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User Defined Functions (UDF) with three major macro programming was used to update the centroid position and vibration state of the pier, a numerical model of vortex induced vibration of the pier was established and combined with nested grid technology to analyze the hydrodynamic characteristics of the pier with and without pre partition plates. The results show that after setting up the front partition, the downstream length and vortex length of the backflow zone of the pier significantly decrease with the increase of the reduced velocity when the reduced velocity is 6-7, while the pier without a pre baffle shows the opposite trend. The pre baffle effectively suppresses the wake disturbance. When the reduced speed is between 7 and 9, the length of the downstream and vortex in the recirculation zone of the pier with a front baffle is smaller than that of the pier without a front baffle. The front baffle reduces the impact of vortex induced vibration on the pier. The front partition effectively delays the vortex shedding time, and the pressure distribution on the upper and lower surfaces of the pier is more uniform, weakening the vortex induced vibration response of the pier. [ABSTRACT FROM AUTHOR]

The paper presents three methods of the numerical modeling of a 60 m long integral bridge structure resting on an elastic half-space. For the analysis, three bridge models were built using Abaqus FEA software. Models A and C represent complex three-dimensional numerical models consisting of the bridge structure and the soil layer beneath it. The soil layer on which the bridge is resting was modeled as a homogeneous, isotropic, continuous, and elastic semi-infinite body elastic half-space. Model B represents a simple three-dimensional numerical model consisting of just the bridge structure. The stiffness of the soil layer beneath the structure in model B was modeled with spring constants derived for shallow footing foundation based on the theory for an elastic half-space. This model represents an engineering approach to the design of an integral bridge. In all models, the bridge deck is monolithically connected with abutment walls and intermediate piers. The bridge is made of cast-in-situ reinforced concrete. All material constants used in the analysis are presented in the table. Self-weight, uniformly distributed load, and thermal longitudinal expansion of the bridge deck were applied to the bridge models. Due to the nonlinear boundary condition used in the supports of the bridge model A, such as contact and friction, the superposition principle cannot be used in the calculations of this model. For this reason, all the loads involved in all bridge models were combined into a single load case and the large displacement formulation was used in the static analysis. The self-weight of the soil layer beneath the structure was omitted in the analysis. The author is focused on the method of modeling an integral bridge structure resting on elastic soil. For the purpose of this paper, only two piers from each model were selected, from which the internal forces and displacements were compared. Based on the analysis, it was concluded that it is possible to design an integral bridge by building its simplified numerical model, once the conditions given in the conclusions are met.

Excess scour developing around tandem and eccentric piers of side-by-side bridges may aggravate bridge failure. Thinking differently, this combination of pier-like structures may increase scour and shift sediments towards the bank, which may help in self-dredging. Therefore, accurate estimation of temporal scour depth (dst) around such piers has a very high priority nowadays. However, little work has been done in this regard. Most of the previous equations predict dst only for an isolated pier. Here, two to three piers are placed eccentrically in line in addition to isolated piers to derive equations empirically for accurate prediction of dst considering circular, triangular and square pier shapes. The present experimental results for an isolated circular pier are validated using equations from the literature, cross-validated with other published experimental data. Predictive equations are proposed for two to three piers with eccentrically in-line arrangements, taking their intermediate spacings as key variables. These equations are established based on dimensional analysis and non-linear regression. Overall analysis reveals that the estimated temporal scour depths based on the proposed integrated equation are closely within the ±80% accuracy band. The proposed equations can be used to predict temporal scour accurately for selected combinations of piers within the given experimental ranges. [ABSTRACT FROM AUTHOR]

Ductility deficiency in reinforced concrete (RC) piers is a substantial factor contributing to earthquake damage in bridge structures. In this study, the conventional concrete in the potential plastic hinge area was substituted with polypropylene fiber-reinforced engineered cementitious composite (PP-ECC), thereby leveraging its high ductility characteristics to explore the seismic performance of RC piers strengthened by PP-ECC. A finite element model was established to discuss the reinforced height, axial compression ratio, longitudinal reinforcement ratio and stirrup ratio on the hysteresis performance by referring to a published paper with a 1/5 scale test specimen. Based on the results of the parameter analysis, an ideal set of configuration parameters was proposed. Subsequently, a full-size simplified mechanical model was established with ideal reinforcement parameters. Time-history and pushover analysis were utilized to test the seismic response. The study indicates that the two analytical methods were largely consistent. The improvement in the displacement and shear force of the strengthened pier gradually decreased with the increase in acceleration amplitude. Time-history analysis reveals a decrease in the enhancement of displacement from 82.26% to 17.98% and a reduction at the bottom reaction from 12.2% to 1.5%. Under the pushover analysis method, the retrofitting level of the top displacement decreased from 77.22% to 11.53%, whereas the improvement level of the bottom shear decreased from 9.62% to 3.69%. These results provide a theoretical basis and reference standard for the application of PP-ECC. [ABSTRACT FROM AUTHOR]

This experimental study investigates the effect of surface waves that are superimposed on a unidirectional current around a bridge pier in a gravel bed, which employs particle image velocimetry (PIV). A comprehensive examination of various flow characteristics, which include the intermittency factor (IF), turbulent kinetic energy (TKE), and vorticity analysis, is conducted to elucidate the variations around the pier with respect to the Keulegan–Carpenter (KC) number. The findings reveal a correlation between the KC number and the flow dynamics in combined conditions: specifically, due to combined wave–flow conditions, escalation in the frequency of vortices near the pier and the increment in turbulent strength, in terms of the TKE. Of note, this augmentation in turbulent strength is associated with an increase in the KC number. At a low KC number, the maximum scour depth occurred downstream near the pier, which shifted to upstream with an increase in the KC number. In addition, the results could be utilized for the development and validation of numerical models, which accurately estimate the local scour under combined flow conditions. [ABSTRACT FROM AUTHOR]

Context: In Western Australia, the heritage-listed Busselton Jetty is a popular tourism, fishing and diving destination renowned for its unique marine communities. Aims: This research describes and quantifies the fish assemblages (mean number of individuals, species diversity and biomass) at the Busselton Jetty, and makes comparisons with natural habitats in Geographe Bay. Methods: Diver-operated stereo-video systems filmed 25-m transects along the length of the jetty, and a remotely operated vehicle stereo-video filmed 25-m transects in nearby reef, seagrass and sand habitats. Fish at all habitats were counted, identified and measured. Results: Fish assemblages at the defined inshore, mid-shore and offshore zones of the jetty differed significantly, whereas the number of fish, species diversity and biomass increased with distance from shore. There was no measurable effect of protection within the small sanctuary zone at the end of the jetty. Fish assemblages at the jetty differed from those in all three natural habitats, and the number of fish, species diversity and biomass were highest at the natural reef, followed by the jetty, the seagrass and the sand habitats. Conclusions: The Busselton Jetty supports a distinctive fish assemblage, high species diversity and a variety of benthic communities. Changes in the fish assemblages were attributed to differences in habitat type, complexity, depth and distance from shore. Implications: The ecological and social benefits of future man-made marine structures can be optimised by incorporating design features that promote habitat diversity and complexity. We described and quantified the fish assemblages at the heritage-listed Busselton Jetty, and made comparisons with natural reef, seagrass and sand habitats in Geographe Bay. The mean number of fish, species diversity and biomass all increased with distance along the jetty. The fish assemblage at the jetty was unique and different from that in all three natural habitats. Habitat complexity, depth and distance from shore were the key drivers of these differences. [ABSTRACT FROM AUTHOR]

Scour is a significant concern for bridge design/maintenance, and scour countermeasures are often used to prevent or reduce erosion caused by scouring. The W weir is a grade control structure serving many purposes, including scour control at bridge piers. A series of laboratory experimental runs was conducted, changing the size, height and location of the pier in relation to the weir to optimise the structural configuration of the downscaled W weir. These experiments revealed that the scour hole profile upstream of the downscaled W weir changes with weir height. At a weir height of 1.0D (D = diameter of pier), two small depressions of almost identical size were observed inside the main scour hole, one just in front of each upstream apex of the W weir. One cone-shaped scour hole was observed when the W weir height was 0.5D with its maximum depth in between the upstream apexes. Reduction of scour in front of the pier was greater when the weir height was 1.0D. The maximum scour control achieved among all different structural combinations of downscaled W weir was 47.66%. This was achieved when the downscaled W weir was 2.0D in size and 1.0D high, placed 2.0D distant from the pier. [ABSTRACT FROM AUTHOR]

Debris flows represent a prevalent natural disaster in mountainous regions, frequently devastating roads, bridges, and other vital transportation infrastructures due to their abrupt onset and immense destructive power. This study introduces a three-dimensional numerical model that employs the SPH-FEM adaptive coupling algorithm to examine the destruction process of bridge piers under the influence of debris flows. It conducts flume experiments to assess the effectiveness of this approach. The findings indicated that the coupled SPH-FEM method, combined with a cross-rheological model, effectively captures the dynamic progression of debris flows and accurately calculates the impact forces exerted on a pier. The process is subsequently simulated in the LS-DYNA software by analyzing the destruction of the Liziyida Bridge in Sichuan Province, China, as a case study. The research proposes an empirical model for estimating the impact force of debris flows on piers derived from the numerical simulations and additional flow tests around piers. These results offer theoretical insights and a design framework for debris flow disaster prevention and mitigation projects. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract To reduce the trend of scouring, understanding the flow pattern around the bridge piers is necessary. By using hydraulic structures such as submerged vanes, it is possible to alter the flow pattern of water, thus scouring process and sediment transport in riverbeds. Since the scouring mechanism for pier groups differs from single pier, experiments were conducted in a 180° sharp bend channel in the laboratory to investigate the flow pattern around pier group and single pier under the influence of 25% submerged vanes. Furthermore, a comparison was made between the flow patterns in single pier and pier group conditions. Three-dimensional velocities along the bend and different depths were measured using an Acoustic Doppler Velocimeter (ADV(. The results suggest that the maximum vorticity value at the apex position of the bend (location of piers) and the maximum secondary flow value, at the distance between the piers and the vanes, were found to be, 0.15 and 0.89, respectively. In the twin pier experiment, the maximum Reynolds shear stress value $${\tau }_{yx}$$ τ yx decreased by about 36%, and the minimum value decreased by about 49% compared to the single pier experiment. The final results indicated that using submerged vanes obtained the maximum $${\tau }_{yx}$$ τ yx and $${\tau }_{zx}$$ τ zx near the vanes. Near the bed and mid-depth of the water flow, the geometric location of the maximum velocity also occurred around the vanes in both experiments. Therefore, the vanes are important in altering the water flow pattern, diverting the flow from around piers and consequently reducing the bridge pier scouring.

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]

To reduce the trend of scouring, understanding the flow pattern around the bridge piers is necessary. By using hydraulic structures such as submerged vanes, it is possible to alter the flow pattern of water, thus scouring process and sediment transport in riverbeds. Since the scouring mechanism for pier groups differs from single pier, experiments were conducted in a 180° sharp bend channel in the laboratory to investigate the flow pattern around pier group and single pier under the influence of 25% submerged vanes. Furthermore, a comparison was made between the flow patterns in single pier and pier group conditions. Three-dimensional velocities along the bend and different depths were measured using an Acoustic Doppler Velocimeter (ADV(. The results suggest that the maximum vorticity value at the apex position of the bend (location of piers) and the maximum secondary flow value, at the distance between the piers and the vanes, were found to be, 0.15 and 0.89, respectively. In the twin pier experiment, the maximum Reynolds shear stress value τ yx decreased by about 36%, and the minimum value decreased by about 49% compared to the single pier experiment. The final results indicated that using submerged vanes obtained the maximum τ yx and τ zx near the vanes. Near the bed and mid-depth of the water flow, the geometric location of the maximum velocity also occurred around the vanes in both experiments. Therefore, the vanes are important in altering the water flow pattern, diverting the flow from around piers and consequently reducing the bridge pier scouring. [ABSTRACT FROM AUTHOR]

The growth in energy demand, particularly in the oil & gas sector, influences investment decisions for jetty development to enhance supply capacity. The Dolphin Jetty, a prevalent type used by the National Oil Company, incorporates cylindrical or pile-like structures called dolphins to guide and moor vessels safely. As energy consumption in Indonesia shows a consistent upward trend, optimizing the supply chain and fuel distribution becomes imperative. In this context, maritime transportation, specifically through dolphin jetties, emerges as a strategic choice to efficiently meet fuel distribution needs. This paper emphasizes the importance of preparing Capital Expenditure (CAPEX) documentation in the feasibility studies stage, influencing the economic value of the investment. The paper uses historical data to introduce a parametric modeling approach for Dolphin-configured jetties, considering variations in mooring capacity, dead weight tonnage (DWT), and estimated construction implementation years. The outcomes aim to inform the CAPEX Class 4 preparation, contributing valuable insights for the economic assessment of jetty construction projects. [ABSTRACT FROM AUTHOR]

As the scale of underground rail transit construction in urban areas continues to expand, the tunnel construction environment has become progressively more complex. In recent years, an emerging artificial intelligence (AI) method in the civil engineering field, called the Random Forest (RF) method, has been widely used. In the construction of Zhengzhou Metro Line 7, the RF method was used to predict and control the vertical displacement of the bridge pier pile foundation. Such displacement can indicate the deformation of the structure, particularly under long-term utilization and strenuous circumstances that could sink or lift the pier body. Moreover, the vertical displacement of the bridge pier can affect the stiffness and bearing capacity of the bridge, thus impacting driving safety and the bridge's service life. Therefore, the vertical displacement of bridge piers has become the main prediction and control indicator for research. In the Zhengzhou Metro Line 7 tunnel, the tunnel continuously passes through 78 bridge pier foundations, among which the pile foundations of 4 key bridge piers are less than 0.5 times the tunnel diameter with a clear distance planned for the tunnel. However, limitations such as surface traffic and environmental conditions prevent the reinforcement of the bridge pier foundation in advance. Therefore, determining and setting sensible shield construction parameters is crucial to effectively controlling the vertical displacement of these essential bridge piers. This project can serve as a model for future endeavors. The study combines Random Forest with Particle Swarm Optimization Algorithm (PSO) to upgrade the technology of shield tunneling through Pier 2, introduces the Bayesian principle for statistical analysis, and optimizes various main construction variables. Random Forest is an ensemble learning method based on decision trees, which has high flexibility and predictive performance. It can automatically filter out important features from a large number of input features, thereby establishing an effective prediction model. The primary research objective is to enhance tunnel construction by accurately predicting and controlling the vertical displacement of pier foundations. To achieve this objective, the study utilizes the PSO to optimize the parameters and structure of the RF model. By doing this, the model's ability to predict the pier's vertical displacement accuracy can be improved. By combining these two methods, the accuracy of the prediction model and the optimization effect of construction parameters can be improved. In addition, the reliability of the model is further improved by using the Bayesian principle for statistical analysis. The paper compares and evaluates the engineering data objectively, presenting the evaluation index and feature selection method. This approach is innovative and purposeful, aiming to enhance the predictive ability, construction efficiency, and quality. This method can provide support for decision-making and optimization of engineering projects and promote sustainable development of the project. After the construction was completed, the model was established, and the results were predicted. The actual engineering measurement data of Pier Two was taken for comparison with it. Two parameters, Root-Mean-Square Error (RMSE) and Linear Curvature (R2), were introduced to evaluate the prediction results, and the results were subjected to Correlation-based Feature Selection (CFS). The test sets for the downstream and the upstream tunnel were extracted, in which R2 for the three extracted comparisons of the downstream were 0.83, 0.82, and 0.89, respectively, while R2 for the upstream was 0.88, 0.86, and 0.86, respectively. From this, it can be seen that the optimized model has good predictive performance. In the construction process of other projects, the model can be used to predict the vertical displacement of bridge piers, which has real-time performance in preventing accidents.

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.

High-speed railway bridge piers with large stiffness, structure and construction are different from those of highway and municipal bridges and we need to conduct in-depth and systematic research to ensure whether a large number of existing highway and municipal bridge pier research results are applicable to socket type railway piers. The nonlinear finite element models of socket and castin-place double column hollow piers are established, and the correctness of the modeling method is verified by combining with the existing test results. By simulating the mechanical behavior of the pier under the quasi-static reciprocating action, the force-displacement curve of the hollow pier is obtained. The difference of hysteretic behavior between the socket pier and cast-in-place pier is compared. The reasonable range of the socket depth is determined based on the strain permeability effect and the development length of longitudinal reinforcement, and the calculation formula of the minimum socket depth is proposed. The results show that the bearing capacity difference between socket pier and cast-in-place pier is very small, the maximum difference is 2. 8% when the pier height is 5m and 10m. The stiffness degradation law of socket pier and cast-in-place pier is basically the same, the stiffness decreases with the increase of lateral displacement, and the stiffness degrades faster when the displacement is small, and it slows down when the displacement is large. The longitudinal reinforcement yields in the plastic hinge area and the strain permeation area below the cap top, and the strain decreases rapidly in the range of 400 mm below this area, the strain permeation area is the vulnerable part of the cap and socket pier. According to the calculation formula of the minimum socket depth proposed in this paper, the design value of the minimum socket depth of the hollow high-speed rail pier is 0. 5D(D is the outer diameter of the pier column). In order to ensure the safety of cap and plug bridge pier, reasonable structural measures should be taken to ensure the seismic performance of the pier in the strain permeation section, and it is recommended that the bearing depth of bridge pier in high intensity area should be greater than 0. 5D. [ABSTRACT FROM AUTHOR]

Precast segmental bridge piers attract engineers due to the strengths of accelerated construction, reduced traffic disturbance and enhanced quality control. However, their widely applications in high-seismicity areas are hindered, for the insufficient capacities of energy dissipation. In this study, precast segmental piers' seismic behaviors were investigated, focusing on the connection of 'grouted sleeves/bonded tendons'. To this end, four piers were cyclically loaded, of one cast-in-place pier, one precast segmental pier, and two prestressed precast segmental piers. Among them, Benefits of bonded tendons were evidenced, in terms of lateral strength, ductility, energy dissipation capacity and residual drift. Of particular, bonded tendons prevented the shear-induced slip between the shaft and footing segments. Enlightened from observations, cyclic dowel-friction effect is proposed and implemented within a zero-thickness sliding spring in the finite element model, capable of capturing the shear-induced joint slip. Furthermore, seismic vulnerability assessments of the bridge piers are obtained in terms of fragility curves, by performing incremental dynamic analyses. In addition, the effects of bonded or unbounded tendons are also discussed. Two criteria are adopted to define the limit states, namely displacement ductility and residual drift. It is suggested that bonded tendons could significantly ameliorate the fragility curves of precast segmental piers. Four bridge piers were cyclically loaded, with various prestressing levels. A reliable fiber-based model was constructed, considering shear-induced slip at the segmental joint for the first time. Seismic vulnerability assessments were performed to quantify the piers' behaviors. [ABSTRACT FROM AUTHOR]

Small overwater structures (SOWS) such as residential docks are common along marine shorelines. Large overwater structures like ferry terminals and commercial piers cast shadows that impair submerged aquatic vegetation and habitat, and alter salmon behaviour and migration. Because of large overwater structure impacts, it is possible that SOWS may also impact marine habitats and organisms. Here, we review the evidence for marine SOWS impacts, finding that relatively little research has been dedicated to the topic. Outside of reducing light and causing well-documented impacts on seagrasses in multiple parts of the world, there is inconsistent or inconclusive evidence for impacts on macroalgae or fish. There is insufficient research on SOWS to draw robust conclusions about these structures' overall impacts on nearshore environments or how to mediate any possible impacts. Unfortunately, freshwater SOWS or large marine structures are imperfect analogues for inferring marine SOWS impacts. However, we emphasise that an absence of evidence is not evidence for an absence of impacts by SOWS. We outline critical research questions and the relevant study approaches that would address data gaps surrounding SOWS impacts and management. Pervasive components of marine shoreline development – such as residential docks – are a growing concern for sustaining nearshore ecosystems. We review the impacts of small docks, finding robust evidence for impacts on seagrasses but sparse or inconsistent evidence for impacts on kelps and fishes. We highlight substantial data gaps that preclude informed policies, permitting, and restoration actions. [ABSTRACT FROM AUTHOR]

Pier columns, as primary bridge supports, are vulnerable to extreme loading demands resulting from fire, vehicle collisions, and blasts. The combined effects of these demands may cause significant strength reduction, extensive damage, and potentially collapse. Although the response of bridge columns subjected to independent or combined vehicle impact and air blast has been widely investigated, the cumulative effects of fire in conjunction with these dynamic loads have received limited attention. Consequently, this study presents a unique and advanced multistep finite-element modeling approach using LS-DYNA to simulate the response of isolated round reinforced concrete bridge columns subjected to fire prior to and after a vehicle collision and subsequent air blast. The developed modeling approach incorporates uncoupled implicit heat transfer analyses and explicit structural analyses and was validated against published fire, impact, and blast test results. A parametric study that investigated the effects of various column diameters and fire exposure scenarios on performance was completed, considering fire occurring before or after impact and blast. Column performance was assessed based on damage levels, residual load capacities, and lateral displacements. Study findings enhance the understanding of bridge column performance under this combination of hazards, provide insight into improving bridge resiliency, and could potentially have practical implications for the design and maintenance of bridge columns. Specifically, the study reveals that fire prior to impact and blast was a more critical load sequence for larger column diameters that could potentially remain in service in their final damage states while being repaired. Moreover, the study indicated that for the same fire duration and column diameters, residual capacities and displacements corresponding to half-surface-area exposure were slightly lower than those exposed to fire on the full surface area, a finding that could be beneficial in many practical applications where protective techniques and tools could be implemented. [ABSTRACT FROM AUTHOR]

Due to hydraulic, mechanical, electromagnetic and other reasons, vibration will inevitably occur during the operation of the hydroelectric generating set. As the supporting structure of the hydroelectric generating set, the stability of the pier is very important. In this paper, the whole model of the pier, volute, draft tube and foundation is established. The amplitude of any part of the pier under the resonant load can be obtained by numerical simulation. On this basis, the response surface method is used by statistical method. The two parameters of the inner diameter and thickness of the pier are taken as the design variables, and the information weight method is used to replace the maximum amplitude of the pier in the vertical, radial and circumferential directions with a comprehensive objective function, and the comprehensive objective function is used as the optimization objective. The response surface model is established and the pier model is optimized. The results show that the maximum amplitude of the optimized pier in the vertical direction is reduced by 17.8%, the maximum amplitude in the circumferential direction is reduced by 4.7%, and the maximum amplitude in the radial direction is reduced by 1.4%. The recommended value range of the inner diameter of the pier is 1.73D1 - 1.83D1, and the recommended value range of the pier thickness is 0.50D1 - 0.63D1. The optimization design method of response surface can be effectively applied to the vibration reduction design of hydropower station pier. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Introduction: A physical model was prepared to investigate the effect of the geometric shape of the bridge pier with the abutment attached to it on the reduction of scour depth. This model was made of a laboratory flume with a length of 7.5 meters, a width of 30 cm, a depth of 45 cm with a variable slope and a glass body with bridge pier width of 4 cm were used. For bed sediments, a layer of natural river sand with an average diameter of 0.9 mm and a standard deviation coefficient of 1.1 and a uniformity coefficient of 1.25 were selected and used in a layer with a thickness of approximately 14 cm for experiments. Methods: The geometric shape of the bridge piers, as well as the presence of the footing, prevents direct contact of the descending current, reduces the activity of horseshoe vortices and thus reduces the scouring speed, and delays the scouring start time. Findings: According to the results of the experiments, the greatest decrease in scour depth was related to (0.26 descent and p1 base). The results showed that in the same condition, the relative scour depth at p1 base was less than other bases and reached its maximum in the control base. Also, the relative scour depth increased with increasing the number of landings in the same position. The abutment attached to the bridge base has reduced the scour depth by 29.6%.

Local scour around bridge piers and abutments is one of the most significant causes of bridge failure. Despite a plethora of studies on scour around individual bridge piers or abutments, few studies have focused on the joint impact of a pier and an abutment in proximity to one another on scour. This study conducted laboratory experiments and flow analyses to examine the interaction of piers and abutments and their effect on clear-water scour. The experiments were conducted in a rectangular laboratory flume. They included 18 main tests (with a combination of different types of piers and abutments) and five control tests (with individual piers or abutments). Three pier types (a rectangular pier with a rounded edge, a group of three cylindrical piers, and a single cylindrical pier) and two abutment types (a wing–wall abutment and a semi-circular abutment) were used. An acoustic Doppler velocimeter was used to measure the three-dimensional flow velocity for analyses of streamline, velocity magnitude, vertical velocity, and bed shear stress. The results showed that the velocity near the pier and abutment increased by up to 80%. The maximum scour depth around the abutment increased by up to 19%. In contrast, the maximum scour depth around the pier increased significantly by up to l71%. The presence of the pier in the vicinity of the abutment led to an increase in the scour hole volume by up to 87% relative to the case with a solitary abutment. Empirical equations were also derived to accurately estimate the maximum scour depth at the pier adjacent to the abutment.

In this research, the performance of the combination of a cable and a collar and their effect on scouring in single and pier groups in clear water conditions has been investigated. The piers have been tested in 3 groups: a single pier, a double pier group, and a triple pier group. In addition, studies were carried out with and without cables and collars aligned in a linear manner, in the direction of flow. The diameter of the tested cylindrical piers was 3 cm, and the distance between them was three times the diameter. The cable diameter was 15% of the diameter of the piers, and the twisting angle of the cable around the piers was 15 degrees. The collars were 2.6 times the diameter of the pier and 2 mm thick. The synchronous combination of the cable and collar causes the reduction of horseshoe vortices due to the impact of the flow and the decrease of scour depth. The maximum decrease of the final scouring depth related to the single pier with a cable and a collar compared to the single pier without a collar and a cable is 66.82%. In addition, the final scouring depth of the first pier of the triple group compared to the first pier of the double group is 78.61%. [ABSTRACT FROM AUTHOR]

The behavior of river flow patterns on the condition of the pillar dimensions can affect the geomorphology conditions of the river, namely the unbalanced local scouring between sediment transport and sediment supply so that it will affect the strength of the pillar. This study aims to study the effect of pillar dimensions on scour depth and channel base changes in the pillar area. The method of observation was carried out by simulations using Nays2DH with the same parameters for each test of each dimension with discharge (Q) = 0.5 m3/s, sediment diameter (D50) = 0.35 mm, channel width (B) = 5 m, channel length (L) = 25 m, slope (i) = 0.005 and drainage time (t) = 7200 s. The simulation results show the basic scour pattern of the channel which has the smallest value, the diamond type pillar. Degradation - Basic channel agitation on diamond type pillars, showing a pattern that tends to be evenly distributed compared to semi rounded, rectangle, or octagonal types. Period (t) 7200 s downstream of the pillar, semi rounded type scours change

In this study, we analyzed the problems of the conventional response spectrum analysis method. Thereafter, we derived methods to improve it by considering the dynamic behavioral characteristics of a pile-type mooring facility with a crane. The applicability of the standard design response spectrum analysis method of crane pile mooring facilities was analyzed, and the results of previous studies on dynamic behavioral characteristics were reviewed to derive improvements and the applicability of the derived improvements in practice. when the analysis was performed with the application of the improvement, the stress of the pile during the earthquake was 70% of that of the conventional method. As a result of the study, in the recent trend where more stringent seismic design standards are required, applying the derived improvements will enable a more precise analysis than the conventional method, and reduce unnecessary costs of seismic retrofitting, contributing to the improvement of cost efficiency. [ABSTRACT FROM AUTHOR]

The present analysis focuses on the investigation of the two-dimensional flow passing a bridge pier nearby a splitter plate in different regimes of a laminar flow. The splitter plate is T-shaped and two different cases have been studied based on the form of the splitter plate relative to the bridge pier. The analysis is implemented for steady and incompressible water flow in an open channel. The current study deals with velocity vectors, drag coefficients, lift coefficients, and skin friction. The analysis of the velocity vector gave a good indicator about the separation process and dissipation, which occurs at the splitter plate before the occurrence of these processes at the front face of the pier, especially the flow separation process. Moreover, the velocity vector gave a good image about the flow direction at two regions, the first region is located between the rear portion of the splitter plate and the frontal face of the pier, while the second region is the wake region, which is located at the downstream of the pier. Negative drag coefficient, lift coefficient, and skin friction coefficient values are obtained from the analysis. This happens due to the existence of the splitter plate that leads to the reduction of these values. [ABSTRACT FROM AUTHOR]

The present analysis focuses on the investigation of the two-dimensional flow passing a bridge pier nearby a splitter plate in different regimes of a laminar flow. The splitter plate is T-shaped and two different cases have been studied based on the form of the splitter plate relative to the bridge pier. The analysis is implemented for steady and incompressible water flow in an open channel. The current study deals with velocity vectors, drag coefficients, lift coefficients, and skin friction. The analysis of the velocity vector gave a good indicator about the separation process and dissipation, which occurs at the splitter plate before the occurrence of these processes at the front face of the pier, especially the flow separation process. Moreover, the velocity vector gave a good image about the flow direction at two regions, the first region is located between the rear portion of the splitter plate and the frontal face of the pier, while the second region is the wake region, which is located at the downstream of the pier. Negative drag coefficient, lift coefficient, and skin friction coefficient values are obtained from the analysis. This happens due to the existence of the splitter plate that leads to the reduction of these values.

Literature review revealed that scour modeling using artificial intelligence (AI) lacks majorly in two aspects - one is the Input variable selection (IVS) and secondly, the relative ranking of scour models based on their performance. In this study, state-of-the-art AI algorithms, including artificial neural network (ANN), artificial neuro-fuzzy interface system (ANFIS), support vector machine (SVM), model tree (M5P), gene expression programming (GEP), and group method of data handling (GMDH) were employed to compute the Local Scour Depth (LSD) and to address identified lacunas. A total of 378 data set consisting of laboratory and field data was used for modeling. Evaluation criteria such as the index of agreement (IOA), Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), Skill Score (SS), Correlation (Correl), and Taylor diagram were employed to check the goodness-of-fit of the proposed models. IVS was performed using partial mutual information (PMI). The findings of the study showed that velocity (V), the diameter of the pier (b), Reynolds pier number (Rp), and particle densimetric Froude number (Frd) were highly sensitive parameters to the scour. Quantitative and qualitative results indicated that SVM performed better with RMSE (0.06), MAPE (0.04) and SS (0.9). Tayler diagram also confirmed the above findings. [ABSTRACT FROM AUTHOR]

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To improve the local scour protection of the pier using solid sacrificial piles, a kind of permeable sacrificial pile filled with stones is put forward in this study. Four influencing factors, including the size of the filling gravel of the permeable sacrificial pile, the distance between the pile and pier, the diameter ratio D1/D (D is the diameter of the pier and D1 is the diameter of the pile.), and the submergence rate of the pile, are studied in clear water condition with indoor tests and numerical simulations. The test results show that it has the best reduction effect on the local scour of the pier when the filled gravel size is 0.2–0.25 D, the distance between the pile and pier is 3.0 D, the diameter ratio is 1.0, and the submergence rate is 0.8. Results of the numerical simulation show that the permeable sacrificial pile has a significant weakening effect on the downflow in front of the pile and the flow velocity around the pile. In the same conditions, the reduction effects of the permeable sacrificial pile and the solid sacrificial pile on the pier are similar, but the local scour around the permeable sacrificial pile is less than that around the solid one. The pressure difference outside and inside the permeable pile causes the water to flow in the direction perpendicular to the isobars. This significantly impacts the flow velocity, the vortex system, and the shear stress around the permeable sacrificial pile and pier, which leads to a huge decrease in the local scour depths. The maximum shear stress on both sides of the permeable sacrificial pile and the pier is about 1/2 and 1/4 of those around the solid sacrificial pile respectively. And the area with lower velocity and shear stress behind the permeable sacrificial pile is larger than the area behind the solid ones. [ABSTRACT FROM AUTHOR]

Local scour of piers is a potential danger threatening the operational safety of the sea-crossing bridge. Reliable scour depth prediction of piers can make the economic maintenance of the sea-crossing bridge. Considering the Hangzhou Bay Sea-crossing Bridge as the research prototype, based on the measured data and numerical simulation, the flow-field structure in front of the pier and the shape of the scour hole around the pier are simplified, and the prediction equation of the maximum depth of local scour is derived based on the energy balance theory. Based on the measured data, the equation is verified and compared with the local scour calculation equation in the design code, and the sensitivity of the parameters in the equation is analyzed. The results reveal that the equation is feasible and accurate and can provide guidelines for future decision-making regarding the early warning and maintenance of local scour of sea-crossing bridges. [ABSTRACT FROM AUTHOR]

Piers can be severely damaged by earthquakes. When an action of a massive earthquake is assumed, the seismic performance of the pier can be improved by widening the foundation width. A previous horizontal loading study indicated that extending only the Foundation Bottom (FB) width, rather than the complete foundation, can boost seismic resilience while suppressing the increase in building cost. However, the research dealt with only two types of FB width, i.e. normal and widened, and the data for sufficiently assessing the inclination angle of the pier with loading were not obtained. In this study, to evaluate the seismic performance of piers with different FB widths in more detail, horizontal loading tests on piers with ordinary columnar foundations and two types of piers with widened FB were conducted, and the seismic resistance of the three pier types were compared. It was shown that horizontal displacement and inclination angle of the pier can be reduced by widening the FB. Furthermore, finite element analysis was carried out to reproduce the experimental results. The analysis results showed good agreement with the experimental results in terms of pier horizontal displacement and inclination angle. [ABSTRACT FROM AUTHOR]

Oil spill, a frequent pollution in the utilization of rivers, is receiving increasing attention in the study of river ecosystems. Taking the Zhuankou–Yangluo Reach (ZYR) of the Middle Yangtze River as an example, the spatial and temporal behaviors of leaked oil in the river under uniformly arranged piers with varying densities were studied based on a MIKE21 hydrodynamic and oil drift model. The results show that the oil spill spread is less affected by the piers when the upstream oil spill point is located on the other side of the shoreline with piers. However, the influence of the piers on the same shoreline of the oil spill point on oil spill transportation cannot be ignored. The piers significantly reduce the oil spill drift speed in the engineering area, resulting in a significant increase in slick retention time and slick area, especially when the density of piers is greater than 1.25 units/km. These results will provide useful reference for river management, for example, in the upstream river of the water conservation area, especially on the same bank as the water intake, where a large number of piers should not be built. HIGHLIGHTS The influences of river pier densities on hydrodynamic and oil spill transport were studied using MIKE21.; When the piers are on the same side as the oil spill point, the influence on oil spill transportation is much greater than when on the other side.; A pier density of more than 1.25 units/km will significantly reduce the oil spill drift speed and increase the slick retention time and slick area.;

The aim of the study was to indicate the procedure of using laboratory physical model tests of scour around bridge piers for the purposes of determining the potential scour of a riverbed on field bridge crossings. The determination of the uniform modeling scale coefficient according to the criterion of reliable sediment diameter limits the application of the results of tests on physical models to selected types of sediment. The projected depths of scouring of the riverbed at the pier in nature were determined for an object reproduced in the scale of 1:15 determined from the relationship of flow resistance, expressed by hydraulic losses described by the Chézy velocity coefficient, the value of which, in the model and in nature, should be the same. Expressing the value of the Chézy velocity coefficient with the Manning roughness coefficient and introducing the Strickler parameter, it was shown that the coarse sand used in the laboratory bed models the flow resistance corresponding to the resistance generated by gravel in nature. The verification of the calculated size of scouring was based on popular formulas from Russian literature by Begam and Volčenkov [16], Laursen and Toch’s [20] from the English, and use in Poland according to the Regulation ... (Journal of Laws of 2000, No. 63, item 735) [32].

Under a flow in supercritical regime, depending on the pier width to water depth ratio, the flow pattern around a bridge pier can take the form of a wall-jet-like bow wave or a detached hydraulic jump. The present work aims at analysing the maximum scour depth at piers in both flow patterns. A dedicated experimental set-up was used to produce the live-bed scour experiments, varying the inflow velocity and pier diameter. During the experiments, scour developed very rapidly, achieving equilibrium conditions after few minutes. No major differences between the maximum scour depth in the wall-jet-like bow wave and detached hydraulic jump cases were observed. Measured scour depths were of comparable magnitude and followed similar tendencies with controlling parameters as in subcritical flows. Scour formulas for piers in subcritical flow thus achieve a good accuracy in prediction of maximum scour depth at piers in supercritical flows. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)