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Stretchable displays based on conventional materials exhibit a trade‐off relationship between the pixel density and the stretchability. In this paper, we have demonstrated overcoming the technological limitations of stretchable displays through the optimization of serpentine‐shaped bridge design and the application of stretchable metal electrodes. The application of stretchable electrodes has increased stretchability by over 30% without compromising pixel density. [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]

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]

In Sweden, steel bridges are the most common solution regarding prefabricated short-span (15-35 m) pedestrian bridges. The most common bridge type for this application is a carbon steel truss bridge with an orthotropic deck consisting of a 10-12 mm deck plate and trapezoidal stiffeners. For these bridges, the deck is the main driver regarding economic and environmental costs, originating from, e.g., high material consumption and maintenance activities. This paper aims to compare the economic aspects between a conventional steel deck and an extruded aluminum deck from an investment cost perspective. The aluminum deck is homogenous, i.e., containing no mechanical connections. To perform this case study, an optimization routine is developed and executed for the aluminum alternative. This optimization study targets the minimum weight and is constrained by the Eurocode design code. A sub-model approach is adopted for the numerical analysis, based on shell and solid elements. The procedure to go from a cross-section defined by a set of parameters to reach the optimized bridge deck is presented. The studies that are reported in this paper show that the developed optimization routine gives satisfactory results. Furthermore, they indicate that homogenous extruded aluminum decks can be a viable deck option for pedestrian bridges. [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]

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]

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

The safety risk analysis of urban elevated bridge construction is an important management method to reduce the loss of safety accidents, and it has significant scientific research value and engineering application value. Therefore, this study proposes a novel analysis method to address these challenges. Firstly, this paper constructs a Work Breakdown Structure (WBS)–Risk Breakdown Structure (RBS) matrix for the safety risk of urban elevated bridge construction in order to achieve a comprehensive and complete identification of the indicator system. Then, a combination of static weights and dynamic weights calculation methods is developed. The static weights are obtained using the analytic hierarchy process, while the dynamic weights are obtained based on the relationship between the dynamic scores of construction safety risk indicators in different construction stages and the preset evaluation levels. Finally, a case study of the Longlingshan elevated bridge project in Wuhan, China, is conducted to validate the feasibility of the proposed model and its potential application in projects. The case analysis for the first time reveals that with the progress of construction, the weights of each indicator continuously change, and the secondary indicators related to environmental factors, such as extreme high-temperature weather, undergo the greatest changes. A comparison of different dynamic weight calculation methods is conducted to highlight the advancement of the proposed model. The research findings of this paper will provide new insights and guidance for improving the construction safety of urban elevated bridge projects. [ABSTRACT FROM AUTHOR]

The city development is closely related to the performance of the transportation network system. Bridges and roads are important parts of the transportation system, and are also inseparable components of the transportation network. However, the effect of the correlation between bridges and roads on the network system has not been studies thoroughly in the literature. Therefore, it is necessary to analyse the vulnerability of the road network when both bridges and roads are involved. In this paper, the urban road network is modeled into the form of network connection and node, based on the analysis of the related research results of road network vulnerability in the literature. Taking the urban roads at all levels as the connection and the transportation hubs (including bridges) as the nodes, the paper puts forward the corresponding measurement indexes and calculation methods, and establishes the importance and correlation analysis model of roads and bridges in the urban road network. At last, the model is applied to the road network which is 5 × 3 km2 besides Yangpu Bridge of Shanghai for verification, the importance and correlation of specific roads and bridges in the analyzed urban road network are calculated, which provides a certain basis for dealing with various emergencies leading to the decline of urban road network vulnerability. In this paper, the importance analysis of urban road network is extended to the bridge correlation analysis, so that the proposed model of the vulnerability assessment of the urban road network system is more suitable for the increasingly demand of road and bridge construction in China, and provides a certain basis for dealing with the decline of road network vulnerability caused by various emergencies. [ABSTRACT FROM AUTHOR]

The paper describes load and resistance factor design (LRFD) calibration for the resistance factor used in the Stiffness Method internal stability soil failure limit state for geogrid mechanically stabilized earth (MSE) walls. The Stiffness Method was recently adopted in the current American Association of State Highway and Transportation Officials LRFD Bridge Design Specifications in the US, and will appear in the next edition of the Canadian Highway Bridge Design Code. The paper describes the details of the calibration of the soil failure limit state which is unique to the Stiffness Method. Calibration outcomes include consideration of the concept of level of understanding in the selection of nominal load and resistance values which is unique to LRFD foundation engineering practice in Canada. A practical conclusion from these calculations is that if product line-specific creep test data are available to estimate the reinforcement secant creep stiffness used for design, then a resistance factor of 1.0 is reasonable for US practice. If only minimum average roll value tensile strength data are available, then a value of 0.95 is recommended for US practice. For Canadian practice, the corresponding values for typical level of understanding are 0.90 and 0.85, respectively. [ABSTRACT FROM AUTHOR]

Early tied-arch bridges cannot satisfy the current traffic load demand due to their load grades and maintenance levels. Also, these tied-arch bridges have accumulated structural damage with increasingly prominent safety risks. In order to accurately evaluate the characteristics of tied-arch bridges' structural-influenced lines and identify damage of their arch ribs and suspenders, two analytical solutions are derived and established in this paper for the thrust-influenced lines of parabola and catenary two-hinged arches with a tie beam. A new method and an index for identifying damage of arch ribs and suspenders of tied-arch bridges are proposed. The results of numerical simulation in this paper verified that the proposed analytical solution has good analytical accuracy in practice on those two-hinged nonflat arches. With the use of equivalent thrust-influenced line difference curvature, the effectiveness of damage identification and the verification method were verified on the tie beam, suspender, and arch rib of plane tie arch structure as well as the suspender and arch rib of tied-arch bridges in this research. Furthermore, combining with grey relation analysis, the noise immunity of the proposed index method can be verified. Also, thrust-influenced line recognition based on VMD (variational mode decomposition) is introduced, and a practical process of bridge health assessment based on the quasistatic-influenced line loading of three-axle heavy vehicles is established. Theoretical analysis and numerical verification show that the calculated error of the analytic solution of two-hinged arches with a rise-span ratio greater than 1/8 is less than 9.57%, and the error decreases with the increase of the rise-span ratio. Therefore, it can be applied to the calculation and analysis of tied-arch bridges with a rise-span ratio range between 1/4 and 1/5. With the equivalent thrust-influenced line index proposed in this paper, the damage of suspenders and arch ribs of tied-arch bridges can be accurately located. It has been found that the proposed method is more effective to identify the damage of suspenders than the damage of arch ribs does, showing good noise immunity. In summary, this research has provided theoretical support for arch bridge design and evaluation. Combining with existing bridge-monitoring methods, the new bridge damage identification method proposed in this paper has the prospect of realizing the normal health status assessment of existing tied-arch bridges. [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 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]

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]

To address the rapidly growing demands of traffic congestion, more highway bridges have been constructed, especially curved bridges. With more curved bridges designed and constructed, people have conducted a comprehensive analysis of the structural performance. Due to the nature of the structural complexity of curved bridges, dynamic responses of the curve bridges vary dramatically from the standard linear bridges. Although some work has been conducted to investigate the curved bridge dynamic analysis under seismic inputs, the framework for analyzing the curved bridges' vulnerability under various angles of inputs is still lacking. In this paper, we conducted a series of curved bridge seismic analyses based on different inputs and conducted a parametric study of the bridge performance using finite element models. We conducted time history analyses by applying seismic inputs to investigate the bridge dynamic responses based on different angle inputs and other different structural parameters. We developed an approach identifying the most vulnerable direction of the seismic inputs and the strongest dynamic responses for curved bridges based on time series analysis. This approach was validated with the dynamic analysis of a simplified bridge model. The method developed in this paper will help improve the curved bridge design code and further provide suggestions about mitigating seismic response for device design. [ABSTRACT FROM AUTHOR]

The numerical model-based design is commonly applied to steel structures using advanced numerical models and analysis. These models often contain stress concentration zones, which can cause problems for designers within the evaluation process. There are two basic questions to answer in the design: (i) are these stress concentrations real physical stresses or numerical singularities and (ii) should these stresses be considered in the design process or can be neglected? The current paper shows a proposal to separate the real physical stresses from the numerical stress concentrations and an improved design method is introduced to consider or neglect them in the daily design. The proposed evaluation method is presented through a design example taken from the daily bridge design practice. The calculation method of the design check is presented first by using (i) linear analysis and (ii) geometrical and material non-linear analysis. Based on the comparison of these two calculation methods the evaluation process of the stress concentration zone is presented as an example. The paper introduces an evaluation method for the stress concentration zone, which can be applied to different structures similarly. [ABSTRACT FROM AUTHOR]

The Gordie Howe International Bridge project is providing a new modern border crossing between Windsor, ON, Canada and Detroit, MI, USA. The centrepiece of the project is a 2.5 km long cable-stayed bridge with 853 m main span over the Detroit River and 220 m tall towers on both sides of the river. In addition to the bridge, the project includes ports of entry on both sides of the border and a new freeway interchange with Interstate-75 in Detroit. The project was procured as a public–private partnership that allowed the proponents to propose either a suspension or cable-stayed bridge, with the ultimate selection creating the longest cable-stayed bridge in North America. The paper outlines the need for the new border crossing and results of the environmental assessment process, as well as describing the project evolution from planning through procurement and into detailed design. The scoping of the bridge design parameters is discussed, including: comprehensive geotechnical investigation; load study to develop project-specific live loading; the approach for durability requirements to achieve a service life of 125 years; special considerations for security; wind engineering; and compliance with both Canadian and US design codes. The paper also discusses the approach to achieving an aesthetically pleasing bridge design. [ABSTRACT FROM AUTHOR]

The process of bridge construction is accompanied by many uncertainties. These uncertainties can have an impact on the quality of bridge construction and are thus directly related to the safe operation of the bridge. Therefore, it is very important to conduct bridge construction quality control evaluations for safe bridge construction and operation. In this paper, a three-tier bridge construction quality control evaluation system is established. This study uses a combination of subjective and objective assignment methods and TOPSIS theory to carry out an evaluation calculation of bridge construction quality. The CWM-TOPSIS theory was applied to the actual engineering calculation by taking the construction process of a mega bridge across the Yellow River as an example. After a series of calculations, the bridge construction quality evaluation results were obtained as level IV. This showed that a construction quality control method was needed for this bridge as soon as possible, and inspection and protection of the bridge should be started to avoid the emergence of bigger quality problems. Finally, the accuracy and applicability of the method proposed in this paper were proved by comparing and analyzing the evaluation results with the standard element theory. [ABSTRACT FROM AUTHOR]

The structural development in bridge engineering along with efficiency have got much attention in few decades. Leading to the development, Optimization of structure established on mathematical analysis emerged mostly employed strategies for productive and sustainable design in the bridge engineering. Despite the widespread knowledge, there has yet to be a rigorous examination of recent structural optimization exploration development. Thus, the primary objectives of this paper are to critically review previous structural optimization research, provide a detailed examination of optimization goals and outline recent research field limitations and provide guidelines for future research proposal in the field of bridge engineering structural optimization. This article begins by outlining the relevance of efficiency and sustainability in the bridge construction, aswell as the work done required for this review. Suitable papers are gathered and followed by a statistical analysis of the selected publications. Following that, the selected papers are evaluated in terms of the optimization targets as well as their spatial patterns. Structure's optimization four key steps, includingmodeling, optimization techniques, formulation of optimizationconcernsandcomputational tools, are also researchedandexaminedindepth. Finally, researchgaps in contemporary works are identified, as well as suggested guidance for future works. [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]

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]

Owing to undesired hydraulic effects, bridge collapse accidents have become increasingly frequent during the flooding season. Considering hydraulic effects in bridge design is paramount to controlling and mitigating hydrological damage. Despite the efforts in previous studies on bridges under floods, a proper partial factor of hydraulic effects considering foundation scour is still lacking for bridge design against floods. To bridge the gap, this study proposed an inverse reliability analysis framework to generate a proper partial factor of hydraulic effects and a corresponding partial factor of resistance. First, failure modes of typical short- to medium-span bridges were summarized to construct limit state functions. Then, an inverse reliability analysis framework considering hydraulic effects was proposed. The optimum partial factors of hydraulic effects and corresponding partial factors of resistance were calculated for various design specifications. Finally, a classification early warning system of foundation scour was built to forecast hydraulic failure accurately. This paper reveals the necessity of considering the hydraulic effects of floods in bridge design. The proposed framework and warning system can effectively enhance bridge safety against floods. [ABSTRACT FROM AUTHOR]

Composite steel bridges in the United Sates are typically constructed using 22 mm-diameter (7/8 in.-diameter) shear studs. The number of shear studs on a girder can be significantly reduced by using larger-diameter studs. This study employed 11 push-out tests to investigate the static performance of 29 mm-diameter (1-1/8 in.-diameter) shear studs. An extensive welding investigation was conducted to develop the optimum welding parameters for 29 mm-diameter studs. Results from experiments showed the static strength of 29 mm-diameter studs satisfied stud strength equations in the AASHTO LRFD Bridge Design Specifications and Eurocode 4. The ductility of the 29 mm studs was comparable or better than that of 22 mm-diameter shear studs. Concrete cracking under service level loading was similar between specimens with 22 and 29 mm studs. Observations indicate that the minimum allowable stud penetration into the concrete deck may need to increase in order for the 29 mm-diameter studs to have good static performance. Using partial-depth precast concrete panels in the bridge deck reduced the static strength of both 22 and 29 mm-diameter shear studs in push-out specimens. Efficient steel bridge girder design makes use of a composite action between the concrete deck and the steel girders. Composite action is achieved by welding shear studs to the top flange of the steel girder during fabrication or erection. The number of shear studs needed is directly related to the individual stud strength, which is controlled by the stud diameter. The shear stud diameter most commonly used in steel bridge construction throughout most of the United States is 22 mm. This paper presents laboratory experiments evaluating the static strength of 29 mm-diameter shear studs. The test results showed that 29 mm-diameter shear studs have a static strength that satisfies US bridge design standards. Compared with 22 mm-diameter shear studs, the use of 29 mm-diameter shear studs is estimated to reduce the number of studs needed on a steel bridge girder by 40%. This reduction in the number of shear studs can enhance construction safety, reduce the cost of fabrication, and facilitate the use of partial-depth precast concrete deck panels, which in turn can increase the speed of construction. [ABSTRACT FROM AUTHOR]

Modern bridge construction towards a higher degree of low carbonization and assembly has been the general trend, while developing and broadening the low-carbon and assembled-oriented Accelerated Bridge Construction (ABC) technology can better realize the trade-offs between construction quality, efficiency, cost and sustainability. In the current mainstream ABC technologies such as precast-assembled concrete bridge and assembled steel bridge schemes, it is difficult to achieve an excellent balance between the above multicriterion trade-offs. To this end, this paper proposes a novel low-carbon and assembled composite bridge scheme as an innovative case of ABC technology based on a 26.7 km-length urban viaduct project in China with urgent environmental protection and assembly demands. Construction sustainability, the comprehensive economy and low-carbon performance are well balanced by the collaborative application of new steel–concrete composite structures, the rapid assembly interface design and low-carbon material technologies. The proposed scheme has been applied to a completed real-scale bridge, and the whole construction process only experienced 105 days of effective time, accompanied with slight environmental interference and construction noise and a small amount of labor and equipment input. In addition, the safety of the bridge, the rationality of the design concept and the calculation method have been verified by the static and dynamic loading tests of the real-scale bridge. [ABSTRACT FROM AUTHOR]

Before the construction of a bridge begins, workers arrange the necessary parts and then cut and process them. The quality of the cutting layout directly affects the material utilization rate and the efficiency of the subsequent processes. During bridge construction, an intelligent part layout can improve work efficiency, save time, and reduce the labor intensity and production costs for the company. In this study, we studied a layout optimization algorithm, focusing on rectangular parts in the material preparation process. A mathematical model for the rectangular layout problem was constructed, and a hybrid genetic whale optimization algorithm is proposed that is a combination of the whale optimization algorithm and the genetic algorithm. Based on the "one size fits all" layout strategy, the materials are divided into strips, which are further divided into stacks, serving as the positioning strategy to determine the positional relationships of the parts. Test cases and actual engineering data were used to compare the layouts generated using different algorithms. The results show that the genetic whale algorithm proposed in this paper results in a high utilization rate and is highly effective. [ABSTRACT FROM AUTHOR]

The complexity of the wharf components and the harshness of the offshore construction environment increase the safety risk of hazards, which has highlighted the importance and urgency of safety risk management in high-pile wharf constructions. This paper established a visualized digital construction safety risk model for high-pile wharf based on a so-called FAHP method (the combination of fuzzy comprehensive evaluation (FCE) and analytic hierarchy process (AHP) methods). The construction safety risk indicators were constructed as the target layer, the principle layer and the scheme layer, and then the corresponding safety risk assessment algorithm was established. The physical, functional and safety risk assessment parameters of the component in the BIM model were employed to the safety risk assessment algorithm, and the risk assessment level of each sub-process was subsequently classified. The case study indicated that the high-pile wharf construction project included five elements in principle layer and 15 risk indicators in the scheme layer. Moreover, it was demonstrated that the sub-processes with the highest construction risk level were steel pipe pile sinking in wharf construction and steel pipe pile, steel sheath-immersed pile sinking and embedded rock pile construction in approaches to bridge construction with a risk level of III. In this way, the quantitative visualization of the construction safety risk was effectively realized, which facilitates the safety risk management of construction sites and timely warning and response to unexpected safety accidents. [ABSTRACT FROM AUTHOR]

Purpose: This paper shows how Bruno Latour's novel work and methodological approach can enrich management and organization studies, accounting and science and technology studies on what it takes to redesign sustainable societal infrastructures. Latour's notions of trials of strength, macro-actor and design as redesign are used in a case study to describe and analyse how the laboratory becomes decisive in negotiating the bridge design and project budget to the benefit of a more sustainable transport infrastructure. Design/methodology/approach: Latour's notion of the detective-author is used to research and write a longitudinal qualitative case study that reconstructs the project processes and chain of related events by following the actors/actants. Findings: The case analysis shows how a project design becomes an emerging powerful macro-actor through the mobilization of laboratory simulations and calculations. The role of the project budget changes; from a strong supporting role as input to a decision option in favour of a cheaper stayed bridge to a weak role as an output from a process of redesign supporting a much larger, costlier and more sustainable suspension bridge. Originality/value: We use Latour's methodological approach to engage primarily in detailed process descriptions to go beyond the often-pointless call for further theory development and to rather account for what is at work in specific situations. Latour's notions of redesign as an outcome from trials of strength, we consider a useful approach to further our understanding since it also takes account of the distributed knowledge production that is integral to the actors' cognitions and recognitions. Relatedly, the specific Latourian notion of redesign opens up new avenues for researching the more or less powerful role accounting devices such as a project budget can play in valuing, supporting and/or undermining the design of sustainable societal infrastructures. [ABSTRACT FROM AUTHOR]

Automatic modal identification via automatically interpreting the stabilization diagram provides key technique in bridge structural health monitoring. This paper reviews the progress in the area of automatic modal identification based on interpreting the stabilization diagram. The whole identification process is divided into four steps from establishing the stabilization diagram to removing the outliers in the identification results. The criteria and algorithms used in each step in the existing studies are carefully summarized and classified. Comparisons between typical methods in cleaning and interpreting the stabilization diagram are also conducted. Real structure benchmarks used in the existing studies to validate the proposed automatic modal identification methods are also summarized. Based on the review and comparison, the specific ratio method for cleaning the stabilization diagram, the hierarchical clustering method for interpreting the stabilization diagram and the adjusted boxplot for removing the outliers in the identification results are the most suitable methods for each step. The key point of automatic modal identification based on interpreting the stabilization diagram has also discussed, and it is recommended to pay more attention to cleaning the stabilization diagram. Future study about automatic modal identification under situation with very few sensors deployed should be more concerned. This review aims to help researchers and practitioners in implementing existing automatic modal identification algorithms effectively and developing more suitable and practical methods for civil engineering structures in the future. [ABSTRACT FROM AUTHOR]

The paper is related to a research project focused on tools for an evaluation and preservation of the historical value and function of arch and vaulted road bridges. It deals with the beginning of use of concrete vaulted and arch bridges in the area of the Czech Republic from the first structures built at the end of the 19th century up to the time just before the WWII. The paper includes examples of built structures as well as a general summary and development of the used technical solutions. Important part of the paper is a proposal of criterions for evaluation of their structural and historical value. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction (ABC) has attracted much attention in China as a new and efficient construction method. However, the seismic performance of the connections between precast piers and other structures limits the application of ABC in medium and high seismic zones. In this paper, a quasi-static test was conducted to investigate the seismic performance differences between a cap–column socket connection (PSC) specimen, which reinforced an embedded RC column-to-precast cap beam with a socket connection, and a cast-in-place (CIP) cap–column specimen. A fiber-based finite element model that considers bond slippage between the connection reinforcement and wet joint concrete is proposed. The numerical simulation results compared with the experimental results show an error of about 12% in peak bearing capacity and about 2% in initial stiffness. The experimental and numerical results show that the PSC specimen demonstrates comparable seismic performance to the CIP specimen. Experimental results verified that the finite element model in this paper is adequate to predict the seismic responses of a precast column with a reinforcement-embedded socket connection. A reinforcement-embedded RC column-to-precast cap beam with socket connection can be an effective solution for construction in medium and high seismic areas. [ABSTRACT FROM AUTHOR]

(1) In recent years, with China's increasing investment in the transportation industry, the construction of highways and bridges has flourished, bringing great convenience to people's lives. At the same time, there are many uncertain factors in the process of bridge construction, being prone to construction risks. In order to meet the requirements of sustainable development, it is necessary to accurately evaluate the safety risk level of bridge construction. Therefore, it is necessary to establish a new scientific safety risk evaluation system for highway bridge construction. (2) Methods. Based on the relevant standards and specifications, this paper establishes a highway bridge construction safety risk evaluation index system, and then uses the cloud entropy weight method to objectively weight each risk index, using cloud model theory to conduct a risk assessment, and through the cloud model images directly determine the overall risk level of bridge construction, and the level of risk indicators. (3) Results. Applying this method to the construction safety risk assessment of a particular bridge, the overall construction risk level of the bridge is obtained as "level 4", and the risk levels of the four first-level indicators are also all "level 4". (4) Conclusions. The cloud entropy weight method proposed in this paper and the traditional AHP-Extenics method are applied to a bridge construction safety risk evaluation, and the evaluation results obtained are consistent. However, this paper uses the cloud model to improve the entropy weight method in order to calculate the weights, which fully reflects the objectivity of the assignment. The cloud model is used for evaluation, and the risk level of indicators can be determined visually with images. [ABSTRACT FROM AUTHOR]

Featured Application: This paper will provide a theoretical basis for the selection of spherical hinge lubrication materials for rotary bridges and promote the research and development of lubricants for rotary bridges under special conditions. The spherical hinge is an important part of rotating bridge construction, but over a long period of time, spherical hinge self-lubricating coating is easily eroded by water vapor. In this paper, the tribological properties and seasonal freezing damage evolution characteristics of a variety of rotating spherical hinge self-lubricating coating materials were studied by means of friction coefficient measurement experiments, friction and wear experiments and shear rheological experiments based on a self-developed indoor spherical hinge rotational friction coefficient tester. The results show that the self-developed indoor spherical hinge rotational friction coefficient tester can effectively and truly represent the working state and tribological properties of self-lubricating coating in practical engineering. A seasonal freezing environment has obvious influence on the tribological properties of spherical hinge self-lubricating coating, which is an irreversible process of deterioration. With the increase in the freezing–thawing cycle, the friction coefficient and viscosity of self-lubricating coating materials increase gradually, and the thixotropy and elastic recovery become worse and worse. When the content of graphene is 0.1%, the performance is the best. At room temperature and in a freeze–thaw environment, the friction coefficient of graphene grease is lower than that of PTFE 0.007 and 0.008, respectively. The diameter of the grinding plate is less than 0.075 mm and 0.001 mm, respectively. The maximum bite load without card is higher than 8.1% and 11.5%. The area of the thixotropic ring is lower than 41% and 42%. Phase transition points were higher than 42% and 64%. The apparent viscosity was higher than 6.6% and 74%. Graphene greases show the greatest bearing capacity, thixotropy and structural strength in conventional and seasonal freezing conditions and exhibit excellent tribological properties. [ABSTRACT FROM AUTHOR]

Various random factors in the bridge construction process directly affect the safety of the bridge life cycle. The existing theories on the reliability of bridge structure mainly focus on the reliability of components and the reliability of the bridge structure system in the completion and operation stages, while the research on the reliability of the structure system in the construction stage is relatively lacking. Therefore, this paper proposed using the Copula function to calculate the reliability index of the bridge structure construction process system. The basic theory of the Copula function was introduced in detail, and the formula was improved according to the actual situation of bridge construction. Finally, the sensitivity analysis of bridge system reliability was carried out. The research results showed that the method proposed in this paper based on Copula theory to calculate the reliability index of the bridge structure construction process system has strong applicability, simple calculation, and can be used in conjunction with the "interval estimation method", which is suitable for large and complex bridge structural engineering. At the same time, the conclusion that the influence of failure mode correlation on structural reliability should not be ignored in the actual engineering construction process is confirmed. [ABSTRACT FROM AUTHOR]

Long precast, prestressed concrete girders are becoming popular in bridge construction. Several states have constructed bridges using slender I-girders that exceeded 200 ft (61 m) in length. When such a girder is seated on flexible supports such as a jeep and dolly, it can roll about an axis located beneath its center of mass. This movement induces lateral bending, which raises concerns about the lateral stability of particularly long girders. While the stability of these girders is largely influenced by the hauling equipment, very few state transportation agencies offer guidelines addressing the rotational stiffness of transport vehicles and other critical parameters. This paper presents comprehensive field measurements of rotational stiffness from various precast concrete plants. It covers two methods--namely, the placement of eccentric loads and the parking of vehicles on a substantial cross slope--to gauge rotational stiffness. The measurements included a variety of transport vehicles with air and leaf suspensions. The examined vehicles displayed a rotational stiffness ranging from 22,000 to 42,000 kip-in. (2486 to 4745 kN-m) per radian. The paper also suggests a guideline for tilt measurements to gather essential data and pinpoint the rotational stiffness. [ABSTRACT FROM AUTHOR]

This research delves into the intricate dynamics of landslides, emphasizing their consequences on transportation infrastructure, specifically highways and roadway bridges in North Carolina. Based on a prior investigation of bridges in Puerto Rico after Hurricane Maria, we found that bridges above water and situated in valleys can be exposed to both landslide and flooding risks. These bridges faced heightened vulnerability to combined landslides and flooding events due to their low depth on the water surface and the potential for raised flood heights due to upstream landslides. Leveraging a dataset spanning more than a century and inclusive of landslide and bridge information, we employed logistic regression (LR) and random forest (RF) models to predict landslide susceptibility in North Carolina. The study considered conditioning factors such as elevation, aspect, slope, rainfall, distance to faults, and distance to rivers, yielding LR and RF models with accuracy rates of 76.3% and 82.7%, respectively. To establish that a bridge's location is at the bottom of a valley, data including landform, slope, and elevation difference near the bridge location were combined to delineate a bridge in a valley. The difference between bridge height and the lowest river elevation is established as an assumed flooding potential (AFP), which is then used to quantify the flooding risk. Compared to traditional flood risk values, the AFP, reported in elevation differences, is more straightforward and helps bridge engineers visualize the flood risk to a bridge. Specifically, a bridge (NCDOT ID: 740002) is found susceptible to both landslide (92%) and flooding (AFT of 6.61 m) risks and has been validated by field investigation, which is currently being retrofitted by North Carolina DOT with slope reinforcements (soil nailing and grouting). This paper is the first report evaluating the multi-hazard issue of bridges in valleys. The resulting high-fidelity risk map for North Carolina can help bridge engineers in proactive maintenance planning. Future endeavors will extend the analysis to incorporate actual flooding risk susceptibility analysis, thus enhancing our understanding of multi-hazard impacts and guiding resilient mitigation strategies for transportation infrastructure. [ABSTRACT FROM AUTHOR]

Bridge infrastructure assets should be planned, designed, constructed, and operated to account for the physical processes that may occur over their service lives. In ice-affected rivers, this includes the interaction of bridge infrastructure with river ice. Advancements in river-ice science and modelling of ice processes in ice-covered rivers have enhanced the abilities of civil/hydrotechnical engineers to plan, design, and construct bridges in and along rivers with seasonal ice covers. In this paper, an overview is presented of ice-related considerations with respect to bridges. The bottom-chord elevation of the bridge superstructure with respect to water and ice levels, pier design to withstand ice forces, the waterway opening for ice passage, ice-induced scour, and research needs are discussed. However, as outlined in the paper, research on ice loads and passage at bridge sites and on hydroclimatic and ice conditions that led to bridge damage and failure remains needed. [ABSTRACT FROM AUTHOR]

Bridges are among the key elements of the transportation network. Many bridges are severely damaged or destroyed when subjected to earthquakes. One of the effective methods to reduction of a bridge's seismic damage is to upgrade the seismic codes. Equivalent static analysis (ESA) is the most conventional method for the seismic design of bridges. Bridges can be classified into two groups based on the connection system between the superstructure and substructure, namely isolated bridges and integrated bridges. In this paper, the adequacy of the ESA method is investigated to estimate the seismic base shear force (BSF) of controlled (isolated) bridges and integrated bridges according to AASHTO, Caltrans, and ATC-32 provisions. For this purpose, three bridges are modeled in three dimensions. The effects of lead rubber bearings, friction pendulum bearings, and viscous dampers on the response of bridges are evaluated using eigenvector analysis, ESA, and nonlinear dynamic analysis. The results indicate that there are significant differences between the BSF estimated by the ESA method and in different provisions. The results of nonlinear dynamic analysis indicate that energy dissipation equipments can decrease the seismic response of structures. Also, the use of the ESA method can only be employed for an initial estimate of the BSF of vibration-controlled bridges. For the detailed study and design of bridges, the ESA method does not provide an accurate estimate of the BSF. This is why the use of the ESA method is not recommended. [ABSTRACT FROM AUTHOR]

There is no analytical solution to the deflection influence line of catenary hingeless arches nor an explicit solution to the deflection influence line difference curvature of variable section hingeless arches. Based on the force method equation, a deflection influence line analytical solution at any location before and after structural damage is obtained, and then an explicit solution of the deflection influence line difference curvature of the structural damage is obtained. The indexes suitable for arch structure damage identification are presented. Based on analytical theory and a finite element model, the feasibility of identifying damage at a single location and multiple locations of an arch bridge is verified. This research shows that when a moving load acts on a damaged area of an arch structure, the curvature of the deflection influence line difference will mutate, which proves theoretically that the deflection influence line difference curvature can be used for the damage identification of hingeless arch structures. This research has provided theoretical support for hingeless arch bridge design and evaluation. Combined with existing bridge monitoring methods, the new bridge damage identification method proposed in this paper has the potential to realize normal health status assessments of existing arch bridges in the future. [ABSTRACT FROM AUTHOR]

Featured Application: This study is aimed at sensitivity of seismic fragility demand parameters caused by structural uncertainty of high-speed railway extradosed cable-stayed bridge considering the Yuanjiang extra-large bridge on Huaihua–Shangyang–Hengyang Railway in China. Based on the probability distribution and correlation of random parameters, a sampling analysis method is proposed herein. Furthermore, a dynamic 3D finite element model of the employed bridge is established by using OpenSEES nonlinear software with full consideration of the randomness of structural parameters using sampling analysis. Based on these findings, some important conclusions were drawn. We believe that our study makes a significant contribution to the literature because although existing studies have focused on static parameter sensitivity analyses and have provided evidence for the design and construction control of cable-stayed bridges, the dynamic sensitivity studies especially for the structural parameter uncertainty of high-speed railway extradosed cable-stayed bridges have not been extensively studied. Further, we believe that this paper will be of interest to the readership of your journal because our analysis employs innovative research techniques, and our findings have the potential to provide guidance for the seismic fragility analysis of high-speed railway extradosed cable-stayed bridges. This manuscript has not been published or presented elsewhere in part or in entirety and is not under consideration by another journal. We have read and understood your journal's policies, and we believe that neither the manuscript nor the study violates any of these. There are no conflicts of interest to declare. It is known that the extradosed cable-stayed bridge, a hybrid bridge, possesses the virtues of both classic cable-stayed bridges and girder bridges in mechanical behaviors. In this paper, the sensitivity of seismic fragility demand parameters (SFDP) of a high-speed railway extradosed cable-stayed bridge is studied systematically along with the consideration of structural parameter uncertainty. Based on the probability distribution and correlation of random parameters, the Latin hypercube sampling method is adopted herein. The dynamic 3D finite element model of the employed bridge is established by using powerful and attractive OpenSEES nonlinear software. A nonlinear incremental dynamic analysis is performed to consider the randomness of structural parameters using sampling analysis. Some important conclusions are drawn indicating that the structural design parameter uncertainty predominantly has influence on the SFDP for fragility analysis of bridge structures. The design parameters of extradosed cable-stayed bridges are categorized and identified as primary, secondary and insensitive parameters. The high sensitivity parameters of extradosed cable-stayed bridges for fragility analysis include friction coefficient of bearing, concrete bulk density, damping ratio, peak compressive strength of confined concrete, component size and peak strain of confined concrete. Additionally, the strength and strain of unconfined concrete cannot be ignored. Furthermore, the uncertainty of structural design parameters fails to be responsible for the cable force responses due to larger girder stiffness. The structural design parameter uncertainty has a significant influence on the responses of extradosed cable-stayed bridges for seismic fragility analysis. [ABSTRACT FROM AUTHOR]

In the 1950s and 1960s, some Louisiana's bridges were constructed using steel twin-girder or truss systems, in which floorbeams are carried by the main members and continuous (spliced) stringers are supported by the floorbeams. The main members are either two-edge (fascia) girders or trusses. One of the byproducts of this type of design is that stringer bottom flanges are in compression in the negative moment region over the floorbeams, which could result in lateral torsional buckling (LTB) should inadequate lateral bracing be provided. When the continuous stringers are load-rated using AASHTOWare Bridge Rating analysis software (BrR 7.1), their LTB resistance is calculated in accordance with American Association of State Highway Officials (AASHTO) LRFD Bridge Design Specifications, which do not account for potential bracing provided by a noncomposite deck and could underestimate flexural strength. As a result, the rating may be low enough to require restrictive load posting or even bridge closure. This paper summarizes extensive experimental and numerical studies investigating the behavior of this type of floor system by testing two-span, continuous, steel stringers in a grillage that included three stringer lines, an interior transverse support (floorbeam), and transverse diaphragms at the end supports. The tests and finite-element analysis studies encompassed a variety of unbraced lengths and support conditions with steel diaphragms or timber ties acting as bracing members. The findings demonstrated that, for the systems examined, minimal bracing could substantially enhance LTB resistance and supported the use of higher flexural strengths than those currently predicted using AASHTO Specifications. This paper illustrates the use, challenges, and successes in LTB modeling beams with various support and bracing conditions. The most flexible cases were the most difficult to achieve close agreement with experimental results. [ABSTRACT FROM AUTHOR]

Fibre-reinforced polymer composites (FRPs) offer various benefits for bridge construction. Lightweight, durability, design flexibility and fast erection in inaccessible areas are their unique selling points for bridge engineering. FRPs are used in four bridge applications: (1) FRP rebars/tendons in concrete; (2) repair and strengthening of existing bridges; (3) new hybrid–FRP bridges with conventional materials and (4) all–FRP composite new bridges made entirely of FRP materials. This paper reviews FRP bridges, including all–FRP and hybrid–FRP bridges. FRP bridges' history, materials, processes and bridge components—deck, girder, truss, moulded parts and cables/rebars are considered. This paper does not discuss the use of FRP as an architectural element and a strengthening system. While lack of design codes, material specifications and recycling are the major challenges, the high cost of FRPs still remains the most critical barrier to the progress of FRPs in bridges. [ABSTRACT FROM AUTHOR]

Highly-skewed steel I-girder bridges are commonly used across the US, especially in congested areas, despite complications in their analysis and design. The American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specification provides suggestions for design values of flange lateral bending stress in addition to line girder analysis when bridge skew exceeds 20° for certain cross-frame layouts. For bridges with skew exceeding 60°, a higher level of analysis is often required, with cross-frames considered primary members in design. Neither the magnitude of additional lateral stress nor the associated skew limits are particularly well understood, so more study is needed to refine and support this analysis and design approach. In addition to short-term response and load distribution, long-term bridge behavior for thermally induced stresses and deformations also needs to be more thoroughly studied. In support of an ongoing research initiative in Illinois, an agency survey was formulated and distributed across the US to understand practices used and challenges faced by state transportation agencies when designing and constructing skewed steel I-girder bridges. Findings from the responses of 23 state agencies illuminate issues, concerns, and current practice related to design, construction, and service life of those bridges. The agency survey informed selection of two bridges in Champaign, Illinois, for field monitoring, in order to provide new understanding of skew effects on bridge superstructure behavior. Three-dimensional finite-element analysis was conducted to guide field instrumentation planning, and initial measurements from the monitored bridges under traffic load confirmed good predictions compared to the planning-stage numerical study. This paper presents the initial stages of a long-term project that employs field monitoring and three-dimensional finite-element analysis of skewed steel I-girder bridges. Findings from a survey of state transportation agencies describe issues, concerns, and current practice related to design, construction, and service life of these bridges, which can be of interest to practicing engineers and contractors. This paper illustrates the integration of data from current practice and targeted numerical simulations to establish a rigorous basis for planning a bridge superstructure field monitoring campaign. The information and experiences summarized can be helpful to both practicing engineers and researchers. [ABSTRACT FROM AUTHOR]

The paper is concerned with the development and comparison of alternative machine learning methods of determining the type of truck crossing a bridge from the dynamic response it induces within the bridge structure, the so-called weigh-in-motion problem. Weigh-in-motion is a rich engineering problem presenting many challenges for current machine learning technologies, and for this reason is proposed as a benchmark for guiding and assessing advances in the application of this field of artificial intelligence. A review is first provided of existing methods of determining truck types and loading attributes using both machine learning and heuristic search techniques. The most promising approach to date, that of artificial neural networks, is then compared to support vector machines in a comprehensive study considering a range of configurations of both modeling techniques. A local scatter point smoothing schema is adopted as a means of selecting an optimal set of design parameters for each model type. Three main model formats are considered: (i) a monolithic model structure with a one-versus-all truck type classification strategy; (ii) an array of sub-models each dedicated to one truck type with a one-versus-all classification strategy; and (iii) an array of sub-models each dedicated to selecting between pairs of trucks in a one-versus-one classification strategy. Overall, the formats that used an array of sub-models performed best at truck classification, with the support vector machines having a slight edge over the artificial neural networks. The paper concludes with some suggestions for extending the work to a broader scope of problems. [ABSTRACT FROM AUTHOR]

There has been a growing interest in using large-diameter strands to alleviate congestion by using fewer strands, reduce the total number of girders by increasing girder spacing, increase the span length, and allow shallower girders. While the 2020 AASHTO LRFD Bridge Design Specifications included 17.8-mm (0.7-in.) strands by reference to AASHTO M203, these larger-diameter strands were not used in bridge construction primarily because AASHTO LRFD was silent about the design aspects of members reinforced with 17.8-mm (0.7-in.) strands. The presented multifaceted, multiyear research involved an extensive parametric design case study, nonlinear finite-element analyses, material characterization, component tests, and full-scale girder experiments. This paper focuses on the full-scale girder tests, which were used to examine development length, detailing requirements, and flexural and shear behavior and strength. Experimentally determined development lengths were found to be shorter than those prescribed by the AASHTO LRFD Specification. Flexural and shear strength could be determined using established procedures. The current minimum required amount of confinement reinforcement was found to be sufficient to confine 17.8-mm (0.7-in.) strands. The extension of bottom flange confinement reinforcement was found to be inadequate for cases with partially debonded 17.8-mm (0.7-in.) strands, but extension of bottom flange confinement reinforcement to 1.5d beyond the end of the girder was adequate for cases with no debonded strands. The minimum bottom flange confinement reinforcement required by the AASHTO LRFD Specification must be extended to at least 1.5d beyond the termination of the longest debonded length of 17.8-mm (0.7-in.) strands. [ABSTRACT FROM AUTHOR]

Many of the procedures used in bridge design are force-based and may be considered reasonable design approaches that will lead to safe structures. But they do not directly address performance criteria at the initial stage of the design. On the other hand, the previously presented displacement-based design procedures of isolated bridges only considered the displacement of the deck, which means the pier's seismic performance and the substructure mass effects are ignored. This paper presents a new performance-based design method for isolated RC bridges considering the contribution of substructure mass. This method allows the designer that selects the performance level of the superstructure and substructure at the beginning of the design procedure. In this respect, the two degrees of freedom analytical model of the isolated bridge containing substructure mass is presented to quantify its effect on the performance of the seismically isolated bridge. The proposed design method is applied to two continuous-span bridges with regular and irregular substructures, and different target performance levels, including elastic and yielded substructures. The results of the proposed design method have been compared with nonlinear time history analyses, AASHTO, and National Cooperative Highway Research Program simplified methods. The results showed that the seismic performances are close to the results of the nonlinear time history analyses. However, the other design approaches, which ignore the substructure mass, underestimate the responses of the substructure. [ABSTRACT FROM AUTHOR]

Metro systems provide an efficient, convenient, and expeditious way to travel around crowded routes. Because these systems are established in cities, residential buildings close to metro viaducts are significantly affected by structure-borne noise (SBN). Although most previous studies developed SBN prediction with a focus on the accuracy and computational efficiency of a specific bridge type, only limited studies on parameters for the SBN on bridges were carried out. Thus, eliminating SBN is still a challenging task for both the design and operation phases of bridge design. Therefore, this study integrates simplified experiments with numerical analyses to evaluate the influential parameters on the structure-borne noise level (SBNL) for two types of bridge girders, that is, the double-box pre-stressed concrete girder and the double-box steel girder. The present study also proposes an optimization method for reducing the SBNL in the bridge design and operation phases and identifies the sources of SBN for these two types of bridges. In this paper, the solutions to mitigating SBN are first reviewed and briefly introduced. Theories associated with SBN are then derived and experimentally verified using a concrete or steel plate with a unit area. A hybrid evaluation method is developed to integrate transient finite-element simulation with experimental results, and the main sources (e.g., plate thickness, train speed, fastener stiffness, and track irregularity) that induce SBN are examined by this hybrid method. Consequently, the approach to resolving the SBN problem can be optimally determined. As demonstrated in the results from the hybrid evaluation method, the track condition dominates the SBNL for both types of bridges, and the relationship between train speed and plate eigenfrequency should be carefully investigated to avoid the effect of plate resonance. The pre-stressed concrete box girder is the recommended bridge type for use in urban areas from the viewpoint of minimizing the SBNL. [ABSTRACT FROM AUTHOR]

This paper employs probability methods to evaluate the fire safety performance of prestressed steel–concrete beam bridges based on simulation experimental research. Firstly, fire simulation experimental sample analysis was conducted on actual small box girder bridges to assess the structural response of prestressed steel–concrete structures to fire, as is in line with engineering practice. Next, we constructed a reliability analysis model to investigate the fire resistance performance of prestressed steel–concrete beam bridges. Combining reliability theory with the finite element method, we established a reliability analysis method for the fire resistance performance of prestressed steel–concrete beam bridges. Subsequently, we proposed a safety factor evaluation model for the fire resistance performance of prestressed steel–concrete beam bridges and then established a safety factor evaluation method for the fire resistance performance of prestressed steel–concrete beam bridges based on reliability back analysis. Finally, based on the analysis of the post-fire structural response in the specific case of a steel–concrete continuous beam bridge project moving from conditions of being simply supported to continuously prestressed, a structural resistance sample of the prestressed steel–concrete beam bridge was generated via the uniform design method, and statistical analysis was conducted. Subsequently, probability methods were used to evaluate the safety of the prestressed steel–concrete beam bridge after a fire. Through analysis, we concluded that the duration of the fire had a significant impact on the structural performance of prestressed steel–concrete beam bridges and that the randomness of parameters had a significant impact on the safety reserve of prestressed steel–concrete beam bridges following the fire. Going forward, it is necessary to pay attention to this factor in specific engineering practices and strengthen the monitoring and statistical analysis of structural random characteristics. [ABSTRACT FROM AUTHOR]

This paper is focused on uncertainty quantification (UQ) of an existing bridge structure represented by non-linear finite element model (NLFEM). The 3D model was created according to the original drawings and recent inspections of the bridge. In order to reflect the realistic mechanical behavior, the mathematical model is based on non-linear fracture mechanics and the calculation consists of the three construction stages. The single calculation of the NLFEM is very costly and thus even the elementary task of stochastic analysis - the propagation of uncertainties through a mathematical model - is not feasible by Monte Carlotype approach. Thus, UQ is performed via efficient surrogate modeling technique - Polynomial Chaos Expansion (PCE). PCE is a well-known technique for approximation of the costly mathematical models with random inputs, reflecting their distributions and offering fast and accurate post-processing including statistical and sensitivity analysis. Once the PCE was constructed, it was possible to analyze all quantities of interest (QoIs) and analytically estimate Sobol indices as well as the first four statistical moments. Sobol indices directly measure the influence of the input variability to a variability of QoIs. Statistical moments were used for reconstruction of the probability distributions of QoIs, which will be further used for semi-probabilistic assessment. Moreover, once the PCE is available it could be possible to use it for further standard probabilistic or reliability analysis as a computationally efficient approximation of the original mathematical model. [ABSTRACT FROM AUTHOR]

As bridge structures become older and older, they are subject to wear and tear due to ageing, weather conditions or environmental effects, as well as due to surprise structural modifications substantially affecting the condition of the structures. Therefore, the condition assessment of bridge structures is a must for the safety and absence of risk. The condition assessment of bridge structures is also necessary for the maintenance and repair of existing structures having been in service for more than 30 years, in order to avoid breakdowns and save human lives. This paper states the condition assessment performed with the use of various nondestructive test methods. [ABSTRACT FROM AUTHOR]