This study investigates the underlying causes of pier displacement and cracking in a highway link bridge. The initial geological assessment ruled out slope instability as a contributing factor to pier movement. Subsequently, a comprehensive analysis, integrating in situ soil investigation and finite element modeling, was conducted to evaluate the influence of additional fill loads on the piers. The findings reveal that the additional filled soil loads were the primary driver of pier tilting and lateral displacement, leading to a significant risk of cracking, particularly in the mid- of the piers. Following the removal of the filled soil, visual inspection of the piers confirmed the development of circumferential cracks on the columns of Pier 7, with the crack distribution closely aligning with the high-risk zones predicted by the finite element analysis. To address the observed damage and residual displacement, a reinforcement strategy combining column strengthening and alignment correction was proposed and validated through load-bearing capacity calculations. This study not only provides a scientific basis for analyzing the causes of accidents and bridge reinforcement but, more importantly, it provides a systematic method for analyzing the impact of additional filled soil loads on bridge piers, offering guidance for accident analysis and risk assessment in similar engineering projects.

Wall piers are widely used to enhance lateral stability in bridges with tall piers and relatively narrow decks. For this type of structure, the longitudinal direction of the bridge is commonly acknowledged as the governing direction for seismic performance, with wall piers serving as the seismic critical members. However, progressive scouring reduces foundation strength and stiffness, leading to increased transverse seismic deformation. This deformation amplifies the risk of pile damage and may shift the seismic critical member to the foundation. This study investigates the seismic performance of wall pier bents in bridges, explicitly focusing on the effects of riverbed scouring. Through a Taiwan-based case study, seismic performance is evaluated at various scour depths, identifying the seismic critical member through capacity spectrum analysis and the peak ground acceleration corresponding to the performance limit of the wall pier bent. The findings highlight that seismic performance is frequently controlled by the transverse direction, emphasizing the foundation as the seismic critical member. The effect of employing foundation strengthening as a retrofit strategy is also assessed, revealing that it provides only limited improvement in seismic performance. Even after retrofit, the seismic performance of wall pier bents remains primarily governed by the pile foundation.

As transmission lines extend into mountainous regions, engineering practices must address the challenging geological conditions of soil-over-weathered-rock strata and the complex loads imposed by extreme climates. This study introduces a novel perimeter anchor pier composite foundation designed specifically for soil-weathered rock strata, aimed at optimizing the mechanical performance of piles and anchors. Initially, material pretests were conducted to determine the appropriate proportions and mechanical properties for scaled models. Subsequently, tension-compression-bending loading tests were performed to investigate the deformation and failure patterns of the novel foundation. Finally, by analyzing the deformation and failure characteristics of the piles and test data, load-displacement-failure curves for the composite structure were derived. The results show that under compression-bending loads, cracks penetrate the pier, causing splitting failure of the pier body and shearing failure of the short piles at the base. Under tension-bending loads, the base short piles experience tensile rupture without damaging the rock mass, while the anchor undergoes significant deformation. The study also reveals that the load-bearing capacity of the base rock mass is not fully utilized, and it recommends enhancing pile strength to improve the overall bearing capacity of the perimeter anchor pier composite foundation.

Here, a seismic-response analysis model was proposed for evaluating the nonlinear seismic response of a pile-supported bridge pier under frozen and thawed soil conditions. The effect of a seasonally frozen soil layer on the seismic vulnerability of a pile-supported bridge pier was evaluated based on reliability theory. Although the frozen soil layer inhibited the seismic response of the ground surface to a certain extent, it exacerbated the acceleration response at the bridge pier top owing to the low radiation damping effect of the frozen soil layer. Furthermore, the frozen soil layer reduced the lateral displacement of the bridge pier top relative to the ground surface by approximately 80%, thereby preventing damage caused by earthquakes, such as falling girders. Compared to the thawed state of the ground surface, the bending moment of the bridge pier in frozen ground increases. However, the bending moment of the pile foundation in frozen ground decreases, thereby lessening the seismic vulnerability of the bridge pile foundation. The results of this can provide a reference for the seismic response analysis and seismic risk assessment of pile-supported bridges in seasonally frozen regions.

Vessel collisions on bridge piers have become a potential threat to the safety of bridges crossing navigation waterways. Such collision will cause inevitable damage on bridge piers and hence reduce the performance of the whole structure. It is therefore critical to identify the condition of abridge pier after a vessel collision event to judge whether it can still be used or certain rehabilitation is required to recover its normal operation. This paper develops an intelligent approach based on machine learning algorithms to identify the evolution process of damage on abridge pier during collision using sensor-measured acceleration time-history data considering the effects of multi-hazards. A barge vessel is employed and atypical reinforced concrete (RC) bridge pier is considered in this study. A coupled vessel-pier collision model (CVCM) considering soil-pile interactions and material non-linearity of RC components is developed and employed to generate pseudo-experimental data to assess the accuracy of the proposed damage identification strategy. The results demonstrate the potential of the proposed strategy for intelligent damage identification of waterway-crossing bridge piers after vessel collision.

This study explores the transverse response of bridge piers in riverbeds under a multi-hazard scenario, involving seismic actions and scoured foundations. The combined impact of scour on foundations' stability and on the dynamic stiffness of soil-foundation systems makes bridges more susceptible to earthquake damage. While previous research has extensively investigated this issue for bridges founded on piles, this work addresses the less explored but critical scenario of bridges on shallow foundations, typical of existing bridges. A comprehensive soil-foundation structure model is developed to be representative of the transverse response of multi-span and continuous girder bridges, and the effects of different scour scenarios and foundation embedment on the dynamic stiffness of the soil-foundation sub-systems are investigated through refined finite element models. Then, a parametric investigation is conducted to assess the effects of scour on the dynamic properties of the systems and, for some representative bridge prototypes, the seismic response at scoured and non-scoured conditions are compared considering real earthquakes. The research results demonstrate the significance of scour effects on the dynamic properties of the soil-foundation structure system and on the displacement demand of the bridge decks.

Bridge piers embedded in a riverain region are commonly supported by pile foundations. This provides a flexible restraint to the bridge pier instead of a theoretical rigid foundation type. In this work, a cylindrical bridge pier with a monopile foundation is introduced as an example. A modeling framework is proposed to investigate the dynamic response of bridge piers to the impact of flash flooding. The fluid-structure interaction is directly investigated via a two-way fluid-structure coupling approach and the p-y springs distributed over the interface between the soil and pile are adopted to model the lateral restraints from the soil. The effect of the soil-structure interaction (SSI) on the structural dynamic response is investigated on the basis of 3D numerical models with and without a pile foundation. Moreover, the soil around the pile foundation is vulnerable to erosion by flood flow. This continuous exposure of the pile foundation reduces the lateral load bearing capacity and consequently increases the dynamic responses of bridge structures to flash flooding. To demonstrate the effects of increased exposure of bridge pile foundations on structural dynamic responses, several different scour depths with scour ratios ranging from 0 to 0.5 are included in the numerical analysis. Two different considerations of the pile bottom are included in this study: completely fixed and only vertically fixed. The behavior of bridge piers subjected to flash flooding is thoroughly analyzed, and the damage mechanisms for these two foundation types are investigated. The relationships between peak responses and fundamental periods are determined via regression analysis.

The unclear impact of small-spacing construction between new road piles and railway piers in China's coastal soft soils can threaten the safety of operating high-speed railways. By field monitoring and numerical simulation tests, this study examines the deformation characteristics of railway piers and the surrounding stratum due to adjacent pile construction in soft soils. The stratum-lateral deformation (SLD) and the displacement of the bridge pier group with various pile-forming processes or pile construction schemes were measured in field monitoring. Furthermore, the intricate interplay between varying pile diameters and spacing was examined using comprehensive numerical methodology. On this basis, a comprehensive evaluation model for the Construction Deformation Comprehensive Index (CDCI) was established to compare the multi-stage combined effects of pile construction. The results indicate that the bored pile drilling and concreting procedures significantly affect the deformations of the stratum and pier. Specifically, a negative correlation is observed between stratum deformation and the bored pile's distance and depth. The most significant deformation is in the depth direction within the three-direction pier profile. The displacement amplitude caused by single-pile construction surpasses about 2-3 times that of non-construction. Additionally, the CDCI could provide valuable insights for evaluating the holistic impacts on stratum and pier deformation in similar pile construction projects.

Concrete bridge piers are critical components of bridge structures and their performance under seismic loading is of utmost importance. Traditional reinforced concrete bridge piers have shown limitations in terms of residual deformations and seismic resilience. This has led researchers to explore alternative reinforcement materials, such as Shape Memory Alloy (SMA) coupled with steel reinforcing bars, which have demonstrated promising attributes like energy dissipation as well as self-centering capacity. This study aims to fill this gap by evaluating the performance of concrete bridge piers with SMA-Steel coupled (SMASC) reinforcing bars under various intensities of vertical gravity loads and the action of pulse-like ground motion components, throughout a probabilistic framework. To this end, a group of bridge piers with different reinforcement types, including pure steel and SMASC are considered. These piers are subjected to 55 near-fault (NF) pulse-like records as well as 32 far-fault (FF) ground motions, throughout the Incremental Dynamic Analysis (IDA). The influence of distinct frequency components is analyzed by decomposing NF records into low-frequency pulses and high-frequency residual components. Also, the role of pulse to the 1st modal period of the piers (Tp/T1) is investigated by evaluating the piers' response under the action of NF records, which were clustered into four groups. Results were assessed by evaluating the intensity measure and capacity of the studied piers at the desired performance objectives according to the FHWA manual. Moreover, the mean annual frequencies of exceeding performance limit states and the confidence levels of meeting performance objectives are studied. The results of the study indicate that the dominance of the component of NF ground motions depends on factors such as the intensity of gravity loads, ground motion characteristics, and the Tp/T1 ratio. The components of NF records within certain clusters of the Tp/T1 ratio are necessary for accurate response assessment, while FF records can be used for conservative design purposes, depending on the level of ground motion intensity and the intensity of applied gravity load. The SMASC-reinforced piers with specific lambda factors (i.e. lambda = 0.5 or lambda = 1.0) and low intensity of gravity loads lead to a higher (1.6 times higher) mean annual frequency of exceeding a limit state, compared to pure steel rebars. Also, the confidence levels for meeting performance objectives vary depending on the ground motions, but, as gravity load intensity increases, confidence levels decrease, particularly for piers with a lambda factor of 0.5.

Submerged floating tunnels (SFTs) represent a promising innovative transportation infrastructure, offering advantages for crossing long, large, and deep bodies of water in the future. However, critical issues regarding their responses mechanism and technique remain unclear, leading to the absence of constructed SFT prototypes globally. A pier-type SFT (PSFT) is a typical SFT configuration with relatively high stability and safety. This study reviews the progress in PSFT research and discusses critical issues and solutions, including structural design, dynamic response characteristics, and feasibility analysis. Suggestions are provided for future research and applications. PSFTs can be considered as immersed tunnels supported by underwater bridge piers. Although adequate research has been conducted on piers, piles, and tunnel tubes, limited investigations have focused on PSFTs. Existing studies are primarily based on conceptual designs of PSFT, lacking theoretical and experimental investigations. The dynamic response characteristics and progressive collapse mechanism of PSFTs under the influence of waves, currents, and earthquakes are complicated. Scouring and liquefaction can significantly reduce the bearing capacity and alter the dynamic responses of PSFTs. Refined numerical simulations and underwater shaking table tests for PSFTs remain limited. In addition, the performance degradation mechanism and damage evolution process caused by accidental loads, such as impact and explosion, should be emphasized. PSFTs are recommended for broad waters with depths ranging from 30 m to 150 m and lengths larger than 1000 m. Although construction technologies for PSFT components are sufficient and mature, guidelines specifically for PSFTs remain imperative. This highlights the necessity for extensive investigations on PSFTs, considering their mechanism and characteristics under extreme environmental loads.