A wharf is typically constructed as an engineering structure for loading and unloading goods. This structure may be built on weak layers of sand and gravel, depending on the beach conditions. In this way, if a wharf is poorly designed or experiences a rupture, all activities at the site might be halted for a significant period, potentially causing damage to nearby facilities. For this reason, it is of great importance to evaluate the behavior of coastal structures against rupture factors, such as earthquakes and their liquefaction effects. Generally, numerical methods are used to analyze the performance of wharves against liquefaction. This article aims to simulate liquefaction in the soil around the wharf by applying the capabilities of FLAC3D software to analyze nonlinear effective stress and generate excess pore water pressure in a continuous soil environment. The simulation was conducted using the P2PSand behavioral model, a multi-directional model, under bidirectional earthquake loading. Subsequently, the effect of various earthquake parameters on wharf behavior was investigated to extract results for excess pore water pressure, horizontal displacement, soil settlement, and bending moments of piles. Further, an attempt was made to assess the correlation of these parameters with different earthquake factors. Earthquake intensity measures are crucial in the probabilistic seismic demand assessment of various structures. Thus, this study seeks to investigate determinant indicators such as efficiency, practicality, proficiency, and sufficiency in relation to earthquake magnitude and the distance from the center of earthquake propagation to evaluate the quality of earthquake intensity measures. The results indicated good agreement between earthquake CAV parameters and response parameters.

The batter piles of a pile-supported wharf are severely damaged under excessive lateral loads, and effective reinforcement strategies are of great concern. In this paper, the effect of different reinforcement strategies on the lateral bearing performance of the wharf, taking into account the pile-soil interaction, was investigated using centrifuge test and numerical simulation. The results showed that both reinforcement strategies were effective in improving performance, with results generally aligning with those of the intact wharf in terms of load-displacement relationships, and significantly reduced the magnitudes of pile lateral deflection, soil pressure, bending moment, and shear force compared to the broken wharf. However, the concrete jacketing method resulted in larger lateral deflections in the middle sections of the retrofitted batter piles, and then abruptly reduced to match those of the steel-bonding method in the cap-pile regions. The degree of abrupt changes of bending moment in retrofitted batter piles was more distinct in the concrete jacketing wharf than that in the steel-bonding wharf. The steel-bonding method distributed the lateral load more evenly than the concrete jacketing, which involved more abrupt changes in shear forces. Overall, although the performance of both retrofitting methods was slightly better than that of the intact wharf at component level, the steel-bonding method appeared to prove superior due to the smaller change in stiffness and the more even distribution of lateral loads.

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.

Combined with the research results of shaking table test, through the deformation performance of steel pipe pile foundation, the seismic damage and seismic performance of steel pipe high pile wharf are evaluated, and the appropriate evaluation method is given. By setting the numerical analytical model of multi working condition steel pipe high pile wharf with different water depth, different pile types and different pile diameters, the limit displacement of the pile in the soil under different ground motions is calculated. The calculated results show that, the plasticity ratio (defined as mu = delta u/delta y) of the structural system of steel pipe high pile wharf ranges from 1.5 to 3.0; and the fitting relationship between plasticity ratio mu and the diameter thickness ratio D/t was obtained. The fitting relationship is tested by the existing experimental research results. The results show that the given fitting relationship can be in good agreement with the experimental results in the range of +/- 15%. On the basis of this fitting relationship, taking the diameter thickness ratio as the basic parameter, a seismic damage evaluation method of steel pipe high pile wharf structure based on deformation performance is proposed.

The approach bridge of the pile-supported wharf is an important structure that connects the pile foundation platform and the land, and it has a significant impact on the safety of the high-pile wharf. However, the influence of an approach bridge on the seismic dynamic response of a pile-supported wharf has often been neglected in previous studies. Besides, the excess pore water pressure (Delta u) generated under combined vertical and horizontal seismic components is typically greater than that induced by unidirectional excitations, which may further impact the dynamic response of pile-supported wharf. Firstly, this study developed a numerical method for simulating the approach bridge of a pile-supported wharf. Secondly, the three-dimensional finite element model of a pile-supported wharf with an approach bridge is established to investigate the dynamic response during horizontal and vertical seismic components. Additionally, the effects of seismic frequency and relative density of liquefied layer on the dynamic response of pile-supported wharf were also studied. By comparing with the experimental results, the numerical model effectively simulated the overall response of the pile-supported wharf and the liquefaction behavior of the surrounding soil. During high-frequency earthquakes, the influence of the approach bridge on the dynamic response of the pile-supported wharf is minimal, whereas it has a more significant impact during low-frequency earthquakes. Furthermore, vertical seismic components significantly amplify the effect of approach bridge on the lateral displacement and internal forces of piles. The effect of the approach bridge on the lateral displacement and internal force of the pile decreases with the increase of the relative density of the liquefaction layer.

The soft soil foundations of gravity wharves are subject to the wharf weight and wave forces, and the deterioration of the wharf soil foundation strength under such cyclic loading affects the structural safety of gravity wharves. This study investigated the weakening characteristics of soft soil strength. Undrained triaxial tests were conducted on undisturbed saturated soft soil specimens under isotropic consolidation conditions, and a dynamic finite element model of the wave-gravity-structure-soft-soil-foundation interaction was established. The results indicated that the shear modulus of the soil was related to the effective confining pressure and shear strain; this relationship was fitted using the Van Genuchten equation. As the internal friction angle of the soft-soil foundation decreased, its stability decreased nonlinearly, the strength decreased, and the sliding failure surface expanded. Simply increasing the riprap layer thickness had a limited effect on the overall wharf stability. These findings will guide the design of gravity wharves with foundations on soft soils in port areas that are subjected to intense wave actions.

The gravity -type wharf is generally more vulnerable during earthquakes due to its massive gravity quay wall, especially when located in a liquefiable area. Therefore, this study aims to develop numerical analysis procedure for its seismic performance assessment and fragility analysis considering the influence of soil liquefaction. Firstly, the quantitative damage criteria for gravity -type wharves were introduced and verified by case histories. Then, the finite element (FE) modeling of a gravity quay wall founded on liquefiable ground for seismic response analysis using PLAXIS 2D was suggested. Utilizing this modeling, the earthquake -induced damage cases of two gravity -type wharves in two ports in Taiwan were simulated for validation. The seismic performance of both wharves was further assessed by comparing the analyzed response under design earthquake with the damage criteria. Finally, the procedure of seismic fragility analysis based on massive numerical analysis was proposed. Actual earthquake records were scaled to various seismic intensity levels to serve as input motions. Thus, the relationships between the seismic intensity and the damage probability of a gravity -type wharf corresponding to different damage levels, namely, the fragility curves, can be accordingly obtained. These results benefit the seismic performance design and rapid estimation of possible seismic damage of port facilities.

Seismic fragility analysis is an effective method to evaluate the seismic performance of retrofitted wharf systems affected by the uncertainty of soil-cement strength. Nevertheless, fragility analysis usually consumes a large consumption of computational power. In this study, seismic fragility analysis using the artificial neural network (ANN) for the retrofitted wharf, considering the aleatory uncertainty of soil-cement strength and the epistemic uncertainty of the ANN, is carried out; On this basis, the fragility surface for two types of damage limit states considering the uncertainty of soil-cement strength is obtained. It was found that: (1) overall, the soil-cement strengthening strategy is effective for improving the seismic safety of wharf systems, however, the strengthening effect is limited, especially under strong earthquakes, will be further weakened; (2) ANN can effectively predict the maximum seismic response of retrofitted pile-supported wharves, so as to quickly carry out seismic fragility analysis. Examples show that the prediction method has good generalization; and (3) the fragility surface model considers the aleatory uncertainty of soil-cement strength and the epistemic uncertainty of the ANN, which makes the performance-based evaluation of retrofitted pile-supported wharves more comprehensive.