-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 1
(20)
SMARTRAIL WP1
User Guidelines
BRIDGE SCOUR MONITORING
- A GUIDELINE
This project has received funding from the European Unions
Seventh Framework
Programme for research, technological development and
demonstration under grant
agreement no FP7- 285683.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 2
(20)
Table of Contents
1 Introduction
...................................................................................................................
3
2 Bridge Scour
..................................................................................................................
3
3 Bridge Scour Monitoring
...............................................................................................
4
Fixed or discrete monitoring instrumentation
......................................................................
7
3.1.1 Single use Buried Devices
...............................................................................
7 3.1.2 Pulse / Radar Devices:
.....................................................................................
9 3.1.3 Piezo-electric Film Sensor Devices
.................................................................10
3.1.4 Buried / Driven Rods:
......................................................................................10
Structural Health Monitoring
..............................................................................................12
4 Recommended practice
..............................................................................................
17
5 References
...................................................................................................................
19
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 3
(20)
1 Introduction These guidelines provide a description of the
work necessary to deliver the benefits as described focused on the
use of remote monitoring of bridge scour in the SMARTRAIL Work
Package WP1. The project website www.fehrl.smartrail.org contains
full details of the results of the other aspects of work completed
in this Work Package and further information concerning the
project.
2 Bridge Scour Bridge scour is the term given to the excavation
and removal of material from the bed and banks of rivers as a
result of the erosive action of flowing water (Hamill, 1999). There
are three main forms of the scour process, namely: general scour,
contraction scour and local scour. General scour occurs naturally
in river channels and arises as a result of the aggradation and
degradation of the riverbed due to natural river flow processes.
Contraction scour occurs as a result of obstructions in the river
channel obstructing the flow of water such as the presence of a
bridge. The decrease in flow area leads to an increase in flow
velocity and associated bed shear stresses inducing scour in the
vicinity of the obstruction. Local scour occurs around bridge
components such as the piers and abutments (Heidarpour, Afzalimehr,
& Izadinia, 2010). Due to pressure differences, downward flow
is induced at the upstream end of piers, which leads to localised
erosion around the structure (Hamill, 1999). Scour reduces the
foundation stiffness and can lead to resultant sudden structural
failure. The three scour mechanisms combine together to create an
overall depth of scour around sub-structural bridge components,
which can be detrimental to the stability and safe operation of
these structures. A schematic of the scour process is shown in Fig.
1. Scouring of bridge foundations is the number one cause of bridge
failure in the United States (Briaud et al., 2001; Briaud, Chen,
Li, Nurtjahyo, & Wang, 2005; Melville & Coleman, 2000). One
US study of over five hundred bridge failures which occurred
between 1989 and 2000 deemed flooding and scour to be the cause of
53% of failures of all failures (Wardhana & Hadipriono, 2003).
Another review claims that over the past thirty years, 600 US
bridges failed due to scour (Briaud, Ting, & Chen, 1999;
Shirole & Holt, 1991). In addition to the risk to human life
caused by bridge scour, these failures cause major disruption and
also economic losses (De Falco & Mele, 2002). Lagasse et al.
(1995) estimate that the average cost for flood damage repair of
bridges in the United States is approximately $50 million per
annum, a cost that is certainly higher in todays economic climate.
Scour is relatively difficult to predict and poses serious risks to
the stability of vulnerable structures. It typically results in a
loss in foundation support, soil-structure stiffness and can
compromise structural safety. Visual inspections are expensive and
time consuming and tend to have limited effectiveness. There is a
reliance on over the deck visual assessment, and whilst divers can
be used to examine the condition of the foundation, this is
dangerous in times of flooding, when the risk of scour is highest
and the effectiveness of even a direct visual assessment may be
reduced by the presence of debris in the water. Scour holes also
tend to re-fill as floodwaters subside, making visual inspections
undertaken after a flood event somewhat ineffective. These may fail
to detect the loss in stiffness resulting from scour as the
backfilled material may be loose and therefore have significantly
reduced strength and stiffness properties. Many mechanical and
electrical instruments have been developed that aim to remotely
detect the presence of scour. A comprehensive overview of the
instrumentation available is given in section 3.
http://www.fehrl.smartrail.org/
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 4
(20)
Wake Vortices
Bridge Pier
Scour Hole
Downflow
Horseshoe Vortices
Figure 1 Scour prcess schematic (Prendergast & Gavin,
2014)
3 Bridge Scour Monitoring An effective method of combatting
scour is to monitor its evolution over time and implement
remediation works as they are required (Briaud et al., 2011). The
most widespread monitoring scheme in place as part of any national
bridge asset management framework is to undertake visual
inspections. Visual inspections are commonplace in engineering and
are used to detect structural anomalies such as cracking and other
damage (Sohn et al., 2004). With regard to scour, visual
inspections involve the use of divers to inspect the condition of
foundation elements and to measure the depth of scour using basic
instrumentation (Avent & Alawady, 2005). Two particular
disadvantages associated with this inspection method include the
fact that inspections cannot be carried out during times of
flooding, when the risk of scour is highest, and the maximum depth
of scour may not be recorded as scour holes tend to fill in as
flood waters subside (Foti & Sabia, 2011; Lin, Lai, Chang,
Chang, & Lee, 2010). The fact that scour holes tend to refill
can be dangerous and misleading as the true extent of the scour
problem may be missed in the inspection. A more effective
alternative is to use fixed or discrete scour depth recording
instrumentation, See Table 1. A number of instruments have been
developed that can monitor the depth of scour around bridge piers
and abutments. Some of these sensing instruments are discussed in
the following subsections. Another alternative is to use damage
detection methods that are currently under development in the area
of Structural Health Monitoring (SHM). These methods are also
discussed in the following subsections.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 5
(20)
SMARTRAIL Work Package (WP) 1 BRIDGE SCOUR MONITORING - A
GUIDELINE
Title: Assessment Techniques for Bridge Scour
Failure Mode:
Detection Mechanism:
1 Pier Tilting (Due to differential settlement) Inclinometer
2 Pier Settlement
Strain Gauge placed at deck level will alert to stresses from
differential
settlement of different piers / supports
3 Pile Group Tilting Inclinometer
4 Deck sliding off supports due to hydraulic loading Stage
Height Measurement Device such as a Stream Gauge
will alert before river height reaches deck level
5 Scouring of foundation leading to lack of lateral pile
Accelerometers detect differences in acceleration signals /
frequencies
Stability
6 Deck falling off abutment due to adverse tilt of support
Inclinometer, Strain Gauge
7 Deck buckling upwards due to adverse tilt of support
Inclinometer, Strain Gauge
8 Scour holes develop and become filled in once flood Ground
Penetrating Radar
subsides (compromising of support from soil)
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued 20.09.2014 6
(20)
9 Scour hole developing over time Sounding Rod (Rests on bed and
moves down as hole appears, base
rests on riverbed at lowest elevation of scour hole)
Measure displacement of top of rod to determine scour hole
depth
10 Scour hole developing over time
Sonic Fathometer (Like GPR above) - Reflects Acoustic Wave to
detect
interface between water and riverbed
11 Scour hole developing over time "Scubamouse" - Used in NZ - A
radioactive collar is placed around a
vertical tube and rests on the riverbed. Once scour occurs,
the
displacement of the collar can be measured from a probe placed
down
the tube. (Collar remains on riverbed and sinks as hole
develops)
12 Scour hole developing over time
"Wallingford Tell-Tail Device" - Omni-directional motion
sensor
placed at various depths and connected to a data-logger.
Measures
motion on the soil thus detecting scour hole development
13 Scour hole developing over time Buried Rods such as:
(a) Piezoelectric film sensors - Exposure by scour detected by
change in
electrical signal caused by vibration
(b) Mercury Tip Switch - Flip down and break circuit when
exposed by
Scour
(c) Magnetic Sliding Collar - Movement detected by magnets in
tube
14 Scour hole developing over time
Time-Domain Reflectometery (TDR):
Using buried sensors that detect changes in dielectric
properties of
surrounding materials in order to detect movements in the
soil-water
Interface
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
7 (20)
Fixed or discrete monitoring instrumentation
3.1.1 Single use Buried Devices
These devices are installed in the river bed, near the pier or
abutment of interest. They can be buried at multiple depths. They
cummincate with a data acquisition system informing the user as to
their status, be it in-position or floated-out. Once the device
floats out of the ground, it indicates that scour hole has reached
this level. The difficulty with these devices is that they
typically have a single use and once the scour depth reaches their
installation depth, they must be re-installed. They also have a
fixed battery life and only give an indication of scour depth at a
single point, i.e. scour above the device and further scour below
is not known.
Figure 2 Positioning Float-Out Devices (NCHRP, 2009)
3.1.1.1 Instrument: Tethered Buried Switch
This device is buried in the river bed at the location of
interest for scour measurement (see Fig. 2). It is a type of
float-out device that is buried vertically into the streambed. It
can be hard-wired to a data acquisition system. When the rod
changes from a vertical orientation to a horizontal one (as would
occur during the float-out stage) an electrical switch triggers. An
image of a typical sensor is shown in Fig. 3.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
8 (20)
Figure 3 Tethered Buried Switch (TBS) (Briaud et al., 2011)
3.1.1.2 Instrument: Float-Out Device
A float-out device is a cylindrical device (see Fig. 4) that may
be installed in the streambed at various locations of interest near
abutments and bridge piers. They are installed using a vertical
orientation. They may be installed at various depths. They become
activated when scour levels reach the upper level of the sensor and
the sensor floats out of position. An on-board trigger mechanism
sends a signal to a data acquisition system that alerts the user
that the device has floated out of the installed position. This is
indicated by the orientation changing from vertical to horizontal.
These are reliable instruments in that they provide an easy method
to detect if scour has reached the sensor datum. Their use is
recommended in areas where exceeding a certain scour depth is very
detrimental to stability, i.e. at the formation level of a shallow
foundation.
Figure 4 Typical Float-Out Device (NCHRP, 2009)
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
9 (20)
3.1.2 Pulse / Radar Devices:
Pulse / radar devices utilize radar signals or electromagnetic
pulses to determine changes in material properties that occur when
a signal is sent through a changing medium as would occur at a
water-sediment interface. These signals henceforth determine the
depth of a scour hole, at a given time.
3.1.2.1 Instrument: Time-Domain Reflectometry
This method was originally developed by electrical engineers
interested in detecting discontinuities in power and communication
transmission lines. It works on the principle of measuring changes
in the dielectric permittivity constants of various materials.
Measuring probes are installed in the streambed at the location of
interest. A fast rising step impulse is sent down a tube, buried
into the ground. When the wave reaches an area where the dielectric
permittivity changes, a portion of the energy is reflected to the
receiver. Dielectric permittivity properties are different for air,
water and sediment hence a geophysical profile may be established,
that will show the progressive depths of scour at the particular
location of interest (Elsaid, 2012). It is a good method in that
relatively clear geophysical images can be obtained that show the
water-sediment interface and hence, the depth of scour. However,
the requirement that long probes be installed into the riverbed can
make it a somewhat expensive method for scour monitoring (See Fig.
5).
Figure 5 Time-Domain Reflectometer (Briaud et al., 2011)
3.1.2.2 Instrument: Ground Penetrating Radar (GPR)
A GPR transmitter is floated out in a river to the location. An
electromagnetic pulse is then sent through the water and the waves
are partially reflected as they pass through the different media.
The waves are of a very high frequency (in the range of MHz). The
method works on a very similar principle to Time Domain
Reflectometry (TDR) approach, whereby changes in the dielectric
properties are identified as the waves reflect at different stages.
The reflected signal is recorded by the receiver and an overall
geophysical map may be generated, showing clearly the submerged
scour
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
10 (20)
hole and its depth. An example of a geophysical map is shown in
Fig. 6 where the scour depth is cleary detectable. The
disadvantages of the method is that it requires manual operation,
is not ideally suited to continuous monitoring and it cannot be
deployed in a flood scenario as the equipment would be washed away.
However, if used as part of a discrete bridge monitoring scheme, it
is quite adept at detecting scour.
Figure 6 Typical GPR Profile (Anderson, Ismael, &
Thitimakorn, 2007)
3.1.3 Piezo-electric Film Sensor Devices
Piezo-electric film sensors utilize strain deformations to
generate an electrical signal, which
can alert the person monitoring that scour levels have reached a
certain level. An array of sensors can be placed onto plates that
are buried. When buried, no bending deformation occurs. When
exposed to flow, deformation occurs and a signal is sent to a
datalogger to alert that scour levels have reached the particular
level of the sensor.
3.1.3.1 Instrument: Fibre Optic Sensors using Fibre Bragg
Grating (FBG) methods
These fibre optic sensors are composed of Fibre Bragg Grating
(FBG) elements that can monitor bridge scour in real-time. Optical
fibres are useful in that they are reliable against corrosion, long
term degradation and general environmental damage. Several Fibre
Bragg Grating sensors can be arranged linearly along an optical
fibre. This can then be mounted onto a cantilever plate, and
installed at different levels of a steel pipe fixed to a pier or
abutment. The system works on the principle of picking up strain
deformation that will occur in the plate if it becomes exposed to
the impulse force of flowing water. Only plate elements exposed to
the flow will bend hence an accurate measurement of scour levels
can be derived from this. The resolution of scour depth monitoring
is only as good as the number and spacing of sensors along the
array.
3.1.4 Buried / Driven Rods:
These instruments work on the principle of a manual or automated
gravity based physical probe that rests on the streambed and moves
downward with increasing progression of a scour hole during a flood
scenario. The system utilises some form of remote sensing mechanism
to detect the level change of the gravity sensor. The sensor must
be sufficiently large to prevent penetration into the bed while in
a static
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
11 (20)
stage, prior to the occurrence of scour as this will affect the
accuracy of the perceived results.
3.1.4.1 Instrument: Magnetic Sliding Collar
A Magnetic Sliding Collar incorporates a magnetic collar placed
around a structurally rigid pipe that is driven or augered into the
streambed at a particular location near a bridge pier or abutment.
The magnetic nature of the collar allows it to trigger sensors in
the rod at the location of the sensor. As the streambed erodes, the
collar slides down along the rod allowing magnetic triggers to
detect that it has changed its elevation. The data from the device
may be manually or automatically read. In the automatic case,
flexible cables are attached to a datalogger and convey magnetic
switch closures corresponding to collar movement. The manually read
case requires the use of a hollow metal tube to connect the sensor
to the bridge deck. This device is useful and pretty accurate at
detecting scour. It cannot, however, measure infill as the sensor
typically remains at the maximum scour depth. It gives a good
indication of the previous maximum scour depth measured at the
location of the sensor. The device is only good at measuring scour
at its installation location and may miss the global effect of
scour if placed in an area where the scour is not so severe (see
Fig. 7).
Figure 7 Magnetic Sliding Collar (NCHRP, 2009)
3.1.4.2 Instrument: Scubamouse
The scubamouse is a device that was created in New Zealand. It
consists of a steel pipe that is buried or driven into the
streambed in front of a bridge pier. The steel pipe has a
horseshoe-shaped collar around the outside, which rests initially
on the un-scoured streambed. As scour progresses during a flood,
the collar remains at rest on the riverbed, which lowers in
elevation. As water stages reduce when the flood begins to subside,
the scour hole begins to fill with sediment, thus burying the
collar. The
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
12 (20)
collar remains at rest at a depth corresponding to the maximum
depth of scour reached during the flood. A radioactive detection
mechanism is slid down the inside of the steel buried pipe in order
to detect the resting location of the collar. A signal may then be
sent back to a datalogger device. This device operates on similar
principles to the magnetic sliding collar.
3.1.4.3 Instrument: Wallingford Tell Tail Device
This type of device has been installed on many older high risk
structures in the UK at the location where the maximum scour is
expected. It consists of a set of omnidirectional motion sensors,
mounted on tails connected to a rod and buried in the streambed at
a range of depths. It can be connected to a datalogger via a cable.
The motion sensors detect bed movements that are indicative of
scour having reached the depth of embedment of the sensor. The
device must be reset when scour reaches its depth of installation,
which can make it labour intensive which has a significant cost
implication.
3.1.4.4 Instrument: Mercury Tip Switch
A number of mercury tip switches can be arranged along a support
pipe that is driven or augured into the ground near the front of a
bridge pier or abutment. The devices work on the premise that, as
the rod or pipe is driven into the streambed, the tip switches
become folded up against the rod, which closes the circuit. The
presence of the streambed material is what is responsible for
ensuring the switch remains open. As the streambed erodes away due
to scour, the material around the switch will no longer hold the
switch open and it will flip into the closed position, breaking the
circuit.
Structural Health Monitoring
Structural Health Monitoring (SHM) techniques have been
developing rapidly in recent years. Advances in this technology
have led to the use of the structure itself to detect damage by
observing changes in the structures condition. The method explored
for scour detection as part of this project is to use the frequency
response of the structure to detect the presence and in some cases
the extent of the scour. The frequency response of the structure is
expected to change as scour removes soil from around the foundation
elements. Fig. 8 shows a schematic of the pre- and post-scour
process on a bridge.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
13 (20)
Road Surface
Water Surface
Riverbed
Embankment
Vehicle
Previously
validated
pile model
(a)
Road Surface
Water Surface
Scour Hole
Embankment
Vehicle
(b)
Figure 8 Frequency change due to scour schematic
Accelerometers placed on the bridge structure can be used to
detect the presence and extent of scour by measuring vibrations and
obtaining the frequency content of the signals. An experiment
undertaken on a pile, the dimensions of which were typical of those
used to support road and rail bridges, highlights the change in
frequency due to scour. A schematic of this test is shown in Fig.
9.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
14 (20)
Blessington Sand
Initial Level
2260
6500
Scour Level -1
Scour Level -2
Scour Level -3
Scour Level -4
Scour Level -5
Scour Level -6
Scour Level -7
Scour Level -8
Scour Level -9
Scour Level -10
Scour Level -11
Scour Level -12
Base Level
500
Pile
500
500
1000
A A
Section A-A
R170
R157Accelerometer 4
Accelerometer 3
Accelerometer 2
Accelerometer 1
8760
Figure 9 Experimental test (Prendergast, Hester, Gavin, &
OSullivan, 2013)
A vibration test was undertaken on the pile in order to
establish the sensitivity of the frequency response of the
structure to a change in the level of soil surrounding the
structure. The results of this test are shown in Fig. 10. From the
figure, it is evident that significant changes in frequency can be
obtained due to scour. Therefore, this method is suggested as a way
to monitor the presence of scour developing around critical
foundation elements of bridge structures. Fig. 10 also shows the
frequency change of a cantilever with the same free length as the
scoured pile to highlight that the results are as expected (i.e.
they should be less than a cantilever at each depth because this
has an infinitely stiff foundation).
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
15 (20)
0 5 10 15 20 25 30 35 40-7
-6
-5
-4
-3
-2
-1
0
Frequency (Hz)
Sco
ur
Dep
th (
m)
Experimental Frequency
Fixed Cantilever Frequency
Figure 10 Frequency change with scour (Prendergast et al.,
2013)
The method of using changes in frequency to detect scour was
further tested by developing a full numerical finite-element bridge
model and subjecting it to a vehicular moving load to assess if it
is possible to detect frequency changes arising from a loss of soil
support from around the foundation. The bridge modelled is shown in
Fig. 11.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
16 (20)
6001800
150
00
38
00
19
00
32
50
26
25
171
00
3500
4500
60
00
25000 25000
500 1375 500
750
16
00
2500
A A
Bridge Deck
Abutment
Columns
Bridge Pier
Pier Foundation
Pier Cross-HeadBank Seat
Abutment Piles
6001800
Piles
Pier Column
Piles
Abutment Columns
Reinforced Earth
(a)
(b)
Figure 11 Bridge model
Scour was modelled as the removal of numerical springs from the
model, similar to those shown in Fig. 8. The purpose of the
investigation was to assess if it is possible to detect scour using
the vibration response of the bridge due to the passage of a
vehicle along the deck (similar to a train carriage or otherwise).
The results of this numerical investigation are shown in Fig. 12,
where a clear reduction in detected natural frequency may be
observed with increasing depth of scour.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
17 (20)
0.9 1 1.1 1.2 1.3 1.4 1.5 1.6-10
-8
-6
-4
-2
0
Frequency (Hz)
Sco
ur
dep
th (
m)
Loose sand
Figure 12 Change in frequency with scour - numerical bridge
model
4 Recommended practice The recommendation for scour monitoring
using instrumentation (in lieu of visual inspections) is to use a
combination of instruments at critical scour locations to reduce
the dependency on any one system, each of which has its
limitations. The Smartrail project has demonstrated clearly the
potential to couple the use of accelerometers (for frequency
measurement) with a depth monitoring instrument such as a magnetic
sliding collar or similar so that an estimate of frequency change
with scour depth can be obtained. This allows for the estimation of
a datum for the use of accelerometers only on certain bridges to
reduce maintenance associated with re-installing instruments as
discussed in previous sections. The following flowchart highlights
the recommended practice:
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
18 (20)
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
19 (20)
5 References
Anderson, N. L., Ismael, A. M., & Thitimakorn, T. (2007).
Ground-Penetrating Radar : A Tool for Monitoring Bridge Scour.
Environmental & Engineering Geoscience, XIII(1), 110.
Avent, R. R., & Alawady, M. (2005). Bridge Scour and
Substructure Deterioration : Case Study. Journal Of Bridge
Engineering, 10(3), 247254.
Briaud, J. L., Chen, H. C., Ting, F. C. K., Cao, Y., Han, S. W.,
& Kwak, K. W. (2001). Erosion Function Apparatus for Scour Rate
Predictions. Journal of Geotechnical and Geoenvironmental
Engineering, 105113.
Briaud, J. L., Chen, H., Li, Y., Nurtjahyo, P., & Wang, J.
(2005). SRICOS-EFA Method for Contraction Scour in Fine-Grained
Soils. Journal of Geotechnical and Geoenvironmental Engineering,
131(10), 12831295.
Briaud, J. L., Hurlebaus, S., Chang, K., Yao, C., Sharma, H.,
Yu, O., Price, G. R. (2011). Realtime monitoring of bridge scour
using remote monitoring technology. Security (Vol. 7, pp. 1440).
Austin, TX. Retrieved from
http://tti.tamu.edu/documents/0-6060-1.pdf
Briaud, J. L., Ting, F., & Chen, H. C. (1999). SRICOS:
Prediction of Scour Rate in Cohesive Soils at Bridge Piers. Journal
of Geotechnical and Geoenvironmental Engineering, (April),
237246.
De Falco, F., & Mele, R. (2002). The monitoring of bridges
for scour by sonar and sedimetri. NDT&E International, 35,
117123.
Elsaid, A. (2012). Vibration Based Damage Detection of Scour in
Coastal Bridges. North Carolina State University.
Foti, S., & Sabia, D. (2011). Influence of Foundation Scour
on the Dynamic Response of an Existing Bridge. Journal Of Bridge
Engineering, 16(2), 295304.
doi:10.1061/(ASCE)BE.1943-5592.0000146.
Hamill, L. (1999). Bridge Hydraulics (pp. 1367). London: E.&
F.N. Spon.
Heidarpour, M., Afzalimehr, H., & Izadinia, E. (2010).
Reduction of local scour around bridge pier groups using collars.
International Journal of Sediment Research, 25(4), 411422.
doi:10.1016/S1001-6279(11)60008-5
Lagasse, P. F., Schall, J. D., Johnson, F., Richardson, E. V.,
& Chang, F. (1995). Stream stability at highway structures.
Washington, DC.
Lin, Y. Bin, Lai, J. S., Chang, K. C., Chang, W. Y., & Lee,
F. Z. (2010). Using mems sensors in the bridge scour monitoring
system. Journal of the Chinese Institute of Engineers, 33(1),
2535.
Melville, B. W., & Coleman, S. E. (2000). Bridge scour.
Highlands Ranch, CO: Water Resources Publications.
NCHRP. (2009). Monitoring Scour Critical Bridges - A Synthesis
of Highway Practice. Traffic Safety. Washington, DC.
-
SMARTRAIL User Guidelines: BRIDGE SCOUR MONITORING A
GUIDELINE
SMARTRAIL Guidelines BRIDGE SCOUR MONITORING issued
20.08.2014
20 (20)
Prendergast, L. J., & Gavin, K. (2014). A review of bridge
scour monitoring techniques. Journal of Rock Mechanics and
Geotechnical Engineering, 6(2), 138149.
Prendergast, L. J., Hester, D., Gavin, K., & OSullivan, J.
J. (2013). An investigation of the changes in the natural frequency
of a pile affected by scour. Journal of Sound and Vibration,
332(25), 66856702.
doi:http://dx.doi.org/10.1016/j.jsv.2013.08.020i
Shirole, A. M., & Holt, R. C. (1991). Planning for a
comprehensive bridge safety assurance program. In Transport
Research Record (Vol. 1290, pp. 137142). Washington, DC: Transport
Research Board.
Sohn, H., Farra, C. R., Hemez, F., Shunk, D., Stinemates, D.,
Nadler, B., & Czarmecki, J. (2004). A Review of Structural
Health Monitoring Literature : 1996 2001 (pp. 1311).
Wardhana, K., & Hadipriono, F. C. (2003). Analysis of Recent
Bridge Failures in the United States. Journal of Performance of
Constructed Facilities, 17(3), 144151.
doi:10.1061/(ASCE)0887-3828(2003)17:3(144)