) e-mail
to the authorized team for any result exceeding
present alarm and critical levels.
41
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STRUCTURAL HEALTH MONITORING OF TUNNELS
The system provides an accurate, continuous,
real-time data, eliminating any human
error/delay in manual data. The raw data is
processed, analysed and the result is majorly
used for predictive maintenance, alarming for
safety.
42
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STRUCTURAL HEALTH MONITORING OF TUNNELS
Tunnel Monitoring Instrumentation Scheme
43
8
STRUCTURAL HEALTH MONITORING OF DAMS
Dam monitoring instrumentation plays a key role
in safety monitoring for dam and people,
providing necessary information on the
performance of the dam and detect problems at an
early and preventable stage.
44
8
STRUCTURAL HEALTH MONITORING OF DAMS
The extent and nature of instrumentation depend
not only on the complexity of the dam and the
size of the reservoir but also on the potential
for loss of life and property downstream. This
information is critical for the dams owner who
is directly responsible for any consequences of
its failure. Instrumentation includes different
type of sensors used for measuring pore pres-
sure, water flow, lateral movement, deformation,
stress, strain and temperature, in- stalled in
the dam and its auxiliary structures. It also
includes geodetic targets measured using
surveying techniques.
45
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STRUCTURAL HEALTH MONITORING OF DAMS
Monitoring solutions for dam Following solutions
are available with Encardio-rite for online
monitoring
  • Geotechnical sensors to measure all relevant
    parameters required to monitor different types
    of dams
  • Automatic monitoring of geotechnical sensors with
    SDI-12 digital interface using SDI-12 data
    logger with GSM/GPRS telemetry
  • Automatic monitoring of geotechnical sensors
    using nodes and gateways Geodetic monitoring
    with automatic total stations (ATS) with GSM/GPRS
    telemetry Laser scanning
  • Survey by UAVs (unmanned aerial vehicle) or drones



46
8
STRUCTURAL HEALTH MONITORING OF DAMS
Public cloud-based web data management service
(WDMS) that provides data online (with alarms)
to authorised users at different locations on
their computers/mobile devices.
47
8
STRUCTURAL HEALTH MONITORING OF DAMS
Dam Monitoring Instrumentation Scheme Concrete
Dam
48
8
STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor pore pressure or seepage of water through the cross-section of the dam Pore pressure meter Dam blocks at different elevations
Monitor stresses in the concrete of the dam body Stress meter Near foundation where the height of the dam is maximum (can be just below the gallery)
Monitor pore pressure to adjust it from stress meter readings to get true stress Pore pressure meter Near stress meters
Monitor joint opening between the blocks Joint meter Uniaxial and triaxial Between the concrete blocks
Monitor tilt of the dam Tilt meter Dam block, at the top
Monitor deformation due to all causes including those due to stress Strain meter rosette In dam body in a group of five-four strain gages at angles of 0,45,90, 135 in one plane and one strain gage at right angles to this plane
49
8
STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor deformation due to changes in temperature, moisture or autogenous growth in the mass concrete of the structure. Adjusting this from strain meter readings gives strain due to stresses in the dams No-stress strain meter Near strain meter rosette -inside the no stress container
Monitor water level in the reservoir Automatic water level recorder The upstream side of the dam
Monitor temperature of concrete during the casting of the concrete blocks to prevent undesirable micro-cracks. Temperature variation is also one of the major factors causing stress on the surfa- ceof the dam that results in material fatigue Temperature meter Dam blocks and spillway
50
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STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor water pressure on the base of the dam caused due to water seepage from the reservoir to the foundation. This pres- sure exerts a vertical upward force on the base of the dam and tries to lift it up Uplift pressure meter In the dam Gallery downwards with a stop valve on the uplift pressure pipes, which is opened to release the water and reduce pressure on the base of the dam.
Monitor tilt of dam caused by thrust applied by water pressure on the dam Normal plumbline (telecoordinometer) Blocks
Monitor relative displacement between the dam bottom and the foundation base rock Inverted plumbline (telecoordinometer) In the same block as that of the Normal plumbline
Monitor lateral movement of the foundation Digital inclinometer or in-place inclinometer Dam foundation with top in cross or transverse gallery
51
8
STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor vertical displacement of the dam bottom in respect to the foundation base rock Borehole extensometer Dam foundation with the top assembly in cross or transverse gallery
Monitor amount of seepage through, around and under embankments Monitor 3D movements or deformations Seepage measurement device The downstream side of the dam In the same block as that of the Normal plumbline
Monitor lateral movement of the foundation Optical targets and robotic total stations with control box Dam surface
Monitoring of construction progress Monitoring and inspection of dams for maintenance Unmanned Aerial Vehicle (UAV) equipped with a high-performance camera or laser scanner Aerial
52
8
STRUCTURAL HEALTH MONITORING OF DAMS
Earth and rockfill dam and concrete faced
rockfill dam (CFRD) Typical instrumentation
scheme in an earth and rockfill dam section
53
8
STRUCTURAL HEALTH MONITORING OF DAMS
Typical instrumentation scheme in a concrete face
rockfill dam section
54
8
STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor pore pressure or seepage of water through the cross-section of the dam Pore pressure meter Dam body at different elevations.
Monitor compressive forces and stress Monitor lateral movement of the foundation Soil pressure meter Dam body at different elevation near foundation where the height of the dam is maximum (can be just below gallery)
Monitor pore pressure to adjust it from stress meter readings to get true stress Pore pressure meter Near soil pressure meters
Monitor lateral movement of the foundation Digital inclinometer or in-place inclinometer Across dam body from the base of the dam to the top
Monitor amount of settlement that occurs when a soil is loaded or dewatered Settlement cell and magnetic extensometer Across dam body from the base of the dam to the top
55
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STRUCTURAL HEALTH MONITORING OF DAMS
Purpose Instrument Location
Monitor water level in the reservoir Automatic water level recorder The upstream side of the dam
Monitor lateral movement along with the settlement Inclinometer-cum magnetic exten- someter Dam body, towards the downstream side, with top inaccessible area to take manual readings
Monitor soil or rock movement, lateral strains and settlement Soil extensometer Dam body from upstream side to down- stream side
Monitor soil or rock movement, lateral strains and settlement Soil extensometer Dam body from upstream side to down- stream side
Monitor amount of seepage through, around and under embankments Seepage measure- ment device The downstream side of the dam
Monitor strain in the concrete face Strain gages The concrete face of CFRD
56
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STRUCTURAL HEALTH MONITORING OF BUILDINGS
Encardio-rite offers online web-based monitoring
services for the following
  • Safety of existing multiple storey buildings,
    hotel complexes, corporate offices and buildings
    of critical importance
  • Safety of old and depleted buildings and
    structures subject to long-term movement or
    degradation of materials
  • Safety of buildings, monuments and structures
    during nearby construction activity (like the
    construction of Metros, deep excavation for high
    rise buildings etc.) Safety of monuments and
    structures of historical importance
  • Safety of buildings and structures in hills and
    landslide-prone areas




57
9
STRUCTURAL HEALTH MONITORING OF BUILDINGS
Structural monitoring solutions for
buildings/monuments For buildings, structures
and bridges etc., it is recommended that
Structural Health be continuously monitored to
ensure proper maintenance and safety of man and
material.
58
9
STRUCTURAL HEALTH MONITORING OF BUILDINGS
A basic system offered by Encardio-rite that can
be used for most structures essentially consists
of the following
  • Encardio-rite model EAN-92M-B biaxial tilt meter
    mounted at one or more locations on the
    structure. The tilt meter should ideally be
    installed at an indoor location or in shade to
    prevent effect of large temperature fluctuations
    on the monitored results. Readings should
    possible be retrieved in the morning hours when
    temperature induced stresses in the buildings
    are minimum.
  • Encardio-rite model ESDL-30 SDI-12 data logger
    with integral GSM/GPRS modem for storing and
    transmitting data to a server with the service
    provider.
  • Encardio-rite online web data monitoring service
    (WDMS)



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STRUCTURAL HEALTH MONITORING OF BUILDINGS
Some other instruments that may be used depending
upon the structure to be monitored and its
location are
  • Encardio-rite model EDJ-40V vibrating wire crack
    meter (with ESVI-01-01 SDI-12 interface box) to
    monitor structural cracks
  • Encardio-rite model EPP-30V vibrating wire
    piezometer (with ESVI-01-01 SDI-12 interface
    box) to monitor sub-surface water level
  • Encardio-rite model EAN-52MV vertical in-place
    inclinometer system with several biaxial probes
    (with integral SDI-12 protocol) mounted
    vertically in a borehole to monitor sub-surface
    lateral movements around the structure.
  • Instruments used for surface as well as
    sub-surface monitoring of structures are
    illustrated on next page.




Subsurface monitoring gives important information
on ground/soil movement which may affect the
stability of the structure.
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STRUCTURAL HEALTH MONITORING OF BUILDINGS
Reference guideline for building damage
classification
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10
STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
Encardio-rite offers online web-based monitoring
services for the long-term safety monitoring of
Nuclear Power Plants.
It has a wide range of sensors which have a
proven track record for reliability and
long-term performance under harsh conditions. It
also offers newer monitoring technologies such as
automatic 3D deformation monitoring using ATS,
laser scanning and aerial survey using drones for
keeping a tab on the structural health of
Nuclear Power Plants.
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STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
Structural monitoring solutions for
buildings/monuments For buildings, structures
and bridges etc., it is recommended that
Structural Health be continuously monitored to
ensure proper maintenance and safety of man and
material.
It is noteworthy that subsurface monitoring gives
important information on the ground/soil
movement which may affect the stability of the
plants structure.
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STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
  • Encardio-rite Model ELC-30S resistive strain gage
    type centre hole load cell (with ES BI-10 SDI-12
    interface box) for monitoring tension in
    restressing cables and ground anchors used for
    stabilizing the foundation.
  • Encardio-rite Model EDS-11V hermetically sealed
    vibrating wire strain gage or Model EDS-21V
    extended range vibrating wire strain gage (with
    ESVI-01-01 SDI-12 interface box) embedded in the
    walls and the base slab of the plants structure
    to monitor change in strains. Stress can be
    derived from the strain data.
  • Encardio-rite Model ETT-10V vibrating wire
    temperature sensor (with ESVI-01-01 SDI-12
    interface box) embedded in the walls and the base
    slab plants structure to monitor the
    temperature.
  • Encardio-rite Model EGS-30V settlement
    measurement system (with ESVI-01-01 interface
    box) to monitor settlements occurring in the base
    slab.
  • Encardio-rite Model EDS-70V electrical multipoint
    borehole extensometer system with vibrating wire
    displacement transducers (with ESVI-01-01 SDI-12
    interface box) for monitoring relative vertical
    movements





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STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
  • Encardio-rite Model EDS-50 normal plumb line with
    telecoordinometer (with ESDI-420I SDI-12
    interface box) to monitor relative horizontal
    movements.
  • Encardio-rite model ERT-20P2 mini prism target to
    be installed on the fascia of the structure to
    monitor 3D deformations using an automated total
    station (ATS).


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STRUCTURAL HEALTH MONITORING OF NUCLEAR POWER
PLANTS
The following sensors may also be considered for
structural health monitoring
  • Encardio-rite Model ESDL-30MT SDI-12 data logger
    with in-built tilt meter to measure and log tilt
    data (to be installed ideally at an indoor
    location or in shade to prevent the effect of
    large temperature fluctuations on the monitoring
    results). ESDL-30MT is provided with an integral
    GSM/GPRS modem for storing and trans mitting
    data to a central server.
  • Encardio-rite Model EDJ-40V vibrating wire crack
    meter (with ESVI-01-01 SDI-12 interface box) to
    monitor structural cracks.
  • Encardio-rite Model EAN-93M-B biaxial tilt meter
    with an integral SDI-12 interface Encardio-rite
    Model ESDL-30 data logger for the above-mentioned
    sensors, with integral GSM/GPRS modem for
    storing and transmitting data to a server.
  • Encardio-rite online web data monitoring service
    (WDMS) that provides data online with alarms to
    the authorized users at different locations, on
    their computer/ laptops.





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