scholarly journals Improvement on Structural Forms of Pile Group Foundations of Deepwater Bridges

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Enbo Yu ◽  
Sen Ren ◽  
Haojun Tang ◽  
Yongle Li ◽  
Chen Fang
Keyword(s):  
Slenderness Ratio ◽  
Wave Theory ◽  
Pile Group ◽  
Internal Force ◽  
Induced Response ◽  
Wave Forces ◽  
Long Span ◽  
The Stability ◽  
Wave Induced ◽  
Pile Length

As long-span cross-sea bridges extend to deeper sea areas, the bridge pile tends to increase in its slenderness ratio and becomes more susceptible to waves. To improve the structural stability at the construction stage, this study analyses wave-induced response of foundations. The wave theory and the method used for computing wave forces on foundations are first introduced. Then, a pile group foundation is taken as the research object, and different pile lengths ranging from 16 m to 46 m are considered. The wave-induced response of the piles and the cap is calculated. After understanding the effect of the pile length, three optimized foundations are proposed with the aim of reducing the free length of the pile, and the corresponding finite element models are established to compare their wave-induced response. The results show that the displacement at the top of the foundation increases with the increase in the pile length until the cap partly emerges from water and so does the internal force at the bottom. Setting a constraint in the middle of the piles can reduce their free lengths and is favourable to the wave-induced response of the foundation except for the shearing force. A stronger constraint shows better effects on improvement of the stability of the foundation. The conclusions provide reference for optimization on pile foundations of deepwater bridges.

3D Numerical Modelling of the Wave-Induced Response Around the Circular Caisson Founded on the Seabed

2008 ◽  
Author(s):  
Andrew H. C. Chan ◽  
Jian-Hua Ou
Keyword(s):  
Three Dimensional ◽  
Dynamic Interaction ◽  
Induced Response ◽  
Marine Structures ◽  
Finite Element Program ◽  
3D Numerical Modelling ◽  
Element Program ◽  
Main Factors ◽  
The Stability ◽  
Wave Induced

Wave-induced liquefaction is one of the main factors influence the stability of marine structures. However, the investigation on this phenomenon is complicated as the dynamic interaction between soil, pore fluid and the structure is closely coupled. In order to obtain a better understanding of the wave-induced response around the circular caisson founded in the seabed, three dimensional numerical analyses have been performed using the 3D finite element program DYNE3WAC in order to investigate the wave-induced response around the circular caisson.

scholarly journals WAVE FORCES ON PILES OF VARIABLE DIAMETER

1982 ◽  
Vol 1 (18) ◽  
pp. 108
Author(s):  
Bernard LeMehaute ◽  
James Walker ◽  
John Headland ◽  
John Wang
Keyword(s):  
Wave Field ◽  
Intertidal Zone ◽  
Wave Theory ◽  
Wave Force ◽  
Wave Forces ◽  
Linear Wave ◽  
Inertial Effects ◽  
Linear Wave Theory ◽  
Variable Diameter ◽  
Wave Induced

A method of calculating nonlinear wave induced forces and moments on piles of variable diameter is presented. The method is based on the Morrison equation and the linear wave theory with correction parameters to account for convective inertial effects in the wave field. These corrections are based on the stream function wave theory by Dean (1974). The method permits one to take into account the added wave force due to marine growth in the intertidal zone or due to a protective jacket, and can also be used to calculate forces on braces and an array of piles.

Response and Instability of Sloping Seabed Supporting Small Marine Structures: Wave-Structure-Soil Interaction Analysis

2021 ◽  
pp. 1-20
Author(s):  
Amin Rafiei ◽  
M.S. Rahman ◽  
M.A. Gabr
Keyword(s):  
Interaction Analysis ◽  
Plastic Material ◽  
Wave Structure ◽  
Element Model ◽  
Induced Response ◽  
Perfectly Plastic ◽  
Marine Hydrokinetic ◽  
Elastic Perfectly Plastic ◽  
The Stability ◽  
Wave Induced

Abstract Wave-induced liquefaction in seabed may adversely impact the stability and bearing capacity of the foundation elements of coastal structures. The interaction of wave, seabed, and structure has been studied mostly for only mildly sloping seabed (<5°) using a decoupled approach. However, some of the marine hydrokinetic devices (MHKs) may be built on or anchored to the seabed with significant steepness. The wave-induced response and instantaneous liquefaction within sloping seabed supporting a small structure (representing a small MHK device) are evaluated herein by developing an almost fully coupled finite element model. The effects of coupling approach on the stress response and liquefaction of the seabed soils are investigated. Subsequently, post-liquefaction deformation of seabed soils around the structure is assessed. The poroelasticity equations governing the seabed response coupled with those for other domains are solved simultaneously. For post-liquefaction analysis, the soil is modeled as elastic perfectly plastic material. The development of instantaneously liquefied zones near the foundation is studied in terms of seabed steepness and wave parameters. The changes in the effective stress paths due to the development of liquefied zones are evaluated in view of the soil's critical state. The results indicate that the decoupled solution yields significantly larger stresses and liquefaction zones around the structure. The seabed response and the liquefaction zones become smaller for steeper slopes. The presence of liquefied zones brings the stress state closer to the failure envelope, reduces the confining stresses, and induces larger plastic strains around the foundation element.

Retrofitting of Floating Bridges With Perforated Outer Cover for Mitigating Wave-Induced Responses

2018 ◽  
Author(s):  
K. G. Vijay ◽  
T. Sahoo
Keyword(s):  
Structural Parameters ◽  
Domain Boundary ◽  
Wave Theory ◽  
Hydrodynamic Characteristics ◽  
Wave Forces ◽  
Vertical Force ◽  
Integer Multiple ◽  
Bridge Structures ◽  
Floating Bridges ◽  
Wave Induced

An investigation has been carried out based on multi-domain boundary element method to analyze the mitigation of wave-induced hydrodynamic loads on a pair of floating rectangular bridges by retrofitting the structures with external porous plates. The study is based on the assumptions of small amplitude water wave theory in finite water depth with the characteristics of wave-body interactions remain unaltered along the bridge. Wave past porous structure is modelled using Darcy’s law. Various hydrodynamic characteristics are studied by analyzing the wave forces acting on the floating bridges and the retrofitted porous structures for different wave and structural parameters. With the introduction of a retrofit, the horizontal force on the bridge reduces irrespective of wave and structural parameters, whilst vertical force increases under certain conditions. Moreover, when the distance between the bridges is an integer multiple of half of the wavelength of the incident waves, both the bridges experience optima in horizontal and vertical wave forces, with both these forces being 180° out of phase. The present study is expected to be useful in the design of efficient bridge structures which will reduce wave-induced hydrodynamics loads on the structure and thus enhance the service life of floating bridges.

The Wind-Induced Response of High-Pier Long-Span Continuous Rigid Frame Bridge

2013 ◽  
Vol 639-640 ◽  
pp. 502-509
Author(s):  
Jia Wen Zhang
Keyword(s):  
Element Model ◽  
Internal Force ◽  
Induced Response ◽  
Three Dimension ◽  
Construction Stage ◽  
Comfort Index ◽  
Long Span ◽  
Rigid Frame ◽  
High Pier ◽  
Rigid Frame Bridge

The fluctuating wind field is simulated for digital by using the AR method. A three-dimension finite element model of high-pier long-span rigid frame bridge is presented in this paper. Based on this model, the gust-induced static response of the bridge under the longest cantilevered construction stage is computed. By comparing with those of two similar span rigid frame bridges with low piers, the gust-induced response characteristics of the internal force under the bottom of the piers of the high-pier long-span bridges are investigated, which is helpful for the safe design of bridges. The buffeting responses of the bridge under the longest cantilevered construction stage are also calculated in the time domain, taking account of the longitudinal and vertical turbulence action. Through the spectral analysis of the response, the comfort index of Diekemann is obtained. The effects of buffeting response on the workers’ safety under the most unfavorable construction stage are discussed.

Pier Form Selection and Parameter Analysis of Reinforced Concrete Thin-Wall High Pier

2012 ◽  
Vol 463-464 ◽  
pp. 239-243
Author(s):  
Xiao Mei Dong ◽  
Yan Wen
Keyword(s):  
Reinforced Concrete ◽  
Internal Force ◽  
Parameter Analysis ◽  
Thin Wall ◽  
Force Analysis ◽  
Nonlinear Stability Analysis ◽  
Long Span ◽  
Rigid Frame ◽  
High Pier ◽  
The Stability

Two forms of reinforced concrete pier were compared by internal force analysis and nonlinear stability analysis. According to the restriction of the stability and intensity, size optimization of the high piers’ section is calculated by means of differential coefficient. The results of the calculation and analysis indicate that the parameter optimization of the piers’ section of Long-span continuous rigid frame bridges is feasible by using the optimization model, and the results are provided to the optional design of Long-span continuous rigid frame bridges.

Simulations and Stability Analysis of Wave-Induced Motions of a Freely Floating Body Using ADINA

2015 ◽  
Vol 775 ◽  
pp. 14-18
Author(s):  
Tao Yao ◽  
Zong Yu Chang
Keyword(s):  
Numerical Test ◽  
Wave Theory ◽  
Floating Body ◽  
Hydrodynamic Parameters ◽  
Dimensional Interaction ◽  
Direct Numerical Method ◽  
Body Boundary ◽  
The Stability ◽  
Wave Induced ◽  
Incident Waves

In this article, a direct numerical method is developed to solve two-dimensional interaction problems of wave and floating body with ADINA software. Motion’s equation of the floating body and hydrodynamic parameters are expressed based on potential flow theory. The force and response on the floating body boundary is described in terms of linear minor wave theory. The numerical test is carried out. The result intuitively shows the dynamic response and the stability of floating body under incident waves.

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

Less=Moor: A Time-Efficient Computational Tool to Assess the Behavior of Moored Ships in Waves

2017 ◽  
Author(s):  
Yijun Wang ◽  
Alex van Deyzen ◽  
Benno Beimers
Keyword(s):  
Dynamic Response ◽  
Research Effort ◽  
Equations Of Motion ◽  
Line Tension ◽  
Mooring Line ◽  
Induced Response ◽  
Wave Forces ◽  
Computational Tool ◽  
The Time Domain ◽  
Nonlinear Equations Of Motion

In the field of port design there is a need for a reliable but time-efficient method to assess the behavior of moored ships in order to determine if further detailed analysis of the behavior is required. The response of moored ships induced by gusting wind and/or waves is dynamic. Excessive motion response may cause interruption of the (un)loading operation. High line tension may cause lines to snap, introducing dangerous situations. A (detailed) Dynamic Mooring Analysis (DMA), however, is often a time-consuming and expensive exercise, especially when responses in many different environmental conditions need to be assessed. Royal HaskoningDHV has developed a time-efficient computational tool in-house to assess the wave (sea or swell) induced dynamic response of ships moored to exposed berths. The mooring line characteristics are linearized and the equations of motion are solved in the frequency domain with both the 1st and 2nd wave forces taken into account. This tool has been termed Less=Moor. The accuracy and reliability of the computational tool has been illustrated by comparing motions and mooring line forces to results obtained with software that solves the nonlinear equations of motion in the time domain (aNySIM). The calculated response of a Floating Storage and Regasification Unit (FSRU) moored to dolphins located offshore has been presented. The results show a good comparison. The computational tool can therefore be used to indicate whether the wave induced response of ships moored at exposed berths proves to be critical. The next step is to make this tool suitable to assess the dynamic response of moored ships with large wind areas, e.g. container ships, cruise vessels, RoRo or car carriers, to gusting wind. In addition, assessment of ship responses in a complicated wave field (e.g. with reflected infra-gravity waves) also requires more research effort.

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