Wharf Structure Research Articles

Dynamic Response Characteristics and Pile Damage Identification of High-Piled Wharves under Dynamic Loading

In port dock engineering, high-piled wharves represent one of the primary structural forms. Damage to the foundation piles is a common issue, influenced by external loads such as impact forces during vessel berthing, slope deformations, and operational loads. This study focuses on the Jungong Road Wharf in Shanghai, utilizing FLAC 3D version 6.0 to conduct dynamic calculations under ship impact loading. The dynamic responses of the structure were analyzed, and various internal forces were extracted during the impact event. By combining concrete cracking failure criteria and fatigue damage theories, the effects of ship collisions on the cracking damage of high-piled wharf structures under different scenarios were assessed. Additionally, the applicability of modal flexibility in high-piled wharf scenarios was evaluated through finite element simulations. The results indicate that the dynamic amplification factor caused by dynamic loading is approximately 1.5, underscoring the necessity of considering this effect in the design and impact analysis of high-piled wharves. The impact loading significantly influences the bending moments of the piles, with inclined piles showing the greatest sensitivity. When a designed ship model collides with the high-piled wharf structure at a speed of 0.2 m/s, the tensile stress in the inclined piles reaches 87% of the ultimate tensile strength of the reinforcement. The impact loading has a relatively minor effect on the axial forces of the piles, a limited influence on the bending moments of the beams, but a considerable impact on the axial forces of the beams. Berthing by oversized vessels and unexpected incidents can lead to more severe damage to high-piled wharf structures. In the finite element simulations, modal flexibility effectively identified the locations of damage, with greater changes in modal flexibility correlating with increased damage severity.

Overall structural degradation of a high-piled wharf under chloride invasion and the impact force of ship berthing

The security of high-piled wharfs in offshore environments is subject to long-term threats from chloride invasion and the impact force of ship berthing. This paper presents a comprehensive investigation of the deterioration of high-piled wharfs under the combined effects of chloride invasion and the impact force of ship berthing in a marine environment. A theoretical method is developed to model the degradation of the structural performance of high-piled wharfs based on the full process of reinforcing steel corrosion under the combined action of chloride invasion and stress. The proposed method is validated via comparisons with different theoretical solutions, experiments and field investigations. Furthermore, a three-dimensional finite element model is developed for the overall high-piled wharf structure with pile‒soil interactions using the Drucker‒Prager model (D‒P pile‒soil interaction) under different stiffness degradation states and different impact forces of ship berthing. The FEM model comprehensively considers the degradation of the beams, panels and piles of the wharf structure due to differences in the environment of chloride invasion. After verifying the finite element model, further research is conducted on the time-dependent behaviour of the ultimate lateral bearing capacity and the deformation of the overall structure of the high-piled wharf under different stiffness degradation states at different ages in the service life. The results reveal the failure mechanism of the lateral bearing deformation and the degradation pattern of the lateral bearing performance for the overall high-piled wharf structure under the combined effects of chloride invasion and the impact force of ship berthing. The outcomes of the present solution possess theoretical significance and application value for the security and risk control of high-piled wharfs in service.

Seismic performance assessment of pile supported wharves with seismic isolation system considering pile-soil interaction

Pile-Supported Wharves (PSW) are critical for maritime operations but are highly vulnerable to seismic events, which can disrupt port activities. Previous seismic events have highlighted that short free length piles in wharf structures are particularly prone to earthquake damage. This paper aims to mitigate damage between the wharf deck and piles connections by adopting the seismic isolation systems. Conventional Wharf (CW) and Isolated Wharf (IW) structures were comprehensively assessed, focusing on Pile-Soil Interaction (PSI), using the finite element software OpenSees for advanced numerical simulations. Non-Linear Time History Analysis (NLTHA) of CW and IW has been conducted to verify the design under Contingency Level Earthquake (CLE) and Maximum Considered Earthquake (MCE) scenarios. The analysis aims to enhance the performance of short free length piles within the IW structure. Comparative analysis of fragility curves between CW and IW structures shows that isolation systems significantly reduce seismic fragility by 49%, 60%, and 67% at the MCE level for minimal damage, control & repairable damage and life safety protection across three performance levels, respectively. These findings indicate that the implementation of isolation measures has significantly enhanced the seismic performance and safety of PSW structures.

A data-based and physics-informed Bayesian updating method for deterioration models of RC structures in marine environment

Deterioration models of reinforced concrete (RC) in marine environment, to be applied to existing structures, usually need to be calibrated with long-term in-situ data. The Bayesian model updating provides a framework to incorporate measured data into existing models to make them more realistic. The measured chloride concentrations of concrete at different depths are related to each other through the Fick’s second law, but they are treated as independent in existing updating methods, which affects the accuracy of model updating. To solve this issue, this paper proposes a data-based and physics-informed (DBPI) likelihood function to incorporate the physical law behind the measured data into Bayesian updating framework, whose validity is first confirmed through numerical examples, and then it is applied to the durability assessment of an existing wharf structure in marine environment. The parameters involved in the chloride ingress model and the critical chloride concentration model are updated using the data from durability inspections. The durability performance of the structure is then assessed using the updated models, which is consistent with the actual surface deterioration observed in the two inspections. Discussion of the updated results reveals that ignoring the physical law behind the measured data may result in incorrect inferences of the chloride ingress model and multi-mode distribution of the updated parameters, which is solved by using the proposed DBPI likelihood function, and the accuracy of Bayesian updating is significantly improved.

Interaction characteristics between the large ship-rubber fenders-wharf structure in deep-water considering the flexibility of the wharf structure

High pile-supported wharf structures in offshore deep water have significant flexibility due to long free ends and large slenderness ratios of the pile bodies, resulting in substantial deformation of the pile body under kinds of loads. In the design of this new type of wharves, it is expected to consider the characteristic of elastic deformation of pile body absorbing a portion of the ship impact energy reasonably. However, the existing calculation method still adopts the theoretical formulas of traditional wharf structures, failure to incorporate this advanced design concept fully. In order to solve this, firstly, a comprehensive three-dimensional numerical simulation model encompassing large ship, rubber fenders and wharf structure, was developed using Ansys/LS-Dyna, and the calculation model was validated against the existing research results. Subsequently, dynamic response characteristics of wharf structures during the normal berthing of ships were examined meticulously, and the variations in absorption energy and reaction forces of rubber fenders and wharf structures were analyzed systematically. And then the analysis results were compared with previous research, the limitations of the existing design code for wharf structures were discussed as well. Finally, the findings demonstrate that peak values of absorption energy and energy transfer times increase with the increase of ship loading capacities. And the elastic deformation of the wharf structure indeed absorbs considerable partial of the impact energy effectively, with about 30 % for conditions in this study, leading to lower impact forces acted on the wharf structure. Moreover, the maximum pile top displacement of the wharf structure is also smaller than that reported in the existing literature in the same load condition, indicating that considering the structural flexibility in the design of this new type of wharf structure is more in line with reality, and it is more reasonable and economical as well.

High-Accuracy and Fast Calculation Framework for Berthing Collision Force of Docks Based on Surrogate Models

The accurate prediction of the collision force magnitude resulting from ship berthing on docks is crucial for the rationality and safety of dock structural design. This paper presents a novel framework for the calculation of berthing collision force for ships (CBCF), which integrates field data, finite element models, and surrogate models. Based on field data and finite element analysis, the framework constructs and compares four surrogate models with low sample requirements, ultimately selecting the optimal surrogate model for predicting collision force. Furthermore, a sensitivity analysis of the parameters is conducted based on the selected model, followed by a comparison with the various methods used for collision force prediction. The results illustrate the effectiveness of the proposed framework in replacing finite element models for the rapid and accurate prediction of collision force. Comparison with existing methods also underscores the advantages of the proposed framework, including low sample requirements, high calculation accuracy, and exceptional efficiency. In summary, this study not only introduces a novel and precise surrogate model framework for the swift prediction of berthing collision force, but it also offers valuable insights into the prevention of ship collision with wharf accidents and facilitates the rational and safe design of wharf structures.

Research on Engineering Characteristics of Cement Mixing Piles Strengthening Steel Sheet Pile Structure Wharf

In order to solve the technical problem of using steel sheet piles in soft soil foundations of deep water docks, the use of grid type cement mixing pile walls to reinforce the in-situ soft soil behind steel sheet pile docks is a new type of composite structure attempt. This paper combines practical engineering and uses finite element analysis software to study the vertical displacement, vertical stress, and horizontal displacement changes of reinforced soil in three layout forms: non-mixing pile structure, grid type cement mixing structure, and dispersed mixing pile structure. The results show that the grid type cement mixing pile structure can reduce soil settlement, improve the stability of reinforced soil, and reduce lateral soil pressure on steel sheet piles compared to the non-mixing pile structure and the dispersed mixing pile structure. In the practical application of steel sheet pile wharf engineering, the use of grid type cement mixing piles can improve the stability and engineering benefits of the wharf structure.

Study on the dynamic characteristics of pile wharves subjected to underwater explosion

A test was conducted to investigate the dynamic response characteristics and damage modes of pile wharves subjected to underwater explosions. To simulate the explosion process, a fluid-solid coupling finite element model of the pile wharf was constructed. The structural damage process, response characteristics, and failure modes of the pile wharf were analyzed based on the experimental and numerical simulation results. The results showed that the main damaged components of the pile wharf were the piles, with damage modes of cracks, spalling, and brittle shear. The probability of moderate or more significant damage to the inclined piles was 25% higher than that of the vertical piles. The inclined piles with low deformation ability were more prone to local concrete brittle failure, significantly increasing the possibility of instability and failure of the pile wharf structure. The acceleration response spectrum indicated that although the structure of the pile wharf was severely damaged, the personnel on its surface slab still had a high probability of survival. The study indicates that replacing inclined piles with alternative optimized structures benefits the blast resistance of pile wharves.

Investigation of residual protection of a 55 years old marine structure after 20 years subject to impressed current cathodic protection

It has been reported that structures to which impressed current cathodic protection (ICCP) has been applied for a long period have displayed evidence of residual protection when ICCP has been halted, ranging from several days up to significantly longer periods. To study this phenomenon this paper reports the de-activation of a 20 years old ICCP system installed on a 55 years old wharf structure. The ICCP was de-activated for 84 days and the reinforcing steel potentials at locations on the front pile cap and front wall were monitored via the existing installed reference electrodes (RE). The results showed that all the RE installed in the structure initially demonstrated a positive shift in potential, with 61% maintaining a positive trend over the entire trial period.

Two-stage deterioration model updating of RC structures in marine environment using long-term field inspection data

For the deterioration of reinforcement concrete (RC) structures in marine environment at various stages, models on chloride penetration, crack initiation and crack propagation have been proposed and studied in literature. However, to be applied to real existing structures, these models, usually associated with significant uncertainties, have to be calibrated and modified with long-term in-situ inspection data. Toward this goal, this paper develops a two-stage updating framework to incorporate measured data into existing models to achieve a more realistic modeling of deterioration process. To improve the computation efficiency, the framework can be integrated with simple rejection sampling and other advanced sampling techniques such as the modified sequential adaptive importance sampling (SAIS). A real case study of high-pile wharf structure in Guangzhou Port is carried out to demonstrate the updating effect of the proposed framework. The observed data of chloride content profile and steel bar corrosion depths from one field inspection are used to construct the likelihood functions in the two updating stages. Comparison between the results of the first and second updating stages is made, and the sensitivities of different parameters to the data are analyzed, subsequently the year of reinforcement corrosion initiation and the evolution of corrosion depth are inferred using these results. At last, the data from an early inspection are also incorporated to investigate the impact of two inspections on updating effects.

Seismic Performance Evaluation of Wharf Based on ASCE 61-14

The adequacy of the structural performance of a wharf in withstanding seismic loads is of paramount importance. Therefore, this research aims to conduct an accurate pushover analysis on the adequacy of a wharf located in North Sulawesi, Indonesia. The study provides a comprehensive overview of the seismic performance of the wharf by examining displacement and strain parameters of its plastic hinge components under various loading conditions. To simulate accidental torsion, the wharf structure was analyzed by introducing variations in the eccentricity offset of the lateral pushover load of -5%, 0%, and 5% from the center of mass. The analysis of the torsion behavior involved a comprehensive examination of four control points located at each corner of the wharf plan. Additionally, the investigation took into account, the crucial aspect of soil-structure interaction by considering the equivalent fixity depth of the pile, which was used to evaluate the fixity length of the structure. In order to determine the target displacement of the wharf, analysis was performed in accordance with the established methodologies outlined in FEMA 356. It is also important to note that the seismic performance of the wharf was evaluated based on acceptance criteria in the form of strain limits imposed on various components, including concrete elements, reinforcing steel, and steel pipes, as prescribed by ASCE 61-14. In this study, a total of 30 models were examined, and the obtained results showed that the structure exhibited controlled and repairable damage even when subjected to a 475-year earthquake return period (CLE: Contingency Level Earthquake). Following this, the analysis of variations in displacement control point served to determine the inherent torsion exhibited by the structure, and the introduction of different lateral load eccentricity offsets and variations in pushover loading direction were found to contribute to the increased displacement and strain in the plastic hinge components.

PROPOSAL THE SUITABLE STRUCTURE ON SMALL VESSEL AND BARGE IN THICK SOFT SOIL AREA IN THE GEOLOGICAL AREA OF TRA VINH PROVINCE, VIETNAM

Tra Vinh Province with its interlaced river system is convenient for navigation, especially for barges and small vessels under 1000 DWT. Geology in Tra Vinh primarily has a thick soft soil surface layer, averaging from 20 m – 40 m, even over 50 m in some places, structural solutions for docks in most regions choose piers. Thus, the high platform on the pile foundation. However, in practice, we found that most of the proposed wharf structure solutions for barges and small ships are not reasonable, the piles in the berth structure have not brought into full play their bearing capacity, leading to excessive and inefficient investment costs for large-scale projects. Within the scope of the paper, we propose a more reasonable wharf structure solution based on the integrated analysis of the geological features of the structure, the load due to the ship, and the operating loads on the berth.

A Study on Methods to Enhance the Stability of Riverbanks in Seaport Areas

In the construction of irrigation structures, especially the wharf structures, it is important to learn about the deformation and damage of river banks in the wharf area. From assessing the stability of the river banks, a solution can be proposed to enhance the stability of the seaports, ensuring their safety during operation. Currently, the number of seaports located in soft soil accounts up to half the total number of seaports in Vietnam. The process of planning, designing, and constructing the foundation of the seaports is not optimized in Vietnam. Some seaports have uncounted problems when they are constructed on the soft soil. This paper aims to develop a method to reinforce the foundation of the riverbank so that the stability of the seaports can be maintained and any undesired deformation, or landslide, can be avoided. This method can help stabilize the structure that protects the seaports. The results obtained for the embankment structure with a stable wharf and a deep sliding with K=2.014 is larger than the allowable coefficient [K] = 1.25 in 22TCN 207-1992.

Theoretical studies on dynamic impedances of symmetrically–distributed inclined piles with an elevated pile cap

Inclined pile foundations are commonly adopted in the support of wharf, harbor, bridge, and wind turbine structures. In the context of offshore wind turbines, inclined piles are typically arranged symmetrically around a circle with an elevated pile cap above sea level, referred to as an elevated pile-cap foundation. However, limited research exists on the impedances of inclined pile foundations with elevated pile caps. In this study, a theoretical model was developed that incorporates a homogeneous soil half-space and an inclined pile foundation with an elevated pile cap. The pile and soil half-space were modeled as Euler-Bernoulli beams and linear-elastic continuum, respectively. The soil’s contribution to the pile’s dynamics was represented by the receptance matrix, established at discrete interactions points along the pile’s embedded section. The effects of the rake angle and scour depth on the dynamic impedances of the inclined pile foundation with an elevated pile cap were investigated. It was observed that the peak frequency of impedance shifts to a lower value as the scour depth increases; whereas the peak frequency shifting effect is less prominent when the rake angle changes. The impedance of the elevated pile-cap foundation is more sensitive to the pile’s rake angle compared to the scour depth.

Study on damage effect of caisson wharves subjected to underwater explosion

This study aimed at investigating the destructive effect of explosion shock waves on caisson wharves in shallow water. First, underwater explosion tests were conducted on caisson wharves, full-size finite-element models of caisson wharf-water-explosive were established, and the accuracy of the models was verified by comparison. The destruction pattern and damage characteristics of the caisson wharf structure were then studied, and the effects of different explosion depths and different explosive quantities on the dynamic response of caisson wharves were analyzed. The results show that the destruction pattern of shock waves on the caisson wharf is manifested as plastic damage at the joint of the reinforced concrete (RC) box wall, shear destruction at the lower edge of the explosion loading wall, and integral displacement of the superstructure. When the scaled distance remains unchanged and the explosion depth and explosive quantity increase, the bottom reflection effect strengthens, turning the bending damage on the explosion loading wall into shear damage. By strengthening the performance of the RC box wall joints, explosion loading wall, and superstructure joints, and taking measures to reduce the reflection effect, the anti-explosion capacity of caisson wharves can be effectively improved.

Improving Seaport Wharf Maintenance and Safety with Structural Health Monitoring System in High Salt and Humidity Environments

Due to the harsh working conditions, the durability of the seaport wharf structure is poor compared with similar hydraulic structures. According to the structural characteristics of coastal port wharf and the particularity of a high salt and high humidity environment, the stress features of the coastal wharf structure are analyzed, and the health inspection indicators of the wharf structure are proposed. A fiber grating sensor-based structural health monitoring system for coastal high-pile piers is established. A corresponding system for detecting structural health is designed according to the standard structural section of the wharf’s front platform. The corresponding monitoring implementation scheme, sensor selection, and performance parameters are proposed. Finally, the realization technology and related indicators of data acquisition and transmission subsystem are given. The experimental results indicate that the waveform of the structural response to the wave load has a consistent sine wave pattern with the actual wave load. The maximum strain of the berthing pier appears at 4.35 m and 6.14 m, and the elevations reach 4.66 με and 5.31 με, respectively. The strain at other positions also has an obvious change trend. The experimental results provide some help for the research of the wharf health monitoring system.

Analisis Struktur Portal Bidang Dengan Beban Lateral Menggunakan Metode Elemen Hingga

It is necessary to carry out a safety and comfort inspection of the existing wharf structure to ensure the facility’s service life. To check the safety and comfort, it is necessary to do a structural analysis. In the world of civil engineering, there are many problems in analyzing structures that need to be analyzed for working loads or assessing the existing wharf structures that are loaded by ship berthing loads and loads on the floor plates. This research is limited by conducting research on port ports that are burdened with berthing loads. The results of this study are deformation at the nodes in the horizontal and vertical directions of the global and local axes. Based on the analysis carried out, a maximum horizontal deformation of 4.363 cm is obtained and is less than 0.5% H (or 7.4 cm) as required in SNI 8460:2017. Thus, it can be concluded that the structure can still bear the impact of a ship weighing 30,000 DWT.

Parameter Sensitivity Analysis of the Seismic Response of a Piled Wharf Structure

To investigate the seismic response characteristics of piled wharf structures, a numerical model of the soil-structure interaction system is established. Extensive fiducial error and grey correlation analyses are also conducted to obtain the grey correlation degree sequence of the internal force of piled wharf structure and deformation, as well as the acceleration of surrounding soils. The results show that the peak acceleration at the typical point of the soil is more sensitive to the variations in friction angle and ground motion intensity, while the lateral extreme displacement is the most sensitive to the variations in the elastic modulus of the soil. The grey correlation sequences of the peak acceleration and lateral extreme displacement at the feature points of the soil around the pile greatly vary, indicating that the key factors of the different sequences control the target parameters corresponding to them. The sensitivity of the internal force of the pile foundation of the pier structure to the ground motion intensity and friction angle is more sensitive than the elastic modulus and cohesion. This presented parameter sensitivity analysis procedure for the seismic response of piled wharf structures can provide a reference for the seismic design of piled wharf structures, as well as for disaster prevention prediction.

Finding a New Home: Rerouting of Ferry Ships from Merak–Bakauheni to East Indonesian Trajectories

As an archipelagic country, Indonesia needs ferry transportation to connect and support the economic activities between areas bounded by the sea. The famous crossing route is the Merak–Bakauheni one, which connects the Java and Sumatra economic corridors. Many ships operate on this route, but limited port facilities significantly affect the efficiencies of the services provided, hence, they have to be moved. Therefore, this research analyzed the suitability of ships to operate on the eastern crossing. The analysis method used the financial aspect (revenue) feasibility, the suitability of the port infrastructure, and the oceanographic conditions. The financial analysis used the ships’ operating cost method to determine the crossing passage rates based on their specifications. It simulated the ships with various load factors to identify potential gains or losses. Furthermore, the infrastructure suitability analysis used the under keel clearance and comparative methods to compare the suitability of the ship dimensions and tonnage with the port infrastructure capacity. The oceanographic analysis used the Weibull method to simulate the redefinition of the distribution of significant wave heights, which was compared with the ratio of the ship dimensions and wave slope to determine its heel angle using the IMO Weather Criterion method (IS Code 2008). The results showed that the relocation of ships from the Merak–Bakauheni route directly to Eastern Indonesia through the existing crossing routes is feasible from the aspect of shipping safety, but it is not feasible financially or in terms of infrastructure. The Benoa–Labuan Bajo route is a potential new route recommendation, with regulatory support for the operation of ships in the form of tariffs and operational costs, and it permits the use of subsidized fuel. On the other hand, ship owners must consider modifying the ramp door to suit the port wharf structure.

Numerical modeling of a pile-supported wharf subjected to liquefaction-induced lateral ground deformations

Fully-coupled nonlinear dynamic analysis is increasingly used for assessing the seismic performance of pile-supported wharf structures subjected to liquefaction-induced lateral ground deformations. Several numerical challenges exist for analysis of this highly nonlinear soil-structure interaction, which require robust, yet practical, solutions that are validated with experimental data. This study presents a numerical model of a pile-supported wharf and evaluates the applicability of a soil constitutive model, and modeling assumptions and methods by using recorded data from a well-instrumented, large-scale centrifuge test. The objectives of this study include: (a) evaluating the performance of a recently developed pressure-dependent multi-yield surface constitutive soil model (PDMY03) to simulate the behavior of a liquefiable sand (b) assessing the effectiveness of a soil–pile interaction modeling approach in capturing the kinematic displacement demands on piles from a laterally spreading ground, and (c) evaluating the effectiveness and limitations of the 2D numerical model in approximating the 3D behavior of a wharf structure supported by multiple rows of piles, including the dynamic response of the centrifuge container. The implications of these assumptions and lessons learned from this study provide guidance for researcher modelers and practitioners for numerical modeling of similar soil–structure systems.