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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]

The Shennong Lake Bridge stands as a prominent landmark in Changzhi City, located in Shanxi Province. Constituting the primary span is a "herringbone" configuration, employing a single tower double cable plane cable-stayed design with spans of 2 × 130 m and a deck width of 47 m. The complex bridge tower structure poses a challenge to the design of the bridge. This study elucidates the procedural intricacies of employing a three-dimensional parametric approach in shaping the cable tower. By leveraging the merits of history-based parametric modeling and skeleton-template design, a comprehensive landscape blueprint has been developed, with a primary focus on the architectural layout of the cable tower. The collision rectification issue between the bridge tower and the cable has been resolved using a 3D parametric model. Following the culmination of construction efforts, the final structure harmoniously aligns with the initially envisioned landscape depictions. Through meticulous optimization of design protocols for intricate landscape-integrated bridges, this endeavor extends its potential utility as a salient reference for akin undertakings. [ABSTRACT FROM AUTHOR]

Yunxi Bridge for pedestrians and non-motorized vehicles is a double inclined cable plane curved steel tied arch bridge. The inclination of the arch rib of a single box and single chamber is 15° to the vertical direction. The steel box girder sidewalk is overhanging. Relying on the inclination of the arch ribs and the two cable planes to bear all loads, the bridge is a thrust free inward tilting self-balancing system. The bridge has a beautiful appearance and obvious spatial effects. The difficulty of design and construction is significant. Based on the bridge, this article introduces the design and construction of the bridge and analyzes the static and dynamic mechanical characteristics and stability of the structure in order to provide a reference for similar bridges. [ABSTRACT FROM AUTHOR]

Urban pedestrian bridges should contribute to the improvement of the overall image and function of the place where the footbridge is located. In order to establish a complete pedestrian access area of a Green Belt Park, an elegant pedestrian landscape bridge with Y -shaped piers and mixed decks was designed and built, providing an open and diverse viewing experience. Accelerated bridge construction technologies were adopted to build the footbridge. Finite-element models, including the full bridge model and local model, were established and a continuous rigid frame and continuous girder composite bridge system was proposed after scheme comparison. Preliminary statics and dynamics analysis, as well as detailed calculations for the local stresses of Y -shaped piers and the shear lag effect of the deck, were carried out aiming to demonstrate its safety and suitability. [ABSTRACT FROM AUTHOR]

The design of suspension bridges predominantly emphasizes wind and earthquake loads, frequently overlooking the consideration of extreme events in the design stage, thus posing a threat to bridge safety. The purpose of this research is to spread awareness among engineers for identifying weak zones in a bridge and to provide a new insight into how much damaging the blast loading could be for the long-span suspension bridges if not designed properly under the blast loads. The current dynamic analysis procedures for bridges under blast loads are complex and computationally expensive, making them unsuitable, especially for long-span bridges. To address this, a simplified dynamic analysis approach is proposed to assess the structural response and extreme limit state of suspension bridges exposed to blast loads. The method involves a bilayer solution: blast loading is modeled as nodal loads, and the structural aspect is represented by a three-dimensional (3D) fishbone skeleton finite-element (FE) model. Time-history simulations of blast loads are conducted for various bridge locations and explosive sizes. The parametric dynamic analysis reveals that the tower top node is the most vulnerable location in the suspension bridge under blast loads, which potentially exceeds the stress limits of nearby main cable elements and triggers the zipper-type progressive failure of the entire suspension bridge. Similarly, blasting at the deck nodes nearby tower on the main span side as well as on the side span side significantly amplifies axial stresses in nearby suspenders and the main cable, i.e., demand-to-capacity ratios of C18 and C19 surpass unity under BS4-6W and BS4-8W, respectively confirming that the failure state has reached for C18 and C19 under medium- to large-sized explosives. Therefore, it is recommended that the maximum demand-to-capacity ratio for all bridge components under medium- to large-sized explosives shall be kept below 0.8 to ensure the safety of the entire structure under extreme limit state. Practical Applications: This paper provides a methodology to investigate the structural redundancy of suspension bridges under extreme limit state by providing a bilayer solution: the blast aspect, which is simulated as nodal loads on the bridge road surface and the structural aspect, is simulated as a 3D fishbone skeleton FE model. The implicit dynamic analysis approach is adopted parametrically by considering variable explosive weights and locations. For each blast scenario, the time-history of nodal loads is applied to various locations of the bridge considering small- to large-sized blasts. From a practical viewpoint, this study is relevant to develop comprehensive understanding of the dynamic behavior exhibited by long-span bridges when subjected to extreme loading scenarios. In essence, the aim is to explore the benefits and applicability of this research to the design of long-span bridges under blast loading conditions. The simplified approach presented in this paper, along with the corresponding bridge response results, allows a bridge design engineer to analyze a suspension bridge effortlessly. This method eliminates the need for intricate computations required to assess blast pressure over a solid bridge model, enabling a straightforward visualization of the anticipated behavior under blast loading. The research serves a crucial role in checking and verifying the extreme limit state, in addition to assessing the serviceability and ultimate limit states according to AASHTO's requirements. For existing suspension bridges, the study proves beneficial in formulating a comprehensive blast-resistant plan through retrofitting and strengthening identified weak zones. Consequently, this research holds practical significance, serving as a foundation for further exploration and investigation into the effects of blast loading on various types of long-span bridges. [ABSTRACT FROM AUTHOR]

The number of ground motions used in nonlinear response history analysis (NRHA) determines the precision of the parameter estimates obtained in seismic performance assessments. While this issue has been extensively studied in the earthquake engineering literature, the relationship of probability model misspecification to parameter estimation uncertainty, and the implication to the required number of ground motions needed for NRHA, has not been examined. Probability model misspecification has the potential to increase estimation uncertainty and hence requires a greater number of ground motions to achieve the same precision compared to when misspecification is disregarded. This study develops a procedure to determine the required number of ground motions in seismic code-prescriptive and risk-based assessments with possible probability model misspecification. Specifically, we employ the quasi-maximum likelihood estimation (QMLE), which is robust to probability model misspecification, to evaluate estimation uncertainty. The QMLE approach is applied to an archetype California bridge under the two seismic assessment scenarios. In the code-prescriptive assessment, misspecification errors are identified for dispersion estimates of the bridge column ductility demand. In the most extreme case of the risk-based evaluation, misspecification increases the estimation uncertainty of the mean annual frequency of exceeding a limit state by as much as three times, which substantially increases the required number of ground motions. Based on the findings from this study, we advocate for the use of QMLE to detect and rectify the implications of model misspecification to estimation uncertainty and the number of ground motions used in probabilistic seismic performance assessments. [ABSTRACT FROM AUTHOR]

Interface shear transfer is vital to maintain the structural integrity of concrete composite elements. Therefore, shear connectors are provided at the concrete joint interface to maintain such integrity. Due to its high tensile strength and non-corrodible nature, glass fiber-reinforced polymer (GFRP) reinforcement can be used as shear connectors in composite elements, particularly those in harsh environments. Fifteen pushoff specimens were constructed and tested to failure. The specimen consisted of two L-shaped concrete blocks cast at two stages to provide the cold joint interface. The test parameters were the type, shape, and ratio of shear-friction reinforcement and concrete strength. It was demonstrated that GFRP-reinforced concrete RC) specimens with reinforcement ratios of 0.36% or more could resist the shear-friction stresses similarly to their steel-RC counterparts. Also, increasing the concrete strength increased the shear-friction capacity significantly. Moreover, the design model in the Canadian Highway Bridge Design Code resulted in very conservative predictions. [ABSTRACT FROM AUTHOR]

The bundled parallel strand stay cables are important structural components of modern cable-stayed bridges. Strands commonly used in modern stay cables are seven-wire greased-and-sheathed strands. Stay cables primarily resist tension loads imposed by various loads, but they also resist bending stresses due to wind loads, vibration, and any traverse load applied on the cable. The movements of the deck and towers (at termination points of stay cables) also impose rotations at the cable ends, which will induce bending stresses in the strand bundles. Calculating and analyzing a stay cable's bending-induced stresses is an important consideration, especially regarding fatigue resistance. Traditionally, designers have assumed a noncomposite moment of inertia for the bundle of parallel strands because of the presumed lack of sufficient interstrand bond along the length of cables. Therefore, the composite effect is generally not considered, and the moment of inertia is typically assumed to be equal to the number of strands times the moment of inertia of an individual strand. This assumption neglects the fact that unrestrained relative slippage between strands cannot occur because the anchorage plates enforce displacement compatibility at cable ends. Also, deviation clamps and periodic cable bands (tying of the strand bundle together) along the free length of the cable may provide some degree of composite action. This study examines the global bending-induced stresses developed near the termination points of stay cables due to the application of transverse loads on the cable. Experiments and computational analyses are conducted to assess these stresses. The computational models are verified using laboratory experiments performed on a five-strand cable. Detailed and simplified finite-element models are developed. Bending-induced stress calculation procedures are developed using a simplified stay cable model. Practical Applications: This study proposes calculation procedures to address the important issue of bending-induced stresses in the design of the most crucial components of cable-stayed bridges—stay cables. At present, there are no reliable equations to estimate the maximum strand stresses due to bending action of stay cables under transverse loading. Therefore, qualification tests of relatively short stay cable specimens are sometimes utilized to evaluate fatigue resistance under bending action. For bridge design engineers, the proposed analysis approach and equations can be useful in assessing the long-term fatigue resistance of strands. This study establishes that bundles of greased-and-sheathed seven-wire strands do not act independently within the transition zone of stay cables near anchorages, and the angle change imposed due to transverse loading is not the only factor affecting bending-induced stresses. The size (number of strands) and the length of the cable are the other influential factors that must be considered. [ABSTRACT FROM AUTHOR]

Translation abstract Mattensteg, rehabilitation and relocation of a 150 year old frame bridgeAt the existing Mattensteg – a 150 year old riveted truss‐girder steelbridge, a condition survey in 2005 revealed that the local concrete bridge deck was in poor condition. Based on this assessment and the bridge‘s previous service life, it was decided to carry out a comprehensive renovation of the bridge. At the same time, the AWEL (Amt für Abfall, Wasser, Energie und Luft des Kantons Zürich) planned to renew the Platzspitzwehr. In recent years, access for maintenance work on the weir has been via the Platzspitz, as the Mattensteg cannot be used by heavy vehicles. This is unsatisfactory for the park with its protected plane trees. It was therefore decided to build a new service bridge at the site of the Mattensteg for the construction and future maintenance work. However, as the existing Mattensteg is a listed building, the existing old truss bridge was to be retained, moved some 80 m upstream and rebuilt. The reinforcements were riveted analogously to the existing construction. Due to the protected status of the building, the new piers will be built in the original style with stairs. As a result, the footbridge is no longer accessible to cyclists, wheelchair users or maintenance vehicles. The construction costs for the relocation, the construction of the new supports and piers as well as the restoration of the bridge amount to CHF 2.5 mio. [ABSTRACT FROM AUTHOR]

This article investigates the precipitation behavior of Mo element in the continuous cooling phase transformation process of weathering steel of bridge construction and its influence on microstructure and hardness. The results demonstrate that the addition of Mo leads to the narrowing of the phase transformation interval of proeutectoid ferrite and pearlite, the expansion of the bainite transformation zone, a delayed bainite phase transformation process, and the refinement of bainite microstructure. Moreover, theoretical calculations of bainite phase transformation kinetics reveal that the average activation energy for bainite transformation in Mo‐free and Mo‐containing steels is 94.8 and 134.0 kJ mol−1, respectively. The new grains of Mo‐free steel mainly grow in a 2D mode, while Mo containing steel mainly grows in a 1D mode, which confirms the retarding effect of Mo on bainite grain growth. Additionally, Mo significantly increases the number density and refines the size of precipitated phases in weathering steel of bridge construction. Within the cooling rate range of 0.1–30 °C s−1, the hardness of weathering steel of bridge construction is enhanced by Mo, with the magnitude of hardness increment decreasing as the cooling rate increases. This behavior is primarily governed by the combined influence of phase transformation strengthening and precipitation strengthening. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction is crucial in bridge engineering. In order to improve the seismic performance of prefabricated columns, this study proposes using ultra‐high performance concrete (UHPC) in the plastic hinge areas of prefabricated columns with bellows grouting connections. In particular, cyclic loading tests are carried out on four 1/3‐scaled columns, including two cast‐in‐place columns and two bellows grouting connection columns. The results show that columns with UHPC in the plastic hinge areas exhibit larger lateral and ultimate bearing capacity, ductility, cumulative energy dissipation, and stiffness compared to those with conventional concrete. Additionally, bellows grouting connection column with UHPC shows superior seismic performance compared to cast‐in‐place column with conventional concrete. The proposed finite element analysis model is in a good agreement with the test results. Through using finite element analysis, three key parameters influencing the seismic performance of bellows grouting columns are examined, and the optimal combination of these parameters is identified. [ABSTRACT FROM AUTHOR]

On the load bearing and fatigue behaviour of headed anchor studs with defective welds The 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]

Evaluation and strengthening of existing bridges – historical outlines and findings regarding the Hessian road bridge inventory Two 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]

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]

Automated construction has become urgently needed because the construction industry faces labor safety and cost challenges. However, these developments require investments in new equipment to facilitate automation in construction, resulting in even higher capital costs. Therefore, the research proposes a gravity-triggered rotational connecting (GTRC) method for automating segmental bridge construction. In this automated construction method, a segment-to-segment connector is developed to exploit an eccentric moment introduced by gravity and achieve segmental connections. For implementation, a specific rigging method is presented for a conventional telescopic crane to maintain a particular orientation. Meanwhile, crane path planning is also proposed to guide one segment toward the other segment. A combined computational and experimental verification program is established and employs a simply supported bridge as an example for the proposed method. With the designed connector and rigging assembly, the proposed method is computationally and experimentally verified to automate segmental bridge construction. [ABSTRACT FROM AUTHOR]

A depth precast deck panel (FDDP) is one element of the prefabricated bridge element and systems (PBES) that allows for quick un-shored assembly of the bridge deck on-site as part of the accelerated bridge construction (ABC) technology. This paper investigates the structural response of full-depth precast deck panels (FDDPs) constructed with new construction materials and connection details. FDDP is cast with normal strength concrete (NSC) and reinforced with high modulus (HM) glass fiber reinforced polymer (GFRP) ribbed bars. The panel-to-girder V-shape connections use the shear pockets to accommodate the clustering of the shear connectors. A novel transverse connection between panels has been developed, featuring three distinct female-to-female joint configurations, each with 175-mm projected GFRP bars extending from the FDDP into the closure strip, complemented by a female vertical shear key and filled with cementitious materials. The ultra-high performance fiber reinforced concrete (UHPFRC) was selectively used to joint-fill the 200-mm transverse joint between adjacent precast panels and the shear pockets connecting the panels to the supporting girders to ensure full shear interaction. Two actual-size FDDP specimens for each type of the three developed joints were erected to perform fatigue tests under the footprint of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading. The FDDP had a 200-mm thickness, 2500-mm width, and 2400-mm length in traffic direction; the rest was over braced steel twin girders. Two types of fatigue test were performed: incremental variable amplitude fatigue (VAF) loading and constant amplitude fatigue (CAF) loading, followed by monotonically loading the slab ultimate-to-collapse. It was observed that fatigue test results showed that the ultimate capacity of the slab under VAF loading or after 4 million cycles of CAF exceeded the factored design wheel load specified in the CHBDC. Also, the punching shear failure mode was dominant in all the tested FDDP specimens. [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]

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]

To improve the informatization and intelligence level of high-speed railway (HSR) bridge construction, a parametric modeling method for continuous beam bridges based on Building Information Modeling (BIM) is proposed in this study. By this method, the parametric families of continuous beam components and key construction machinery are established, and the rapid modeling of overall continuous beam bridge and the simulation of critical construction process are realized as well. Taking the Caoxian-Shangqiu bridge of Xiong'an-Shangqiu HSR as a case study, the parametric modeling method is applied to conduct the engineering application on the prestressed duct layout and rebar clash detection. The results indicate that the modeling efficiencies of HSR continuous beam bridge and construction machinery are significantly increased by the established parametric modeling method. Based on the BIM model of continuous beam bridge, the improvement in the precision of prestressed duct layout and the elimination of rebar clash points can be achieved. The research achievement can guide the visualization of construction disclosure, enhance construction efficiency, and provide reference and technical support for the construction management and control of HSR continuous beam bridges. [ABSTRACT FROM AUTHOR]

Bridge construction collapse is one of the most common bridge safety accidents. At present, evaluation results are often affected by the ability and experience of the assessor. Therefore, it is difficult to quickly, accurately and effectively evaluate the risk in the process of bridge construction. Moreover, key factors that can prevent accidents can hardly find from the existing bridge construction safety management and evaluation method. This paper analyzes and classifies the artificial and environmental risk factors that affect the bridge construction stage, and establishes 26 risk factors in 5 categories according to the characteristics of bridge construction and the actual situation of the project. Random forest (RF) algorithm is a non-parametric machine learning method based on decision tree, which does not need to be scored by experts in advance and avoids the influence of subjective factors. Compared with other analysis methods, random forest algorithm has the advantages of accurate and robust risk assessment results. Based on the advantages of random forest algorithm and the characteristics of bridge construction risk, this paper uses random forest algorithm to evaluate the bridge construction risk, and ranks the importance of indicators, and identify the index that has a greater influence on the risk. In order to verify the applicability and feasibility of the proposed method, a typical urban complex pedestrian bridge was taken as an example for actual engineering evaluation and verification. The results obtained are basically consistent with the actual risk assessment results of the pedestrian bridge. [ABSTRACT FROM AUTHOR]

Steel bridge, as one of the main structural types in bridge design, has been widely used in rail transit. However, the train-induced vibro-acoustic problem of the bridge has become increasingly prominent. The vibration and noise characteristics must be more significant and complex than steel truss bridge because of too many components. Viscoelastic damping materials (VDMs) have the characteristics of both viscous liquid and elastic solid, and have better damping performance than other damping materials. Therefore, VDM plays an important role in vibration and noise reduction technology. In applications, VDM is usually combined with constraining materials to form composite viscoelastic damping materials (CVDM). In this paper, based on the dynamic receptance method and superposition principle, the coupling model of vehicle–track–bridge in the frequency domain is first established, and then the vibration and noise prediction model of a steel truss bridge with CVDM is established based on RUK theory and statistical energy analysis (SEA) method. Based on the prediction model, the natural dynamic characteristics of typical components of steel truss bridges with CVDM were investigated, and the control mechanism and influence rule of CVDM on train-induced vibration and noise of steel bridges were revealed. [ABSTRACT FROM AUTHOR]

With the continuous increase of vehicular traffic, the safety caused by bridge crack damage is becoming increasingly prominent. Bridge crack analysis and measurement are of great significance for promoting road traffic safety. However, existing bridge crack image segmentation methods have shortcomings in processing image detail features, resulting in the inability to better measure the actual size of bridge cracks. Therefore, to further optimize the calculation method, a bridge crack image segmentation method based on improved SOLOv2 is designed to achieve more accurate bridge image segmentation. Based on the image segmentation results and combined with the skeleton data extraction method, a bridge crack calculation method is designed. From the results, the segmentation accuracy for crack images was 92.05 % and 93.57 %, respectively. The average mIoU of AM-SOLOv2 method was 0.75, significantly lower than commonly used crack image segmentation methods. In addition, the mIoU value variation amplitude of the AM-SOLOv2 method was relatively smaller. The crack length and width errors were within 0.05 mm and 0.06 mm, significantly lower than the comparison method. It indicates that this method can achieve more accurate crack image segmentation and calculation. This is beneficial for a deeper understanding of the performance degradation and crack damage evolution of bridge structures, thereby improving bridge design and construction technology. [ABSTRACT FROM AUTHOR]

Objectives: Accurately describing and understanding the bridge construction process is of great significance to students' learning and field personnel's fine management. However, the bridge construction process involves a large number of objects, complex behaviors, and variable states, which leads to problems such as poor standardization and low cognitive efficiency in expression. Methods: This paper proposes a knowledge-guided three-dimensional visualization method of spatiotemporal narrative of bridge construction process. First, we construct a bridge construction knowledge map with "object-behavior-state" three-domain association by analyzing the bridge construction process, then break through the key technologies of narrative element analysis and matching, 3D scene mapping and instantiation, and 3D dynamic visualization of spatiotemporal narrative. Finally, we develop a prototype system and carries out case study experimental analysis. Results: The results show that the correct rate of answering questions in the experimental group reaches 76.5%, which is 13.2% higher than that of the control group; under the comprehensive perspective of clarity, richness and comprehension difficulty, 78.8% of the personnel in the experimental group have good cognitive experience, which is 45.5% higher than that of the control group. Conclusions: By accurately describing the bridge construction objects, features and interrelationships, the unified expression and association management of bridge construction knowledge map is realized, and based on this, the three-dimensional dynamic visualization expression of the bridge construction process is carried out by using spatiotemporal narratives, which effectively enhances the education level of bridge construction process cognition with the help of interactivity and immersion of three-dimensional scenes. [ABSTRACT FROM AUTHOR]

Bridges are one of the most important infrastructures because they are a link between 2 different points that have an impact on a country's economy. The impact of bridge construction can be controlled with good design and design. In this paper, the author will model the planning of the lower structure of the bridge using Revit Software as a form of Building Information Modeling (BIM) technology. This paper uses references from international and national journals taken from Google Scholar. The references obtained are useful in making a literature review that has a relationship with the topic discussed by the author, namely bridges. It is known that the use of BIM technology is very helpful and makes it easier for engineers in the implementation of a construction project. Therefore, this research enhances the understanding and application of digital tools in civil engineering projects, contributing to innovation in construction practices. [ABSTRACT FROM AUTHOR]

Steel corrosion is by far the biggest durability issue for many reinforced concrete bridge structures worldwide. The columns in these bridges can be critical, especially for seismic resistance. In this study, glass-fibre-reinforced-polymer bars were investigated as an alternative to steel for sustainable and resilient bridge construction. As lateral reinforcement is more susceptible to corrosion, and structures fully reinforced with fibreglass bars display softer responses with lower shear and flexural capacity, fibreglass spirals and longitudinal steel reinforcement were used in the tested columns. The experimental programme included the design, construction and seismic testing of full-scale (508 mm diameter) and half-scale (356 mm diameter) columns. The other variables investigated were the axial load and the amount and spacing of spirals. For both column sizes, fibreglass spirals provided increasing confining pressure to the concrete core with increased deformations. For the full-scale columns, no adverse size effects were observed in comparison to the half-scale columns. The columns produced large ductility and energy dissipation. Results from selected representative specimens are presented here to establish the feasibility of using fibreglass spirals in circular bridge columns. Resilience can thus be built into new columns through innovative durable fibreglass lateral reinforcement, with similar if not superior behaviour to steel-reinforced columns. [ABSTRACT FROM AUTHOR]

The Canadian highway bridge design code (CHBDC) uses the concept of a target reliability index for evaluating the load-carrying capacity of existing bridges. This index, which is based on risk to human life, is related to three aspects of uncertainties inherent in a bridge: element behaviour, system behaviour and inspection level. Analysis is yet another uncertainty in bridge evaluation. It is assumed that all bridge inspections are manual. Citing examples of tests on many instrumented bridges, another level of inspection is proposed, carried out with the help of electronic instruments and tests under controlled vehicle loads. Simple additions to the clauses of the CHBDC are proposed, which can be used to determine the optimum load-carrying capacities of existing bridges where structural monitoring information is available. [ABSTRACT FROM AUTHOR]

The data collected at Weigh-in-Motion (WIM) stations have many applications. Primarily, the data are used for pavement design, bridge design, freight studies, transportation planning, and enforcement. The WIM data are also used in mechanistic-empirical pavement design guide (Pavement-ME) for predicting performance. Highway agencies and the state department of transportation (DOTs) are the main users of WIM data. With a number of important applications, all WIM users desire to collect accurate loading data. This paper addresses three core issues related to WIM systems accuracy and calibration procedures, i.e., how to; (1) perform successful calibration of a WIM system by quantifying the effect of sample size (truck runs), speed, temperature, and truck type on measurement errors, (2) model gross vehicle weight (GVW) WIM errors as a function of individual axle errors [(single axle (SA) and two tandem axles (TA), (drive and trailer)], and (3) estimate WIM measurement errors using the long-term pavement performance (LTPP) and the ASTM protocols. The research objectives were accomplished by synthesizing and analyzing the WIM error data available in the LTPP database for bending plate (BP) and quartz piezo (QP) sensors. Successful WIM equipment calibration can eliminate systematic weights, speed, and axle spacing errors. The ASTM and the LTPP accuracy estimation methods agree; however, the methods should be compared when the sample size is small (10 or fewer truck runs). The representative pre- and post-calibration data can be collected accurately using one test truck with 12 or more runs at multiple speed points for QP and BP sensors. The developed models showed that the GVW errors could be accurately predicted using SA and two TA. The results also show that if GVW errors are within ASTM Type I tolerance, the SA and TA errors will likely be within acceptable limits. Therefore, calibrating a WIM site using GVW errors should continue. The suggested changes in current WIM procedures can significantly reduce time and resources for successful equipment calibration. [ABSTRACT FROM AUTHOR]

The study of railway dynamics remains an active and fertile field of research, given the technological evolution of this transport system. Several modeling methods have been developed to explore the dynamic interactions of a train-rail-bridge system, and these numerical models enable optimization of bridge design, especially for high-speed lines. In this perspective, this work joins this huge modeling project by proposing a procedure for assembling the elementary matrices of a dynamic system composed of a train, a rail and a bridge, in order to obtain the global differential equations of the system. The model studied consists of a moving part, the vehicle, modeled by a mass-spring-damper system, and a fixed part, the rail and bridge deck, modeled by two Bernoulli beams. The elements to be assembled are not identical, which increases the complexity of their assembly, as the position of the vehicle wheel changes as a function of time and passes from one element to another, creating loaded and unloaded elements. The dynamic equations were solved using the Newmark Beta numerical method. The model developed was subjected to a validation process based on a comparison of the dynamic responses of the bridge and vehicle obtained by the present study and those presented by previous studies. [ABSTRACT FROM AUTHOR]

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]

Shui Su Ravine Bridge is built in Bai Shui County in Shaanxi Province, which is a part of the highway linking Heyang and Tongchuan. The bridge has been designed as a composite steel‐concrete truss bridge with 3 spans in total of 240 meters and a deck of 4 lanes. To meet the harsh environmental demand and lessen the future maintenance, the solution adopts the weathering steel Q420qENH similar strength as S420NL in European code. The bridge is erected by incremental launching and post‐installation of the pre‐cast concrete slab. Since the truss segment is all welded, two‐step models have been developed to evaluate the fatigue performance of the steel truss joint. In the simplified two‐dimensional model, Phase‐Field (PF) approach has been implemented to make a full fatigue evaluation of crack propagation in the truss. [ABSTRACT FROM AUTHOR]

This contribution describes the architectural and structural solutions of a unique pedestrian footbridge in Hradec Králové. The new significant construction was built over the Elbe River in the pedestrian area. The bridge design was challenging for architects, planners even though contractors, especially due to accounting for the influence of shipping traffic. Completed structure has two asymmetrical spans, whereas the main span across the river is 69 m long. In the final static scheme, the structure forms a virtual Vierendeel truss of variable height. A slender UHPFRC bridge deck supported by a pair of cables through thin steel crossbars creates a delightful bridge, which has become a new symbol of the city. [ABSTRACT FROM AUTHOR]

Once constructed, the Baku White City pedestrian bridge will be a landmark for the newly developed White City district in the east of the Capital. Designed by UNStudio, the bridge crosses the highway of 8th November Avenue and connects the newly build city to the seaside, forming a wide promenade. Due to the pending construction of the mall as future bridge support, the bridge had to be redesigned. A cantilevering viewing platform will highlight the bridge's ending. This paper covers the structural design of the architecturally shaped cable stayed bridge, supported through a 46 m high A‐shaped, slightly curved pylon. Based on 3‐D modelling in Rhino® and Grasshopper®, the FE‐software SOFISTIK® is used both for cable force finding and bridge design. The structural system, steel structure's specific detail for cable connection and its design approach have been documented. [ABSTRACT FROM AUTHOR]

A novel prefabricated steel‐concrete composite girder is proposed, which aims to provide an economic and sustainable solution for small bridge construction. The girder consists of composite dowels and concrete slabs. The depth of composite girder is analyzed in a span range of 8‐20m. A continuous deck joint between the simply supported bridge is proposed to enhance the durability of the girder. Carbon emissions from construction materials are compared between different schemes. The efficiency of the schemes is evaluated through Live Load Structural Index. [ABSTRACT FROM AUTHOR]

Responsible for 70% of the global CO2 emissions, infrastructure has a significant impact on our climate and the related consequences. Bridges are a major keystone of the infrastructure and take a leading position in its decarbonization. In this framework, low‐carbon emission steels play an important role. Low‐carbon emission steels, like ArcelorMittal's XCarb® recycled and renewably produced steels, are already available on the market. Combining scrap and renewable electricity, it offers very low levels of CO2 emissions per ton of finished steel. The present paper describes how different steel solutions can be combined to lower the material input, to simplify the construction process and to reduce the maintenance efforts in bridge construction. The impact of efficient design has been assessed by a Life‐Cycle Assessment (LCA) for bridge solutions with small and medium spans of up to 40 m. The paper concludes with a summary of recently realized bridge projects in Poland. [ABSTRACT FROM AUTHOR]

The continuous improvement of bridge construction technology has resulted in an ongoing expansion of bridge spans, which has concomitantly increased the difficulty of controlling the alignment of long-span bridges during construction. In order to address the issue of the grey prediction model exhibiting a significant discrepancy in its alignment predictions for long-span continuous girder bridges, a pre-camber prediction method for bridges based on a combination of the grey model (GM) and BP neural network (GM-BP) is proposed. Firstly, the parameters are identified according to their influence on the pre-camber, and the appropriate parameters are selected as the original data to improve the efficiency of prediction. Subsequently, the original data are preliminarily fitted by the GM(1,1) model, and the predicted values are used as inputs for training the neural network. Finally, the new predicted values are output using the nonlinear fitting ability of the BP neural network. To assess the efficacy of the model, it is applied to the prediction of the pre-camber of the girder segments of a bridge under cantilever construction. The pre-camber prediction for 11#–13# girder sections was based on 10 sets of monitoring data from constructed girder sections. The results demonstrated that the average relative error of the GM-BP combined prediction model was 3.01%, which was 5.68% less than that of the GM(1,1) model, and the overall prediction exhibited a closer alignment with the original data. The GM-BP combined prediction model is an effective method for ensuring the alignment control of bridge construction and is able to achieve high accuracy and stability in its predictions in the case of limited and irregular data. [ABSTRACT FROM AUTHOR]

Steel beams are widely used load-bearing components in bridge construction. They are prone to internal stress concentration under low-frequency vibrations caused by natural disasters and adverse loads, leading to microcracks and fractures, thereby accelerating the instability of steel components. Therefore, dynamic stress monitoring of steel beams under low-frequency vibrations is crucial to ensure structural safety. This study proposed an external stress sensor based on PMN-PT material. The sensor has the advantages of high sensitivity, comprehensive frequency response, and fast response speed. To verify the accuracy and feasibility of the sensor in actual engineering, the LETRY universal testing machine and drop hammer impact system were used to carry out stress monitoring tests and finite element simulations on scaled I-shaped steel beams with PMN-PT sensors attached. The results show that: (1) The PMN-PT sensor has exceptionally high sensitivity, maintained at 1.716~1.726 V/MPa in the frequency range of 0~1000 Hz. The sensor performance is much higher than that of PVDF sensors with the same adhesive layer thickness. (2) Under low-frequency random vibration, the sensor's time domain and frequency domain output voltages are always consistent with the waveform of the applied load, which can reflect the changes in the structural stress state in real time. (3) Under the impact of a drop hammer, the sensor signal response delay is only 0.001 s, and the sensitivity linear fitting degree is above 0.9. (4) The simulation and experimental results are highly consistent, confirming the superior performance of the PMN-PT sensor, which can be effectively used for stress monitoring of steel structures in low-frequency vibration environments. [ABSTRACT FROM AUTHOR]

Considering the complex construction processes involved, there are significant risks during the construction of long-span cantilever casting arch bridges. In this study, a risk assessment method for the construction process of cantilever casting concrete arch bridges was developed. The compositional elements and characteristics of safety risks in the construction of cantilever casting concrete arch bridges were clarified, and a safety risk source list that includes seven major risk sources and thirty-three minor risk sources was formed. Then, a Bayesian model for the risk analysis of cantilever casting concrete arch bridge construction was established, and a method was proposed to determine the prior and posterior probabilities of the Bayesian network using triangular fuzzy numbers. This method fully utilizes the experience of experts while avoiding the subjectivity of expert opinions. A cantilever casting concrete open spandrel arch bridge (Bridge A) with a total span length of 287 m was taken as an example, and a safety risk assessment was conducted during its construction process. The calculation results show that the construction safety risk level of Bridge A was level III. This engineering application verified the feasibility of determining key node parameters of the Bayesian network using triangular fuzzy numbers. [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]

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

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

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

The results of an experimental program conducted to evaluate the performance of shear-critical post-tensioned I-girders with grouted and ungrouted ducts are presented. The experimental program involved the design, construction, and testing to failure of six fullscale specimens with different duct layouts (straight, parabolic, or hybrid) and using both grouted or ungrouted ducts. All tests resulted in similar failure modes, such as localized web crushing in the vicinity of the duct, regardless of the duct condition or layout. Furthermore, the normalized shear stresses at ultimate were similar for the grouted and ungrouted specimens. The current shear design provisions in the AASHTO LRFD Bridge Design Specifications (AASHTO LRFD) were reviewed, and updated shear-strength reduction factors to account for the presence of the duct in the web and its condition (that is, grouted or ungrouted) were proposed. The data generated from these tests served as the foundation for updated shear-strength reduction factors proposed for implementation in AASHTO LRFD. [ABSTRACT FROM AUTHOR]

This study proposes a method for assessing the effect of stochastic vibrations resulting from track irregularities which are rarely studied but significant on bridge fatigue. First, the pseudo-excitation method is utilized to determine the power spectrum density of stress. Subsequently, the trigonometric series method is employed to acquire the stress time history set. Then, a traditional fatigue life calculation method is employed for analysis. By utilizing a post-sampling method, the need for costly repetitive solutions of the vehicle-bridge coupling system is eliminated. Numerical simulations are conducted on a steel truss bridge, revealing the non-negligible effect of track irregularity on bridge fatigue performance. The study investigates the underlying mechanism, highlighting the pronounced influence of long-wave track irregularity. Moreover, the research explores the correlation between track smoothness and bridge fatigue performance, demonstrating that a decrease in track smoothness leads to an increase in fatigue loss. These findings emphasize the necessity of considering stochastic vibrations when evaluating bridge fatigue, providing valuable insights for bridge design and maintenance. [ABSTRACT FROM AUTHOR]

The interface shear transfer mechanism in concrete structures has been studied for several decades and its investigation has served as the basis for the provisions of current design specifications. However, most of the studies on interface shear transfer have used steel bars as interface shear reinforcement, with minimal experimental and analytical research conducted on glass fiber–reinforced polymer (GFRP) reinforcement. In this study, tests were conducted to quantify the contribution of GFRP rebars to interface shear transfer by using the push-off test. A total of 27 specimens were built and tested using a single concrete compressive strength of 36.5 MPa (5,300 psi); 9 of them included no reinforcement crossing the shear plane, 6 had steel stirrups, and 12 had GFRP stirrups with two quantities of reinforcement. Additionally, during the construction process, six of the specimens were built in two stages to simulate a cold joint condition at the interface. The experimental results showed that GFRP reinforcement contributes substantially to the interface shear strength with ultimate resistance values higher than the results from specimens without reinforcement. Furthermore, once the ultimate strength is reached, the GFRP reinforcement allows the specimen to deform and prevent sudden failure. As for the theoretical capacities estimated by current codes, the experimental tests for GFRP showed an overestimation in the calculation of these capacities. Therefore, the research findings will be helpful in the development and improvement of design guide specifications for concrete structures reinforced with GFRP stirrups where interface shear effects are significant. Practical Applications: Numerous concrete structures depend on the effective transfer of shear forces at joints where concrete sections may slide past one another. This is particularly crucial in scenarios such as bridge construction, where a precast, prestressed concrete girder must seamlessly integrate with the reinforced concrete deck. Ensuring this connection can adequately handle shear forces is vital for the structure's overall stability and integrity. While the shear-friction mechanism, a key aspect of the design of reinforced concrete structures, has been extensively explored with steel reinforcement, research on GFRP reinforcement has been limited. This study focuses on experimental investigations to understand how GFRP influences shear-friction behavior. Although numerous factors can affect shear-friction performance, this research primarily aims to clarify the fundamental behavior of shear-friction when using GFRP reinforcement. The findings suggest that it is important to consider the effect of reinforcement stiffness in tension, rather than its strength. [ABSTRACT FROM AUTHOR]

Glass fiber–reinforced polymer (GFRP) reinforcements can be used as shear friction connectors at the interface of concrete composite elements to maintain structural integrity. However, the shear friction mechanism at the interface greatly depends on the interface condition and the stiffness of the reinforcement crossing the interface plane. A total of 18 GFRP-reinforced concrete (RC) push-off specimens were constructed and tested until failure under monotonic load. The test parameters included the shear plane condition (roughened or not roughened, cold joints and monolithic), type (steel and GFRP), and ratio (0.24%–0.47%) of reinforcement crossing the shear plane. Roughening the interface had a little effect on the overall behavior and shear capacity of the specimen. Conversely, the monolithic specimens carried approximately 60% higher load than their cold-joint counterparts; nevertheless, the failure was more brittle. The capacity prediction by the Canadian Highway Bridge Design Code showed conservative results. By contrast, the predictions of the American Concrete Institute's model for steel-RC elements overestimated the test results for cold-joint and monolithic specimens with reinforcement ratios of 0.43% or higher. [ABSTRACT FROM AUTHOR]

Tapered beams are characterized by varying moments of inertia along their span, commonly the pier cap configuration used in bridge construction. This study presents the shear behavior of tapered beams reinforced with basalt fiber–reinforced polymer (BFRP) bars through experiments and analyses. Eight BFRP beams were tested to explore the influence of changing inclination angles and the presence of BFRP stirrups. These beams were divided into two groups, each consisting of four beams: one control straight beam and three tapered beams with different tapered angles. The first group was without shear reinforcement, while the second group was reinforced with BFRP stirrups. Results revealed that increasing tapered angles decreased the shear strength of BFRP tapered beams without stirrups but increased it in beams with BFRP stirrups. The analytical part proposed equations to estimate the shear strength of BFRP tapered beams, with findings indicating conservative estimations consistent with experimental data trends. [ABSTRACT FROM AUTHOR]