"Pavement condition measurement at high speed using a TSD" presented at ESREL2017 by Daniel Martinez Otero

Pavement Condition Measurement
at High Speed using a TSD
Abdollah Malekjafarian*
Daniel Martínez Otero*
Eugene OBrien*
* University College Dublin
1

Index
Pavement Condition Measurement at High Speed Using a TSD
Daniel Martínez Otero / University College Dublin
• Measuring Strategies
• What a TSD is?
• TSD for Pavement Condition
• TSD for Bridge Condition
• Conclusions
2

Measuring Strategies: Visual Inspection
• Frequently used in
bridges
• Expensive
• Worker dependence
Measuring Strategies
Daniel Martínez Otero / University College Dublin 3

Direct Monitoring
• Sensors installed on the
bridge
• Electricity supply needed
• Great number on sensors
involved, specially on
bridges
Hong Kong Stonecutters bridge, 1.6 km
length
• Parts of the road
removed for analysis.
• Damaged caused in
pavements.
• Non reliable data.
Sampling

Indirect Monitoring (Drive-by)
• Sensors installed
in a passing
vehicle
• Quick
• Cost affordable
• No risk

What a TSD is?
• A Traffic Speed
Deflectometer (TSD) is
an equipped vehicle that
allows us to know the
road profile parameters.
• Its characteristics make
us to think about the
suitability of this kind of
vehicle for the bridge
measurements.
What a TSD is?

• Truck
oPuts axle load on the pavement.
oIncludes most of the equipment.
oConstant temperature
• Beam
oEquipped with gyros,
accelerometers and Laser
Doppler Vibrometers.
oParallel to the road.
Main components of the TSD
7
What a TSD is?

• Doppler Lasers
oInstalled on the
beam.
oReference laser
between the two
axles.
oChange in frequency
allows to calculate
the relative velocity.
Main components of the TSD
8
What a TSD is?

What is the TSD measuring?
9
What a TSD is?

TSD for Pavement Condition
• Deflection slope is calculated using the relative velocities
measured.
• Basic slope formula is adapted from the data obtained.
𝛼 =
∆𝑣
∆𝑢
=
𝑣 × ∆𝑡
𝑐 × ∆𝑡
=
𝑣
𝑐
Slope
Deflections
Velocities
Vertical
divided by
horizontal
10

• Using TSD data the slope formula changes.
• Assuming that reference laser is in a zero deflection
point, the absolute slope can be obtained.
• Vehicle’s body bounce is removed in the
subtraction.
Slope Calculation
𝛼 =
∆ 𝑣 𝑛 − ∆ 𝑣 𝑅𝑒𝑓
𝑐
Vertical velocity
measured in
sensor n
Vertical velocity
measured in
reference sensor
Vehicle’s
horizontal
velocity
11

• A simple Winkler model is able to model the
characteristics of the road.
• Two key parameters are considered: Young Modulus (E)
and Pavement Stiffness (Kp)
Winkler model
12

TSD for Bridge Condition

Curvature Methods
κℎ𝑒𝑎𝑙𝑡ℎ𝑦(𝑥) =
𝑀(𝑥)
𝐸𝐼
κ 𝑑𝑎𝑚𝑎𝑔𝑒𝑑(𝑥) =
𝑀(𝑥)
𝐸𝐼𝑟𝑒𝑑

Instantaneous Curvature
• In a moving reference situation this curvature
cannot be calculated using only one sensor.
• Instantaneous Curvature (IC) is calculated
using three different sensors.
IC x, 𝐭 =
v x−∆x,𝐭 −2v x,𝐭 +v x+∆x,𝐭
∆x2

Deflection Contour Plot with IC calculation

Contour Plot with IC calculation

Rate of Instantaneous Curvature
• Same idea is used for
relative velocities (q).
• Rate of Instantaneous
Curvature (RIC) is defined
similar to IC.
RIC x, 𝐭 =
q x−∆x,𝐭 −2q x,𝐭 +q x+∆x,𝐭
∆x2
q = v 𝑏𝑟𝑖𝑑𝑔𝑒 − v 𝑣𝑒ℎ𝑖𝑐𝑙𝑒

Rate of Instantaneous Curvature

Damage Indicator for Bridge Condition
• Moving Average Difference (MAD):
MAD x =
1
Z
n=−
(Z−1)×L
2f
(Z−1)×L
2f RICDamaged (x+n)−
1
Z
n=−
(Z−1)×L
2f
(Z−1)×L
2f RICHealthy(x+n)
min RICHealthy
× 100 (%)
Z is the number of points for the moving average.
f is the measuring sampling frequency of the sensors.
L is the length of the bridge.

MovingAverage Difference

Summary

Conclusions
Conclusions
• Pavement under TSD can be modelled with a
simple Winkler model with reasonable accuracy.
• Curvature methods have great potential in drive-by
monitoring.
• Relative velocities can be used in bridge damage
detection.
• Moving Average Difference (MAD) has the ability of
locate damage on bridges.

Thank you for your attention
Pavement Condition Measurement at High Speed Using a TSD
This project has received funding from the European Union’s Horizon 2020
research and innovation programme under the Marie Sklodowska-Curie grant
agreement No. 642453

"Pavement condition measurement at high speed using a TSD" presented at ESREL2017 by Daniel Martinez Otero

Recommandé

Recommandé

Contenu connexe

Similaire à "Pavement condition measurement at high speed using a TSD" presented at ESREL2017 by Daniel Martinez Otero

Similaire à "Pavement condition measurement at high speed using a TSD" presented at ESREL2017 by Daniel Martinez Otero (20)

Plus de TRUSS ITN

Plus de TRUSS ITN (20)

Dernier

Dernier (20)

"Pavement condition measurement at high speed using a TSD" presented at ESREL2017 by Daniel Martinez Otero