Wave and wave-current actions on a bridge tower: An experimental study

2018 ◽  
Vol 22 (6) ◽  
pp. 1467-1478 ◽  
Author(s):  
Chengxun Wei ◽  
Daocheng Zhou ◽  
Jinping Ou
Keyword(s):  
Pile Group ◽  
Ocean Waves ◽  
Experimental Results ◽  
Dynamic Responses ◽  
Wave Forces ◽  
Base Shear ◽  
Shear Forces ◽  
Natural Period ◽  
Motion Responses ◽  
Bridge Tower

With a scale of 1:100, an experimental model was set up to investigate the dynamic responses of a bridge tower subjected to ocean waves and wave-currents. The bridge tower was designed for a sea-crossing bridge. Based on a pile-group foundation, it was designed to be a typical gate-type structure. Wave-induced base shear forces on the foundation and motion responses of the tower were measured and analyzed. The experimental results show that when a wave period is close to the natural period of the structure, an obvious resonance will be induced on the structure. For different wave action angles, the longitudinal incident waves induced the largest longitudinal base shear forces on the foundation and the greatest dynamic motions on the upper tower of the structure. Because of the pile-group effectiveness, the incident directions of the waves and the wave periods affect the acting forces on the foundation of the structure. For wave-current actions, forward currents increase the forward wave forces on the foundation and decrease the backward forces, but do not significantly affect the motion responses of the upper tower. The experimental results can be used as the verification data for numerical calculations. With the structural forms of the pile-group and the gate-type tower being typical, the results given in this study can be used as a reference for similar engineering designs.

scholarly journals Experimental study on dynamic effect of freestanding tower of sea-crossing bridge under wave load

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhou Daocheng ◽  
Zhang Bo ◽  
Xue Sisi ◽  
Wei Chengxun ◽  
Ou Jinping
Keyword(s):  
Experimental Study ◽  
Dynamic Effect ◽  
Pile Group ◽  
Test Model ◽  
Wave Loads ◽  
Test Results ◽  
Base Shear ◽  
Wave Load ◽  
Vibration Period ◽  
Bridge Tower

AbstractThere is a debate over whether the sea-crossing bridges undergo dynamic motions when exposed to wave loads. In order to verify the dynamic effect of the tower of sea-crossing bridge under wave load, an experimental study on dynamic effect of a freestanding tower of sea-crossing bridge is accomplished in this paper. Firstly, a test model for a typical bridge tower of pile group foundation under wave load is established by using a scale of 1:100. Secondly, a typical sea condition is designed for the response test of the bridge tower under wave load. The test results indicated that obvious vibration of top the tower occurs when the wave load period is close to the natural vibration period of the structure, and both displacement and base shear are amplified. The results in this paper will provide an important reference for whether the dynamic effect of wave load should be considered in the designs of bridge structure under wave load.

scholarly journals Numerical investigation of dynamic responses and mooring forces of submerged floating tunnel driven by surface waves

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xuebin Chen ◽  
Zhiwu Chen ◽  
Shuqun Cai ◽  
Wei Xu ◽  
Xianrong Zhuo ◽  
...  
Keyword(s):  
Numerical Model ◽  
Surface Waves ◽  
Stokes Equations ◽  
The Body ◽  
Dynamic Responses ◽  
Floating Body ◽  
Wave Forces ◽  
Motion Responses ◽  
Submerged Floating Tunnel ◽  
Mooring Forces

Abstract Based on Navier–Stokes equations, a numerical model for studying the dynamic responses and mooring forces of the moored Submerged Floating Tunnel (SFT) driven by surface waves is presented in this paper. The mechanics models of the vertically and inclinedly moored floating body under wave forces are built, and the overset meshing method is employed to dynamically configure the computational meshes. Two laboratory experiments are used for validating the numerical model in terms of motion responses and mooring forces of the SFT, indicating the proposed model is capable of accurately simulating the instantaneous position of the body under the wave action. This hydrodynamic model is then utilized to simulate the wave–structure interaction of the prototype SFT designed for Qiongzhou Strait located between Mainland China and Hainan Island. The effects of the fundamental structure parameter, or the inclined mooring angle (IMA), on the dynamic responses of SFT are analyzed. The numerical experiments not only shed light on the mooring forces, as well as pitch, sway and heave responses of the SFT with various values of IMA, but also provide guidance for the choice of IMA in engineering design. The range of IMA is separated into five zones, and Zone 2 is regarded as the best choice for the design of IMA for both motion displacements and mooring forces are relatively small in this zone. Zone 3 is considered to be the worst choice as not only are motion responses of SFT severe in this zone, but also the mooring chains are at the risk of going slack under severe wave conditions.

A NUMERICAL STUDY OF DAMAGE DETECTION OF UNDERWATER PIPELINE USING VIBRATION-BASED METHOD

2012 ◽  
Vol 12 (03) ◽  
pp. 1250021 ◽  
Author(s):  
XUE-LIN PENG ◽  
HONG HAO
Keyword(s):  
Condition Monitoring ◽  
Wave Force ◽  
Ocean Waves ◽  
Dynamic Responses ◽  
Ambient Vibration ◽  
Wave Forces ◽  
Fe Model ◽  
Noise Levels ◽  
Vibration Properties ◽  
Pipeline Vibration

This paper presents a numerical investigation of the feasibility of condition monitoring of untrenched pipelines at seabed through ambient vibration measurements. A finite element (FE) model is developed to calculate the dynamic responses of pipelines to ambient wave forces. The model takes into consideration the interaction between the ocean waves, submarine pipeline, and seabed. The fluid around the pipeline is simulated using the acoustic fluid elements, while soil is simulated by springs and dashpots. The ambient hydrodynamic force in the marine environment is simulated based on the Joint North Sea Wave Observation Project (JONSWAP) spectrum. The transfer function from the wave surface elevation to the wave force is used to get the wave force spectrum. The dynamic responses of the pipe structure with different assumed damage conditions to the ambient wave forces are calculated. The calculated dynamic responses are assumed as measured ambient vibration data in condition monitoring to extract the pipeline vibration properties, which in turn are used in the FE model updating calculation to identify the pipeline conditions. Different noise levels are introduced into the calculated dynamic responses to simulate uncertainties that may arise from measurement and ambient hydrodynamic environment. The effect of noise levels on the extraction of pipeline vibration properties, and on the identification of the pipeline conditions is investigated.

Characteristics of wave forces on pile group foundations for sea-crossing bridges

2021 ◽  
Vol 235 ◽  
pp. 109299
Author(s):  
Zhenguo Wang ◽  
Wenliang Qiu
Keyword(s):  
Pile Group ◽  
Wave Forces

scholarly journals A simplified method for seismic analysis of rooftop telecommunication towers

2007 ◽  
Vol 34 (10) ◽  
pp. 1352-1363
Author(s):  
Rola Assi ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Seismic Excitation ◽  
Base Shear ◽  
Shear Forces ◽  
Modal Superposition ◽  
Dynamic Analyses ◽  
Simplified Method ◽  
Excitation Dynamic ◽  
Telecommunication Towers ◽  
Definition Of

A simplified method is presented in this paper for the estimation of forces at the base of telecommunication towers mounted on building rooftops due to seismic excitation. Although some codes and standards propose simplified methods for the evaluation of base shear forces for towers founded on ground, no method yet exists for the evaluation of overturning moments. The proposed simplified method is based on numerical simulations using truncated modal superposition, which is widely used for seismic analysis of linear structures. The method requires the prediction of input seismic acceleration at the building–tower interface, the definition of an acceleration profile along the building-mounted tower, and the determination or evaluation of the mass distribution of the tower along its height. The method was developed on the basis of detailed dynamic analyses of three existing towers assumed to be mounted separately on three buildings. It was found that the method yields conservative results, especially for the overturning moments.Key words: self-supporting towers, earthquake, horizontal excitation, dynamic analysis, acceleration, modal superposition.

scholarly journals Wave interaction with Floating platform of different shapes and supports using BEM approach

2017 ◽  
Vol 14 (2) ◽  
pp. 115-133
Author(s):  
Anoop I. Shirkol ◽  
Nasar Thuvanismail
Keyword(s):  
Numerical Model ◽  
Elastic Plate ◽  
Wave Interaction ◽  
Wave Force ◽  
Ocean Waves ◽  
Wave Forces ◽  
Thin Elastic Plate ◽  
Floating Platform ◽  
Floating Elastic Plate ◽  
Different Shapes

Wave interaction with a floating thin elastic plate which can be used as floating platform is analyzed using Boundary Element Method (BEM) for different shapes such as rectangular, circular and triangular. Different support conditions are considered and the performance of the floating platform under the action of ocean waves is explored. The study is performed under the assumption of linearized water wave theory and the floating elastic plate is modelled based on the Euler-Bernoulli beam theory. Using Galerkin’s approach, a numerical model has been developed and the hydrodynamic loading on the floating elastic plate of shallow draft (thickness) is investigated. The wave forces are generated by the numerical model for the analysis of the floating plate. The resulting bending moment and optimal deflection due to encountering wave force is analysed. The present study will be helpful in design and analysis of the large floating platform in ocean waves.

A Study of Biomass Material Pretreatment by Microwave-Based Heating

2011 ◽  
Vol 347-353 ◽  
pp. 2991-2995
Author(s):  
Kuo Hsiung Tseng ◽  
Yong Fong Shiao ◽  
Yu Ting Yeh
Keyword(s):  
Taguchi Method ◽  
System Performance ◽  
Experimental Results ◽  
Dynamic Responses ◽  
Pennisetum Purpureum ◽  
Actual System ◽  
Arx Model ◽  
Parameter Combination ◽  
Plan Optimization ◽  
Auto Regressive

This study discussed the application of microwave-based heating for the pretreatment of biomass material, and selected Pennisetum purpureum for pretreatment. The Taguchi method was used to plan optimization experiments for pretreatment parameter levels, and measured the dynamic responses. With lower frequency of experiments, this study analyzed and determined a parameter combination in which Pennisetum purpureum can be rapidly heated to 190°C. The experimental results indicate an eight-order ARX model (Auto-Regressive eXogeneous) was representative of actual system performance, and the fit was 99.13%.

Influence of Wave Group Characteristics on the Motion of a Semisubmersible in Freak Waves

2014 ◽  
Author(s):  
Yanfei Deng ◽  
Jianmin Yang ◽  
Longfei Xiao
Keyword(s):  
Time Lag ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Hydrodynamic Performance ◽  
Wave Crest ◽  
Time Lags ◽  
Wave Group ◽  
Freak Waves ◽  
Motion Responses ◽  
Group Characteristics

In the last few decades, the hydrodynamic performance of offshore structures has been widely studied to ensure their safety as well as to achieve an economical design. However, an increasing number of reported accidents due to rough ocean waves call for in-depth investigations on the loads and motions of offshore structures, particularly the effect of freak waves. The aim of this paper is to determine the sea conditions that may cause the maximum motion responses of offshore structures, which have a significant effect on the loads of mooring systems because of their tight relationship. As a preliminary step, the response amplitude operators (RAOs) of a semisubmersible platform of 500 meters operating depth are obtained with the frequency-domain analysis method. Subsequently, a series of predetermined extreme wave sequences with different wave group characteristics, such as the maximum crest amplitude and the time lag between successive high waves, are adopted to calculate the hydrodynamic performance of the semisubmersible with mooring systems in time-domain. The paper shows that the maximum motion responses not only depend on the largest wave crest amplitude but also the time lags between successive giant waves. This paper will provide an important reference for future designs which could consider the most dangerous wave environment.

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