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Despite technological progress in the maritime industry, navigators are still the final link of the decision-making chain and rely not only on equipment, but also on human senses. Visual observation of the vessel's surroundings still plays a crucial role in navigation. Four different ships in service were visited to investigate the work of professional navigators and carry out a pilot experiment on real crews to test the methods for future full-scale research. The main objective was to better understand the influence of bridge design on lookout routines of navigators, while the additional goals were to check the presence of navigators in certain parts of the bridge and to determine if it is reasonable to forbid navigators to sit, as the practice is still used on some ships. Considering space limitations and differences in layouts of the wheelhouse, rarely mentioned in this kind of study, the movement of watch-keeping officers was analysed. In total, twenty observations were made to generate the heatmaps of presence during the routine duties. The results of the research indicate that many factors, including bridge design and layout of equipment, might affect lookout routines but it is possible to find similar patterns on the bridges of different shapes and arrangements. The pilot experiment confirms that it is reasonable to carry out a full-scale study, as there is still room for improvement in the area of ergonomic bridge design. Better understanding of modern lookout and movement routines might lead to the development of adequate ergonomic regulations and result in increased work comfort and the well-being of seafarers. [ABSTRACT FROM AUTHOR]

This paper presents the shake table testing and finite element (FE) modeling of a modular prefabricated concrete bridge‐like specimen. The specimen comprised four equal‐height cylindrical reinforced concrete (RC) columns capped with an RC slab. The structural connections were non‐monolithic. Hence, controlled relative motion of the members, including rocking (uplift) of the piers, was allowed. The columns were connected to the slab with stiff tendons that provided positive post‐uplift stiffness. The specimen was subjected to 184 triaxial shake table tests, so that a statistical validation of numerical models can be performed. Subsequently, a detailed three‐dimensional FE model of the bridge was developed. The objectives of the present study were to: i) investigate the shake table response of a modular bridge with positive post‐uplift stiffness under multiple ground motions, ii) develop an FE model of the proposed structural system, iii) investigate the influence of geometrical imperfections on rocking bridges, and iv) evaluate the efficiency of using additional dissipative rebars. After being subjected to 184 shake table tests, the specimen showed zero damage, moderate displacements and tendon forces (TFs), low slab torsion, and zero residual displacements. The shake table tests were practically repeatable. The proposed FE model accurately captured the experimental results. Geometrical imperfections heavily affect the response of negative stiffness systems. However, they have a marginal influence on positive stiffness systems. When comparing systems with equivalent uplift resistance and post‐uplift stiffness, the use of additional dissipative rebars results in lower slab torsion and TFs, provided that the rebars do not fracture. [ABSTRACT FROM AUTHOR]

Translation abstract On the load bearing and fatigue behaviour of headed anchor studs with defective weldsThe welding of headed anchor studs (KBD) is a technically demanding process. The main difficulty for contractors is that it is not yet possible to provide non‐destructive evidence that the product is free of defects. The publication of Allgemeines Rundschreiben Straßenbau (ARS) No. 18/2019 on quality assurance when welding headed stud dowels in bridge construction has significantly tightened the requirements for headed stud dowel welding. Since a company owes a defect‐free trade at the time of handover, but the freedom from defects of headed anchor studs can currently only be proven by means of destructive testing, this creates a considerable entrepreneurial risk for the practice. Although the standards and guidelines provide information on the procedure that can be used to ensure defect‐free bolts, there is no guarantee of success. For this reason, companies had to rely on the tolerance of the acceptance criteria provided by the current standards for headed anchor studs. This article deals with faulty headed anchor stud welds as well as repair methods commonly used in practice to gain initial insights into whether the tightening within the framework of the document Allgemeines Rundschreiben Straßenbau No. 18/2019 was expedient or necessary. Initial results from the PAUT (Phased Array Ultrasound) method will also be examined to determine whether it may be possible in the future to use this method to enable non‐destructive testing of headed anchor studs. [ABSTRACT FROM AUTHOR]

Translation abstract Evaluation and strengthening of existing bridges – historical outlines and findings regarding the Hessian road bridge inventoryTwo short histographical sketches introduce the concepts of refurbishment, condition and load‐bearing capacity assessment between 1700 and 2010 and take a look at the development of the recalculation of existing bridges. Based on project sketches, the hidden safety features of existing road bridges are worked out and procedures for achieving efficient structural bridge strengthening are presented. The focus is on the determination of real object‐specific traffic load models, calibrated structural analyses and additive and non‐destructive strengthening methods. Some critical comments on planning acceleration and the current approval system, together with the demand that bridge construction should be reflected in the common objective of “traffic”, broaden the definition of strengthening holistically. This offers the opportunity to stimulate a discussion about the sensible handling of existing bridges as part of our road infrastructure. [ABSTRACT FROM AUTHOR]

The frequent occurrences of bridge fires and the substantial disruptions and direct/indirect economic losses resulting from these events highlight the immediate need for effective fire-safety-oriented design of new bridges and retrofit approaches for vulnerable existing bridges. In this Perspective, we discuss why a holistic engineering approach integrating innovative fire analysis methods and structural design/retrofit strategies into multi-hazard and future-oriented risk modeling frameworks represents the way forward to more sustainable and resilient infrastructure in an uncertain and rapidly changing built environment. Bridge fires cause significant disruptions and economic losses in modern society, yet fire hazards are still often ignored or oversimplified in bridge design. This Perspective emphasizes the need for more holistic and comprehensive fire-safety design when retrofitting or designing new bridges. [ABSTRACT FROM AUTHOR]

One particular challenge in constructing geotextile tubes is ensuring proper alignment and leveling, especially when connecting them in a series. This study introduces a novel connection configuration to address this challenge by inserting an auxiliary tube between two main tubes. The proposed connection method offers the advantage of consolidating individual geotextile tubes into a unified structure while maintaining a consistent horizontal level. The proposed connection technique was successfully applied both at test site and on dry construction platform for bridge construction. This study is beneficial for practicing engineers as it presents a new and effective method for connecting geotextile tubes, offering valuable insights into its practical application. • A novel, robust, and easily implementable method for connecting geotextile tubes is proposed. • The proposed connection ensures the cohesive formation of individual geotextile tubes into a unified structure and maintains the vertical profile levels. • Successful application demonstrated in a test site. • Application extended to a temporary platform for bridge construction in a real-world case study. • Its availability to the engineering community makes it adoptable, serving as a foundation for future improvements in geotextile connections. [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]

The International Federation for Structural Concrete (fib) offers various publications and resources for those interested in concrete structures. One publication, fib Bulletin 111, focuses on modeling the performance of existing concrete structures, considering factors such as increased traffic loads and material deterioration. The fib Model Code (2020) provides comprehensive guidelines for planning, designing, and constructing concrete structures. The fib also recognizes and promotes innovative design and construction practices through awards and symposiums. The document also highlights the career and contributions of Peter Marti, a professor at ETH Zurich, who has made significant contributions to the field of structural engineering. Lastly, the document mentions upcoming congresses and symposia related to structural concrete. [Extracted from the article]

A novel concept of hybrid reinforcement in the form of glass fiber‒reinforced polymer (GFRP) longitudinal column bars combined with steel longitudinal column bars and high-strength post-tensioning all-threaded rods is investigated in this research to construct bridge columns for seismic regions. Two half-scale specimens were constructed using grouted ducts to connect the columns to the footings as an accelerated bridge construction method. The first column was reinforced with a combination of mild steel and GFRP longitudinal bars (hybrid column) and the second with all-mild steel longitudinal bars, and both columns were confined with a double layer of GFRP spirals; this arrangement improves column longevity since GFRP materials do not corrode. Both specimens utilized high-strength all-threaded rods for post-tensioning. Carbon fiber‒reinforced polymer jackets were externally wrapped at the column bottom to confine the concrete in the plastic hinge region. The seismic behavior of both precast concrete specimens was assessed through quasi-static cyclic tests. Both columns exhibited satisfactory strength and deformability. The combination of post-tensioning bars with GFRP longitudinal bars improved the self-centering capability. The residual displacement of the hybrid column was decreased by 46% compared with the all-steel-reinforced column at 6.0% drift ratio. The elastic nature of the GFRP longitudinal bars provided substantial self-centering by reducing the residual displacement of the hybrid specimen thereby enhancing seismic resilience. [ABSTRACT FROM AUTHOR]

The fatigue provisions for bridge design in North America and Europe are highly simplified for the sake of practical implementation, in comparison with the state of the art in understanding of the true fatigue behavior. Historically, one significant simplification in the calibration of damage equivalence factors has been to assume that trucks cross the bridge one at a time, when in reality trucks are known to platoon, and multiple truck presence is not uncommon on longer span structures with higher traffic volumes. While code writers have taken steps more recently to consider multiple presence effects, these efforts have been limited, and a clear understanding of the influence of key design parameters on multiple presence effects has not yet been fully established. Against this background, the present work considers real-time multilane weigh-in-motion (WIM) data and compares fatigue damage from recorded loading events over years to the damage resulting from the same vehicles crossing the bridge individually, to better understand the significance of multiple vehicle presence effects on fatigue damage. For both finite and infinite life fatigue design, the results show that multiple vehicle presence effects can be significant, depending on traffic volume, road configuration, and influence line characteristics. Multiple presence factors are therefore defined, allowing practitioners to consider multiple presence effects appropriately when designing bridges where they may be relevant. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) is widely used in precast concrete-steel composite beams because of its beneficial properties, including reduced structural weight, higher flexural rigidity, and reduced tensile crack formation. In comparison to conventional steel-concrete composite beams, steel-UHPC composite beams exhibit superior characteristics, including reduced structural deadweight, enhanced flexural stiffness, and the capacity to withstand tensile cracking. One successful attempt at meeting the current demands for expedited girder engineering is the development of steel-UHPC composite beams with full-depth precast slabs as key components affecting the overall structural performance using dismountable single embedded nut bolts (SENBs) and widely used studs as competitive alternatives. In contrast, shear connectors are exposed to a combined tensile and shear stress in service life rather than shear only. The corresponding scientific problem is the problem of combined effects under stress in practical applications, but there is currently no relevant research. The shear performance of SENBs in precast steel-UHPC composite beams under tension and shear loads remains unclear. For this purpose, ten push-out specimens and theoretical analyses were performed in this paper, considering the influence of the connector's type and tensile-to-shear ratio. However, ten specimens were conducted to investigate the tensile-to-shear ratio, and the connector's type on shear performance is limited. In the future, an increasing number of specimens and test parameters should be considered to investigate the shear performance of precast steel-UHPC composite beams. An increase in the tension-to-shear ratio resulted in a substantial reduction in the ultimate shear capacity, initial shear stiffness, and ductility of the studs. The increase in the tensile-shear ratio from 0 to 0.47 resulted in a 16.9% decline in the ultimate shear capacity, a 30.4% reduction in the initial shear stiffness, and a 21.7% decrease in the ductility of the Series I samples. However, an increase in the tensile-to-shear ratio of the Series II samples from 0 to 0.47 resulted in a 31.3% decline in ultimate shear strength, a 33.2% decline in initial shear stiffness, and a 41.9% decline in ductility. The SENBs demonstrated minimal deviations in ultimate shear capacity compared to their stud counterparts, despite exhibiting notable differences in shear stiffness, and ductility. A lower tensile-to-shear ratio was recommended in practical engineering, which might achieve a larger ultimate shear capacity, stiffness, and ductility. The design-oriented models with enhanced applicability were developed to predict the tension-shear relationship and the load-slip curve of SENBs in prefabricated steel-UHPC composite beams subjected to combined tensile and shear loads. For a tensile-shear relationship model, the point error range was 0 to 0.08, with an average error of 0.03. The square coefficient (R2) was 0.99 for a load-slip curve model. The study findings could offer a credible reference for the shear mechanism of such economical and environmentally friendly precast steel-UHPC composite beams in accelerated bridge construction. [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]

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]

The primary priority of bridge construction over a waterway is to support and confirm constant communication. Conversely, it may locally disrupt the health of the river which will have an adverse influence on the hydrological as well as morphological behavior of nearby regions by way of the river's narrowing. The current study evaluated the effect of bridge structure on river morphological characteristics for Teesta River. Hence to do, this work robbed two approaches. Firstly, the Landsat images from a pre-road bridge (2001 and 2006) and post-road bridge construction (2011, 2016, and 2021) are processed and used for bar formation and bank line shifting. Secondly, the bar properties, differences in channel width, and changes in river bank were evaluated using geospatial technology. The outcomes revealed a recurrent change of bar area and channel width at the upstream side of the bridges and likewise dominating at the downstream side. Throughout the post-road bridge period, the average bar area has increased noticeably by 32.45 sq.km which is 7.75% of the total river area and the downstream bar area has also increased considerably. Besides, both bank lines of the river were dominated by erosion in the post-road bridge construction era. Accordingly, the Teesta Road bridge's existence has had a significant impact on the morphological modification in recent years. The study also reveals that the bars and islands of Teesta River undergo a drastic change and the river can be treated as a braided one, and also showed the minor trend of meandering. The findings of this research may be supportive for sustainable and long-term planning and development of the rivers and neighboring floodplains in Bangladesh. [ABSTRACT FROM AUTHOR]

In order to analyze the stability of the bridge above the goaf, the disturbance influence of goaf residual deformation on the bridge is studied. Firstly, an equivalent numerical simulation method of goaf residual deformation evolution process is studied by quantitative analysis the sensitivity of residual subsidence to the rock parameters using the OAT (one-variable-at-a-time). Then, the collaborative deformation of ground, pile, and bridge floor is studied under the condition of a simply-supported beam bridge above the goaf center. Finally, the mechanism of collaborative deformation of ground, pile, and bridge floor is revealed. The results show that the goaf residual deformation process can be obtained by weakening the elastic modulus of fractured rock in the caving zone. At the final residual deformation stage, the subsidence ratio of ground to pile is about 10, and the subsidence ratio of pile to bridge floor is about 2, while the ground horizontal movement ratio of ground to pile is about 7, and the bridge floor horizontal movement can be ignored. The bridge floor is always in the positive curvature influence zone, and the pile has an inhibitory effect on the curvature deformation of the bridge floor. The compression deformation occurs between the piles locations, while the tensile deformation occurs at the pile location. The evolution of negative frictional resistance derived from goaf residual deformation is the main reason for the change in the collaborative deformation law among the ground, pile and bridge floor. This research can provide scientific support and theoretical basis for the design, construction, and protection of the bridge above the goaf center, and can also provide reference for the stability evaluation of bridge above goaf under other conditions. [ABSTRACT FROM AUTHOR]

Monitoring and predicting ground settlement during tunnel construction is of paramount importance for ensuring the safety of tunnel construction and the stability of the surrounding environment. Existing studies on settlement prediction mainly rely on single settlement values and often overlook temporal characteristics, and that prediction models struggle to capture the nonlinear trends in actual settlements, leading to suboptimal predictive accuracy. In this study, based on the monitoring data of settlement deformation in a subway section of a certain city, a multi-factor-driven prediction method for surface settlement in subway tunnel excavation using the Informer model is proposed. The predictive accuracy is compared and analyzed with other models, including CNN-LSTM, LSTM, SARIMA, and Transformer. The results indicate that: (1) The Informer model outperforms CNN-LSTM, LSTM, SARIMA, and Transformer in terms of RMSE, MAE, and MAPE evaluation metrics, demonstrating that the Informer model exhibits smaller average prediction errors in forecasting surface settlement during subway construction. (2) Compared to LSTM, CNN-LSTM, Transformer, and other models, the Informer model can better capture the temporal characteristics and long-term forecasting ability of settlement data, while the SARIMA model fails to capture the temporal features in actual settlement data effectively. (3) Considering the influencing factors of temperature and soil pressure has a positive impact on the predictive performance of the Informer model, and the relationship between soil pressure information in the case study construction area and surface settlement is more closely associated. In summary, the Informer model, which takes into account temporal characteristics and multiple influencing factors, demonstrates good predictive ability for nonlinear settlement data. It provides a new method for analyzing settlement trends caused by subway tunnel excavation under complex environmental conditions, facilitating efficient and accurate assessment. It also offers objective data support for short-term bridge construction scheduling and long-term construction planning. [ABSTRACT FROM AUTHOR]

This paper focuses on the design as well as on the experimental and numerical validations of the mechanical behavior of a precast ultra-high performance fibre reinforced concrete (UHPFRC) retaining walls. The design, made in accordance with the Canadian Highway Bridge Design Code (CSA S6, 2019), led to the fabrication of a full-scale UHPFRC retaining wall with 3% fibre content which had dimensions of 3 m in height, 2 m in length, 2 m in width, with two vertical and horizontal stiffeners, and very thin vertical and horizontal panels of 40 and 65 mm, respectively. The experimental tests showed that the UHPFRC retaining wall exceeded by 42% the ultimate limit state (ULS) design factored bending moment and showed a very ductile behavior under flexural loading. At service limit state (SLS), the retaining wall had maximum crack opening between 0.15 and 0.28 mm, and a maximum lateral displacement of 4 mm. The finite-element model developed for the application captured accurately the flexural behavior of the UHPFRC retaining wall and was used later in parametric studies to optimize the design. The retaining wall optimal design includes UHPFRC with 3% fibre content and stiffeners with variable cross-section which allows volume reductions of 73% for concrete and 86% for rebars in comparison to the conventional reinforced concrete design. [ABSTRACT FROM AUTHOR]

The study designed a risk assessment scheme to reduce the risk of highway bridge construction in highland mountainous areas, and optimised the existing hierarchical analysis method used for risk weight calculation, using entropy weight and fuzzy numbers for improvement, and designed an optimised fuzzy hierarchical entropy weight comprehensive risk assessment model. The results found that the maximum affiliation degree of site safety management risk is 0.39, which is a low-level risk; the maximum affiliation degree of personnel safety and operation quality category is 0.42, which is an intermediate risk; the maximum affiliation degree of machinery and equipment is 0.40, which is a high-level risk; the maximum affiliation degree of construction materials is 0.69, which is a low-level risk; and the maximum affiliation degree of environment category is 0.51, which is an intermediate risk. The maximum affiliation of the overall construction risk is 0.369, which indicates that the fuzzy comprehensive evaluation of the project is an intermediate risk. The results of the study show that the proposed construction risk assessment scheme for highway bridges in highland mountainous areas can provide certain reference for the construction of highland mountainous areas and avoid the corresponding safety risks. [ABSTRACT FROM AUTHOR]

Standards for the design of bridges, buildings and other infrastructure specify design loads for climatic hazards such as temperature, snow, wind, and floods based on return periods presented in maps or tables that account for regional differences. These design loads were developed from statistical analyses of historical hazard data under the assumption that the past is representative of the future. Climate change may affect the frequencies and intensities of environmental hazards which, depending on regional variations, raises questions as to whether structures designed to current specifications will meet minimum safety standards over their future service lives. This paper critically appraises issues related to using historical hazard data for future designs. It reviews basic principles of uniform reliability, that modern design codes use as the basis for ensuring minimum levels of safety, describing the relationship between hazard return periods, structural reliability, risk and the maximum loads expected within a structure's service life. Simple examples involving wind effects on structures demonstrate how to calibrate structural design hazard maps for climate-related extreme events to meet the minimum standards of safety implied in current specifications. The paper also introduces a possible practical approach to account for climate change when designing new structures and assessing the safety of existing facilities. [ABSTRACT FROM AUTHOR]

This study is part of a master plan by Thailand's Department of Rural Roads to design new bridge and road construction projects across 37 provinces in the North and Northeast regions. Potential sites were evaluated based on physical accessibility and environmental factors, considering eight criteria including slope, road density, distance from existing bridges, accessibility to educational institutions, workplaces, tourist sites, hospitals, agricultural areas, and villages. Using multi-criteria decision-making (MCDA) and the Analytical Hierarchy Process (AHP) within a GIS framework, we assessed origin-destination trips to identify optimal sites for new bridges and roads. Initially, 1,534 potential bridge locations were identified and evaluated using AHP to determine the relative importance of each factor. The GIS-based MCDA process enabled effective spatial data analysis, refining the sites based on environmental constraints and proximity to existing structures. Ultimately, 185 suitable locations for bridge construction were selected, including 98 sites in Northern Thailand and 87 in the Northeast. The study demonstrates the effectiveness of combining AHP and MCDA within a GIS framework for infrastructure planning. It underscores the importance of integrating multiple criteria to achieve sustainable and efficient development. The findings offer a robust framework for policymakers to identify and prioritize infrastructure investments that address both current and future needs. [ABSTRACT FROM AUTHOR]

This study examines the cyclic shear-slip performance of a novel prefabricated composite shear stud (PCSS) connector designed for accelerated bridge construction (ABC) of composite structures. An in-depth experimental procedure is employed involving the design and fabrication of four push-out specimens with two different stud configurations. The specimens are then tested under both monotonic and cyclic-to-monotonic loading protocols. Upon completion of the testing phase, a meticulous inspection of the fractography is conducted to delineate and qualify the failure mode of the PCSS connectors. Simultaneously, a comprehensive shear-slip curve is derived from the measured data, enabling a detailed analysis over the mechanical performance. Furthermore, the study calculates a series of deformation-associated indicators from the shear-slip curve, effectively quantifying the ductility, recoverability, and capacity of the PCSS. The test results accentuate a well-deformed and ductile failure mode of the tested PCSS specimens, marked by the stud fracture and crushing of surrounding concrete. This could be attributed to the constraint of vertical plates of the PCSS on the concrete, which improves the capacity and recoverability of the PCSS. Whereas, the performance of the PCSS is also notably influenced by the group nail effect, for which the ductility and per-stud capacity degrade with the increase in the number of studs. Especially, the PCSS specimen exhibits full elastic-to-plastic hysteresis loops under cyclic loads, together with the satisfied ductility, implying an excellent potential of the PCSS to dissipate energy under impact loads. In addition, the PCSS displays a robust stiffness across different cyclic loading blocks. Hence, satisfactory post-damage ductility has still been observed in the PCSS under the monotonic loading after the cyclic loading. In conclusion, this work elucidates the superiority of the PCSS in terms of capacity, ductility, and recoverability, providing a promising basis for their application in the accelerated construction of composite bridges. [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]

The paper presents a dynamic model of the TMM-3M heavy mechanized bridge during the span lowering stage. The model is constructed as a multi-body mechanical system, taking into account the elastic deformation of the cable, rear outriggers, front tires, and front suspension system. It is a mechanical model driven by a cable mechanism. Lagrangian equations of the second kind have been applied to establish a system of differential equations describing the oscillations of the mechanical system and serve as the basis for investigating the dynamics of the span-lowering process. The system of differential equations is solved using numerical methods based on MATLAB simulation software. The study has revealed laws of the displacement, velocity, and acceleration of components within the mechanical system, especially those related to the bridge span depending on the choice of the drive speed of the engine during lowering by operator. The research results show that the lowering time increases from 52 seconds to 104 seconds when the engine speed decreases from 1800 rpm to 900 rpm. The tension force on the cable is surveyed to confirm the safety conditions during the span-lowering process. The study also provides recommendations for selecting appropriate engine speeds to minimize span-lowering time while ensuring the safety conditions of the TMM-3M bridge during the span-lowering process. This research is an important part of a comprehensive study on the working process of the heavy mechanized bridge TMM-3M to make practical improvements, aiming to reduce deployment time, decrease the number of deployment crew members, and increase the automation capability of the equipment. [ABSTRACT FROM AUTHOR]

During the construction of concrete bridges, vehicle traffic capacity frequently experiences significant disruptions. To assess this impact, this article conducts a new comprehensive evaluation method. Initially, we calculate the equivalent speed and density of traffic on the construction section, subsequently analyze the functional relationship between these two parameters. By categorizing traffic into three distinct flow states, we compute the traffic congestion index. Furthermore, we establish a multi-lane traffic capacity model to estimate the vehicle traffic capacity during concrete bridge construction. This estimated capacity is then compared with pre-construction traffic capacity data. Experimental results reveal that the traffic capacity reduction rate and traffic flow change rate calculated using new methodology align well with actual values, thereby validating the high accuracy of new evaluation approach in assessing the impact of construction on vehicle traffic capacity. [ABSTRACT FROM AUTHOR]

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Conducting vertical control network for super-span cross-river bridges is a key and challenging aspect of bridge construction measurement. Considering requirements of the vertical control network in Changtai Yangtze River Bridge project, the principle of total station ATR technology was studied from the aspects of cross-river line selection, cross-river points determination, vertical angle measurements and trigonometric leveling. The influence of distance, angle and atmospheric refraction on height difference measurement was investigated. Finally, the second order cross-river leveling data of total station with a crossriver distance of 2.97 km was analyzed. The maximum difference between the two circles after averaging was 9.99 mm, which was much smaller than the tolerance. The maximum ring closing difference was 8.89 mm, which met the requirement of tolerance. The random error of mean round-trip measurement was ±0.34 mm/km, which met the requirement of second order leveling accuracy. It is concluded that the total station ATR technique could be used for cross-river leveling for bridges with lengths less than 3.0 km, and the accuracy meets the second order leveling. Compared to traditional manual aiming measurement methods, the ATR technology of total stations can significantly improve measurement efficiency and enable intelligent cross-river leveling. [ABSTRACT FROM AUTHOR]

Precast slab bridges are an attractive option for short- to medium-span bridges; however, the presence of longitudinal joints and concrete overlays adds great complexity to the transverse load distribution (TLD) analysis. Currently, one of the most commonly used methods for simplified analysis relies on the semiempirical formulas provided in AASHTO LRFD Bridge Design Specifications; yet, these formulas have certain limitations in their applicability. This study presents an algorithm based on the transfer matrix method (TMM) to determine the TLD of precast slab bridges. A connection model utilizing shear-and-torsion spring hinges (STSHs) is proposed to simulate the structural behavior of shear keys and the overlay of precast slab bridges in TLD calculations. The transfer matrices and transfer equations between slabs and between joints are established. The TLD for slabs is then computed by introducing boundary conditions and solving transfer equations. In addition, the finite-element method (FEM), along with the existing field tests of two different bridges, is used to verify the accuracy and validity of the proposed method. The study concludes that the TMM shows high algorithmic efficiency compared to the FEM modeling procedure and better precision and applicability than the semiempirical equations provided in AASHTO LRFD. Moreover, extended parametric studies are conducted on the effects of the thickness of concrete overlay and the relative flexibility coefficients of slabs on the TLD of bridges. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction (ABC) has emerged as a faster method of bridge construction. Reinforced concrete (RC) columns in bridges constructed using ABC methods remain vulnerable to corrosion, which impacts their performance during large earthquakes. Three specimens were constructed using ABC methods to investigate the effects of corrosion; two of these specimens were subjected to accelerated corrosion procedures to simulate moderate and severe corrosion levels. The longitudinal steel bars experienced 11% and 24% mass loss, while the steel spirals experienced 18% and 40% mass loss for moderately and severely corroded specimens, respectively. The severely corroded specimen experienced buckling of longitudinal bars at 5.0% drift ratio. Corrosion severity impacted column displacement capacity; the first reinforcing bar fractured at lower drift ratios in the corroded specimens, both of which experienced reduced displacement ductility and hysteretic energy dissipation. The importance of considering corrosion in evaluating seismic performance of RC bridges constructed using ABC methods is demonstrated. [ABSTRACT FROM AUTHOR]

With the rapid development of China's transportation network, the demand for bridge construction is increasing, the traffic volume is increasing yearly, and the average vehicle speed and the frequency of overloaded vehicles crossing bridges are soaring. When a vehicle passes over a highway bridge, it can easily form a coupling vibration between the vehicle and bridge due to the excitation of the expansion joint, the unevenness of the bridge deck, and the existing coating-hole. The impact effect is significant, which seriously affects the operation safety of both the vehicle and bridge, seriously damaging the service life of the bridge. Due to the influence of construction technology, it is common for the vibration to meet transverse and longitudinal expansion joints of a prefabricated girder bridge, where an aging bridge deck frequently results in bulges and potholes in asphalt pavement. The bridge vibration amplification effect under the dynamic load of heavy, high-speed vehicles is significant, and research about the large impact coefficient of bridges with local pavement deterioration is urgently needed. This study used SIMULINK simulation software and involved conducting several bridge model tests. Dynamic simulation analyses and running vehicle tests on scaled and real bridge models were carried out to study the coupling vibration response of bridge decks in the presence of different pothole sizes. The results show that the impact effect of low-speed vehicles passing through a larger-sized pothole is relatively significant, and the impact coefficient can be amplified to 214% of the original value under good road surfaces in extreme cases. The vehicle–bridge coupling impact effect of potholes is similar to bulges. This relevant work could provide suggestions for the operational performance evaluation and maintenance of bridges with local pavement deterioration. [ABSTRACT FROM AUTHOR]

Earthquakes in coastal areas frequently trigger tsunami waves, posing significant threats to low-lying coastal bridges. Investigating extreme wave force on bridge deck is crucial for understanding bridge damage mechanisms. However, the majority of current research focuses on single bridge deck, with limited analysis of wave impacts on twin bridge decks. In this paper, solitary wave is utilized to simulate tsunami wave, and a two-dimensional (2D) computational fluid dynamics (CFDs) model to analyze wave–bridge interactions and investigate the impact of tsunami wave on adjacent twin box-girder bridge decks. The numerical model was validated by solitary wave theory and wave force data obtained from the published experiment. Based on this model, the effects of the submergence coefficient, wave height, and deck spacing on the horizontal and vertical forces on the twin box-girder bridge decks were analyzed and compared with those in a single box-girder bridge deck. The results indicate that, firstly, due to wave reflection and the trapped water, the vertical wave force on the twin forward bridge deck significantly surpasses that on the single bridge deck. Furthermore, the twin backward bridge deck experiences greater horizontal force than single deck when the deck is completely submerged. Secondly, the maximum wave force on the twin bridge decks does not always consistently decrease with increasing deck spacing. Finally, the negative horizontal force would exceed the positive horizontal force on the twin forward bridge deck under higher wave. This paper delineates the disparities between twin and single box-girder bridge deck responses to wave action and analyzes the influencing factors. Such insights are pivotal for coastal bridge construction and natural disaster risk assessment. [ABSTRACT FROM AUTHOR]

As the prefabrication construction method plays an increasingly important role in the construction of cross‐sea bridges, coordinating the schedule between off‐site prefabrication and on‐site assembly becomes crucial and challenging. This paper studies a just‐in‐time single‐machine scheduling problem with due windows and release dates, which originates from the production and supply process of large segments of precast steel box girders in bridge construction. To solve this problem, we equivalently decompose it into the independent and same type of subproblems and formulate a mixed‐integer linear mathematical programming model. Furthermore, we propose a branch‐and‐bound algorithm with the initialization of a novel linear early and tardy dispatching rule with due windows to solve the problem exactly. The dispatching rule, based on the local dominance criteria with due windows, is designed and used to improve the upper bound. Moreover, a lower bound is obtained by further decomposing and relaxing the subproblems. Finally, the parameter of the dispatching rule is calibrated, and the best search strategy of the branch‐and‐bound algorithm is determined. The comprehensive computational experiments carried out show the efficiency and effectiveness of the proposed branch‐and‐bound algorithm. [ABSTRACT FROM AUTHOR]

How bridge refurbishment projects are performed requires a trade-off between the speed and cost of the project and the amount of traffic disturbances during the project. A possible way to help reach a better balance between these two extremes is the ASTRA Bridge developed in Switzerland. The ASTRA Bridge is a 236-meter long steel ramp system on wheels, which is placed on top of the bridge deck undergoing refurbishment to enable vehicles to continue to pass over the bridge while construction work progresses underneath. This study illustrates new refurbishment processes by using the ASTRA Bridge and presents the first quantitative analysis of the effects of using the ASTRA Bridge on the time, costs and traffic disturbances associated with bridge refurbishment. The bridge investigated is a short-span (50 m long) highway bridge requiring refurbishment of its superstructure. The analysis indicates that the use of the ASTRA Bridge resulted in reductions in duration and costs (14% and 3% for the example), and a substantial reduction in user costs (51% for the example). Although more analysis is required for different types of refurbishment projects, the initial results indicate that the ASTRA Bridge may become an integral part of future highway bridge refurbishment projects. [ABSTRACT FROM AUTHOR]

To investigate the performance of in-service skewed bridges, two continuous two-span steel I-girder bridges, one skewed 45° with integral abutments and the other skewed 41° with stub abutments, were instrumented during construction for long-term field monitoring. The bridges are located near each other and experience similar traffic volume and thermal variation, from roughly −18°C to 38°C (0°F to 100°F). Critical girders and cross-frames were instrumented with strain gauges and/or tiltmeters, and temperature was recorded at each sensor. Superstructure response over more than 2 years of data collection was recorded and studied, including for the in-service first-stage half bridges (temporarily for 6 months) and the full bridges. Girder cross-sections and cross-frames were within the elastic range during field monitoring, so stress directly relates to measured strain. The bridge superstructures experienced cyclic stress variation under thermal loading—there was clear linear correlation between bridge response and seasonal temperature variation, especially for decomposed girder axial stress and strong-axis bending stress. Deviation from the correlation was observed due to changes in abutment restraint during seasonal temperature variation and thermal gradient under daily temperature changes. Exterior girders were frequently unevenly heated by direct sunlight, which induced a diverging daily stress–temperature relationship compared to long-term observations. Thermal response of exterior girders is more complex than interior girders regarding both strong-axis and lateral bending, which is often not incorporated in standard bridge design procedures. Several girder bottom flanges and cross-frame members exhibited atypical increasing stress that started during the first cold-weather period; some of the stress development continued over time, regardless of long-term thermal cycles. [ABSTRACT FROM AUTHOR]

The provisions for avoidance of brittle fracture in various bridge design codes vary in complexity, from the simple tables in North American codes, which present impact energy requirements as a function of steel grade, climate zone, and member type, to the more involved methods presented in the Eurocodes, which allow factors such as plate thickness, demand-to-capacity ratio, and strain rate to be considered. While these provisions generally appear to be meeting the needs of the code users, two issues are noteworthy. The first is that the North American provisions offer less flexibility and guidance for handling unusual situations than the Eurocode methods. The second is that very few studies can be found in the literature attempting to assess the level of reliability against brittle fracture provided by any of the existing design provisions. The current paper presents a study that attempts to make a first step in addressing both issues, using the Canadian design provisions as an example. Specifically, this paper describes a time-dependent Monte Carlo simulation (MCS)-based probabilistic model and then uses it to assess the extent to which the Canadian provisions provide consistent and adequate levels of reliability against brittle fracture over a range of steel grades, plate thicknesses, and climates. Based on the analysis results, areas of potential improvement of these requirements are identified. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymer (FRP) composites are promising materials already being used in bridge construction. Lightweight deck panels, mainly used in the rehabilitation or replacement of existing bridges, are the most commonly used FRP bridge components. However, FRP decks are prone to damage due to delamination, matrix cracking, interlaminar cracking, and debonding. In addition, due to their microstructure, FRP materials tend to deteriorate in ways that are not easily detected by visual inspection. Therefore, nondestructive methods should often complement visual inspections aimed at assessing the technical condition of the structure. New measurement techniques are constantly being researched and developed to assist in the evaluation of FRP structures. Distributed fiber optic sensing (DFOS) has been chosen as the main measurement technique of the newly developed FRP bridge deck panel because this technique provides extended advantages compared to the conventional spot gauges. The concept of a component with an integrated DFOS-based system capable of structural control and detection of overloaded vehicles has been developed and verified both in laboratory conditions. The novelty of the presented approach is that sensors (strain-sensing fibers) are precisely embedded in FRP laminates for simultaneous internal strain and vertical displacement (shape change) measurements and delamination detection. The experimental verification of a full-scale deck under static and dynamic loading is described in the paper. The performance of the DFOS system was verified using reference techniques. The results proved the system to be a reliable tool for diagnosing FRP bridge decks. [ABSTRACT FROM AUTHOR]

Metal‐halide perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology. Fabricating PSCs in ambient air can accelerate their low‐cost commercialization, since it can remove the reliance on atmosphere‐controlled equipment. However, the power conversion efficiency (PCE) of air‐fabricated PSCs still lags behind those fabricated in glovebox. Here, based on a technology to fabricate high‐quality perovskite film in ambient air, a compatible optimization is performed on electron transport layer (ETL) to further enhance the photovoltaic performance of PSCs. A soft‐templated deposition strategy is proposed that utilizes tetrasodium glutamate diacetate (GLDA) to finely regulate the chemical bath deposition process, leading to an ideal SnO2 ETL with no additive residual. Adopting this feature of no residual, a molecular bridge using β‐guanidinopropionic acid (βA) is constructed at the buried interface (SnO2/perovskite), which effectively enhances the electron extraction and decreases electron losses. The resulting PSCs (0.08 cm2) achieve an impressive PCE of 25.74% (certificated 25.43%), which is the highest among the air‐fabricated PSCs reported to date. A PCE of 24.61% in 1 cm2‐PSCs is also obtained, exhibiting the scalable potential of the technology. In addition, the excellent operational stability of these PSCs is also demonstrated. [ABSTRACT FROM AUTHOR]

Prefabrication has been widely used in bridge construction, for which precast beams are produced from a beam yard and constructed with a cast‐in‐suit bridge deck. The developments recently are focusing on large dimensions or large quantities of beam units, which leads to the inevitable challenge of beam quality control. Among them, beam surface flatness as one of the important indicators for manufacturing quality needs to be strictly controlled to ensure structural performance. However, the commonly used methods still rely heavily on manually contact‐based inspection, which is not only time‐consuming but also error‐prone. This paper presents an automated flatness assessment for large quantities of full‐scale precast beams by using terrestrial laser scanning techniques. Through axis calibration, target surface segmentation, and flatness deviation calculation, flatness deviations of the segmented surfaces from the point cloud of the entire beam are calculated, and colored maps are generated to visually assess the flatness quality. The proposed approach was applied to numerical simulated models as well as laboratory‐scale specimens for accuracy validation. Besides, its processing time was also compared to conventional contact‐based inspection during a field test. Moreover, efforts are devoted to applying the proposed method on nearly a thousand precast beams in an in‐field bridge construction project. Results can demonstrate its outperformance not only on accuracy but also the efficiency and practicality when applied to large quantities of full‐scale precast beams. [ABSTRACT FROM AUTHOR]

Using traditional algorithms to identify persistent scatterer (PS) points is challenging during bridge construction because of short-term changes at construction sites, such as earthworks, as well as the erection and dismantling of temporary structures. To address this issue, this study proposes a PS point selection method based on statistical theory and Gaussian Mixture Model-Expectation Maximization (GMM-EM) algorithm. This method adopts amplitude information as an incoherence evaluation indicator. Furthermore, the statistical median of the amplitude dispersion index and amplitude mean is screened twice to extract a set of candidate points, including PS points that exhibit stable backscattering over long durations. Temporal coherence is simultaneously used as the coherence evaluation indicator. Another candidate point set is obtained by extracting high-coherence PS points using the GMM-EM algorithm. These sets of candidate points are then combined to obtain a final PS points set. In the experiment, the deformation monitoring of the under-construction Shenzhen-Zhongshan Cross-Sea Bridge in China was selected as a case study, with 28 Sentinel-1A images used as the data source for PS selection and deformation information extraction. The results show that the proposed method enhanced the density and quality of PS points on the under-construction cross-sea bridge compared to existing PS selection methods, thus offering higher reliability. Deformation analysis further revealed fluctuating deformation trends at characteristic points of the Shenzhen-Zhongshan Cross-Sea Bridge, indicating the occurrence of elastic deformation during its construction. [ABSTRACT FROM AUTHOR]

Predicting wind speed in advance at bridge sites is essential for ensuring bridge construction safety under high wind conditions. This study proposes a short-term speed prediction model based on outlier correction, Wavelet Denoising, the Osprey Optimization Algorithm (OOA), and the Transformer model. The outliers caused by data entry and measurement errors are processed by the interquartile range (IQR) method. By comparing the performance of four different wavelets, the best-performing wavelet (Bior2.2) was selected to filter out sharp noise from the data processed by the IQR method. The OOA-Transformer model was utilized to forecast short-term wind speeds based on the filtered time series data. With OOA-Transformer, the seven hyperparameters of the Transformer model were optimized by the Osprey Optimization Algorithm to achieve better performance. Given the outstanding performance of LSTM and its variants in wind speed prediction, the OOA-Transformer model was compared with six other models using the actual wind speed data from the Xuefeng Lake Bridge dataset to validate our proposed model. The experimental results show that the mean absolute percentage error (MAPE), root mean square error (RMSE), and coefficient of determination ( R 2 ) of this paper's method on the test set were 4.16%, 0.0152, and 0.9955, respectively, which are superior to the other six models. The prediction accuracy was found to be high enough to meet the short-term wind speed prediction needs of practical projects. [ABSTRACT FROM AUTHOR]

The presented paper focuses on testing the performance of a SLAM scanner Zeb Horizon by GeoSLAM for the creation of a digital model of a bridge construction. A cloud acquired using a static scanner Leica ScanStation P40 served as a reference. Clouds from both scanners were registered into the same coordinate system using a Trimble S9 HP total station. SLAM scanner acquisition was performed independently in two passes. The data acquired using the SLAM scanner suffered from relatively high noise. Denoising using the MLS (Moving Least Squares) method was performed to reduce noise. An overall comparison of the point clouds was performed on both the original and MLS-smoothed data. In addition, the ICP (Iterative Closest Point) algorithm was also used to evaluate local accuracy. The RMSDs of MLS-denoised data were approximately 0.02 m for both GeoSLAM passes. Subsequently, a more detailed analysis was performed, calculating RMSDs for several profiles of the construction. This analysis revealed that the deviations of SLAM data from the reference data did not exceed 0.03 m in any direction (longitudinal, transverse, elevation) which is, considering the length of the bridge of 133 m, a very good result. These results demonstrate a high applicability of the tested scanner for many applications, such as the creation of digital twins. [ABSTRACT FROM AUTHOR]

As an important part of the boundary conditions on both sides of the high-speed railway track–bridge system, the seismic response of the subgrade structure is different from that of the bridge structure. This difference has become increasingly significant with the widespread adoption of continuous welded rail technology in bridge construction. Therefore, investigating the seismic response of the bridge system, with a specific focus on the longitudinal constraint effects of the subsequent subgrade track structure, is of paramount importance. Utilizing finite element software, two distinct bridge models are developed: one incorporating the subsequent subgrade track structure and another excluding it. Through nonlinear time history analysis under varying seismic intensities, it is demonstrated that the longitudinal constraint of the subsequent subgrade track structure mitigates the longitudinal displacements and internal forces in critical components of the high-speed railway track–bridge system. Concurrently, acknowledging the heightened complexity and cost associated with post-earthquake repairs of the bridge structure compared to subgrade structure, this study uses a risk transfer connecting beam device. This device can redirect seismic damage from bridge structure to subgrade structure, thereby potentially reducing post-seismic repair expenses for the bridge. [ABSTRACT FROM AUTHOR]

In this study, we employed the finite element software COMSOL Multiphysics® (version 6.0) as a simulation tool to analyze the characteristics of accelerometers with different structures. The initial investigation centered around the 114 µm movable comb electrodes of the ADXL150 accelerometer, known for its single-axis differential capacitive bridge design. These electrodes were chosen as the baseline for our study. Our main goal was to examine how alterations in both the length of the movable comb electrodes and the acceleration rates affect the sensing voltage and displacement of the accelerometers. In this investigation, we aimed to provide a comprehensive understanding of the interplay between electrode length variations and acceleration rates on accelerometer performance. At the outset, our aim was to investigate how varying the length of the electrodes would affect the performance of the accelerometer. We methodically decreased the length of the movable comb electrodes from 114 to 20 µm and increased them from 114 to 129 µm. This range of electrode lengths allowed us to observe and analyze the corresponding variations in sensing voltages across different acceleration rates, namely, 25g, 50g, and 75g. Also, the displacements and von Mises stresses under these different acceleration rates and with lengths of the moveable comb electrodes were also investigated in this study. [ABSTRACT FROM AUTHOR]

With rapid advances in design methods and structural analysis techniques, computational generative design strategies have been adopted more widely in the field of architecture and engineering. As a performance-based design technique to find out the most efficient structural form, topology optimization provides a powerful tool for designers to explore lightweight and elegant structures. Building on this background, this study proposes an innovative pedestrian bridge design, which covers the process from conceptualization to detailed design implementation. This pedestrian bridge, with a main span of 152 m, needs to meet some unique architectural requirements, while addressing multiple engineering challenges. Aiming to reduce the depth of the girder but still meeting the load-carrying capacity requirements, the superstructure of this bridge adopts a variable-depth spinal-shaped girder in the center of its deck, thus forming an elegant curving facade, from which one pathway cantilevers on either side. At one end of the bridge, given considerable elevation difference between the bridge deck and the ground, a two-level Fibonacci-type spiral-shaped bicycle ramp is provided. The superstructure is supported by a series of organic tree-shaped branching piers resulting from the topology optimization. The ingenious design for the elegant profile of the bicycle ramp generates an enjoyable and dynamic crossing experience, with scenic views in all directions. By virtue of technological innovation, the pedestrian bridge is expected to create an iconic, cost-effective, and low-maintenance solution. A brief overview of the theoretical background of the bi-directional evolutionary structure optimization (BESO) and the multi-material BESO approach is also offered in this paper, while the construction requirements and challenges, conceptual development process, form-finding strategy, detailed design, and construction method of the bridge are presented. [ABSTRACT FROM AUTHOR]

The safety and serviceability of long-span bridges can be significantly impacted by wind effects and therefore it is crucial to estimate them accurately during bridge design. This study develops full-scale three-dimensional computational fluid dynamics (CFD) simulation models to replicate wind conditions at the Rose Fitzgerald Kennedy Bridge in Ireland. The neglect of bridge geometries and the use of small scales in previous studies are significant limitations, and both the bridge geometry and surrounding terrain are included here at full scale. Input values for wind conditions are mapped from weather simulations that apply the weather research and forecasting model. Wind velocities at four different points calculated by CFD simulations are compared with corresponding data collected from structural health monitoring field measurements. The calculated time-averaged wind velocities at four different locations on the bridge are shown to have relative differences of less than 10% from the wind velocities measured by anemometers 90% of the time. The maximum relative difference among all comparisons was only 15%, shown to be partially due to the inclusion of the full bridge and terrain geometry. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction, with innovative connection details and construction technologies, has been extensively investigated and put into practical application for years. Nowadays, there are three commonly used connection methods of accelerated bridge construction technology, namely, lap‐spliced connection, sleeve connection, and socket connection. Due to the convenience of construction and lower requirements of construction accuracy, the socket connection is more suitable for reconstruction and expansion projects of traffic infrastructure, which could minimize the impact on traffic and accelerate construction progress. According to the structural characteristics of the socket connection, there are some design parameters that may significantly affect the seismic resistance of the structure, such as socket embedment length, fabrication of the shear key, and grouting material strength. To fully study the influence of different design parameters on structural performance, an experiment was carried out to investigate the seismic behavior of the precast pier‐footing socket connections with different design parameters. Five 1:2 scale reinforced concrete precast pier‐footing socket connection specimens with different design parameters were designed and tested under cyclically reversed horizontal loads. The development of hysteresis features, failure mode, load‐bearing capacity, stiffness degradation, structural ductility, energy dissipation capacity, and residual drift are analyzed to reveal the influence of the different design parameters on the seismic behavior of the precast pier‐footing socket connection. The seismic behavior of the precast pier‐footing socket connection was significantly influenced by the embedment length especially when the embedment length was less than 1.0bc. When the embedment length was 0.5bc, the failure mode changed from bending damage at the bottom of the precast pier to the anchorage failure of the precast pier‐footing socket connection. When the embedment length was 1.5bc, the fabrication of the shear key had limited improvement on the seismic performance of the specimen, while reducing the ductility of the specimen. When the embedment length was 1.0bc, the grouting material with a strength grade of C60 could be used in the socket connection between the precast pier and footing. The research presented in this paper provides some design suggestions and a technical basis for evaluating the seismic behavior of precast pier‐footing structures with socket connection. [ABSTRACT FROM AUTHOR]

Diurnal and seasonal temperature variations cause uniform temperature changes, vertical temperature gradients, and horizontal temperature gradients. Vertical temperature gradients occur when the bridge deck absorbs heat due to solar radiation more than the bottom parts of bridge girders. Consequently, the vertical temperature gradient causes redistribution of bearing reactions, and induces additional flexural stresses in continuous spans. Estimating the vertical temperature gradient effect on continuous concrete bridges requires knowledge of thermal analysis of statically indeterminate structures or advanced three-dimensional (3 D) finite element (FE) analysis. Therefore, this article focuses on developing a simplified analysis method for estimating vertical temperature variations effects on continuous prestressed concrete bridge girders, which is required for bridge design. Restraint moments induced by vertical temperature gradients are investigated using 3 D FE analysis. A total of 115 bridges with different configurations (number of spans, girder spacing, and girder type) were analyzed to estimate the positive thermal moments at support locations. Results from these analyses were then used to develop simplified equations for estimating the positive restraint moments due to vertical temperature gradients from AASHTO LRFD Bridge Design Specifications (BDS). The developed equations are validated using John James Audubon Bridge #2 field data, and for other AASHTO LRFD temperature zones. [ABSTRACT FROM AUTHOR]

The given text discusses the design and construction of the Cody Dock Bridge in London, which uses classical geometry and a unique wheel shape to allow boats to pass beneath it. The bridge is able to be smoothly rolled to an upside-down position, relying on a geometric result discovered by James Clerk Maxwell and a preindustrial ethic that emphasizes balance and the ability to be moved by hand. The design process involved addressing various challenges, such as maintaining smooth motion, dealing with wear and tear, and ensuring stability in both normal and inverted positions. The bridge's behavior during the roll was predicted through structural analysis, and its weight and center of gravity were optimized to minimize frictional forces. The bridge design is tied to its functionality and environment, using weathering steel and oak strips for the rolling mechanism. The text also discusses the use of catenary curves in bridge construction and explores the suitability of other shapes for bridge design. [Extracted from the article]