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Research Papers: Structures and Safety Reliability

Numerical Modeling and Dynamic Analysis of a Floating Bridge Subjected to Wind, Wave, and Current Loads

[+] Author and Article Information
Zhengshun Cheng

Department of Marine Technology,
Centre for Autonomous Marine Operations
and Systems (AMOS),
Norwegian University of Science
and Technology (NTNU),
Trondheim 7491, Norway
e-mail: zhengshun.cheng@gmail.com

Zhen Gao

Department of Marine Technology,
Centre for Autonomous Marine Operations
and Systems (AMOS),
Norwegian University of Science
and Technology (NTNU),
Trondheim 7491, Norway
e-mail: zhen.gao@ntnu.no

Torgeir Moan

Department of Marine Technology,
Centre for Autonomous Marine Operations
and Systems (AMOS),
Norwegian University of Science
and Technology,
Trondheim 7491, Norway
e-mail: torgeir.moan@ntnu.no

1Corresponding author.

Contributed by the Ocean, Offshore, and Arctic Engineering Division of ASME for publication in the JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING. Manuscript received April 3, 2018; final manuscript received June 5, 2018; published online July 24, 2018. Assoc. Editor: Francisco J. Huera-Huarte.

J. Offshore Mech. Arct. Eng 141(1), 011601 (Jul 24, 2018) (17 pages) Paper No: OMAE-18-1032; doi: 10.1115/1.4040561 History: Received April 03, 2018; Revised June 05, 2018

Designing reliable and cost-effective floating bridges for wide and deep fjords is very challenging. The floating bridge is subjected to various environmental loads, such as wind, wave, and current loads. All these loads and associated load effects should be properly evaluated for ultimate limit state design check. In this study, the wind-, wave-, and current-induced load effects are comprehensively investigated for an end-anchored curved floating bridge, which was an early concept for crossing the Bjørnafjorden. The considered floating bridge is about 4600 m long and consists of a cable-stayed high bridge part and a pontoon-supported low bridge part. It also has a large number of eigen-modes, which might be excited by the environmental loads. Modeling of wind loads on the bridge girder is first studied, indicating that apart from aerodynamic drag force, aerodynamic lift and moment on the bridge girder should also be considered due to their significant contribution to axial force. Turbulent wind spectrum and spatial coherence play an important role and should also be properly determined. The sway motion, axial force, and strong axis bending moment of the bridge girder are mainly induced by wind loads, while the heave motion, weak axis bending moment, and torsional moment are mainly induced by wave loads. Turbulent wind can cause significant larger low-frequency eigen-mode resonant responses than the second-order difference frequency wave loads. Current loads mainly contribute damping and reduce the variations of sway motion, axial force, and strong axis bending moment.

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References

Watanabe, E. , 2003, “ Floating Bridges: Past and Present,” Struct. Eng. Int., 13(2), pp. 128–132. [CrossRef]
Hartz, B. , 1981, “ Dynamic Response of the Hood-Canal Floating Bridge,” 2nd ASCE/EMD Specialty Conference on Dynamic Response of Structures, Atlanta, GA, Jan. 15–16.
Kvåle, K. A. , Sigbjörnsson, R. , and Øiseth, O. , 2016, “ Modelling the Stochastic Dynamic Behaviour of a Pontoon Bridge: A Case Study,” Comput. Struct., 165, pp. 123–135. [CrossRef]
Langen, I. , and Sigbjörnsson, R. , 1980, “ On Stochastic Dynamics of Floating Bridges,” Eng. Struct., 2(4), pp. 209–216. [CrossRef]
Watanabe, E. , Maruyama, T. , Ueda, S. , and Tanaka, H. , 2015, “ Yumemai Floating Swing Arch Bridge of Osaka, Japan,” Large Floating Structures, Springer, Singapore, pp. 61–90. [CrossRef]
Wang, C. M. , Watanabe, E. , and Utsunomiya, T. , 2007, Very Large Floating Structures, CRC Press, Taylor & Francis Group, London.
Wang, C. , and Wang, B. , 2015, Large Floating Structures: Technological Advances, Springer, Singapore.
Eidem, M. E. , 2017, “ Overview of Floating Bridge Projects in Norway,” ASME Paper No. OMAE2017-62714.
Løken, A. E. , Oftedal, R. A. , and Aarsnes, J. V. , 1990, “ Aspects of Hydrodynamic Loading and Responses in Design of Floating Bridges,” Second Symposium on Strait Crossings, Trondheim, Norway, June 10–13.
Seif, M. S. , and Inoue, Y. , 1998, “ Dynamic Analysis of Floating Bridges,” Mar. Struct., 11(1–2), pp. 29–46. [CrossRef]
Fu, S. , Cui, W. , Chen, X. , and Wang, C. , 2005, “ Hydroelastic Analysis of a Nonlinearly Connected Floating Bridge Subjected to Moving Loads,” Mar. Struct., 18(1), pp. 85–107. [CrossRef]
Fu, S. , Wei, W. , Ou, S. , Moan, T. , Deng, S. , and Lie, H. , 2017, “ A Time-Domain Method for Hydroelastic Analysis of Floating Bridges in Inhomogeneous Waves,” ASME Paper No. OMAE2017-62534.
Sun, J. , Jiang, P. , Sun, Y. , Song, C. , and Wang, D. , 2017, “ An Experimental Investigation on the Nonlinear Hydroelastic Response of a Pontoon-Type Floating Bridge Under Regular Wave Action,” Ships Offshore Struct., 13(3), pp. 1–11.
Lie, H. , Fu, S. , Fylling, I. , Fredriksen, A. G. , Bonnemaire, B. , and Kjersem, G. L. , 2016, “ Numerical Modelling of Floating and Submerged Bridges Subjected to Wave, Current and Wind,” ASME Paper No. OMAE2016-54851.
Sha, Y. , Amdahl, J. , Aalberg, A. , and Yu, Z. , 2018, “ Numerical Investigations of the Dynamic Response of a Floating Bridge Under Environmental Loadings,” Ships Offshore Struct. (in press).
Xu, Y. , Øiseth, O. , and Moan, T. , 2017, “ Time Domain Modelling of Frequency Dependent Wind and Wave Forces on a Three-Span Suspension Bridge With Two Floating Pylons Using State Space Models,” ASME Paper No. OMAE2017-62721.
Cheng, Z. , Gao, Z. , and Moan, T. , 2018, “ Hydrodynamic Load Modeling and Analysis of a Floating Bridge in Homogeneous Wave Conditions,” Mar. Struct., 59, pp. 122–141. [CrossRef]
Cheng, Z. , Gao, Z. , and Moan, T. , 2018, “ Wave Load Effect Analysis of a Floating Bridge in a Fjord Considering Inhomogeneous Wave Conditions,” Eng. Struct., 163, pp. 197–214. [CrossRef]
COWI, 2016, “ Curved Bridge Navigation Channel in South—Environmental Loading Analysis,” Report for the Norwegian Public Road Administration, COWI AS, Oslo, Norway, Report No. NOT-HYDA-018.
COWI, 2016, “ Curve Bridge Navigation Channel in South—Summary of Analyses,” Report for the Norwegian Public Road Administration, COWI AS, Oslo, Norway, Report No. NOT-KTEKA-021 https://www.vegvesen.no/_attachment/1605060/binary/1145259?fast_title=Bj%C3%B8rnafjorden+Endeforankret+flytebun+-+Oppsumering+av+analyser.pdf.
MARINTEK, 2012, Simo-Theory Manual Version 4.0, MARINTEK, Trondheim, Norway.
MARINTEK, 2012, Rifelx Theory Manual, Version 4.0, MARINTEK, Trondheim, Norway
SVV, 2016, Design Basis Metocean, Statens Vegvesen, Oslo, Norway.
Cheng, Z. , Svangstu, E. , Gao, Z. , and Moan, T. , 2018, “ Field Measurements of Inhomogeneous Wave Conditions in Bjørnafjorden,” J. Waterw., Port, Coastal, Ocean Eng. (in press).
Lothe, A. , and Musch, O. , 2015, “ Bjørnafjorden Submerged Floating Tube Bridge: Sea State Simulations,” Norconsult AS, Trondheim, Norway.
Jonkman, B. J. , 2009, “ Turbsim User's Guide: Version 1.50,” National Renewable Energy Laboratory, Golden, CO, USA, Technical Report No. NREL/TP-500-46198 https://www.nrel.gov/docs/fy09osti/46198.pdf.
IEC, 2005, “ Wind Turbines—Part 1: Design Requirements,” International Electrotechnical Commission, Geneva, Switzerland, Standard No. IEC 61400-1:2005 https://webstore.iec.ch/preview/info_iec61400-1%7Bed3.0%7Den.pdf.
Vegvesen, S. , 2015, Handbok N400, Bruprosjektering, Statens Vegnesen, Oslo, Norway.
Faltinsen, O. M. , 1995, Sea Loads on Ships and Offshore Structures, Cambridge University Press, Cambridge, UK.
Cummins, W. E. , 1962, “ The Impulse Response Function and Ship Motions,” Institut fur Schiffbau, Universitat Hamburg, Hamburg, Germany.
DNV GL, 2014, “ Environmental Conditions and Environmental Loads,” Det Norske Veritas AS, Oslo, Norway, Standard No. DNV-RP-C205.
Strømmen, E. , 2010, Theory of Bridge Aerodynamics, 2nd ed., Springer, Berlin. [CrossRef]
Larsen, A. , and Walther, J. H. , 1998, “ Discrete Vortex Simulation of Flow Around Five Generic Bridge Deck Sections,” J. Wind Eng. Ind. Aerodyn., 77–78, pp. 591–602. [CrossRef]

Figures

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Fig. 1

Overview of the end anchored curved floating bridge concept [19]

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Fig. 2

The end anchored curved floating bridge model including a cable stayed high bridge and a pontoon supported low bridge [17]

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Fig. 3

Definition of global coordinate system. Directions of incoming wind, wave, and current are also marked. Note that the fjord boundary condition is not plotted here.

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Fig. 4

Contour plots of directional wave spectrum with the significant wave height Hs=2.4 m, peak period Tp=5.9 s, main direction θp=270 deg, and spreading exponent n = 4

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Fig. 5

Comparison of normalized Kaimal spectra from IEC and from N400. Normalized spectrum is defined as R=fS(f)/σ2, where f is the frequency, S(f) is the spectral density, and σ is the standard deviation of wind velocity component. Here, the mean wind speed is 31 m/s at the reference height of 10 m. The overlaps between Ru(IEC) and Rv(N400) and between Rv(IEC) and Rw(N400) are coincidence.

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Fig. 6

The aerodynamic lift, drag, and moment coefficients as a function of angle of attack. Typical girder cross section in the low bridge part and the high bridge part is considered.

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Fig. 7

Time series of wind velocity components in the global X, Y, and Z directions. The wind comes from west (270 deg). The mean wind speed is 31 m/s at a height of 10m.

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Fig. 8

(a) Time series and (b) power spectra of aerodynamic lift, drag forces and moment acting on the bridge girder per unit length, estimated by approach II. These time series are estimated by assuming that the weak axis of the bridge girder is parallel to the mean wind direction (270 deg). The mean wind speed is 31 m/s at a height of 10 m. The time series of moment is multiplied by a factor of 0.05.

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Fig. 9

The standard deviations of (a) sway motion, (b) heave motion, (c) axial force (Fx), (d) strong axis bending moment (Mz), (e), weak axis bending moment (My), and (f) torsional moment (Mx), along the bridge girder under turbulent wind and irregular waves

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Fig. 10

Comparison of power spectra of axial force of girder node at A11 calculated by three approaches

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Fig. 11

The spatial variation of power spectra of axial force along the bridge girder under turbulent wind and waves: (a) approach I: considering only aerodynamic drag force when calculating wind loads on the bridge girder and using IEC Kaimal spectrum; (b) approach II: considering aerodynamic lift, drag, and moment and using IEC Kaimal spectrum; and (c) approach III: considering aerodynamic lift, drag, and moment and using N400 Kaimal spectrum

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Fig. 12

The mean values of (a) sway motion, (b) axial force, and (c) strong axis bending moment along the bridge girder, subjected to different combination of environmental loads

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Fig. 13

The standard deviations of (a) heave motion, (b) torsional moment (Mx), and (c) weak axis bending moment (My) along the bridge girder, subjected to different combination of environmental loads

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Fig. 14

The standard deviations of (a) sway motion, (b) axial force (Fx), and (c) strong axis bending moment (MZ) along the bridge girder, subjected to different combination of environmental loads

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Fig. 15

The spatial variation of power spectra of sway motion along the bridge girder under turbulent wind and waves

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Fig. 16

Power spectra of sway motion of girder nodes at (a) A6 and (b) A11 under different combination of environmental loads

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Fig. 17

The spatial variation of power spectra of strong axis bending moment along the bridge girder under turbulent wind and waves

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Fig. 18

Power spectra of strong axis bending moment of girder nodes at (a) A6 and (b) A11 under different combination of environmental loads

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Fig. 19

Power spectra of axial force of girder nodes at (a) A6 and (b) A11 under different combination of environmental loads

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Fig. 20

The spatial variation of power spectra of weak axis bending moment along the bridge girder under turbulent wind and waves

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Fig. 21

Power spectra of (a) heave motion, (b) torsional moment (Mx), and (c) weak axis bending moment (My) of girder nodes at A6 under different combination of environmental loads

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Fig. 22

Power spectra contributions from dominant modes for sway motion, axial force, strong axis bending moment, and weak axis bending moment along the bridge girder under LC3 with irregular waves, and under LC5 with turbulent wind and irregular waves. Waves are short-crested and second-order difference-frequency wave loads are considered: (a) sway under waves, (b) sway under turbulent wind and waves, (c) axial force under waves, Fx, (d) axial force under turbulent wind and waves, Fx, (e) weak axis bending moment under waves, My, (f) weak axis bending moment under turbulent wind and waves, My, (g) strong axis bending moment under waves, Mz, and (h) strong axis bending moment under turbulent wind and waves, Mz.

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