Concrete Beam Bridge Research Articles

Analysis of Sunshine Temperature Field and Temperature Effect of Prestressed Concrete Beam Bridge

Temperature stress is one of the important causes of concrete structure cracking. In order to study the development law of temperature field and temperature effect of prestressed concrete beam bridge under sunshine load, taking the construction of a prestressed concrete beam bridge as an example, ADINA finite element software was used for solid simulation and compared with the measured value. The results show that the temperature curve of each point inside and outside the beam is consistent with that of the ambient temperature, but it has some hysteresis. The temperature stress distribution of the beam body calculated by using the temperature gradient in the current code is approximately the same as the measured value. The top and bottom plates are compressed, and the web plate produces large tensile stress.

Long‐term performance monitoring and assessment of concrete beam bridges using neutral axis indicator

Long-term performance of existing bridge structures provides stakeholders with information that facilitates decision making for reasonable and optimal maintenance and management. The neutral axis (NA) is a potentially reliable and robust indicator to evaluate bridge performance since it depends on the loss of elastic modulus or effective sectional area. In this study, the NA indicator is defined and derived, and it is combined with the statistical characteristics of the NA distribution, to assess long-term structural performance. A systematic long-term performance assessment framework based on NA is also proposed. The NA is estimated from strain measurements and related practical signal processing methods. To validate the proposed framework, strain signals acquired from a preinstalled structural health monitoring system on an existing concrete beam bridge were analyzed. For the long-term performance assessment, an NA database was established. The statistical characteristics of the NA sample in the daily evaluation cycle were obtained to evaluate the performance. The results show that different cross sections have their own estimated NA; and during the monitoring period, the NA indicators fluctuate within a reasonable range. With the increase of monitoring data, these results can be continually updated. It can be concluded that the proposed NA indicator, along with the related framework, can be employed effectively in the condition assessment of concrete box girder bridges for long-term health monitoring.

Nonlinear oscillations of a prestressed concrete bridge beam subjected to harmonic perturbation in the conditions of indeterminacy of parameters

This paper deals with the nonlinear oscillations of a prestressed reinforced concrete beam firmly attached to two supports. The beam is subjected to a harmonic force. The calculations of such beams are associated with a number of uncertainties in the initial data. This publication is devoted to questions of their correct accounting. For a long period of time in mechanics, to tack into account some uncertainties, they have been using the probability theory for modeling and such theory dominates. It have been proven that the probability theory can solve a lot of problems but nevertheless it has some weaknesses. In particular, the lack of statistical information or incomplete information does not adequately reflect the real object of study in a mathematical model. Recently, many researchers have noted that the uncertainty in construction is not only stochastic in nature, and this provides an impetus for the introduction of new developing methods and theories of soft computing. Among them, theories of fuzzy and rough sets, the reliability of which has already been proven in solving control problems, etc. They are the most popular and effective theories now. For the beam under consideration, the amplitude of beam oscillations is determined, provided that its parameters are indeterminate (fuzzy) and vary within certain limits. An example of determining the amplitude of the oscillation of the 33-meter-long prestressed beam designed by Soyuzdorproekt is studied. The membership function for the amplitude of the beam transverse oscillations using the theory of fuzzy numbers is constructed. The influence analysis of the fuzziness of the disturbance frequency value on the amplitude of oscillations is performed. It has been revealed that even a small indeterminacy in the frequency setting can cause the beam damage, although there will not yet be any damage when setting the accurate frequency. Thus for the value , the corresponding value of the right endpoint of the amplitude interval exceeds the maximum acceptable value of 0.076 m, although the modal value of the amplitude does not exceed the acceptable value. Therefore, when calculating the amplitude of structural oscillations, the interval endpoints of the frequency variation should be taken into account, and not its modal value. Analysis of the table shows that further increase in the oscillations frequency leads to resonance, because it moves beyond the acceptable limits both the endpoints of the interval of undetermined amplitude, and the modal value.

Management Path of Concrete Beam Bridge in China from the Perspective of Sustainable Development

More and more bridges have entered the maintenance stage, which has potential collapse hazards and threatens life and property safety. More attention has been paid to the improvement of maintenance management levels during the operation period in terms of extending the service life of the bridge, but less attention has been paid to it from the perspective of the whole life cycle. One hundred and ninety examples of concrete beam bridges in China were collected, based on which the collapse characteristics and collapse causes of concrete beam bridges were analyzed. The causes of bridge collapse come from all stages of bridge life cycle, including environmental factors and human factors. Moreover, the effects of the previous phase carry over to the next. Superficially, poor maintenance management during an operation led to bridge collapse. However, the root cause may have occurred at an earlier stage. On this basis, a fuzzy interpretation structure model (FISM) for concrete beam bridge deterioration is conducted. The model can decompose the complex and messy relationship among the factors of bridge collapse into a clear, multi–level and hierarchical structure. Compared with qualitative analysis, an ISM chart can directly reflect the relationship between collapse factors, which is convenient for further analysis. Poor maintenance management during operation is the direct cause, while improper planning, imperfect standards and weak supervision in the early stage are the fundamental causes. Finally, in order to improve the sustainability of concrete beam bridges scientifically, management suggestions are put forward for the participants involved in each stage of the bridge’s life cycle.

Posttensioned Concrete Bridge Beams Exposed to Hydrocarbon Fire

AbstractThis paper presents the experimental and numerical investigations of two types of bonded posttensioned concrete bridge beams under hydrocarbon fire, including the box and tee beams. The fac...

Damage identification method of prestressed concrete beam bridge based on convolutional neural network

Bridges play an important role in transportation, but because of overload and natural factors, bridges will inevitably be damaged, which will affect traffic and even lead to major accidents. Therefore, timely and accurate identification of bridge damage is extremely necessary. Because of the great danger of manual detection, in order to identify the damage of prestressed concrete girder bridge safely, conveniently and accurately, this paper proposes a method of damage identification of prestressed concrete girder bridge based on convolutional neural network, which realizes the intelligent identification of bridge damage. Firstly, the damage identification method based on the flexibility matrix is introduced, and the flexibility diagonal curvature index constructed by the diagonal element of flexibility matrix is introduced. Secondly, the basic principle of applying convolutional neural network to bridge damage identification is elaborated. Finally, combined with the flexibility curvature method and the convolutional neural network, the flexibility of the structure is selected as the input of the convolutional neural network to realize the bridge damage identification. Through simulation, it is found that the use of convolutional neural network for the bridge identification is feasible, and combined with the flexibility curvature method, it can well identify the damage location and damage degree of prestressed concrete beam bridge structure.

Durability Evaluation Method of Reinforced Concrete Beam Bridge Based on Extension Interval Number Theory

In this paper, a method for evaluating the durability of reinforced concrete simple supported beam bridge was proposed based on the extension interval number theory and analytic hierarchy process. Firstly, the multi-layer durability evaluation model of simply supported beam bridge is established, which includes sub index layer, index layer, project layer and target layer. Then, the interval number of extension theory is used to replace the number of points to construct the judgment matrix in the model, which solves the fuzzy and uncertainty problems of the traditional AHP expert experience judgment. Due to the uncertainty of the factors affecting the bridge, the normal correlation function is constructed, and the correlation degree of each evaluation element to each grade is used as the basis for the quantitative evaluation of the bridge. Each layer is evaluated based on the results of the following assessment. The bridge durability can be obtained through the level by level evaluation. Finally, an example of a beam in Chao-yang bridge is used to illustrate the method and process of evaluation. The results are reliable and applicable. The assessment process proved that the method presented here is an effective one to solve the paradox in bridge evaluation, where qualitative and quantitative coexistence takes place.

Construction monitoring analysis on concrete continuous beams across Hanyi Expressway

The Han-Yi high-speed railway bridge is a concrete continuous beam bridge, of which the Han-Yi expressway on the upper span is a (40 + 64 + 40) m two-line continuous beam, and the crossing distance between the center of the left line and the highway is DK1254 + 228.63. The intersection angle is 85 degrees. In order to ensure that the bridge closes smoothly, this article uses the finite element software Midas / Civil to build a finite element model, adopts a cyclic feedback construction monitoring scheme, and implements the control of the cross-section stress and deflection of the main beam in real-time during construction and feedback. In the whole construction process, the main beam elevation and stress are used as the main control indicators. The elevation mainly controls the line shape to ensure that the final bridge line shape and the design line shape are consistent; the stress is mainly found in a timely manner through the regular monitoring and analysis of abnormal conditions that may exist in the construction, and early warning is provided to ensure construction safety.

Possible scope of filler beam bridges on the Russian Railways

One of the most stable trends is the use of multi-component solutions in the practice of bridge construction, one of which is the use of rigid reinforcement elements in bridge girders and decks. The purpose of this work is to assess the possibility of using filler bridge girders on the Russian railway network and determine the scope of their effective application. In the course of the study, the analysis of design solutions was carried out taking into account foreign experience in design and operation and the study of relevant regulatory documents. Also in the course of the work, a comparison of the cost indicators of rigid-reinforced girders and the existing standard projects of the reinforced concrete and steel simple beam bridges was performed. The results of the study are presented by the formed list of the main advantages and disadvantages of girders with rigid reinforcement and the definition of the area of their most effective application. The practical significance of the work is because steel-concrete girders with rigid reinforcement are the most effective solution for the short span bridges up to 15 meters length from both technical, operational and economic sides. The proposed solution allows reducing the resource intensity of the construction and labor costs for its construction and maintenance.

Influence of Chloride Ion Corrosion on the Performance of Reinforced Concrete Beam Bridge in Offshore Environ ment

Influence of Chloride Ion Corrosion on the Performance of Reinforced Concrete Beam Bridge in Offshore Environ ment

Assessment of Existing Bridge’s Beam Bending Stiffness Using Crack Characteristics

At present, the bearing capacity evaluation is mainly based on load detection, which requires closed traffic and has certain risks. With the increase of service time, the cracks of reinforced concrete beam bridge will gradually develop and the stiffness will reduce, resulting in the decrease of bearing capacity. Therefore, in this paper, the calculation of stiffness reduction coefficient by using crack characteristic parameters, which provides basic data for bearing capacity evaluation, has been studied. In this paper, using regression analysis through fracture characteristics of four model beam observation and test load-displacement curve characteristic parameters, crack flexural rigidity of the beam bridge relationship has been set up. The qualitative assessment based appearance of cracks in the structure of checks has been converted to quantitative assessment. And compared with the test results of a real bridge, comparative results show that the assessment is objective and reliable. It makes the assessment more objective and scientific. A new way of Quantitative assessment of the structural performance has been provided for a large number of existing reinforced concrete beam bridge.

Experimental Study on the System Performance of Adjacent Precast Concrete Box Beam Bridges

Analyses of catastrophic collapse of some adjacent precast concrete box beam bridges reveal the fact that the hinge joints between the adjacent beams were not sufficiently designed. The joint failure caused by deterioration is the result of system reliability deficiency of this type of bridges. To understand the system performance of the bridges, the redundancy and robustness of a bridge model with a scale of 1 ∶ 2, based on the prototype design drawings for 10‐meter adjacent box beam bridges in China, were assessed through a system safety evaluation procedure. The result confirmed the assumption that the redundancy and robustness of certain adjacent precast concrete beam bridges did not meet the pertinent requirements proposed in National Cooperative Highway Research Program (NCHRP) reports 406, 458, and 776 as a result of hinge joint failure. To address the current design deficiencies, a system factor is recommended in this paper to calculate the nominal resistance that reflects the level of redundancy of this type of bridges. In addition, a new framework is proposed to address the particular structural feature and topology of adjacent precast concrete beam bridges for the assessment of structural redundancy and robustness, which can reduce the computation complexity compared to existing approaches. The full‐range load test performed in this research verified the previous research results on bridge system safety that were mainly based on theoretical analysis and simulations.

Thermo‐Hydro‐Mechanical Combined Effect Analysis Model for Early‐Age Concrete Bridges and Its Application

The early cracking of concrete beam bridges remains a concern in civil engineering. An analytical model considering the combined effect of thermo‐hydro‐mechanical processes forms the basis for assessing the cracking risk of girders during construction. Based on the equivalent hydration theory, the temperature and moisture conduction processes and the evolution of the mechanical properties of concrete were modeled as a function of the equivalent age. A coupling model for the temperature and moisture fields was established, and a theoretical framework for analyzing the thermo‐hydro‐mechanical combined effect was presented. Based on this, a numerical analysis method was proposed and implemented into ABAQUS; the results were validated with some typical tests. Finally, a long‐span prestressed concrete (PC) box girder bridge with balanced cantilever construction was taken as an example, and the causes of web cracking and its impact degree were analyzed. The results show that the rate of moisture conduction is significantly lower than the rate of temperature conduction; even for thin‐walled components, there exists a significant humidity gradient on the surface layer. The humidity‐induced shrinkage and restraint of the precast members are the main causes of web cracking.

Carrying capacity of reinforced concrete beams of the compound cross-section of the span structures of bridges, extended by the paving slab

Problem. Experimental studies of load-carrying capacity of full-scale reinforced concrete bridge beams of typical 56 type project are described. The beams were dismantled from the existing bridge after 40 years of its operation and combined with fragments of precast-monolithic and precast ribbed paving slab, were used during the reconstruction of the old span structures for widening and simultaneous strengthening of their beams by way of extending the transverse section from above. Goal. Three prototypes of full-length reinforced concrete bridge beams with a total length of 14,06 m were tested, which had a folded cross-section, including a tare section of an existing beam of 0,85 m high and a fragment of a ribbed precast or precast monolithic plate, extended from above for joint work. Thus, the total height of the folded section of the reinforced prototype beams was 1,27…1,29 m. Methodology. The technique of testing the beams of the composite section was to obtain the maximum number of experimental data on a limited number of prototypes, in particular their carrying capacity for normal and inclined cross-sections. For this purpose, during the tests, different schemes of their loading with one or two concentrated forces were created for obtaining different types of destruction on the same prototype – by bending moment and transverse force. Originality. Therefore, the load-carrying capacity of the test beams in both normal and inclined cross-sections were studied. The main purpose of these studies is to evaluate the impact of the inclusion in the joint work with the existing beams of ribbed paving slab on the increase of their carrying capacity both in zonal moment and in transverse force compared with the carrying capacity of the only existing beams. Results and practical value. As the main result of the research, it was found that after the inclusion in the joint work of the ribbed paving slab the carrying capacity of normal and inclined cross-sections increased by 1,55-1,65 times, which is sufficient to provide load capacity of the expanded paving slab of bridge structures.

Topological and Size Optimization of RC Beam Bridges: An Automated Design Approach for Cost Effective and Environmental Friendly Solutions

Abstract This work presents a procedure for the automated design and optimization of reinforced concrete beam bridges. The aim is to find solutions that minimize the investment cost and the environmental impact of the bridge. The complete structure is optimized including: number of spans, pier locations, pier-deck connections and deck dimensions. A detailed design of the deck reinforcement is included as well. Furthermore, constructability is considered and quantified within the investment cost to avoid a merely theoretical optimization. Genetic Algorithm (GA) and Pattern Search (PS) optimization algorithms are used. To reduce the computational time and make the procedure more user-friendly, a memory system is integrated and a modified version of GA is developed. In this paper, the proposed procedure is applied to re-design an existing bridge originally designed according to Eurocodes by an experienced engineer in 2013. Savings of 10-15% for both investment cost and environmental impact have been obtained. Finally, the proposed procedure has been applied to several alternatives with different total bridge lengths to suggest the optimal number of spans for a given total bridge length.

Research on the material properties of prestressed concrete girder bridge after exposed to fire

The factors such as maximum temperature, duration, diffusion condition and concrete bursting at high temperature increase the difficulty of obtaining material properties by using temperature. In order to quickly obtain the real performance parameters of the materials of the pre-stressed concrete beam bridge in the post-disaster bridge evaluation, the appearance classification and material test of 32 hollow slabs demolished after the fire of the existing beam bridge in a highway were carried out. The relationship between the commonly used testing indexes and the properties of materials is obtained by measuring the properties of materials after fire. The applicability of these indexes is verified by the ultimate bearing capacity test and finite element simulation. The results show cracking and spalling of concrete at high temperature not only results in significant loss of section, but also significantly reduces the strength of concrete and prestressing steel strand in this area, which leads to the reduction of bearing capacity. When the spalling depth of concrete exceeds 2/3 of the net protective layer of steel strand after overfire, the reduction coefficient of compressive strength and tensile strength of pre-stressed steel wire reaches 0.7, which will seriously affect the ultimate bearing capacity. The normal plain round steel bar can be deviated safely to the design standard value when calculating the ultimate bearing capacity of the structure. The ultimate bearing capacity of the prestressed hollow beam after fire is analyzed by using the reduction relationship between the conventional inspection indexes and the material properties, and the finite element simulation, so as to meet the engineering precision.

Developing A Semi-Markov Process Model for Bridge Deterioration Prediction in Shanghai

The performance of urban bridges will deteriorate gradually throughout service life. Bridge deterioration prediction is essential for bridge management, especially for maintenance planning and decision-making. By considering the time-dependent reliability in the bridge deterioration process, a Weibull distribution based semi-Markov process model for urban bridge deterioration prediction was proposed in this paper. Historical inspection records stored in the Bridge Manage System (BMS) database in Shanghai since 2004 were investigated. The Weibull distribution was used to characterize the bridge deterioration behavior within each condition rating (CR), and the semi-Markov process was used to calculate the bridge transition probabilities between adjacent CRs. After that, the service life expectancy of urban bridges, the transition probabilities of the deck system and the substructure, and the future CR proportion change caused by deterioration was predicted. The prediction results indicate that the life expectancy of concrete beam bridges is about 77 years. The decay rate of the deck system is the fastest among three major parts, and the substructure has a much longer life expectancy. It suggests that the overall prediction accuracy of the semi-Markov model in network-level is better than the regression analysis method. Furthermore, the proportion of bridges in intact condition will gradually decrease in the next few decades, while the percentage of bridges in the qualified and bad state will increase rapidly. The prediction results show a good agreement with the actual deterioration trend of the urban bridges in Shanghai. In order to alleviate the pressure of bridge maintenance in the future, it is necessary to adopt a more targeted preventive maintenance strategy.

Experience of application of the measuring complex «Measurement System for testing permanent bridges» to determine the possibility of passing on permanent bridges of superheavy loads

The article presents the experience of using the measuring complex SI-PPM 15N1955 to determine the possibility of passing on permanent bridges of superheavy loads used by military engineers. The first part of the article substantiates the need to examine a large number of bridges of various designs on the routes of exit and maneuver of the troops, which in turn puts before the engineering service of associations and connections serious tasks to determine the load capacity of artificial structures on roads. In the 2000s, specialists of the Military engineering Academy and the Moscow Institute of heat engineering developed a unified method for determining the bearing capacity of reinforced concrete beam bridges, which was implemented by STC «Technical diagnostics and precision measurements» in a portable measurement system to check the permanent bridges SI-PPM 15N1955. The basis for the creation of SI-PPM is the calculation and experimental method of operational (on-site testing) determination of the state of the load-bearing structures of permanent bridges, using multi-channel measurements of angular and corresponding vertical movements of various sections of the main beams of superstructures from the impact of mobile test load. Unlike traditional methods of measuring deflections unacceptable in complexity and time of the survey of permanent bridges for the passage of modern missile systems. The main part of the article describes the measurement system. The bearing capacity of a particular bridge span is determined in the calculation program «Bridge» (the structure is presented in the article), which is part of the system. To determine the possibility of skipping the unit for a specific span of the bridge, the calculation program uses the angles of rotation of the main beams of the bridge near the supports from the impact of the mobile test load on the span, the arrangement of the wheels and the weight on the axes for the test load and the unit as the initial data. To learn how to operate the measuring system SI-MRP developed program simulator.

CONDITION ASSESSMENT OF RC BRIDGES. INTEGRATING MACHINE LEARNING, PHOTOGRAMMETRY AND BIM

Abstract. The survey of building pathologies is focused on reading the state of conservation of the building, composed by the survey of constructive and decorative details, the masonry layering, the crack pattern, the degradation and the color recognition. The drawing of these representations is a time-consuming task, accomplished by manual work by skilled operators who often rely on in-situ analysis and on pictures. In this project three-dimensional an automated method for the condition survey of reinforced concrete spalling has been developed. To realize the automated image-based survey it has been exploited the Mask R-CNN neural network. The training phase has been executed over the original model, providing new examples of images with concrete cover detachments. At the same time, a photogrammetry process involved the images, in order to obtain a point cloud which acts as a reference to a Scan to BIM process. The BIM environment serves as a collector of information, as it owns the ontology to recreate entities and relationships. The information as extracted by neural network and photogrammetry serve to create the pictures which depict the concrete spalling in the BIM environment. A process of projecting information from the images to the BIM recreates the shapes of the pathology on the objects of the model, which becomes a decision support system for the built environment. A case study of a concrete beam bridge in northern Italy demonstrates the validity of the process.

Cracking of the End Diaphragm of a Post-tensioned Beam Bridge

Abstract In concrete beam bridges, the end diaphragm at the end of the bridge is a common structural component that connects the main beams and transfers the beam loads to the bridge bearings. In integral bridges the end diaphragm also retains the soil of embankments due to the absence of abutments. Cracking of the front surface on the end diaphragm has been detected in post-tensioned beam bridges in Finland and Sweden. Presumably the post-tensioning of the bridge and the shaping and detailing of the connection of the end diaphragm and main beam have an effect on cracking tendency. The aim of this study is to examine the structural behaviour and the cracking potential of end diaphragms using linear analysis of the post-tensioned bridge and to find measures to prevent the cracking. The observations collected through field surveys are compared to results of linear FE analysis to clarify the cause of the cracking. The verification of model is performed by comparison of patterns of cracking observed in field surveys and the distribution of maximum tensile stresses in the FE model. With model variations, the effectiveness of measures for the prevention of cracking are observed.