Effects of seawater–structure–soil interaction on seismic performance of caisson-type quay wall (original) (raw)
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Investigation of Soil and Quay Wall Interaction Under Seismic Loading
Optimal design of Quay Walls against seismic forces has become a challenge for engineers. For countries that are placed on the earthquake belt, it is very important to investigate the strength and behavior of quay walls against earthquakes. In this study, the behavior of cantilever concrete quay walls placed on the saturated cohesive soil is studied using finite element method in ANSYS Software. Patterns of the interaction between soil and structure prove to be very complicated. On the other hand, with the consideration of the interactions between soil and structure under the seismic forces, the problem will be made much more complicated. In the present study, height of the quay walls, soil type, strength and duration of the earthquake on the Bending moment against the wall are considered and pressure distributions behind the wall have been investigated.
Seismic Behavior Evaluation of the Hump-Back Block Type Quay Wall
A quay is a long platform beside the sea or river where boats and vessels can berth and loaded and unloaded. Gravity quay wall are the most common type of marine structures and some advantages of this type are easy construction technology, good durability and suitable costs. In safety of harbor facilities, gravity quay wall plays a key and drastic role in supporting of harbor structure against some probable dangers. Any abrupt movement or destruction that occurs by an earthquake may result huge economic losses and some irreparable problems. For better understanding of influence of some basic components, dynamic analysis on different geotechnical parameters such as; backfill elasticity module, backfill internal friction, backfill special weight, seabed relative density and wall’s concrete special weight have been done. A two finite element program PLAXIS 2D, is used to carry out all numerical experiments on a reference model. Results show that in all cases where the foundation soil is relatively soft and loose, a gravity quay wall shows more displacements at foundation level and unsuitable behavior to rotate towards the sea. This study has manifested a specific relation between soil seabed density and seabed width, moreover, in a hump-back quay wall maximum amount of settlement of backfill occurs at a predictable distance from the wall that it could account a different and practical behavior, in comparison with other types of quay wall. So, informing of these predictable behaviors could help us in achieving an optimized design.
Evaluation of the seismic performance of a caisson and an L-type quay wall
The damage caused by earthquakes in the past twenty years has revealed a generally high vulnerability of port structures. This fact, together with consideration of the economic importance of port structures, indicates the need for better seismic design approaches for berth structures and cargo handling facilities. In the recent decades, there have been many incidences of failure of gravity quay walls. These failures have stimulated great progress in the development of performance-based design methods. In this paper, several of these design approaches were studied experimentally and analytically. A series of shaking tank 1 g tests was performed using 1/15 scaled a caisson and an L-type quay wall with two different gravel backfill materials on firm sea bed conditions without liquefaction under different sinusoidal seismic loads. 1 g shaking tank tests were executed to verify the applicability of the sliding block concept and to estimate the performances of these quay wall types The shaking tank tests provided insight into the wall displacements and the dynamic thrusts by analyzing force components at the contact surface between the saturated gravel backfill soil and the wall.
Effect of Foundation and Backfill Relative Density on the Seismic Performance of a Quay Wall
2018
The seismic performance of quay walls is of vital importance for trade operations that may affect the local or national economy. Depending on the method or quality of construction, some quay walls may be vulnerable to large permanent seaward movements, settlements and tilt, which may disrupt their operation after a strong ground shaking. This article examines the seismic performance of the quay wall of a Greek port through an extensive numerical investigation using effective-stress analysis. The quay wall consists of a stack of concrete blocks having a height of 14.3 m and founded on a layer of rockfill and sandy gravel. The material properties are obtained from laboratory tests based on three boreholes at the quay wall site, SPT tests and a cross-hole test. For non-cohesive soils, a modification of the generalized plasticity model by Pastor et al. (1990) for monotonic and cyclic loading is used, whereas for cohesive soils, the Mohr-Colomb elasto-plastic model combined with hysteret...
Insight into seismic earth and water pressures against caisson quay walls
Géotechnique, 2008
Motivated by the need to explain the large displacement and rotation that numerous caisson-type quay walls suffered in the port of Kobe during the devastating 1995 earthquake, a detailed numerical analysis is presented for the response of such a wall from Rokko Island. Utilising the Pastor–Zienkiewicz elastoplastic constitutive model, an effective stress dynamic analysis is performed using as input the accelerogram recorded 32 m below the ground surface in the nearby Port Island. The evolution during shaking of lateral displacements, plastic strains and pore water pressures sheds some light on the complex interplay of several simultaneously occurring phenomena: the development of oscillatory inertia forces on the wall, in phase or out of phase with the backfill soil and water pressures; the simple-shear seismic deformation of the soil and the ensuing initial development of positive excess pore water pressures in the backfill and the foundation soil; the extensional deformation devel...
Influence of Far and Near Fault Earthquake on Dynamic Behavior of Block Type Quay Wall
Electronic Journal of Geotechnical Engineering, 2017
By scientific advancement in recent years, our knowledge about earthquake and distance effects of faults fundamentally has improved which it has provided basis of definition in seismic design of structures. Dynamic behavior of a block type quay wall that is placed near or far to a fault is not exceptional. Comparison of time history and frequency content in multiple registrations recorded of far and near quake faults shows that the reached vibration to different points can have severe dependence to fault distance, relative positioning to the direction of the fault, and characteristic of source parameters. In the beginning of this article general characteristics of far and near earthquake-faults is defined and then in separated form, impacts of far or near faults on two different common types of block type quay wall have been considered. All analysis by finite element method and PLAXIS 2D software is performed and soil was modeled, Elasto – Plastic with Mohr-Coulomb criteria.
Seismic Effective-Stress Analysis of Caisson Quay Walls : Application to Kobe
SOILS AND FOUNDATIONS, 2005
Deformation-based seismic design of gravity quay-walls requires realistic computation of residual deformations. This article presents an effective-stress analysis method, which is based on an elasto-plastic constitutive model formulated into a finite-difference algorithm. The model is applicable to cohesionless soils, for a wide range of relative densities and confining pressures. The formulation is applied first to re-analyze one of the failed caisson-type quay-walls of Rokko Island during the 1995 Kobe (Hyogoken-nambu) earthquake (Case 1). Subsequently, it is applied to analyse three closely related case studies of quay-walls, subjected to the same earthquake excitation, to demonstrate the effects of ground improvement on the wall performance. Case 2 considers a quay-wall in which both the foundation and backfill consist of improved, non-liquefiable soils. Case 3 considers a quay-wall in which the backfill soil remains liquefiable, whereas the foundation soil has been improved. Finally, in Case 4 the foundation soil is liquefiable, and the backfill soil improved. The results are consistent with both field observations and earlier independent computer simulations by Iai et al. 1998 which were based on the finite-element method and a different constitutive model.
2021
In this paper, the effect of selecting the earthquake equivalent acceleration coefficient on the seismic performance of the broken-back quay wall of Pars Petrochemical Port has been studied as a case study. In this regard, the recommendations and relationships presented in the old and new editions of the Japanese Maritime Codes (OCDI, 2002, 2009) are more comprehensive and complete than other codes, especially in the seismic design of quay wall structures. The results illustrated that the proposed relationships of horizontal earthquake acceleration coefficient (kh) based on the new version of the Japanese maritime code is more suitable and helps predict the seismic performance of this type of quay walls more accurately and their realistic design. Moreover, based on acceleration time-histories resulting from seismic hazard studies at the site, using FLAC2D software, the values of horizontal displacement of the quay wall have been investigated, and based on that, earthquake coefficien...
Effective-stress seismic analysis of a gravity multi-block quay wall
Soil Dynamics and Earthquake Engineering, 2018
The seismic performance of an existing gravity quay wall consisting of concrete blocks is investigated using effective stress analysis. The study focuses on the effect of the uncertainty associated with the spatial variability of the material properties in the foundation and backfill zones on the horizontal displacements, settlements and rotations of the wall as well as of porewater pressure behind the wall. A modification of the comprehensive generalized plasticity Pastor-Zienkiewicz constitutive model is used for modelling the cyclic behavior of the sandy gravel and rockfill. Four different numerical models are considered in an extensive parametric study consisting of 180 analyses. The results show that, for constant average relative density, the effects of its spatial variability are smaller than the effects of the frequency characteristics of the earthquake excitation. Moreover, it is shown that a foundation of high relative density may decrease significantly settlements and rotation of the wall, but some reduced horizontal displacements caused partly by block-to-block sliding may still take place. Excess porewater pressures immediately behind the wall are mostly negative, increasing the soil resistance.