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

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Zhengshun Cheng ◽  
Zhen Gao ◽  
Torgeir Moan
Keyword(s):  
Axial Force ◽  
Wind Wave ◽  
Bending Moment ◽  
Wave Loads ◽  
Environmental Loads ◽  
Turbulent Wind ◽  
Load Effects ◽  
Floating Bridge ◽  
Bridge Girder ◽  
Sway Motion

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.

scholarly journals Dynamic Response Analysis of a Floating Bridge Subjected to Environmental Loads

2018 ◽  
Author(s):  
Zhengshun Cheng ◽  
Zhen Gao ◽  
Torgeir Moan
Keyword(s):  
Wind Wave ◽  
Bending Moment ◽  
Response Analysis ◽  
Ultimate Limit State ◽  
Wave Loads ◽  
Frequency Wave ◽  
Environmental Loads ◽  
Load Effects ◽  
Floating Bridge ◽  
Sway Motion

Designing floating bridges for wide and deep fjords is very challenging. The floating bridge is subjected to wind, wave, and current loads. All these loads and corresponding load effects should be properly evaluated, e.g. for ultimate limit state design check. In this study, the wind-, wave- and current-induced load effects of an end-anchored floating bridge are numerically investigated. The considered floating bridge, about 4600 m long, was an early concept for crossing Bjørnafjorden, Norway. It consists of a cable-stayed high bridge part and a pontoon-supported low bridge part, and has a number of eigen-modes, which might be excited by the relevant environmental loads. Numerical simulations show that the sway motion and strong axis bending moment along the bridge girder are primarily induced by wind loads, while variations of heave motion and weak axis bending moment are mainly induced by wave loads. Current loads mainly provide damping force to reduce the variations of sway motion and strong axis bending moment. Turbulent wind can cause significantly larger low-frequency resonant responses than second-order difference-frequency wave loads.

Floating Bridge Technology: Prediction of Extreme Environmental Load Effects

2016 ◽  
Author(s):  
Bruno Villoria
Keyword(s):  
Environmental Load ◽  
Environmental Loads ◽  
Load Effects ◽  
Floating Bridge ◽  
Bridge Technology

The present paper describes the different concepts considered for the crossing of Bjørnfjorden. The emphasis is put on the methodology implemented for the estimation of the extreme environmental loads the chosen structure will be exposed to.

Combined Loading Criteria for Titanium Risers

2002 ◽  
Author(s):  
Olav Aamlid ◽  
Kristoffer Aronsen ◽  
Knut Olav Ronold ◽  
Kim Mo̸rk ◽  
Carl Baxter
Keyword(s):  
Axial Force ◽  
State Of The Art ◽  
Bending Moment ◽  
Uncertainty Modeling ◽  
Combined Loading ◽  
Design Equation ◽  
Data Basis ◽  
Load Effects ◽  
Calibration Study ◽  
Pipeline Design

DNV has, in cooperation with partners from the industry, carried out a joint industry project with the aim to develop recommended practice with respect to the design of titanium risers. As a part of this work, calibrated design formulae for combined loading have been established. The considered load situation is a combination of internal overpressure, bending moment and axial force. The data basis for the calibration study encompasses results from 12 finite element simulations with varying diameter to thickness ratio and internal pressure exposed to bending moment and axial force. With the design equation for steel risers, taken from the DNV Offshore Standard (OS-F201) Dynamic Risers, as a basis, the titanium data basis was investigated using state-of-the art methodology with an uncertainty modeling for load effects in compliance with recent research and development projects for risers and pipeline design. The outcome of this work is a design equation with reliability based calibration of safety factors that comply with the overall safety objective in the above offshore standard.

Extreme Response Analysis of an End-Anchored Floating Bridge

2019 ◽  
Author(s):  
Zhengshun Cheng ◽  
Zhen Gao ◽  
Torgeir Moan
Keyword(s):  
Axial Force ◽  
Limit State ◽  
Bending Moment ◽  
Contour Method ◽  
Response Analysis ◽  
Ultimate Limit State ◽  
Extreme Response ◽  
Structural Responses ◽  
Floating Bridge ◽  
Extreme Responses

Abstract During the design of a floating bridge, extreme structural responses are required to be properly evaluated for ultimate limit state (ULS) design check. This study addresses the estimation of extreme structural responses for an end-anchored curved floating bridge. The floating bridge, about 4600 m, consists of a cable-stayed high bridge part and a pontoon-supported low bridge part. The long-term extreme responses are approximated by using a engineering approach, i.e., the environmental contour method. The sea state with 100-year environmental conditions is considered, and a 90% fractile is used to calculate the short-term extreme responses by using the Gumbel method and the mean up-crossing rate (MUR) method based on 100 1-hour simulations with different seeds. The extreme responses are expressed as μ + κσ, where μ and σ are the ensemble mean and standard deviation, and κ is a multiplying factor. Numerical results show that structural responses are close to Gaussian distributed. κ of axial force and strong axis bending moment along the bridge girder estimated by both the Gumbel and MUR methods vary in the vicinity of 4. κ estimated by the two method deviates, especially for axial force. Moreover, for both methods the estimated κ deviates more significantly if fewer ensembles are used.

Closed-form moment-curvature relations for reinforced concrete cross sections under bending moment and axial force

2016 ◽  
Vol 129 ◽  
pp. 67-80 ◽  
Author(s):  
Pedro Dias Simão ◽  
Helena Barros ◽  
Carla Costa Ferreira ◽  
Tatiana Marques
Keyword(s):  
Reinforced Concrete ◽  
Closed Form ◽  
Axial Force ◽  
Cross Sections ◽  
Bending Moment

Preliminary Parametric Assessment of a Bolted Endplate Joint under Combined Axial Force and Cyclic Bending Moment

2011 ◽  
Vol 255-260 ◽  
pp. 718-721
Author(s):  
Z.Y. Wang ◽  
Q.Y. Wang
Keyword(s):  
Finite Element Analysis ◽  
Axial Force ◽  
Seismic Design ◽  
Axial Load ◽  
Failure Modes ◽  
Bending Moment ◽  
Element Analysis ◽  
Cyclic Behaviour ◽  
Joint Behaviour ◽  
Steel Joints

Problems regarding the combined axial force and bending moment for the behaviour of semi-rigid steel joints under service loading have been recognized in recent studies. As an extended research on the cyclic behaviour of a bolted endplate joint, this study is performed relating to the contribution of column axial force on the cyclic behaviour of the joint. Using finite element analysis, the deteriorations of the joint performance have been evaluated. The preliminary parametric study of the joint is conducted with the consideration of flexibility of the column flange. The column axial force was observed to significantly influence the joint behaviour when the bending of the column flange dominates the failure modes. The reductions of moment resistance predicted by numerical analysis have been compared with codified suggestions. Comments have been made for further consideration of the influence of column axial load in seismic design of bolted endplate joints.

Design of floating bridge girders against accidental ship collision loads

2016 ◽  
Author(s):  
Yanyan Sha ◽  
Jørgen Amdahl
Keyword(s):  
Finite Element Models ◽  
Cruise Ship ◽  
Box Girder ◽  
Global Response ◽  
Ship Structure ◽  
Steel Box Girder ◽  
Floating Bridge ◽  
Bridge Girder ◽  
Ship Collision ◽  
The Impact

The Norwegian Public Roads Administration is running a project “Ferry free coastal route E39” which includes replacing ferry crossings by bridges or tunnels across fjords in Western Norway. A floating bridge concept was proposed in the fjord-crossing project for Bjørnefjorden. As there are regular cruise routes passing by the bridge, it raises the concern for the consequences of accidental ship collision with the bridge girder. During the collision, the interactions between the bridge girder and the ship structure can be significant. Thus, in the design of the proposed bridge it is vital to evaluate the safety of the ship and the bridge. In this paper, detailed finite element models of a cruise ship and a steel box girder are developed. The impact scenarios and structural damages are studied. The results show that the proposed bridge girder design is generally safe to resist normal accidental ship collision loads. Numerical model of the whole bridge is also developed for further study of bridge global response subjected to ship collision load.

Load Regime Diagram of a Pipe With Cyclically Plastic Bending

2002 ◽  
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Boundary Curve ◽  
Plastic Behavior ◽  
Cyclic Bending ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Load Regime ◽  
Reversed Cyclic ◽  
Cyclic Bending Moment

The criteria of piping seismic design based on linear elastic analysis has been proved to be conservative, which is mainly because the influence of plastic deformation on piping dynamic response is neglected. In the present paper, a pipe under seismic excitation is simplified as an beam with tubular cross section subjected to steady axial force and fully reversed cyclic bending moment, and the elastic-plastic behavior of the pipe is studied. Various behavior of the pipe under different combinations of axial force and cyclic bending moment is discussed and the boundary curve equations between them are obtained. Also the load regime diagram for a pipe which is formed by the boundary curve equations in the loading plane is given, from which the elastic-plastic behavior of the pipe can be determined directly.

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