Quay Wall Structure Research Articles

Analysis of Covered Pile on Multi-row Pile Quay

The multi-row pile quay wall is an innovative permanent structure comprising multiple piles, relieving slabs, flood control walls, and backfill sand. Although it additionally serves as a functional wharf, the research on multi-row pile quay walls remains insufficient. Considering the Changxing harbor Pool as a case study, this research develops a multi-row pile quay wall structure using the three-dimensional finite element software PLAXIS 3D. We investigated the effects of covered piles, pile row spacing, spacing between covered piles, and the stiffness of the front pile on the internal force and deformation of the structure. The findings indicated that the presence of the covered piles results in minimal overall displacement of the multi-row pile quay wall and reduces the bending moment in the front pile. Considering the site conditions and project costs, the sensitivity of different parameters to the retaining effect was evaluated in the order of the stiffness of the front pile > pile row spacing > spacing between the covered piles. Building on this, an optimized design scheme is proposed to reduce the bending moment in the front pile by 50% compared to the original scheme, thereby offering valuable insights for future engineering projects.

Optimum Open Cell Sheet Pile (OCSP) Quay Wall System in Port Said, Egypt

The principal intent of this paper was to propose a new quay wall system, whose validity was verified; to play the same role of the existing diaphragm quay wall at East Port Said Port in Egypt as an optimum quay wall. Firstly, the background information of the proposed Open Cell Sheet Pile (OCSP) was introduced. Then, a parametric study was conducted including 24 cases using soil constitutive Hardening Soil Model (HSM) by the PLAXIS 3D Finite Element Software. The behavior of the proposed system was presented graphically, and the effectiveness of the OCSP system was found satisfactory with the possibility to increase the seabed depth in front of the wall up to four meters. The system also was consisted of a bored piles group to carry the heavy loads generated by the gantry crane. Finally, the construction cost of the OCSP was compared to the existing quay wall structure system for evaluating the system design optimization.

Dynamic Behavior of Quay Walls According to N-values of Backfill and Amplitude of Seismic Accelerations

Sand soil discharge, which seemed to be the liquefaction damage, was observed in the backfill of a quay wall structure during the Pohang earthquake in 2017. This discharge occurred because the bearing capacity decreased owing to the loss of effective stress, which was caused by the increase in the excess pore-water pressure with the dynamic loads from the earthquake. In this study, the effects of the variations in the N-value of the backfill of the quay structure and the seismic acceleration coefficient were investigated for increasing excess pore-water pressure and decreasing effective stress, owing to the dynamic load from earthquakes.

Seismic performance of block-type quay walls with liquefiable calcareous sand backfill

Block-type gravity quay walls are widely used in remote oceanic regions due to their cost and construction efficiency, where backfill and foundation soil often consist of liquefiable calcareous coral sand. The lack of connection between blocks and hence structure integrity can result in poor seismic performance of block-type quay walls, especially in liquefiable soil. Based on laboratory element tests on calcareous sand, centrifuge shaking table test, and high-fidelity numerical simulation, this paper investigates the seismic performance of block-type quay walls with liquefiable calcareous sand backfill. Undrained cyclic torsional shear tests are conducted on South China Sea calcareous coral sand to determine its dynamic properties, which are used to calibrate the unified plasticity model for large post-liquefaction shear deformation of sand. A centrifuge shaking table test is conducted to obtain the basic physical seismic response of a block-type quay wall in liquefiable calcareous backfill sand. Utilizing the understanding from laboratory tests, fully coupled dynamic effective stress analysis using the calibrated constitutive model is conducted. The influence of seismic input, quay wall structure, and backfill sand properties on the seismic response of the quay wall is analyzed. Input motion intensity and frequency are shown to be influential to the seismic response of the quay wall. Increase of backfill soil density, permeability, and block to block connection can significantly improve the seismic performance of the quay wall.

MINIMIZING BED SCOUR INDUCED BY SHIP BOW-THRUSTERS BY USING QUAY WALL FLOW DEFLECTOR

Recently, the combination of larger bow-thrusters installed with vessels have created higher levels of bed scour action affecting the berthing structure and its overall stability. Therefore, the bed near a quay wall structure must have sufficient strength by placing a bed protection which may cause the cost of the project to rise. This research is carried out to investigate experimentally the effect of modifying the geometry of the quay wall surface on minimizing bed scour. This is done by inserting flow deflectors within the longitudinal direction of the wall surface in order to deflect/minimize the water jet affecting the bed near the quay wall. Experimental tests had been carried out for single and triple deflectors. The results showed that the use of flow deflectors achieved a reduction in bed eroded area in front of quay wall face by about 63%, and causes the start point of erosion to move far away from it; this may improve the stability of quay walls. Therefore, the importance of the present study is testing a new possible measure to improve the stability of quay walls by minimizing the scour in front of the wall and to decrease the cost of bottom protection.

MINIMIZING BED SCOUR INDUCED BY SHIP BOW-THRUSTERS BY USING QUAY WALL FLOW DEFLECTOR

Recently, the combination of larger bow-thrusters installed with vessels have created higher levels of bed scour action affecting the berthing structure and its overall stability. Therefore, the bed near a quay wall structure must have sufficient strength by placing a bed protection which may cause the cost of the project to rise. This research is carried out to investigate experimentally the effect of modifying the geometry of the quay wall surface on minimizing bed scour. This is done by inserting flow deflectors within the longitudinal direction of the wall surface in order to deflect/minimize the water jet affecting the bed near the quay wall. Experimental tests had been carried out for single and triple deflectors. The results showed that the use of flow deflectors achieved a reduction in bed eroded area in front of quay wall face by about 63%, and causes the start point of erosion to move far away from it; this may improve the stability of quay walls. Therefore, the importance of the present study is testing a new possible measure to improve the stability of quay walls by minimizing the scour in front of the wall and to decrease the cost of bottom protection.

Proposal of sheet-pile quay wall structure reinforced by geogrids

Proposal of sheet-pile quay wall structure reinforced by geogrids

THE EFFECT OF SEA SIDE QUAY WALL ROUGHNESS AND INCLINATION ON BED SCOUR INDUCED BY SHIP BOW-THRUSTERS

In order to increase their transport efficiency, modern ships are built with increasingly larger propellers and bow-thrusters. The combination of larger propellers with greater power and a reduction in bed clearance has created higher levels of bed scour action affecting berthing structures. Therefore, propeller-induced scours need to be considered in the design of quay wall structures. In this study, an experimental investigation was carried out to examine the effect of sea side wall roughness and wall inclination angle on the scouring action induced by bowthruster in front of the quay wall. Two different kinds of sea side quay wall surfaces (glass and concrete) as an indicator of wall roughness and four different sea side wall inclination angles ( = 90, 75, 60, and 45) were considered in this study. The results showed that the eroded area has been decreased with the increase of the sea side wall roughness and inclination

Comparative study on the seismic performance of two types of quay wall structures

ABSTRACTA new type of quay wall structure has been proposed to improve the seismic resistance capability of existing sheet pile quay wall structures. The new structure adopts a combination of stabilized soil and geogrid, and this structure is referred to simply as “SG-WALL”. This paper presents a numerical comparative study on the seismic performances of quay wall structures between the newly developed SG-WALL and the traditional anchor pile-reinforced structure. The calculated results, including displacement of sheet pile, ground settlement, bending moment and stress of sheet pile, and excess pore water pressure, were analyzed and discussed. It was shown that both types of improvement methods can effectively reduce the residual displacements of sheet piles after earthquakes. The residual displacements at the top of the sheet piles in SG-WALL structure and the anchor pile-reinforced structure decreased by 35.6 and 38.2%, respectively. In addition, the SG-WALL structure can more significantly reduce the ground settlement due to earthquakes. The maximum ground settlement in SG-WALL structure and the anchor pile-reinforced structure decreased by 67.3 and 58.9%, respectively.

A coupled soil-fluid-structure simulation of the near-field earthquake effects on gravity type quay-walls

This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface (FSI) elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach (IDA) is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.

Numerical simulation of shaking-table tests on soil-stabilized, geosynthetic-reinforced quay-wall structures

ABSTRACT: A new kind of quay-wall structure using geosynthetics has been proposed for renovating existing sheet-pile quay-wall structures to increase their earthquake resistance capability. The proposed structure adopts the combined techniques of stabilized soil and geogrid for a quay-wall, which is referred to simply as an ‘SG-WALL'. The seismic performance of the SG-WALL structure was investigated through a series of shaking-table tests. The test results showed that the SG-WALL structure has a high seismic resistance. A numerical simulation of the shaking-table tests was performed to reproduce the experimental results. The primary objectives of the simulation were to assess the accuracy of the numerical methods adopted in this study in predicting the dynamic responses of the SG-WALL structure, and to identify the key factors that influence its seismic performance. It was found that the displacement of the quay wall during shaking is not sensitive to the length of the geogrid, but the length of the stabilized soil plays a significant role in restricting the displacement of the quay-wall.

Seismic Assessment of Gravity Quay-Wall Structures, Subjected to Near-Fault Ground Excitations

In the current study, a coupled acoustic-structural-soil finite element modelling is used for the seismic assessment of gravity quay-wall structures under near-field excitations. Plane strain elements are used for the wall structure and the neighboring soils. Potential based fluid elements are employed for the seawater modelling. Different types of wave absorption and reflection conditions are presented to the fluid's boundaries. FSI boundary conditions are considered between the seawater interfaces with the quay-wall. Frictional contact elements are employed between the wall/soil interfaces. The numerical model has been validated against field measurements for the permanent drifts for a quaywall located at Kobe Port in Japan. An incremental dynamic analysis approach (IDA) has been used to identify the significance of far and near-field excitations on the non linear response of the structure. In general, at least for models examined in the current study, it is found that the gravity quay-walls are more vulnerable to near-field, in comparison to the corresponding far-field, earthquakes.

DEVELOPMENT OF EARTHQUAKE REINFORCEMENT METHOD FOR GRAVITY-TYPE QUAYWALL BY SHEET PILE INSTALLED AT THE FOOT OF THE CAISSON

The objective of this development is to increase the earthquake resistance performance of gravity caisson quay wall by employing sheet pile at the foot of the caisson. Gravity caisson quay wall with sheet pile realizes the 0.05 point increase of seismic coefficient by comparing usual gravity caisson quay wall. This method can apply existing gravity caisson quay wall which is short of sliding resistance during earthquake. Quay wall structure becomes hybrid type by connecting the head of sheet pile and the caisson and shows both advantages of gravity type structure and sheet pile structure. Underwater shaking table test and 2D dynamic effective stress analysis were done for the proposed hybrid type quay wall structure. Gravity caisson quay wall was designed at the condition of 0.15 design seismic coefficient and 10m water depth at the foot of the structure. The result shows the necessity of 900mmdia. steel sheet pile for the condition of 0.2 design seismic coefficient. 50 percent reduction of caisson crest displacement during earthquake is also obtained. Design criteria for this hybrid quay wall structure is also proposed.

Innovative techniques for quay wall renovation and stabilisation

Very often (old) existing harbour structures have to be renovated and stabilised because of several reasons, such as: - deepening works for modern shipping - capacity increase of the quay - repairs instead of rebuilding - harbour area restrictions This paper will highlight the international experience (design and construct) in quay wall restoration and stabilisation works, using: 1. Marine drilling and foundation techniques (Hydro Soil Services): - ground anchors - VHP grouting - drain structures 2. Innovative bottom protection methods (Bitumar): - prefabricated and immersed fibrous open stone asphalt mattresses and liquid asphalt under water - other, flexible and durable bottom revetments against bottom erosion (scour) near quay wall structures For all those techniques specially designed materials and equipment are developed. A few case studies will illustrate the described methods of quay wall restoration and stabilisation.