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The wind-resistant performance of cable-stayed bridges under construction deteriorates sharply as the cantilever length increases, and the arrangement of the temporary pier is an effective measure to improve aerodynamic stability. To investigate the effect of the temporary pier on buffeting response of a long-span three-tower cable-stayed bridge under construction, the nonlinear buffeting analysis and wind tunnel test of aeroelastic model methods are adopted in this paper. The influence of the type and arrangement positions of temporary piers on mean wind response and the nonlinear buffeting response of double-cantilever construction are studied, and the arrangement of the temporary pier is optimized based on the buffeting response. The results show that the reduction rates of the RMS of the torsional moment at the tower bottom and the lateral buffeting displacement at the girder end with the rigid pier are 35.6% and 59.2% compared to those without the temporary pier. Further, the buffeting response will decrease as the distance between the rigid pier and the tower increases in the state. On the contrary, in the double-cantilever construction state before the constraint of temporary piers, the buffeting response will become significant as the distance increases. Therefore, it is necessary to consider the buffeting response under two construction states when optimizing the arrangement position of the temporary pier. [ABSTRACT FROM AUTHOR]

The Fenshui River Bridge is a steel–concrete composite girder bridge with a main span of 90 m. Due to the topographical constraints, the steel box girder was constructed without the use of auxiliary piers, employing incremental launching techniques. This article focuses on the construction technology used for the steel box girder of the Fenshui River Bridge. Firstly, using the influence matrix method, the cable force is determined based on the maximum cantilever state of the structure, with the vertical deformation of the front end of the guide beam and the horizontal deformation of the top of the tower as the control objectives. The unstressed cable length is then calculated based on the mechanical relationship between cable deformation and cable force. A calculation method for adaptive cable force is proposed, which is based on the variation of the stress-free cable length within the adaptive structural system. Next, the finite element analysis method was employed to determine the optimal layout position for the tower. The results indicate that during the incremental launching construction of the steel box girder, the calculated cable forces using the method proposed in this paper are in close agreement with the measured cable forces. At the maximum cantilever state of the structure, the calculated and measured values of the cable force resulted in a percentage difference of 3.96%. The calculated values of deformation and stress in key sections showed a percentage difference of 6.4% for deformation and 6.6% for stress. To maximize the effectiveness of the tower and cable, the tower should be positioned above the bridge pier when the guide beam crosses the maximum span. The findings of this paper can serve as a reference for the construction of similar types of bridges. [ABSTRACT FROM AUTHOR]

The seismic resilience of structures and infrastructures is affected by damage accumulation phenomena, mainly related to the type of hysteresis. Specifically, pinching drives the cyclic response of several building materials, such as reinforced concrete and masonry. Structural systems affected by pinching phenomena are prone to exhibit a dramatic increment of their displacement response after multiple cycles (e.g. repeated earthquakes). The authors estimate a reinforced concrete pier's response using truncated incremental dynamic analysis by concatenating three earthquake scenarios. The authors adopted a Bouc–Wen class hysteresis model to simulate the reinforced concrete pier's cyclic response, matching its experimental cyclic response. The current analysis proved that ductility and resistance primarily drive the seismic response after a single earthquake. However, the performance after multiple earthquakes strongly depends on the pinching, degradation and drift accumulation, which are generally neglected in standard design practices. [ABSTRACT FROM AUTHOR]

In order to research the influence of bearing arrangement on the seismic response of urban viaduct, the 4 × 30 m standard span and C ramp bridge of the main line are taken as the engineering background. The SeismoStruct software is used to establish and analyse the seismic responses. For the standard span of the main line, under the same ground motion input, the internal force of the pier for the seismic isolation system is reduced by about 1 to 4 times compared with the ductile seismic system, but the displacement of the piers or the bearings are relatively large, and the overall cost of the structure is high. For the C ramp bridge, the shear force, axial force and pier displacement with all lead-core rubber bearings are lower than those with fixed bearings. From the perspectives of structure seismic response, post-earthquake repair and engineering economy, it is suggested that the viaduct of the standard span should adopt the plate type rubber bearing, and the C ramp bridge should adopt the fixed bearing. [ABSTRACT FROM AUTHOR]

The immediate functionality of bridges following severe earthquakes is vital for uninterrupted rescue operations. Regarding the significance of resiliency in bridges, post‐tensioned (PT) rocking piers with low residual displacements and minimal damages have developed over the past few decades. The rocking mechanism at two ends of the pier avoids bending moments and excessive flexural damage. The self‐centering (SC) capacity in this system is provided through post‐tensioning forces. Concerning optimum seismic design and retrofit purposes, it is essential to predict the actual degree of seismic damage and SC capacity of PT rocking systems after seismic hazards. In this case, a self‐centering index (SI) is proposed to evaluate the SC capacity when piers are subjected to cyclic and seismic loadings. This SI, when used in co‐operation with a viable damage prediction model, predicts whether or not the piers remain reparable under cyclic or seismic loading scenarios. After comparing a number of energy‐based damage indices, all of which consider the cumulative hysteresis energy, with the input energy‐based damage index (IEB‐DI), the latter was calibrated against observed damages under cyclic loading tests. This DI was chosen as the most suitable damage prediction model and was considered to be simply applicable after time history analysis. In this study, the seismic performance of a seismic‐resistant dual system, consisting of three RC bents along with an SC bent, was evaluated using the aforementioned damage limit states and the introduced SI. The damage predictions of the monolithic bridge, as the reference model, were compared with the estimated damage to the dual bridge. The results show that the joint application of the IEB‐DI and the proposed SI in predicting the performance level of SC rocking piers results in a comprehensive damage prediction model. [ABSTRACT FROM AUTHOR]

The present paper addresses the effect of placing an intake, as a diversion structure, in different positions and with various angles in a 180° bend to investigate the scour depth around a circular pier in an SSIIM2 numerical model. The simulation was conducted by placing the intake at the 75°, 90°, 115°, 135°, and 150° positions with 45°, 60°, and 90° angles. The results indicated that the greatest effect was associated with the installation of the intake with a 90° angle at the 135° position, which decreased the maximum scour depth by a considerable amount, about 70%, compared with the bend without an intake. However, the maximum scour depth occurred with the installation of the intake at the 150° position with an intake angle of 45° and increased by 20% compared to the bend without an intake. Furthermore, the maximum and minimum scour hole wall slopes around the pier in the case of the bend with an intake respectively increased by 6.24 times and decreased by 5.1 times compared to the bend without an intake at the upstream pier. The maximum sedimentation height around the pier decreased by about 40% in the bend with an intake compared to the one without an intake. [ABSTRACT FROM AUTHOR]

Prediction of scour at complex or non-uniform piers has been mostly aimed at single piers, while most bridges are constructed on a group of non-uniform piers. The novelty of this study is to investigate the effect of foundation level and piers' distance on local scour around the non-uniform twin-piers. The experiments were carried out considering five foundation levels, under and above the bed, with various piers distances in clear-water conditions. Results show that for the case of foundation level above the bed, scour depth at non-uniform twin piers is larger than that of uniform configuration, and distance between piers has no significant influence on scour depth. For the case of foundation at bed level, the distance between piers has no remarkable effect on scour depth while the scour depth around non-uniform twin piers is found to be less than that of uniform ones. When the foundation is under the bed level, the presence of the foundation reduces the scour depth around both front and rear piers, and the distance between piers has a direct effect on the scour depth. In this zone, the foundation delays the scour process and the scour time increases with increasing foundation depth. This study highlights that a proper design of the foundation level increases the duration of scouring and decreases the scour depth. [ABSTRACT FROM AUTHOR]

Interaction between various components of bridge scour is a complex phenomenon. Bridge submergence during high flooding leads to the scour mechanisms becoming even more complex. Thus, to find the interaction between various components of bridge scour, a detailed investigation has been conducted by using scaled-down models in a hydraulic laboratory. Scour experiments were conducted with free, submerged-orifice, and overtopping flow (OT) under clear-water conditions. The results show that the total interactive scour caused by simultaneous effects of pier, abutment and contraction scour results in a reduced equilibrium scour depth compared to the sum of all individual components acting independently. A comparison with HEC-18 methodology shows that the large bias of over-estimation has been eliminated by the suggested model in this study. However, the interaction of pier scour with vertical contraction scour remains as a sum of individual scour components with the exception of the recommendation of using Lyn's modified model to calculate vertical contraction scour. Field examples from past historical events have been used to validate the model, and they show good agreement with the suggested model. [ABSTRACT FROM AUTHOR]

The blast resistance of a typical two-lane steel girder highway bridge structural system was modeled using a nonlinear finite-element approach that considered material damage, fracture, and separation. Critical blast scenarios were based on field observations of terrorist attacks on bridges in Iraq, while system failure was defined in terms of practical emergency serviceability criteria used on actual blast-damaged bridges. The blast resistance of various design parameters was assessed, including the number of girders, deck concrete strength, reinforcement ratio, slab thickness, girder and reinforcement yield strength, girder sectional dimensions, and pier column width. The presented approach uniquely quantifies structural system blast resistance in terms of the charge weight that can be applied at different locations until failure. A sensitivity analysis was conducted to determine the most influential design parameters. It was found that system blast capacity was primarily influenced by the number of girders and girder yield strength, while additional significant parameters were deck compressive strength, deck thickness, web stiffener width, and girder depth. Secondary parameters were deck reinforcement ratio, girder flange, and web thickness, while deck reinforcement yield stress was found to be insignificant. Based on the results, recommendations for improving blast resistance are provided. [ABSTRACT FROM AUTHOR]

Single-column bridges are widely used for urban overpasses and highway bridges. Rising overturning incidents have exposed the vulnerability of this type of bridge, which is inherently susceptible to overturning collapse. A typical solution is to provide vertical restrainers at the beam ends. However, the current antioverturning calculation method was incapable of coordinating deformations between bridge components, which may have severe consequences in engineering practice. For example, the Huahu Viaduct, located in Hubei, China, experienced overturning failure even after applying vertical restrainers, which was not anticipated according to the current engineering experience. In this work, we proposed a modified calculation method regarding deformation coordination to predict the ultimate overturning capacity, verified through forensic investigation and numerical analysis, of the Huahu Viaduct. Compared with bridges without restrainers, overturning failures start with the failure of restrainers. Failure mechanisms are analyzed, including critical states and overturning features. Further comparison indicates that the practical method overestimates the ultimate overturning capacity by up to 38%, while the proposed method provides a more effective reference to this problem in engineering practice. [ABSTRACT FROM AUTHOR]

In recent years, defective TiO2 has caught considerable research attention because of its potential to overcome the limits of low visible light absorption and fast charge recombination present in pristine TiO2 photocatalysts. Among the different synthesis conditions for defective TiO2, ambient pressure hydrogenation with the addition of Ar as inert gas for safety purposes has been established as an easy method to realize the process. Whether the Ar gas might still influence the resulting photocatalytic properties and defective surface layer remains an open question. Here, we reveal that the gas flow ratio between H2 and Ar has a crucial impact on the defective structure as well as the photocatalyic activity of TiO2. In particular, transmission electron microscopy (TEM) in combination with electron energy loss spectroscopy (EELS) revealed a larger width of the defective surface layer when using a H2/Ar (50 %–50 %) gas mixture over pure H2. A possible reason could be the increase in dynamic viscosity of the gas mixture when Ar is added. Additionally, photoinduced enhanced Raman spectroscopy (PIERS) is implemented as a complementary approach to investigate the dynamics of the defective structures under ambient conditions which cannot be effortlessly realized by vacuum techniques like TEM. [ABSTRACT FROM AUTHOR]

In order to accurately and easily predict the variation of the average temperature of the concrete rectangular hollow pier. Firstly, the temperature distribution of the concrete rectangular hollow pier of Changjiahe Special Bridge was observed for 212 days. Then, based on the observation data, the functional relationship between the average concrete hollow pier temperature and the outside air temperature, and the air temperature inside the hollow pier was studied. Finally, based on this functional relationship, a prediction model for the range of variation of the mean temperature of the hollow pier was given and verified. The results of the study show that: the change of external shade temperature can be regarded as the superposition of different cyclic changes and random changes; the change rule of the average temperature of the concrete hollow pier is the same as that of the air temperature, both presenting day-by-day cyclic and step changes; the linear correlation coefficients between the daily maximum and daily minimum average hollow pier temperature and the daily average air temperature are R = 0.980 and R = 0.973, respectively; the daily average air temperature, the daily average air temperature inside the pier and daily average hollow pier temperature are R = 0.980, R = 0.998; the daily variation of the average hollow pier temperature and the daily variation of the air temperature are approximately linear, with a correlation coefficient of R = 0.899; assuming that the average temperature of the concrete hollow pier is a folding change, based on the above relationship, a method of predicting the time-by-time average temperature of the concrete hollow piers is proposed, as well as two methods of predicting the average temperature of the test piers. Average temperature change range method. Comparing the predicted values with the measured values, it is found that the predicted values are in good agreement with the measured values. [ABSTRACT FROM AUTHOR]

Featured Application: A simple and fast tool is proposed for assessing the rehabilitation needs of bridges and the effectiveness of implementing the seismic isolation of decks to reduce the vulnerability of bridges. The creation of an isolation layer between decks and substructures has turned out to be a viable method for reducing the seismic vulnerability of existing bridges. However, to the Authors' knowledge, a practical approach for a preliminary verification of the effectiveness of this intervention is lacking. The paper introduces a practical tool for a preliminary assessment of the needs of the rehabilitation of the bridge and of the effectiveness of the deck isolation to improve its seismic performance by comparing the demands of the as-built structure and of the piers alone, expressed in terms of equivalent accelerations, to the maximum seismic acceleration allowed to maintain the substructure behavior in the elastic range. A practical implementation of the criterion is illustrated in a parametric study, considering prototypes of simply supported and continuous deck bridges with features common to the bridges of the Italian stock. The results of the study provide some indications about the inherent weaknesses of the examined pier typologies and the positive effect of the dead load of the deck on the effectiveness of deck isolation. [ABSTRACT FROM AUTHOR]

In recent years, accelerated bridge construction has led to the substantial application of precast post-tensioned segmental (PPS) bridge piers. However, PPS piers are not widely used in high-seismicity regions due to their low energy-dissipation capacity (EDC). To address this deficiency, a series of shape memory alloy (SMA)–concrete composite PPS piers were examined in this work. Non-linear static and dynamic analyses were performed on experimentally validated finite-element models of the SMA–concrete composite piers and the results were compared with those of piers without SMA bars. It was found that the length, area and post-tensioning ratio of the SMA bars affected the EDC of the piers, and an optimal design of the bars is required to reach the highest EDC possible. The effects of SMA bars on the frequency response functions of piers were investigated for the first time in this study and it was found that, unlike the piers without SMA bars, sub-harmonics and super-harmonics were not seen in the responses of the SMA–concrete composite piers, mainly the drift responses. Furthermore, the SMA–concrete composite piers experienced a significant reduction in drift responses compared with piers without SMA bars. [ABSTRACT FROM AUTHOR]

This paper summarises the equivalent pier method for estimating the settlement of a pile group or a piled raft. Such an approach is very useful for preliminary estimates of settlement, and also for checking on the results of more refined analysis methods. Some suggestions for assessing the properties of the equivalent pier and the supporting soil are provided. A series of finite element analyses are presented in chart form for the settlement of a pier within a two-layer soil system. The accuracy of these analyses has been checked via comparison with some published closed form solutions for a uniform soil mass. Examples of the application of the equivalent pier method are presented for some published case histories to demonstrate that the method is capable of providing adequate preliminary settlement estimates. [ABSTRACT FROM AUTHOR]

This paper contributes to the further development of seismic resilient infrastructure by introducing a novel prototype bridge which integrates tubular steel piers with superelastic shape memory alloy (SMA). The proposed bridge pier is composed of a circular steel tube which is bonded to a superelastic SMA tube in regions of high stress. The pier is distinguished by its ability to minimize residual drifts following inelastic deformations induced by cyclic loading. Three‐dimensional continuum finite element (FE) models are utilized to examine its lateral behavior. Experimental data is used to demonstrate the effectiveness of the continuum FE procedure in replicating the cyclic response and capturing both global and localized behaviors. A novel composite material model is proposed to represent the degradation of strength and accumulation of irreversible strains in the cyclic response of superelastic SMAs. An iterative procedure for the calibration of this material is presented. Investigations, employing the calibrated FE procedure, focus on the quasi‐static cyclic response of steel piers with superelastic SMA in the plastic hinge zone, aiming to identify the optimal length of the SMA tube for achieving a self‐centering response with reduced residual deformation. The study is then further expanded to examine the seismic response of a bridge structure incorporating such piers. Development of the FE model for the prototype bridge includes the modelling of the piers using continuum elements, while the superstructure, bearing units, abutment walls, and backfill material are modelled using discrete elements. Nonlinear time history analyses are undertaken to investigate the effects of column wall thickness and materials used in the plastic hinge zones of the piers. Dynamic FE study results indicate that bridges employing such piers are capable of returning to their original position, provided the SMA tube is of adequate length. [ABSTRACT FROM AUTHOR]

Under the action of cement hydration heat, the construction environment, thermal insulation measures, and pipe cooling systems, a mass concrete pile cap is subject to a complex internal temperature field, which makes it difficult to control its internal surface temperature difference (TISTD), the internal adiabatic temperature rise (TIATR), and the surface temperature (TST). In this study, a mass concrete pile cap of a very large bridge (the length, width, and height were 26.40 m, 20.90 m, and 5.00 m, respectively, and the central-pier pile cap was constructed with C40 concrete) was taken as the research object. The control factors affecting the temperature field of the pile cap were determined by comparing the field temperature measurements with the values calculated with finite element software simulation analysis. By using Midas Civil (2022 v1.2) and Midas FEA (NX 2022) finite element software, these factors (the concrete mold temperature, the concrete surface convection coefficient, the ambient temperature, the pipe cooling system parameters, etc.) were numerically analyzed, and their influence laws and degrees were determined. [ABSTRACT FROM AUTHOR]

This paper focuses on the analysis of the stress state of a large-span frame pier-continuous box girder bridge with pier crossbeams anchored by pier crossbeams on the main pier of the Guangfo-Zhao Expressway. The bridge is constructed by the cantilever method, and a refined finite element model of the entire bridge is established using the finite element software Midas/FEA to analyze the stress state of the frame pier during the cantilever construction process. It is found that under the possible combined action of an unbalanced load during construction, the torsional resistance of the frame pier crossbeam does not meet the requirements of the design code. In order to eliminate the torsion of the frame piers, counterweights were used to monitor the frame piers during the construction of the box girders. In this paper, the theoretical calculation formula of the inclination angle of the end section of the frame pier crossbeam with the change of unbalanced bending moment, the calculation formula of the relationship between the horizontal displacement of the frame pier and the unbalanced bending moment, and the calculation formula corresponding to the relationship with the water tank counterweight are derived using the structural mechanics method. Two monitoring methods for the frame pier are proposed. In the construction monitoring of the bridge, the numerical fitting formula obtained by finite element numerical analysis calculation is compared with the calculated formula obtained by substituting the design parameters of the frame pier into the theoretical formula. The basic constants in both formulas are basically equal, verifying the correctness of the monitoring calculation formula proposed in this paper for the torsional resistance of the frame pier crossbeam. The applicability of the two monitoring methods is also compared and analyzed. This paper takes the main pier of Chaoyang overpass's mainline bridge as the engineering background, which adopts the framework pier with a large-span prestressed concrete continuous box girder bridge. It analyzes the torsional state of the beam of the framework pier during the bridge construction process and conducts research on the construction monitoring of the framework pier crossbeam, providing valuable references for the construction monitoring of framework pier crossbeams in the construction of large-span framework pier continuous bridges in the future. The research results of this paper can provide assistance for the construction monitoring of similar projects. This paper's innovation primarily resides in employing structural mechanics methods to compute the torsion of frame piers. On this basis, a simplified beam torsion calculation formula is proposed to strengthen its practical application in construction monitoring. The findings of this paper can help in the construction monitoring of similar projects. [ABSTRACT FROM AUTHOR]

Vibration control has emerged as a significant concern in civil engineering, aiming to minimize the displacement and stress exerted on structures during seismic events. The accelerated oscillator damper (AOD), which is a damping device that depends on acceleration, has been demonstrated to be highly effective. However, in the case of traditional bridges, it is difficult to accurately place the secondary mass, spring, and damping components at the piers. Additionally, it has been found that as a general single-degree-of-freedom (SDOF) damping device, a significant limitation of the AOD system is its insufficient damping effect in the near-resonance region. This study presents a strengthened AOD with a liner spring (SAOD-LS), in which the secondary spring and damper are linked to the primary structure rather than being attached to the piers. This design not only provides enough space for the secondary system but also has a higher amplification factor of secondary spring and damping components compared with the original layout. In addition, we suggest a nonlinear spring device (NSD) that includes connecting rods and inclined linear springs arranged in a diamond configuration. This innovative design is intended to introduce nonlinear stiffness characteristics into the equivalent stiffness, thereby improving the device's performance and providing effective anti-resonance features in the near-resonance region. We have confirmed the motion equations for the SAOD-LS and used finite element (FE) analysis to validate the formulation of the equivalent external force and deformation of the NSD. We have thoroughly investigated both the SAOD-LS and the strengthened AOD equipped with NSD as the secondary spring (SAOD-NSD) for their potential implementation in a bridge project. These damping systems demonstrate exceptional performance and robustness, making them highly suitable for enhancing structural resistance to seismic activity. [ABSTRACT FROM AUTHOR]

The hydrodynamics of the flow around piers affects the motion of ships navigating near these structures, while the motion of the ships, in turn, affects the distribution of the flow field near the piers. This study investigates the forces exerted on a ship in various ship–pier transverse distances using commercial computational fluid dynamics (CFD) software, Fluent 13.0, based on the RNG k-ε model, complemented by experiments with a physical model. The interaction between the ship's motion and the flow field near the piers was considered. The results indicate that during the encounter between the ship and the pier, the boundary of the approaching ship affects the flow field near the pier, thereby affecting the generation and detachment of vortices behind the pier. The yaw moment of the ship demonstrates a marked "positive peak–negative peak–positive peak" pattern. Moreover, as the ship–pier transverse distance increases, the impact of the pier on the ship's motion decreases, and it becomes negligible when the distance reaches 0.9 times the diameter of the pier (D), suggesting that the pier has a minimal impact on ship navigation if the ship–pier transverse distance exceeds this threshold. [ABSTRACT FROM AUTHOR]

Local scour poses a grave threat to bridge foundations, potentially causing catastrophic collapses. This study uses FLOW-3D with the Reynolds-Averaged Navier-Stokes model to analyze pier scour and dune formation under bridges. It focuses on submerged debris shapes near the water's surface. Results closely match experiments when specific conditions are met. The study introduces an innovative approach to debris impact assessment. Instead of traditional methods, it proposes a novel equation accounting for debris's effective area and elevation. This enhances reliability by over 20%, improving scour depth assessment in debris-laden scenarios. This advances the understanding of debris's role in local scour, benefiting bridge design and management practices. [ABSTRACT FROM AUTHOR]

Catastrophe theory was used to establish a safety assessment model to reduce the reliance on subjective judgments in evaluation of timber-framed heritage buildings. This study was conducted in three phases. Initially, a comprehensive evaluation index system was established from the perspective of foundation. It consisted of eight aspects and 25 safety evaluation indicators using superstructure load-bearing elements, maintenance structures, and their interconnections in timber-framed heritage buildings. The 25 safety evaluation indicators included foundation, base, stone piers, columns, beams, lintels (beams, pads, and other bending components), bracket sets, arches, maintenance walls, beam-brace connections, and roof structures. The bottom-level indicators in the index system were dimensionless. The second phase employed typical catastrophe models (cusp, swallowtail, and butterfly) for normalization, resulting in calculated catastrophe scales and evaluation levels. The case study of the Buddha Hall of Zhihua Temple, Beijing, was applied in the final phase. It was found that the catastrophe scales method solved the subjectivity issues in determining weights. Additionally, the calculations were found to be concise and reliable, providing accurate results. The model can be used as a theoretical reference for the future safety assessment of timber-framed heritage buildings. [ABSTRACT FROM AUTHOR]

This paper investigates nonlinear random vibration of double deck rocking self-centering pier structure subjected to seismic excitation. First of all, a novel type of double deck rocking self-centering pier that offers better resilience is designed. The stochastic dynamical model of the system is then established, in which the seismic excitation is viewed as Kanai–Tajimi filtered white noise and the self-centering restoring force is characterized by classical flag-shaped hysteretic model. Subsequently, the self-centering restoring force is decomposed into equivalent quasi-linear elastic and damping forces by adopting the harmonic balance (HB) scheme. Following this, the stochastic averaging (SA) technique is implemented to derive the averaged Itô equation. The steady-state response probability density with respect to the amplitudes is solved from the averaged Fokker–Planck–Kolmogorov (FPK) equation. Finally, the effects of system parameters on the stochastic response of the double deck rocking self-centering pier structure are performed, and validated by the Monte Carlo simulation (MCS). In addition, with the help of the Laplace transform, the transition function as well as conditional power spectral density are achieved, which are combined with the steady-state probability density to obtain the power spectral density response. This research will contribute to the optimal seismic design of double-deck rocking self-centering piers. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction (ABC) is prevalent all over the world attributable to its technical advantages including the higher construction efficiency, less traffic disruption, and higher construction quality. Grouting sleeves (GS) and grouting corrugated pipes (GCP) are the traditional connection methods of ABC in high seismic regions, with the disadvantages of uncompacted grouting and high requirement of construction accuracy. To this end, this paper developed a new type of prefabricated concrete bridge pier connected with ultra-high performance concrete (PCBP–UHPC) jacketing to solve the problems. To validate the seismic performance of the proposed innovative bridge pier, quasi-static tests on three full-scale specimens PCBP–UHPC, PCBP–GS, and PCBP–GCP were carried out. The results indicated that the failure mode of specimen PCBP–UHPC was similar to that of specimens PCBP–GS and PCBP–GCP with the characteristics of longitudinal steel yielding and concrete crushing at the base of the hollow pier. The obvious plastic hinge outward shifting could be observed during the loading for specimen PCBP–UHPC. The positive ultimate load of specimen PCBP–UHPC was 636.33 kN, which was 14.8% and 13.3% higher than those of specimens PCBP–GS and PCBP–GCP, respectively. In addition, a refined finite element model (FEM) was established by ABAQUS to provide an in-depth understanding on the failure mechanism of the proposed PCBP–UHPC. The parametric analyses were conducted to reveal the influence of the socket depth and axial compression ratio on seismic performance of the proposed PCBP–UHPC. The results indicated that the socket depth had little effect on seismic performance of the prefabricated pier, while the ultimate load bearing capacity of specimen PCBP–UHPC increased to some extent as the increase of the axial compression ratio. The present research work provides an innovative prefabricated bridge pier and a comprehensive experimental–numerical understanding on its seismic performance, which is beneficial for its engineering application. [ABSTRACT FROM AUTHOR]

As more vehicles are being connected to the Internet and equipped with autonomous driving features, more robust safety and security measures are required for connected and autonomous vehicles (CAVs). Therefore, threat analysis and risk assessment are essential to prepare against cybersecurity risks for CAVs. Although prior studies have measured the possibility of attack and damage from attack as risk assessment indices, they have not analyzed the expanding attack surface or risk assessment indices that rely upon real-time resilience. This study proposes the PIER method to evaluate the cybersecurity risks of CAVs. We implemented cyber resilience for CAVs by presenting new criteria, such as exposure and recovery, in addition to probability and impact, as indices for the threat analysis and risk assessment of vehicles. To verify its effectiveness, the PIER method was evaluated with respect to software update over-the-air and collision avoidance features. Furthermore, we found that implementing security requirements that mitigate serious risks successfully diminishes the risk indices. Using the risk assessment matrix, the PIER method can shorten the risk determination time through high-risk coverage and a simple process. [ABSTRACT FROM AUTHOR]

The bidirectional ductile end diaphragm concept uses energy-dissipating buckling restrained braces (BRB) as fuses located at the end of a bridge superstructure's floating spans. This system using BRBs can provide seismic resilient and damage-free bridges fully operational immediately after an earthquake. A shake-table testing program was conducted to subject a 1/2.5-scale specimen to series of ground motions. The specimen tested represents one span of a five-span bridge having BRBs connected to the abutment and the pier next to it. The purpose of these tests was to experimentally validate proposed connection details when subjected to the three-dimensional (3D) displacement histories (compared with the axis of the BRBs) that resulted from bidirectional ground motions and the fact that the connections must accommodate inclined BRB layouts. The test protocol included earthquake displacement histories that represent design demands, cycles of thermal excitations, and (to eventually make the BRBs fail) extreme motions. The testing program validated the effectiveness of the proposed concept and the ability of BRBs to sustain multiple ground motions before failure. [ABSTRACT FROM AUTHOR]

Concrete barriers are used for different purposes in the highway inventory. Different test levels have been specified to help design these barriers to function as expected for their intended purpose of use. Reinforced concrete (RC) Jersey barriers are commonly used to act as intervening structures protecting bridge piers from colliding vehicles during crash events. Thus, they are subjected to vehicular collision force (VCF). According AASHTO, RC barriers used to protect bridge piers should have a minimum height of 1,067 mm and survive test level 5 (TL-5). Many existing barriers that are currently used in roadways do not meet this requirement, hereby, they are referred to as "substandard" barriers. While these barriers are found to be inadequate to solely protect bridge piers against VCF, recent research proved that their presence to intervene in vehicle–pier collisions will contribute to reducing the severity of the crash effects and, consequently, reduce the VCF demand on bridge piers. Therefore, it is important to have a comprehensive understanding about the behavior of substandard barriers during high-level crash events. This will help in proposing methodologies to upgrade these barriers in an efficient and affordable way. In this study, the behavior of a representative substandard barrier, subjected to TL-4 and TL-5 collision events, was investigated through a matrix of dynamic finite-element simulations using the general-purpose finite-element analysis (FEA) program LS-DYNA, version R10.0. The study considered various boundary conditions of the barrier. The investigated quantities were the energy dissipation, velocity reduction, contact force absorption, and lateral displacement. The results showed that the maximum energy dissipation and velocity reduction were about 45% and 30%, respectively. In addition, the highest contact force demand and maximum lateral displacement were 580 kN and 800 mm, respectively. Specific reduction values are addressed in detail in the paper. [ABSTRACT FROM AUTHOR]

Caught between its Chinese and British colonial history, Hong Kong’s path to self-actualization is unsure without preserving its tangible and intangible heritage. This paper examines the region’s several layers of heritage through the movement to preserve the Star and the Queen piers in 2007, using two theoretical frameworks, Abbas’ culture of disappearance and Tunbridge’s dissonant heritage. Despite the piers’ demolition, their role is vital in understanding conflicting histories and decolonizing the region’s identity. [ABSTRACT FROM AUTHOR]

As a potential fire scenario for bridge structures, the safety impact of an FRP anti-collision floating pontoon fire on bridge structures cannot be ignored. Taking the FRP anti-collision floating pontoon fire that occurred in a continuous rigid-frame bridge as the engineering background, the damage condition of the actual bridge fire scene was first investigated. In addition, FDS 5.3 software was used to simulate the FRP anti-collision floating pontoon fire scenario. Furthermore, the thermal–structural coupling method was used to investigate the thermodynamic response of double-armed thin-walled piers under fire. The results show that the FRP anti-collision floating pontoon fire causes localized concrete carbonization and spalling on the surface of the P2 pier, and the FRP anti-collision floating pontoons are largely destroyed. The fire has the greatest impact on the P2-1 pier, with the highest temperature of 667 °C on the windward side and the highest temperature of 326 °C on the leeward side. The temperature impact range is 6 m above the bearing platform, and the maximum damage depth of pier body concrete is 84.58 mm. The deformation and stress of the P2 pier under fire do not show significant changes and do not exceed the allowable limits for structural deformation and material stress. Therefore, the impact of this fire accident on the structural safety of the continuous rigid-frame bridge is minor. This study's results provide reliable guidance for the fire safety assessment and post-fire structural repair of the continuous rigid-frame bridge. [ABSTRACT FROM AUTHOR]

Local scour often causes pier instability; however, the characteristics and mechanism of downflow, representing one of the crucial flow structures, are still unclear. In this paper, the interaction between the downflow and the horseshoe vortex system and the role of the downflow under clear-water local scour conditions are discussed, based on the stress distribution obtained via experiments and simulations. In the present experiment, more accurate data are measured by installing suitable sensors on 3D-printed models that reproduce the scour hole conditions at various times. The obtained results reveal that the downflow exhibits a strong interaction with the horseshoe vortex system. From the perspective of flow structures, the flow structures collide and rub against each other, which weakens the effect of the downflow. From the perspective of energy transfer, the horseshoe vortex system absorbs the energy carried by the downflow to develop and reduce the energy introduced into the sediment. In addition, shear stress is a crucial factor in maintaining a high tangent slope. When the shear stress is down to a minimum and is stable, the tangent slope rises with the growth of the pressure stress, which means that the downflow is able to promote scour depth development. [ABSTRACT FROM AUTHOR]

This paper presents a pioneering artificial intelligence (AI) solution - the Arctic Tern-Optimized Weighted Feature Least Squares Support Vector Regression (ATO-WFLSSVR) system to aid civil engineers in accurately predicting scour depth at bridges. This prediction system amalgamates the strengths of hybrid models by uniting a metaheuristic optimization algorithm with weighted features and least squares support vector regression (WFLSSVR). The metaheuristic algorithm concurrently optimizes all hyperparameters of constituent WFLSSVR models, resulting in a highly effective system. Validation involves a comprehensive assessment using two case studies, which include datasets of scour depths across various complexities and pier foundation types. Comparative analyses against single AI models, conventional ensemble models, hybrid techniques, and empirical methods demonstrate that ATO-WFLSSVR's reliability outperforms others in performance evaluation metrics. Specifically, for the field dataset, ATO-WFLSSVR achieves MAPE and R values of 20.92% and 0.9435, respectively, and for scour depth data at complex pier foundations, it records MAPE and R values of 6.49% and 0.9384, respectively. The automated predictive analytics underscore the robustness, efficiency, and stability of ATO-WFLSSVR compared to existing methods. This study's notable contributions include the development of an innovative optimization algorithm named Arctic Terns Optimizer (ATO), proficiency in solving high-dimensional optimization problems, and the creation of a user-friendly graphical interface system, a promising tool for civil engineers to estimate scour depth at bridges. Further testing and evaluation of ATO-WFLSSVR across diverse datasets encompassing more complex scenarios are recommended. The data and source code for this study are currently accessible at https://www.researchgate.net/profile/Jui-Sheng-Chou/publications. [ABSTRACT FROM AUTHOR]

A self-centering isolated pier (SIP) with an elliptical rocking interface is proposed to enhance the seismic performance of bridge piers. Pseudostatic tests were conducted on two SIPs (one with and the other without tie bars) to study their damage patterns and hysteretic characteristics. Additionally, a finite-element model of a SIP was constructed to study the effect of SIP parameters on its hysteretic characteristics, such as the long radius of the ellipse, the ratio of the long to the short radii of the ellipse, the distance from the tie bar to the centerline of the pier, and the axial compression ratio. The results indicated that the pier bodies of the two SIPs are in the elastic stage. Increasing the long radius of the ellipse and axial compression ratio can enhance the hysteretic characteristics of the SIP. However, these larger values could lead to yield failure of the pier bottom. Furthermore, an increase in the ratio of the long to the short radii of the ellipse results in a progressively less plump hysteretic curve for the SIP, leading to a reduction in energy dissipation capacity. Nevertheless, an increase in this ratio can improve the self-centering ability of SIPs. The distance from the tie bar to the centerline of the pier has little effect on hysteretic characteristics of the SIP. [ABSTRACT FROM AUTHOR]

A simple for dead load and continuous for live load (SDCL) steel bridge system offers an accelerated construction solution for steel bridges. Currently, the available details for this system consist of a girder-end detail and a cast-in-place normal strength concrete (NSC) diaphragm with tight tolerances. This paper presents a study on developing a continuity detail SDCL system using ultrahigh-performance concrete (UHPC) as the diaphragm to simplify construction, improve durability, and increase tolerances. The study involved calibrating a coupled damage plasticity microplane model for UHPC and validating the material models using experimental data on similar continuity details with NSC diaphragms and a large-scale UHPC specimen. The validated models were used in a parametric study to develop a simplified connection detail utilizing UHPC. Compared to the conventional SDCL detail using NSC, the UHPC diaphragm can simplify girder-end details, eliminate the need for continuity of bottom flanges, and subsequently increase construction tolerances. In this paper, the effect of parameters like the gap between girders and the seat height of girders is studied. The diaphragm can be partially cast with UHPC, while the remaining portions can be constructed with the NSC pier. Unlike the NSC diaphragm, the UHPC portion does not require additional reinforcing bars. Implementation of this developed detail could improve the on-site construction time, durability, and constructability of SDCL steel bridge systems. [ABSTRACT FROM AUTHOR]

Collars play an effective role in reducing scour by preventing direct collisions of the flow with the piers. Furthermore, because most rivers meander, this study considered various shapes of bridge piers with collars at various locations along a 180° sharp bend and compared the findings with those of similar cases with no collars installed. The findings show that the aerodynamic shape of the pier and the collar as well as the location of these structures have significant effects on the amount of scouring. The maximum and minimum scour depths which are 2.58 and 0.8 times the pier diameter, occurred in bridge piers with collars at jou.round piers installed at 60° and elliptical piers at 120°, respectively. Moreover, another finding of this study was that use of collars played a significant role in reducing scouring. The greatest effect of the collar was found on the elliptical pier located at the 120º angle with the reduction of the scour depth by 75% and the scour hole volume by 95%. [ABSTRACT FROM AUTHOR]

The new generation of China Railway Track System III (CRTS III) ballastless track structure has been found vulnerable under high-level earthquakes. However, the seismic characteristics and the damage mechanism had not been well studied. In this paper, a 4-span high-speed railway (HSR) simply supported bridge-track system model is established to investigate the seismic response and damage mechanism of the bridge-CRTS III slab ballastless track system under transverse earthquakes by nonlinear history analysis. In accordance with the results, the piers have a good seismic performance under high-level earthquake (0.57 g). The non-uniform vibration of unequal-height piers results millimeter-level inconsistent displacements between the girders. The fixed bearing is vulnerable under the earthquakes with PGA of 0.3 g and 0.57 g, indicating that the seismic design of fixed bearing should be optimized to enhance the seismic resistance under high-intensity earthquake. After the damage of fixed bearing, the friction is not enough to pull the girders to vibrate together with piers which leads the sliding of girders. The sliding of girder exacerbates the non-uniform displacements of girders and roadbed. The non-uniform vibration and residual slips of girders lead deformation of the rail, especially forming turning angles at the girder joints which may impact the safety of train operation. [ABSTRACT FROM AUTHOR]

In January 2020, the footbridge connecting the seaward platform of the Pont del Petroli pier to Badalona beach collapsed due to the severe sea storm named Gloria. Approximately 15 m of the footbridge fell into the sea as a result of prolonged wave action and strong impacts. To understand the complex interaction between waves and structures that led to the pier's collapse during the storm, a composite modelling approach was developed. The loads on each pier element were initially evaluated using the meshless DualSPHysics code, which employs the Smoothed Particle Hydrodynamics (SPH) method. This evaluation was conducted under severe wave conditions analogous to those experienced during the storm. Numerical models informed the design of an experimental campaign carried out at the Maritime Engineering Laboratory of Universitat Politècnica de Catalunya -- BarcelonaTech, using the CIEM large-scale wave flume facility in Barcelona, Spain. Post-storm bathymetric surveys revealed significant alterations in the seabed profile near the affected infrastructure, including sediment deposition and a reduction in water depth from 10 m to 8 m. Consequently, it was anticipated that wave transformation and breaking in the vicinity of the structure would be substantially affected. To explore this phenomenon, various extreme wave impacts were experimentally simulated using focused wave groups. The physical model findings unveiled the forces that the pier endured during the storm Gloria. The results indicate that wave phases influence individual waves, with waves that are biased and asymmetric experiencing higher peaks than those focused on the crest. This insight helps to explain the structural failure of the footbridge during the storm and underscores the importance of considering wave phase impacts in the design and assessment of coastal infrastructure. The combined numerical and experimental approach provides a comprehensive understanding of the forces at play, contributing valuable knowledge to the field of coastal engineering and infrastructure resilience. [ABSTRACT FROM AUTHOR]

Several overloaded-induced overturning incidents of girder bridges with single-column piers have occurred in recent years, resulting in significant casualties and economic losses. Temperature, in addition to overloading, may also play a role in exacerbating bridge overturning. To investigate the association between temperature and bridge overturning, an explicit finite element model (EFEM) of a three-span concrete curved continuous bridge considering nonlinearities was developed to simulate overall collapse. The effects of uniform and gradient temperatures on the overall overturning stability of curved and straight bridges were evaluated based on the EFEMs. Furthermore, the temperature–bridge coupling model and temperature–vehicle–bridge coupling model were utilized to examine how gradient temperature influences bridge overturning. The results show that the overall overturning collapse of a bridge follows four stages: stabilization, transition, risk and overturning. Variations in uniform temperature from −30 °C to 60 °C had a negligible effect on the ultimate vehicle weight for bridge overturning, with a variation of less than 1%. As the gradient temperature ranged from −30 °C to 60 °C, curved bridges show less than a 2% variation in ultimate vehicle weights, compared to a range of −6.1% to 11.7% for straight bridges. The torsion caused by positive gradient temperature in curved bridges can exacerbate bridge overturning, while negative gradient temperature in straight bridges can lead the girder to 'upward warping', facilitating girder separation from bearings. Monitoring the girder rotation angle and vertical reaction force of bearings can serve as important indicators for comparing the stability of bridges. [ABSTRACT FROM AUTHOR]

Hammerhead pier is the preferred option in many bridge sites for its limited ground occupation. Since the bearing reactions act on the short cantilever ends of the cap beam, it is usually treated as stress-disturbed region (D region) in structural concrete. Although finite element model (FEM) can predict the response of such structures, the calculation efficiency will be sharply decreased once it enters nonlinearity. Therefore, strut-and-tie model (STM) has been promoted as an alternative approach for analyzing D regions. In this study, a loading pattern was defined to relate the axial force and bending moment of the pier column with the eccentric load ratio. Sectional analysis method and associated codes were developed to generate the STM. In addition, a full-scale hammerhead pier specimen subject to varying eccentric loads was tested. Besides, nonlinear FEM was also established to numerically investigate the response of the pier. The results indicate that the proposed STM has general applicability for modeling the hammerhead pier and shows better prediction than the FEM. The failure pattern of the hammerhead pier with a prefabricated cap beam was defined. Combining the mechanical analysis of STM and experimental results, the recommended design details for hammerhead piers were proposed. [ABSTRACT FROM AUTHOR]

During the last decades, liquefaction damages induced by earthquakes have underlined the importance of identifying effective soil improvement techniques for mitigation purposes. Vibratory methods, such as rammed aggregate piers, are commonly used to densify sands and silty sands, erroneously neglecting the influence of the lateral stress. This paper presents the results of a series of liquefaction mitigation case studies carried out using rammed aggregate piers in Christchurch (New Zealand), Boca de Briceño (Ecuador), and Bondeno (Italy) following the 2010–2011 Canterbury seismic sequence, the 2016 Muisne earthquake, and the 2012 Emilia seismic sequence, respectively. The availability of coupled piezocone and seismic dilatometer tests before and after treatment enabled a geotechnical characterization of the three sandy sites to be made, along with estimating the at-rest lateral earth pressure coefficient, and comparing the effectiveness of the treatment at the trial sites. Finally, the paper proposes an updated procedure for liquefaction assessment that takes into account both the increase in soil density and lateral stress produced by ground improvement. [ABSTRACT FROM AUTHOR]

To investigate the correlationf between residual drift and remaining seismic capacity, 24 reinforced concrete pier specimens were subjected to lateral load reversals. By normalizing the specified drift against the value at specimen failure, the normalized residual drift exhibits a strong correlation with the normalized lateral drift, thereby providing a predictive model for residual drift. After determining the remaining seismic capacity derived from energy dissipation, a linear correlation was established between the normalized residual drift and the remaining seismic capacity. Consequently, normalized residual drift was selected as a performance indicator for seismic assessment, enabling the quantitative determination of structural damage states. [ABSTRACT FROM AUTHOR]

The objective of this study was to explore the higher-order turbulence statistics of flow and turbulent length scales around a complex pier (CP) and compare the results with those for a simple pier (SP). The velocity data were recorded in a laboratory flume using particle image velocimetry (PIV). The PIV data were analysed to estimate the velocity fluctuations of third order, turbulence production and dissipation rates, turbulent length scales and the contributions of burst–sweep events to the total Reynolds shear stress around the piers mounted on a rigid flat surface. The skewness and advection coefficients indicated a more asymmetric distribution of velocity fluctuations for the SP than for the CP. Ejection and sweep events illustrated the dominance of similar strengths for an extended period, downstream of the piers. The upstream turbulent kinetic energy production was similar for both piers, while the upstream dissipation rate was higher for the CP. The length scales were greater at the upstream for the case of the SP while, downstream, they were greater for the CP. The findings of this work demonstrate the importance of a pile cap in restricting downward-moving flow by showing a lower magnitude of scour-inducing turbulence parameters for the CP as compared with the SP. [ABSTRACT FROM AUTHOR]

The development of pier scour in coastal environments severely affects the bridge's stability. Therefore, estimating pier scour around the vertical cylinder is important for the safety of the bridge structure. The estimation of pier scour depth in combined wave-current conditions has become a challenging task for researchers in recent times. The existing empirical formulations that calculate scour in the combined action of current and wave are scarce and may not always provide accurate results. Machine-learning (ML) techniques have become increasingly popular for their prediction capabilities in the fields of hydraulics and coastal engineering in recent years. Therefore, the present study aims to develop Boosting ML techniques (i.e., AdaBoost, XGBoost, CatBoost, and LightGBM) of ML to estimate pier scour in combined wave-current conditions. The non-dimensional parameters, such as Keulegan–Carpenter (KC) number, Relative flow velocity (Ucw), and Absolute Froude number (Fra), are used as input parameters, whereas scour depth (S/D) is the output parameter in Boosting ML models. The sensitivity analysis has been performed to demonstrate the relative importance of the input parameter on S/D. The performance metrics show that the XGBoost model with the input combination of Fra, KC, and Ucw provides the highest accuracy of 92.47% and outperforms SVM, CatBoost, AdaBoost, and LightGBM models. The XGBoost model also outperforms the existing empirical formulations. Therefore, it can be concluded that the XGBoost techniques can be used as a reliable, accurate, and alternative tool to estimate pier scour depth in the combined action of current and wave. [ABSTRACT FROM AUTHOR]

Local scour around piers is the major cause of bridge failures, and its estimation is critical for safe design. The present study aims to identify a modified pier shape that can reduce local scour compared to a circular pier. In addition, M5 models are developed for maximum scour depth prediction and compared with the existing equations available in the literature. Thus, the effect of pier shape and alignment on local scour is experimentally investigated using three pier models with the same cross-sectional area placed in isolated and tandem arrangements under clear-water conditions. These are circular (M1) and two modified pier shapes (M2 and M3), where M2 is a combination of semi-circle and triangle oriented either way (M2a and M2b), and M3 is a further modification to M2a with a small protrusion on the semi-circular end. The results showed that the local scour depth for aligned (skew angle, α = 0°) M2a, M2b, and M3 piers is reduced by 23.5%, 50%, and 55%, respectively, compared to the M1 pier but not if α > 0°. In tandem arrangements, the least scour depths observed around M1 and M2a at X = 1.0D (X is clear-spacing between piers and D is pier diameter), and M3 and M1 at X = 1.75D placed as front and rear pier, respectively. It is observed that the developed M5 models are more accurate compared to the existing equations. Flow intensity (V/Vc) and α have more influence on the scour depth prediction around tandem and isolated piers, respectively. [ABSTRACT FROM AUTHOR]

The construction industry is a challenging field for the application of robots. In particular, bridge construction, which involves many tasks at great heights, makes it difficult to implement robots. To construct a bridge, it is necessary to build numerous piers that can support the bridge deck. Pier construction involves a series of tasks including rebar connection, formwork installation, concrete pouring, formwork dismantling, and formwork reinstallation. These activities require working at heights, presenting a significant risk of falls. If bridge construction could be performed remotely using robots instead of relying on human labor, it would greatly contribute to the safety of bridge construction. This paper proposes a multi-robot system capable of remote operation and automation for rebar structure connection, concrete pouring, and concrete vibrating tasks in pier construction. The proposed multi-robot system for pier construction is composed of three robot systems. Each robot system consists of a robot arm mounted on a mobile robot that can move along rails. And to apply the proposed system to a construction site, it is essential to implement a compliance control algorithm that adapts to external forces. In this paper, we propose an admittance control that takes into account the weight of the tool for the compliance control of the proposed robot, which performs tasks by switching between various construction tools of different weights. Furthermore, we propose a synchronization control method for the multi-robot system to connect reinforcing structures. We validated the proposed algorithm through simulation. Furthermore, we developed a prototype of the proposed system to verify the feasibility of the suggested hardware design and control. [ABSTRACT FROM AUTHOR]

Coupling beams are used in double-column high-pier bridges to improve the integrity of the two piers. The stiffness of coupling beams has a significant effect on the seismic performance of double-column piers. The seismic behavior of a double-column pier with triple-coupled beams was investigated by cyclic loading test. The failure mode and cyclic response, as well as the shear deformation of a double-column bridge pier, were analyzed to investigate its seismic behavior. The test results, especially after a drift ratio of 1/83, indicated the presence of non-uniform damage characteristics between the coupling beams. Finite element models were developed and parametric analysis was carried out after validation. The focus was on the effects of the variable stiffness of the coupling beam along its height. By analyzing the bearing capacity, ductility, and damage of the double-column piers, the upper flexible and lower rigid coupling beam is a more reasonable arrangement principle. The research results can provide a reference for the innovation design ideas of similar bridge piers. [ABSTRACT FROM AUTHOR]

It is essential and convenient to use accurate and validated numerical models to simulate the seismic performance of post-tensioned (PT) rocking bridge piers, with a particular emphasis on accurately capturing rocking behavior. The primary contribution of this study is a comparison of the effectiveness of four commonly used numerical base rocking models (namely, the lumped plasticity (LP) model and the multi-contact spring (MCS) models with linear elastic (MCS-LE), bilinear elastic–plastic (MCS-EP) and nonlinear plastic (MCS-NP) material behavior, respectively) in modeling both the cyclic and seismic responses of PT rocking bridge piers. Also, this study validates the 3D contact stiffness equation for numerical models and assesses the differences between the dynamic and static stiffness values of the contact springs. Both quasi-static and shaking table tests of typical PT rocking piers are adopted to calibrate/validate these numerical models. These models describing the PT rocking piers' seismic performance are formulated and calibrated, showing good agreement with test results for test specimens. Additionally, the suggested values of model spring stiffness for dynamic and quasi-static analyses are identified by parametric analysis. All base rocking models can predict the pier's cyclic and seismic behavior after the calibration of contact spring stiffness values. The recommended contact stiffness for the dynamic analysis of PT rocking piers is smaller than that used for the quasi-static analysis. The results and findings provide a valuable reference and solution for the numerical simulation of PT rocking piers. [ABSTRACT FROM AUTHOR]

The long-span dual-purpose highway-rail double-tower cable-stayed bridge has the characteristics of a large span and large load-bearing capacity. Compared with the traditional cable-stayed bridge, its wind resistance and seismic resistance are weaker, and the dynamic characteristics of the bridge are closely related to the wind resistance and seismic bearing capacity of the bridge. This study investigated the influence of the variations of bridge member parameters on the dynamic characteristics of the bridge and then improved the dynamic characteristics of the bridge. To provide the necessary experimental theory for the research work of the long-span dual-purpose highway-rail double-tower cable-stayed bridges, this paper takes the world's longest span of the dual-purpose highway-rail double-tower cable-stayed bridge as the background, using the finite element analysis software Midas Civil 2022 v1.2 to establish a three-dimensional model of the whole bridge by changing the steel truss beam stiffness, cable stiffness, pylon stiffness, and auxiliary pier position, as well as study the influence of parameter changes on the dynamic characteristics of the bridge. The results show that the dynamic characteristics of the bridge can be enhanced by increasing the stiffness of the steel truss beam, the cable, and the tower. The stiffness of the steel truss beam mainly affects the transverse bending stiffness and flexural coupling stiffness of the bridge. The influence of cable stiffness is weak. The tower stiffness can comprehensively affect the flexural stiffness and torsional stiffness of the bridge. The position of auxiliary piers should be determined comprehensively according to the site conditions. In practical engineering, the stiffness of components can be enhanced according to the weak links of bridges to improve the dynamic characteristics of bridges and save costs. [ABSTRACT FROM AUTHOR]

To address the persistence of traditional welded joints in the construction of static drill rooted nodular piles, high-strength bolted connections are introduced. Tensile performance tests were conducted on seven sets of full-scale joint specimens to evaluate the ultimate tensile bearing capacity, deformation ductility, and damage characteristics of high-strength bolted joints. Numerical models were established using ABAQUS 2020 software to complement the experimental findings. The results indicate that the ultimate tensile capacity test values of high-strength bolted joints and welded joints are comparable, both exceeding the values calculated by the pile ultimate tensile capacity specification formula. Moreover, the ultimate tensile capacity values of specimens with improved high-strength bolted joints surpass those of ordinary joints. Notably, in the final stages of testing, both high-strength bolted joints and welded joints experienced pull-off at the pier head of the prestressing reinforcement, with the joints remaining intact. The load-displacement curves obtained from the ABAQUS numerical model align closely with the experimental measurements. These findings offer valuable insights and serve as an experimental foundation for promoting the adoption and utilization of high-strength bolt joints. [ABSTRACT FROM AUTHOR]