Modern Bridge Research Articles

Design of Bridge Adaptive Bearing Based on Hydraulic Control

At present, the total number of modern Bridges in China exceeds 1 million, and Bridges across the sea and river bear a huge amount of passenger and freight transport. Because the bridge span is large, so because of weather, war and other reasons when the damage, can only be set up pontoon repair. Limited by hydrological conditions and other factors, the disadvantages of emergency repair of pontoon bridge are very obvious, among which the disadvantages of difficult operation and low traffic speed directly limit the overall emergency repair progress. Therefore, the bridge bearing based on hydraulic control in this paper can control the adaptive bearing to actively compensate and adjust with the help of the rapid calculation of the calculation system without blocking the channel, so as to greatly improve the passage efficiency and reduce the cost of emergency repair.

Lateral-Torsional Buckling Analysis for Doubly Symmetric Tubular Flange Composite Beams with Lateral Bracing under Concentrated Load

Tubular flange composite beams are increasingly applied in modern bridge structures. In order to investigate the overall stability behavior of doubly symmetric tubular flange composite beams with lateral bracing under concentrated load, the analysis of elastic lateral-torsional buckling is conducted by the energy variation method. The analytical solution of critical moment of doubly symmetric tubular flange composite beams with lateral bracing is obtained. Meanwhile, the simplified calculation formula of critical moment is fitted by 1stOpt software based on 26,000 groups of data, and the accuracy is verified by the finite element method. It is found that, the critical moment rises obviously with increasing lateral bracing stiffness, and adding lateral bracing to doubly symmetric tubular flange composite beams is beneficial to improve the overall stability in engineering practice. Finally, the influence of several parameters including concrete strength, span, steel ratio of flange and height-thickness ratio of web are studied. The results show that the concrete strength and the web height-thickness ratio have a weak influence on critical moment of elastic lateral-torsional buckling, while the influence of span-depth ratio and flange steel ratio is very significant.

Influence of Material Toughness on Fracture Reliability in Steel Bridges

The fracture limit state of the AASHTO LRFD Bridge Design Specifications is addressed by requiring minimum impact toughness values for base material and mitigating potential fracture initiators through proper structural detailing. This fracture control approach has been successful in minimizing the number of fractures in steel bridges designed since its inception; however, it is not a calibrated limit state and the structural reliability against sudden brittle fracture has not been previously established. Accordingly, the objective of this study was to quantify the relationship between material toughness and fracture reliability in steel bridge members, considering the probabilistic distribution of fracture toughness and applied stress for a variety of structural steels and assumed crack sizes. The master curve approach is used to account for the probabilistic distribution of fracture toughness, and reliabilities are determined using Monte Carlo simulation and the Hasofer-Lind approach. The results indicate that the fracture reliability for modern bridge steels is consistent with the reliability of AASHTO strength limit states, and that certain steels currently available on the market can provide enough reliability against fracture to essentially eliminate brittle fracture as a limit state of concern. This finding holds the potential for a new way of approaching the design of fracture-critical members.

MODERN STEEL-CONCRETE SPAN STRUCTURES OF SMALL AND MEDIUM-SPAN BRIDGES

The paper reviews the most common reinforced concrete girder structures of modern bridges used in Ukraine and other countries. The scope, advantages and disadvantages of reinforced concrete structures are considered. The peculiarities of the use of reinforced concrete structures in European countries are reviewed. The most common typical structural solutions of reinforced concrete girder structures used worldwide are given. Options for facilitation of reinforced concrete structures without significant loss of load-bearing capacity are also highlighted. Options for facilitation of structures are presented in the article by lightening the metal load-bearing elements and reducing the weight of the reinforced concrete slab of the carriageway. Reducing the weight of metal elements can be obtained through the use of perforated elements, which can be performed by waste-free technology. To reduce the cost of materials and reduce the weight of the reinforced concrete slab, it is designed lightweight – hollow or ribbed. When removing concrete from the stretched zone, only the ribs of the width required to accommodate the welded frames and ensure the strength of the panels on an inclined cross section are retained. In this case, the plate in the span between the ribs work on the bend as beams of T-section. The top shelf of the plate also works on the local bend between the ribs. During the inspection, the article presents a new design of reinforced concrete girder structure, using perforated box metal elements, made by waste-free technology, and lightweight reinforced concrete slab of the carriageway with hollow formers. Metal blocks are connected to each other by bolts. Metal blocks are made of perforated sheet elements made of waste-free technology. Each block consists of two main beams, transverse diaphragms and a lower plate. The upper belt of the main beams is implemented with the device of horizontal shelves along the entire length of the beams, performing the function of a supporting element for the reinforced concrete slab. Combining all structural elements into a single finished unit is carried out in the factory by automatic welding, which, in turn, allows us to achieve the high factory readiness. The diaphragms of the block are made with a comb along the upper border, on which a profiled steel sheet is placed, which is a fixed formwork for a reinforced concrete slab. The plate is made of non-removable formwork. To ensure the joint operation of the metal part and the reinforced concrete slab, a system of discrete-continuous connections in the form of rigid stops connected in the longitudinal and transverse directions by reinforcing rods is proposed.

Analysis of Modern Bridge Design Concept and Development Trend

Analysis of Modern Bridge Design Concept and Development Trend

Research on the key technology of TIED-arch bridge Incremental Launching Method Construction

Steel tied arch bridge has been widely used in modern bridge construction due to its beautiful shape, high material utilization rate and overall structural stiffness. However, there are few cases in which the tied-arch bridge is constructed by incremental launching . Based on the steel tied arch bridge project, this paper uses finite element software to establish the finite element simulation analysis of the construction process, and monitors the construction process of the bridge. The test results show that it is in the most unfavorable state when the cantilever at the end of the bridge reaches the maximum. At this time, the stress at the 117 m position of the beam reaches the maximum, the stress at the top edge is 33.7 MPa, and the stress at the bottom edge is -58.2 MPa. The stress in other sections did not exceed 30 MPa, and the beam was under uniform stress. When the foot of the internal arch passes through the temporary pier, the supporting force of the pier is maximum, which is about 6000 kN. The reasonable range of α is between 0.55 and 0.65, which is the ratio between the length Ln of launching nose and the maximum span L of incremental launching .

On the denoising of structural vibration response records from low-cost sensors: a critical comparison and assessment

Due to the increasing quest of adopting low-cost sensors in structural health monitoring (SHM) processes, which may lead to detecting signals contaminated by significant levels of noise, the need to devise appropriate and effective denoising strategies, at the post-processing stage, is becoming more and more essential. Among several approaches proposed in the literature, it has been demonstrated that the employment of discrete wavelet transform (DWT) as a multi-rate filter bank, as well as the use of singular value decomposition (SVD), may result to be quite effective in signal denoising within various research fields, as biological, acoustic and mechanical. Here, DWT- and SVD-based denoising techniques are first independently reconsidered and reimplemented, aiming at exploring their optimal calibration in purifying noise-corrupted vibration response signals encountered in civil engineering applications. Then, a systematic performance evaluation is provided within a comparative framework, developed at an increasing level of noise affecting the measurements, in terms of noise-to-signal (N/S) ratio. In the study, two specific classes of synthetic response signals are first considered, namely earthquake and ambient vibration signals, since they may be assumed as representative of more general non-stationary and stationary signal typologies, respectively. To achieve a complete description of the clarified signal, strengths and weaknesses of the two denoising approaches are explored, in both time and frequency domains. The results prove the effectiveness of the analyzed implementations, especially in purifying seismic response signals, while some limitations may arise concerning the treatment of ambient vibration signals, in particular for the DWT-based denoising technique. Finally, a real case study is analyzed, where both denoising approaches are adapted and employed for clarifying acceleration signals detected on a modern short-span railway bridge, with rather satisfactory results, for both techniques.

A System for Noise Control of the Technical Condition of Railroad Bridges and Tunnels in Seismically Active Regions

The authors analyze the technical condition of objects of railroad communications with modern bridges, tunnels, stations, overpasses, crossings and power installations. It is noted that, based on the specific features of such objects, control of their technical condition in most cases is carried out at certain intervals. At the same time, existing continuous control systems do not always adequately assess the technical condition of rail infrastructure objects due to the presence of additional noises in the processed signals at the time when a malfunction occurs. In this regard, one of the possible options is proposed for "continuous" monitoring of the beginning of changes in the technical condition of railroad tracks by means of noise technologies. It is pointed out that when the technical condition of rail infrastructure changes, vibration signals caused by the impact of rolling stock contain noises in addition to the useful component. The use of correlation and spectral analysis technologies, as well as other traditional methods does not allow ensuring the adequacy of the control results, due to the influence of the noise on useful vibration signals. Therefore, technologies are proposed for split analysis of the useful signal and the noise received from vibration, as well as for forming informative attributes of identification of the technical condition of rail infrastructure. In this case, the estimates of the characteristics of the useful signal and the noise are used as the main carrier of diagnostic information. Due to the simplicity and reliability of the developed theoretical algorithms, the implementation of the technical equipment and its installation in all objects of the railroad track present no particular difficulties. At the same time, the implementation of the Noise system will ensure real-time control of the beginning of changes in the technical condition of railroad tracks during the movement of the rolling stock. This, in turn, will allow timely detection of malfunctions, significantly enhancing the safety of passenger and cargo rail transportation.

Study on Modern Bridge Structure Health Monitoring System Based on Damage Identification

Study on Modern Bridge Structure Health Monitoring System Based on Damage Identification

Rational cross-sectional design and behavioural analysis of the low-sag stressed ribbon pedestrian bridges/Rationale Querschnittsbemessung und Verhaltensanalyse der Fußgänger-Spannbandbrücken mit geringem Durchhang

Stress ribbon bridges represent one of the simplest and the most efficient modern bridge constructions used in modern lightweight pedestrian bridges. The article presents an analysis of the stress ribbon bridge behaviour by applying different values of constant loads, assessing the possibilities of using steels and composite materials. The article presents the methodology for the rational cross-section and shape design of the low-sag stressed ribbon structure, based on the rigidity conditions. The article discusses the structure‘s behaviour in asymmetric loads and provides recommendations for Design.

Адгезивный фотокомпозитный зубной протез – вариант восстановления дефекта зубного ряда во фронтальных участках (описание клинического случая)

Summary. Having and maintaining a smile aesthetic is an essential component of modern popular culture. Adhesive bridges («Maryland bridge») have been developed to eliminate single included defects in the dentition in the frontal areas, without preparing the supporting teeth. In modern conditions this technology is the method of choice since single defects in the anterior part of the dentition can also be eliminated through orthodontic treatment, manufacturing of a partially removable plate prosthesis, a traditional dental bridges, the manufacturing of cantilever orthopedic structures and prosthetics based on a dental implant. Adhesive dentures are a relatively new dental technology (which is on the border of orthopedic and therapeutic dentistry) the first work in this direction was carried out in the early 80s of the twentieth century. Modern adhesive bridges are divided into two large groups – solid metal and photopolymer (composite) which prevail in practice. The optimal form of the release of the reinforcing element which combines a slight preparation of abutment teeth to a safe depth, high physical and mechanical properties, simple achievement of the anatomical shape of the teeth in the bridge structures of the anterior and posterior teeth is fiberglass in the form of ribbons 2 mm wide, up to 0.5 mm (this is the most effective width and thickness for clinical practice) and braided type. Using adhesive bridges, it is possible to optimally restore the aesthetics of the anterior part of the dentition in one visit without preliminary preparation of adjacent teeth. An example of the manufacture of a photocomposite adhesive prosthesis reinforced with glass fiber for the restoration of a single included defect in the dentition in the frontal area using domestically produced materials is given. Key words: teeth, defect, composite, adhesion, fiberglass.

Knowledge-Based Systems for the Assessment and Management of Bridge Structures: A Review

It is becoming an important social problem to make maintenance and rehabilitation of existing infrastructures such as bridges, buildings, etc. in the world. The kernel of such structure management is to develop a method of safety assessment on items which include remaining life and load carrying capacity. The purpose of this paper is to summarize the finding of up-to-date research articles concerning the application of knowledge-based systems to assessment and management of structures and to illustrate the potential of such systems in the structural engineering. In here, knowledge-based systems include knowledge-based expert systems incorporation with artificial neural networks, fuzzy reasoning and genetic or immune algorithms. Specifically, two modern bridge management systems (BMS’s) are presented in the paper. The first is a BMS to assess the performance and derive optimal strategies for inspection and maintenance of concrete bridge structures using reliability based and knowledge-based systems. The second is the concrete bridge rating expert system (J-BMS BREX) to evaluate the performance of existing bridges by incorporating with artificial neural networks and fuzzy reasoning.

Dynamic reduction in the calculation of bridge structures

In modern bridge construction, on the one hand, there are increasing trends towards increasing bridge spans, which requires reducing the weight of structures. On the other hand, the use of structural elements made of various composite materials is expanding, which allows to significantly reduce the weight of the bridge structures as a whole. However, the creation of new forms of span structures of bridges requires more detailed calculations in order to optimize such forms, in particular the role of calculating the dynamic impact, because with increasing spans and weight loss, increases design flexibility and sensitivity to dynamic loads. In the present paper, the problems of solving an incomplete algebraic problem of eigenvalues and eigenvectors are considered. To increase the accuracy of the calculation and exclude the use of high-order matrices, a method of sequential reduction of the stiffness and equivalent mass matrices is proposed. The method is based on the construction of partial systems using a static transformation, followed by the solution of its own problem for the partial system. In the process of solving this problem through the eigenvectors of the system, the minor unknowns are reduced to the main ones. Dynamic reduction showed high calculation accuracy..

LR-BCA: Label Ranking for Bridge Condition Assessment

Bridge condition assessment (BCA) plays an important role in modern bridge management. Existing assessment methods are time-consuming, labor-intensive and error-prone. The use of machine learning for BCA can effectively solve the above problems. However, the large amount of label noise in the dataset severely affected the performance of the BCA model. In this paper, we present an effective label ranking approach for BCA (LR-BCA). Our proposed LR-BCA method considers the natural order relationship between bridge condition ratings. Moreover, a heuristic data cleaning (HDC) approach is proposed for cleaning bridge condition dataset. The HDC method firstly identifies all the label conflict examples, then iteratively filters out the noise. Experimental results on real-world dataset confirm the effectiveness of the HDC method and demonstrate that our proposed LR-BCA method achieves 99% Top-2 accuracy, which is highly competitive compared to baseline methods.

Dynamic Response Study of a Single Tower Cable Stayed Bridge using Finite Element Method

Cable-stayed bridges are most widely used in modern bridge construction. The dynamic response of a single tower cable-stayed bridge is studied by performing nonlinear dynamic analysis using finite element method based software ANSYS. A three-dimensional bridge model was developed. Steel cables were simulated using a single element approach. Due to the coupling effects, the bridge exhibits complex modal shapes. The response of the bridge in the vertical direction is more elastic and flexible as compared to the longitudinal and transverse direction. The response of the critical sections of girder, tower, and cables was also studied by time-history analysis using the ground acceleration data of EI-Centro 1940. A 10-second ground data with 0.0001 second time step was used.

A Decade of Modern Bridge Monitoring Using Terrestrial Laser Scanning: Review and Future Directions

Over the last decade, particular interest in using state-of-the-art emerging technologies for inspection, assessment, and management of civil infrastructures has remarkably increased. Advanced technologies, such as laser scanners, have become a suitable alternative for labor intensive, expensive, and unsafe traditional inspection and maintenance methods, which encourage the increasing use of this technology in construction industry, especially in bridges. This paper aims to provide a thorough mixed scientometric and state-of-the-art review on the application of terrestrial laser scanners (TLS) in bridge engineering and explore investigations and recommendations of researchers in this area. Following the review, more than 1500 research publications were collected, investigated and analyzed through a two-fold literature search published within the last decade from 2010 to 2020. Research trends, consisting of dominated sub-fields, co-occurrence of keywords, network of researchers and their institutions, along with the interaction of research networks, were quantitatively analyzed. Moreover, based on the collected papers, application of TLS in bridge engineering and asset management was reviewed according to four categories including (1) generation of 3D model, (2) quality inspection, (3) structural assessment, and (4) bridge information modeling (BrIM). Finally, the paper identifies the current research gaps, future directions obtained from the quantitative analysis, and in-depth discussions of the collected papers in this area.

Critical review of data-driven decision-making in bridge operation and maintenance

Bridges are critical infrastructure, and effective operation and maintenance (O&M) is essential for ensuring the good condition of bridges. Owing to the increasing complexity of modern bridges and the availability of information technologies (e.g. sensors, laser scanners, and ultrasonic radar) for the collection of massive data, bridge O&M and decision-making gradually shift toward a data-driven manner. However, both the bridge industry and the academia still do not have a common understanding of the latest progress, challenges, and trends of data-driven bridge O&M decision-making. Thus, through a critical review of 485 articles, this paper investigates current data-driven bridge O&M decision-making in detail, including mainstream data types, issues related to data management, and typical application areas using these data. Challenges to implement data-driven bridge O&M decision-making are identified, such as lack of standard data needs, lack of data integration, and lack of standard procedures. Future research opportunities to address the challenges are proposed. This paper can help bridge O&M teams by identifying suitable data and applications to make informed decisions that align well with their needs meanwhile serve as a basis for future research efforts in this area.

Large-Scale Axial Fracture Experiments of High-Toughness Steel

Abstract Fracture resistance of modern bridge steels has improved through advances in material production techniques. The enhanced performance has been quantified through a number of material chara...

Stress-free-state based structural analysis and construction control theory for staged construction bridges

Structural analysis and construction control of staged construction process is a major subject for modern long-span bridges. This paper introduces the concept of stress-free-state variable of structural elements and deduces the mechanical equilibrium equations and geometric shape governing equations for staged construction structures utilizing the minimum potential energy theorem. As the core of stress-free-state theory, the two aforementioned equations demonstrate following principles, 1) when the stress-free-state variable of a structural element is set, the internal force and deformation of the element are unique at the completion state of the structure regardless of its construction process; 2) the stress-free length of a cable is independent of its external loads, change in stress-free length of the cable corresponds to a unique variation of the cable force when load is constant; and 3) the internal force of a structural element can be independent from its geometric shape within the completion state of a staged construction structure through an active manipulation of stress-free-state variables of the element. Stress-free-state theory establishes the stage-to-stage and stage-to-completion relationships for staged construction bridges, provides a direct and efficient method for theoretical calculations and a flexible and convenient approach for the control of staged construction, and makes parallel construction and auto-filtering of thermal and temporary loading effect possible.

Research on the Integration of Bridge Structure and Landscape Art Combined with Two-dimensional Computer Image

With the change of the public’s aesthetic concept, people’s requirements for the landscape and art of bridges are constantly improving. The connotation of bridge has developed from the original traffic architecture to the carrier of human landscape and historical culture. Therefore, integrating the concept of landscape art into bridge design is an important development direction in the field of bridge design. This paper expounds the connotation of landscape art in bridge design, and enumerates the typical application of the landscape art concept in bridge design. On this basis, this paper analyses the advantages of computer two-dimensional image technology for bridge landscape design, and discusses several aspects that should be improved in future bridge landscape design, which provides new thinking and reference for modern bridge design.