PhDs / research work in connection
with the Coastal Highway Route E39
at the University of Stavanger
Jasna Bogunović Jakobsen
University of Stavanger
uis.no
1
http://nn.wikipedia.org/wiki/Uburen#mediaviewer/File:Lysefjordbroen_sett_fra_Sokkanuten.jpg
Overall research goal
 Improve understanding and modelling of wind loads
and wind-induced response of long-span bridges, in
order to facilitate an economic and safe bridge design.
 Collaboration with the NPRA:
 Support by NPRA for two research positions closely related to the ongoing PhDs:
A) Ambient load and vibration data acquisition and interpretation
B) Wind-induced cable vibrations
 Support and collaboration on the full-scale measurement campaigns
 Partial support to ongoing PhDs
 Adjunct Professor in Wind Engineering: Jonas Snæbjornsson
2
Ongoing PhDs
Heidi Christensen
Aerodynamics of bridge cables
PhD student since 2012.
Etienne Cheynet
Bridge vibrations due to turbulence
PhD student since 2013.
3
B Stay cable vibrations
1
 Focus on vibrations caused by rapidly changing/ unstable flow
states in the so-called drag crises.
Pressure distributions, fixed model, Re=1.1∙105 (left), Re=3.2∙105 (middle), Re=5.8∙105 (right)
4
B Stay cable vibrations
2
 Study of the effect of hellical fillets on cable
aerodynamics.
 Study of the effect of turbulence on cable
aerodynamics.
 Influence of cable non-circularity on the
aerodynamics.
 Research collaboration with the National Research
Council Canada, University of Bristol, the US
Federal Highway Administrataion and the Danish
Technical University.
 Other topics: vibrations of cables/hangers (icewind,…), vibration mitigation measures …
(Model) cable-cross section,
deviation from the circular
shape magnified
5
A Bridge response due to turbulence
 Measurement of wind conditions in complex terrain and the
assocaited bridge vibrations.
 Investigation of the link between the two, ref. the so-called
buffeting theory.
 Efficient techniques for the interpretation of the measured
response data, including wind-structure interaction, and the
structural health monitoring.
 Remote wind velocity sensing in bridge engineering.
6
University of Stavanger
University of Bergen
Christian Michelsen Research AS
Technical University of Denmark
7
http://nn.wikipedia.org/wiki/Uburen#mediaviewer/File:Lysefjordbroen_sett_fra_Sokkanuten.jpg
Lidar measurement principles
Light Detection and Ranging
Doppler shift:
Lidar recording
principles:
Wind flow characterization by a long-range
pulsed Doppler lidar (March 2014 – June 2014)
 Collaboration between UiS and NORCOWE
(UiB, CMR and Leosphere)
 WindCube100S, scanning modes:




Doppler Beam Swinging mode (DBS)
Plan Position Indicator mode (PPI)
Range Height Indicator mode (RHI)
Sequential Fixed Line of Sight mode (LOS)
PPI, elev. 0.8°, 1.8° and 3.2°
RHI Azimuth 37 °,38 ° and 39 °
Azimuth 13° to 63°
Wind characteristics observed by lidars in a “dynamic” scanning mode
Example of a Plan Position Indicator mode (PPI) data by WindCube100S
22.5.2014, 18:19:23 elev=3.2°
22.5.2014, 18:19:10 elev= 1.8°
Non-scanning, fixed line-of-sight, measurements:
Example of a LOS data by WindCube100S,
Radial wind velocity recorded by a LOS scan elev=1.8°
azim=39°; 22.05.2014 starting at 16:12:06
11
Multi-lidar measurements, May 2014
Short range WindScanners deployment
 Two short-range WindScanners developed by the
Technical University of Denmark, building on
ZephIR150, deployed on the bridge walkway on the
West side.
 Synchronized to map the airflow in different planes
(horizontal and “vertical”) SW from the bridge, and
operated remotely.
 High-frequency, separate LOS data also recorded.
 The Doppler spectra averaged such that LOS wind
velocities were provided at about 390 Hz and the
scan pattern frequency was 1 Hz.
 Scanning sequences devoted to capturing the spatial
characteristics of the inflow, as well as various forms
of the bridge signature in the airflow.
Horizontal wind speed along the bridge axis measured
by the WindScanners and the sonic anemometer
22.5.2014 starting from 16:13:24
13
Spectra based on short-range WindScanners and
sonic anemometers
k1=2π∙f /U
Power spectral density of the longitudinal (left) and lateral turbulence (right),
based on 20 minutes data starting at 17:20, 22.5.2014.
14
Coherence based on short range WindScanners and
sonic anemometers
Cohu ( D, k1 ) =
2
FuAuB (k1 )
2
FuA (k1 ) FuB (k1 )
15
Squared coherence of the along-wind turbulence (left) and the lateral turbulence (right).
D is the across-wind projection of the distance Δy between the observation “points”.
Summary
 Coastal Highway Route E39 Project connects well to the
ongoing work and triggers further reserach in wind engineering
at UiS.
 Many more topics to be explored (aerodynamics of multi-box
bridge girders, etc…)
 New staff at UiS in marine technology, CFD….
 Research network facilitates novel applications.
16