Search

Preflex beam girders with remarkable advantages are widely used in bridge structures. With aging, preflex beam bridges undergo concrete cracking and degrade as the cracks propagate and deteriorate due to repeated service load application and exposure to humid and saline environment. The objective of this study was to evaluate concrete cracking, changes in prestress, and consequent changes in sectional properties as the preflex beam undergoes deterioration in its concrete casing under cyclic loading. The experimental study investigated the behavior of a preflex beam specimen under multiple cyclic loading ranges, reproducing different deterioration levels in the concrete casing of the specimen. Relating concrete deterioration to resulting changes in the girder’s structural behavior, the study outlined recommendations for monitoring approaches in actual bridges. The study concluded that with advancement in concrete deterioration, the preflex beam girder loses prestress that results in reduced strength of the girder and remarkable changes in its sectional properties. The study also concluded to minimize prestress loss and changes in sectional properties of the girder, closer spacing for shear ribs welded to the lower flange can be helpful., 論文

Huge uncertainty exists in time dependent effects of deflection, especially for those concrete beam bridges in long-term service stage. The uncertainty has brought about great barriers to reliable assessment or reasonable prediction for the deflection. Most studies in this field focused on qualitative analysis rather than quantitative one. In order to realize the transformation from qualitative analysis to quantitative field of the uncertainty issue for bridge structure and expend the existing research, the Bayesian inference model was employed to conduct uncertainty quantification analysis based on the open-source database provided by Northwest University. The uncertainty coefficient was introduced to measure the differences between the test results and the theoretical ones for creep and shrinkage data. In the meantime, a surrogate model was proposed on deviation between long-term deflection for numerical value and experimental one, in which the former was calculated by ANSYS software and the latter was acquired by the in-door test on a simply supported beam, namely, Faber beam. After that, the uncertainty coefficient was introduced to update the model and the simulating process was performed again in which the corrected mean value of the posterior distribution was utilized. The results show that it narrows the error zone drastically, in which the relative reduction rate range from 49.83% to 82.76% for 95% lower confidence limit and from 11.46% to 98.73% for upper one. These outcomes prove the validity for the posterior distribution and also indicate that it could be a prospective way to improve the accuracy of the model significantly by utilizing the uncertainty coefficient. Besides, the method provided in this study could inspire the researchers who study in similar field and to do further exploration in the future.

Frequency variations are normally employed for damage detection as frequencies possess the advantages of the high accuracy and high anti-noise capability. However, the validity and applicability of such methods are restricted due to the limited order of frequencies. A damage localization and quantification approach is proposed for beam bridges by using the frequency variation of parked vehicle-bridge systems. Firstly, the phenomenon of frequency variation of parked vehicle-bridge systems is briefly illustrated. Secondly, a damage location index (DLI) is defined by the frequency change rate (FCR) of the vehicle-bridge systems with the vehicle parked at different positions before and after damage. Then the relationship between the frequency-parameter change rate (FPCR) and damage severity is established via finite element model (FEM) and further employed to formulate a damage equation(s) for severity estimation. The dimension of coefficient matrix in damage equations is reduced to large extent as the damage locations are determined by DLI in advance, which is meaningful in enhancing the effectiveness of severity estimation. Results of numerical and experimental examples with different damage scenarios indicate that the proposed approach can localize and quantify damages with high accuracy and efficiency by using frequency information only. The effects of measurement noise and FEM error are discussed to examine the robustness of the proposed approach. The cases when damage occurs in neighbor elements are analyzed to investigate the feasibility and robustness of the proposed approach.

Pounding may occur between the main girders under the action of strong earthquakes, so as between main girders and abutments. This causes excessive longitudinal displacement of the main girder and unseating damage to bridges. Because long bridges in mountainous areas with high intensity are easy to unseat, the authors studied the influence of restrainer piers, expansion joint spacings (EJSs), and the span on the seismic performance of long bridges. The ABAQUS finite element software was used to simulate a bridge dynamic analysis model considering the elastoplasticity of the pounding effect of the pier and the beam. By inputting El-Centro, Northbridge, and Taft seismic waves, the time-history analysis of the seismic response of long bridges was carried out. The results indicated that a reasonable number of restrainer piers, an appropriate EJS, and a span could effectively reduce the maximum relative displacement of pier-beams. This behavior will improve the seismic performance of bridge structures. Moreover, for a 24-span equal-height beam bridge, the optimum seismic effect was obtained when 3 restrainer piers, an EJS of 70 mm, and a 50 m span were used.

The bridges monitored within one cluster refer to several medium- and small-span beam bridges with the same or similar structural characteristics located in a local road network, and these bridges suffer the similar traffic and environmental loads. It is still little research on how to detect the damage of all bridges monitored within one cluster utilizing the above-mentioned characteristics of these bridges. To address this issue, a method is proposed for the damage cross-detection between bridges monitored within one cluster by using the difference ratio of projected strain monitoring data under time-varying environmental temperatures. First, a damage feature is established by using the difference ratio of projected strain monitoring data obtained from the same cross-section position of any two bridges monitored within one cluster that have similar or identical structural characteristics. On this basis, the relationship between the statistical characteristics of the proposed damage feature and the degree of structural similarity between two bridges are discussed in detail. Second, a damage detection index is presented by calculating the subspace angle between two damage features. Then, combined with kernel density estimation and a cross-validation strategy, the proposed index is implemented to detect the damage of all bridges monitored within one cluster. Finally, numerical simulation examples are utilized to analyse and discuss the application limitations, noise resistance performance and structural damage sensitivity of the proposed method. Moreover, the effectiveness of the proposed method is also demonstrated by using the strain monitoring data obtained from actual bridges monitored within one cluster.

The forms of U-shaped UHPFRC beams have not been investigated for the highway footbridge. Compared with the traditional section forms, the U-shaped UHPFRC beams can reduce the material consumption under the condition of providing the same bearing capacity. Furthermore, prestressed U-shaped UHPFRC beams are rarely reported in the existing research. This paper explores the flexural behavior of prestressed ultrahigh-performance fiber-reinforced concrete (UHPFRC) beam bridge having unique design and the material properties of prestressed reinforcement combined with UHPFRC. Based on the unique shape of the U beam, the flexural performance test of the full-scale model of the prestressed UHPFRC U beam is conducted. Then, the finite element model considering material nonlinearity and structural ductility is established using Midas FEA software. Finally, the failure mode, failure process, cracking moment, ultimate moment, and strain of the full-scale model are studied. The calculation formulas of the flexural capacity of UHPFRC U beam considering ductile failure are derived. The comparative analysis results show that the prestressed UHPFRC U beam has an excellent flexural performance. The bending failure of a U-shaped beam belongs to the group of ductile failures, which is characterized by the main crack along the central rib and the loading center, which is accompanied by multiple microcracks. The failure process can be divided into four stages: linear deformation, microcracks development, main cracks development, and bearing capacity decline. The incorporation of steel fiber and the interaction between UHPFRC and reinforcement can effectively reduce the development of cracks. The U-beam bending moment is 50–55% of the ultimate bending moment. In the UHPFRC bridge design, the deformation can be used as a control index, and material advantages of the UHPFRC can be used to a certain extent. The strain-hardening characteristics of the UHPFRC are obvious in the loading process. The finite element analysis results show that the maximum strain value appears at the central rib, followed by the transverse strain value of the bottom plate, while the minimum strain is the longitudinal strain value of the bottom plate. The deformation of the rib plate is the largest, and the strain of the other measuring points changes slowly. The farther away from the center the measurement point is, the slower its strain changes. Therefore, the load is mainly caused by the central rib and the loading center plate. With the increase in the deformation, the load on both sides continuously moves to the central rib along the plate surface. This study can provide a useful reference for theoretical analysis and design of prestressed U-UHPFRC bridges.

Bridges are the most vulnerable elements in regional transportation networks. Seismic fragility assessment has significant implications regarding the potential damage of regional bridges and their seismic maintenance operations. Unlike individual bridges, assessing bridges at the regional scale involves greater diversity and distinct ground motions. This paper proposes a Bayesian parameter estimation methodology to assess the seismic fragilities of regional beam bridges and schedule their maintenances. The proposed multi-parameter models contain several structural parameters and intensity measures to comprehensively consider the regional diversity. The selected intensity measures represent the diversity of regional ground motions at the peak effect, spectrum intensity, and the duration of strong motion. To demonstrate the applicability of the proposed methods, this paper analyzes the seismic damage results of 13,500 bridge-ground motion pairs generated to train the fragility models. Results of the proposed models are similar to the seismic fragility probability derived from Monte-Carlo simulation results. This study proposes a two-level strategy to effectively manage regional bridge maintenance. These priority maintenance and secondary maintenance levels are determined based on the results of regional seismic fragility analysis. Additionally, significant sequences of structural parameters and intensity measures are identified using the leave-one-attribute-out analysis method. This process helps bridge designers and managers better understand the sensitive parameters pertaining to different components. This study also tests the proposed models on a virtual transportation network to assess the seismic fragility of its associated regional bridges, resulting in a two-level regional maintenance plan for that specific system.

This paper presents a numerical study on the impact coefficient calculation of a straight-line π-shaped composite beam and a curved box girder beam. A numerical model of vehicle-bridge coupling system is established, where the random irregularity of bridge surface is considered in the model. The effect of lane numbers, bridge surface flatness, vehicle speed, vehicle weight and primary beam stiffness on the impact coefficient are considered. The results indicate that the lane numbers have certain influence on the impact coefficient; the impact coefficient presents nonlinear increment as the bridge surface flatness becomes from grade A to grade D; the vehicle-bridge coupling system can resonate at both low speed and high speed; the vehicle weight has little influence on the impact coefficient; whilst the displacement impact coefficient is decreased with an increment in the primary beam stiffness. Besides, the local and global impact coefficients, the displacement, moment and shear force impact coefficients are also comprehensively discussed.

Currently, the bearings of Poyanghu Bridge, a 636-meter long cable-stayed bridge, have been damaged. According to numerical analyses, the mechanical state of the damaged bridge unfavorably deviates from the ideal design state, and the bridge should be repaired in time to restore its safety and serviceability. However, compared with the bearing repair of beam bridges, much less scientific and engineering endeavors have been made in the history to direct the bearing repair of cable-stayed bridges. This article proposes two innovative bearing repair schemes for cable-stayed bridges and reports the numerical validations, the on-location applications, and the monitoring of the proposed repair schemes under the engineering backgxround of Poyanghu Bridge. Through these works, it is found that the proposed repair schemes are effective in practical use.

The article notes that the software of the complex used in the Russian troops to solve in a short time the actual problem of determining the possibility of safe passage of super heavy loads on girder road bridges has the following disadvantages: 1) it can only be used for split concrete bridges; 2) the decision to pass a large load through the bridge is made only by the value of the deflection in the center of the span, without taking into account the resulting stresses in the bridge span structure structures, and without taking into account the bearing capacity of the supports. In the article, in order to eliminate these shortcomings: 1) a strict formula is obtained for calculating the deflection in the middle of beam spans made of any structural materials from the angle of rotation of their support sections; 2) based on the use of the fundamental relationship between the relative heights of girder spans, the relative deformations of the edges of their cross sections and their relative deflections, it is proved that the maximum stresses in the edges of the cross sections of girder spans from any structural materials can be calculated by the maximum deflection value in the middle of their spans; 3) a method is established for determining the ability of beam bridge supports to ensure safe passage of a heavy vehicle by the nature of changing the rotation angles of the supporting cross sections of the span structures under the influence of the movement of the heavy vehicle layout. Taking these three results into account, when upgrading the software of the measurement system, ensures that the goal of the work is achieved.

This paper proposes a time-dependent probability method to predict the time-variant pounding risk, owing to this reason that the required separation gap width fails to accommodate the relative movement between two adjacent decks, of bridge systems subjected to non-stationary stochastic seismic excitations. Firstly the pseudo excitation method in random theory is utilized to transform the motion equation of system under the non-stationary stochastic seismic excitations into the transient response equation under deterministic external loads. And then the high precision direct integration method (HPDIM) is also employed to reduce the large number of transient analysis into two times for overcoming the challenges of strenuous computing effort. The time-dependent pounding system probability of bridges is derived by the combination of extreme value distribution theory and matrix-based system probability theory. Finally based on the proposed time-dependent probability method the numerical analysis of a real two span simply-supported beam bridge subjected to spatial and non-stationary ground motions is conducted herein for the pounding risk assessment. The results of this study provides in-depth insight into the time-dependent pounding probability of bridge systems subjected to spatially varying and non-stationary ground motions.

Summary Modeling and vibration control of a bridge beam system are considered in this article. The beam bridge with both ends fixed can be regarded as an Euler‐Bernoulli beam, which is a typical di...

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.

Filler beam bridge constructions with hot-rolled steel sections at close centres and filled with concrete meet all the requirements of small- and medium-span railway bridges. Filler beam bridges have thus been used for many years with considerable success, in particular where construction depth restrictions are relevant for the design. Moreover, they are perfectly suitable for use with high-speed railway lines. Since the late 1970s, various railway companies have established standard designs with guidelines, supplemented with calculation tables that correspond to their own rules. Some of these guidelines have become outdated with introduction of the Eurocodes. However, since on one hand there is growing interest in this type of construction and, on the other, a desire to evaluate large amounts of design data economically, there is a need for a calculation tool that enables quick, efficient and reliable designs. For this reason, new design tables for filler beam bridges in the German high-speed railway network up to 350 km/h have been developed, which enable a quick and direct evaluation of all relevant cross-sectional data of single-track single-span bridges in the span range 5–35 m without costly statics. The tables and the software, with which the tables were generated, are shown in this article.

Traditional statistical pattern identification methods, such as artificial neural network and support vector machine, have limited ability to identify minor damage of bridges. Deep learning can mine the inherent law and representation level of sample data. As a typical algorithm of deep learning, convolutional neural network is a feedforward neural network with deep structure and convolution calculation, and its ability of image identification is very outstanding. The recurrence graph of structural response can reveal the internal structure, similarity, and damage information. The original structure response signal involves the coupling vibration of vehicle and bridge is filtered and reconstructed by wavelet packet, and then the recurrence graph of different damage cases is obtained, which is used as the input image of convolutional neural network as a new type of damage feature; thus, a damage identification method based on convolutional neural network and recurrence graph is established. The results of numerical simulation and model experiment show that the recurrence graph contains more damage information; compared with the traditional statistical pattern identification methods, convolutional neural network can achieve more accurate feature extraction and identification through intelligent learning layer by layer, so as to realize more accurate identification of damage location and damage degree.

This paper considers a vibration control problem for a multi-span beam bridge under pier base vibrating excitation by using nonlinear quasi-zero stiffness (QZS) vibration isolators. Three linear springs are needed to construct a nonlinear vibration isolator with quasi-zero stiffness. The vibration of the multi-span beam bridge under control and without control is governed by partial differential equation and several ordinary differential equations which are derived from Galerkin method. Modal superposition method with numerical modes of the structure and an iterative method are combined to predict the vibration response of the structure under pier base excitation. The influence of the quasi-zero stiffness vibration isolators on isolation of multimodal vibration of beam bridge is studied. The absolute motion transmissibility is proposed to evaluate the performance of the quasi-zero stiffness vibration isolator and is compared with an equivalent linear viscoelastic vibration isolator. The results demonstrate the effectiveness of the these two potential control method as well as a good control performance in suppressing vibration for high frequencies. But at low frequencies, only the quasi-zero stiffness vibration isolator can reduce the vibration amplitude of the beam bridge around the resonance frequency region. The effects of each control parameter on the absolute motion transmissibility of steady-state behaviors are investigated for a better isolation performance.

Introduction. Studying the designing and constructing experience of beam bridges with composite log girders indicates the possibility of the load bearing capacity rising of the structures and their further usage in the IV and V categories bridges’ construction under A-11 and H-11 loads. The purpose of the research is to evaluate the effect on the magnitude and distribution of shear forces in shear bonds, considering the permissible pliability of fixation in wood and on the nature of the stress state change in the rods of the composite girders.Materials and methods. The authors presented the construction of the composite girder in the form of three rows united by means of tie bolts and gaskets of four-tier single-row composite girders and made of edged logs. The proposed studying method of a composite girder stress-strain state with discrete placement of concentrated shear bonds in the joints based on the classical method of forces for rod systems, taking into account the interaction of longitudinal forces and bending moments arising in the rods composing the girder of unknown forces in the shear bonds.Results. The determination of single displacements with joint account of bending and stretching-compression deformations haв a significant impact on the redistribution of shear forces in the direction of increasing them in the support zones and reducing them in the middle of the span, and, consequently, on the design of the connecting elements. The character of distribution of normal stresses on the stretching-compression indicated the rods’ girders between relationships under the eccentric compression (stretching).Discussion and conclusions. The proposed solutions demonstrate the most accurate assessment of the composite girders in the structures of spans wooden bridges and present the application possibility in modern conditions.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

In this study, vehicle-to-vehicle (V2V) radio channel measurements at 5.9 GHz were conducted on a suspension bridge and a beam bridge. Given that a different structure of the two bridges will result in different channel properties, the authors study small-scale and large-scale propagation characteristics for the bridge scenarios based on measurement data. By using Akaike's information criteria, the study determines optimal small-scale fading distribution. Owing to that Ricean distribution occupies the dominant position, Ricean K-factors in the two bridge scenarios are modelled separately and compared with each other. Afterwards, power delay profiles, Doppler power spectral densities, root-mean-square (RMS) delay spread and RMS Doppler spread are estimated and analysed in different cases. They employ bimodal Gaussian mixture distribution (BGMD) to model the RMS delay spreads and the RMS Doppler spreads. Fitting results of the BGMDs show good matching levels. For the large-scale propagation characteristics, path loss model for the beam bridge scenario is proposed based on the two-ray theory. On the other hand, path loss for the suspension bridge scenario is modelled by using an empirical function derived from WINNER II. Finally, grey relational grade–mean absolute percentage error, and RMS error criteria prove the effectiveness of the two proposed path loss models.

In this article the main frequency of vibration obtained in 31 spans of steel beam bridges are presented, and studied together with other 25 steel beam bridges vibration frequencies presented in previous studies. An equation that estimates the main period of vibration as a function of the span length of these bridges is presented. Additionally, matching of frequency of vibration in adjacent spans with different lengths was observed in some non-continuous-beam multi-span bridges; this phenomena is considered to be related to forced vibration in the shorter spans caused by the natural vibration of the longest spans. In addition, an equation to estimate an upper bound period of vibration as a reference to identify atypical bridges, whose vibration periods are considerably far from the trend., En este artículo se presenta la frecuencia de vibración principal de 31 luces de puentes de viga de acero, y se estudian en conjunto con la frecuencia de vibración de otras 25 luces de puentes de acero presentadas en estudios anteriores. Se presenta una ecuación que estima el período de vibración principal en función de la longitud de la luz estudiada. En algunos puentes se observó una sincronización de la frecuencia de vibración en tramos adyacentes (los cuales presentan diferentes longitudes entre ellos) en puentes de varias luces con vigas no continuas; se propone que este fenómeno está relacionado con la vibración forzada en los tramos más cortos, causada​ por la vibración natural de las luces adyacentes más largas. Además, una ecuación para estimar el período de vibración que se puede utilizar como límite superior, una referencia para identificar puentes atípicos, cuyos períodos de vibración son considerablemente mayores a la tendencia

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.

The reasons for the ever-increasing ship traffic and ship size are given, the site-dependent choice of high-level fixed bridges versus low-level movable bridges is discussed and the different types of movable bridges are described in general terms in an introduction. Next, one lift bridge, three swing bridges, and one bascule bridge are described in more detail, including older bridges that at the time of being designed and built had innovative, unique features. The examples comprise bridges in Brazil, Egypt, France, Germany, Iraq, Malaysia, Spain, and Turkey. At the end, a totally new type of bascule bridge is presented: the double balance beam bridge (DBBB). The design of movable bridges requires an uncommon and extremely demanding interaction between civil, mechanical, hydraulic and electric engineering; here we concentrate on the civil engineering aspects.

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.

The impact effect of vehicle loads is an important and challenging problem in bridge engineering. In the last few decades, experimental and numerical researches on this problem have been e...

A beam bridge is a bridge that uses struts as a method of supporting the deck. A bridge consists of three sections: the foundation consisting of protrusions and supports and the substructure consisting of protrusions and quay and the superstructure (bracing, cantilever or curve) and the deck. A beam bridge is probably the most manufactured and used bridge on the planet. Its basic plant, at its best, can be likened to a tree trunk extending to one side to alternate across a stream or river. All decks consist of two main parts: the substructure and the superstructure. The superstructure is everything from the support cushions to - it's the thing that supports the posts and it's the most distinctive part of the deck. The substructure is the device that exchanges the poles of the superstructure on the ground. The two sections must work together to form a strong and durable bridge. Prestressed concrete is basically concrete where the internal concern is reasonable and the pressure propagation created by the external load is concentrated to the desired extent. In this research, we analyze a beam bridge with the effect of prestressed concrete and compare it to a generic deck bridge. Regarding the finite element analysis, the analysis of forces and costs. Here it is concluded that the implementation of a prestressed ceiling results in an economical, stable and load-resistant element.

Stress is one of the most important physical indexes reflecting the mechanical behavior of concrete structures. In general, stress in structures cannot be directly monitored and can only be estimated through an established model of stress and strain. The accuracy of the estimated stress depends on the rationality of the established model for stress and strain. As the strain measured by sensors contains creep, shrinkage, and elastic strain, it is difficult to establish an analytical model for strain and stress. In this paper, a statistical inverse method was utilized to estimate the stress in continuously pre-stressed concrete beams based on the monitored strain. Stress in the beams and the model uncertainty factors were treated as model parameters. A linear-simplified method was adopted to determine the prior distribution of the stresses. The posterior distribution of the stresses at different locations during bridge construction can be obtained by the proposed method. A continuously pre-stressed concrete beam bridge was taken as the case study to verify the effectiveness of the proposed method. Additionally, the constitution of the total strain in the different construction stages was calculated. It was concluded that the creep strain is the dominant part of the total strain.

The functional and structural characteristics of civil engineering works, in particular bridges, influence the performance of transport infrastructure. Remote sensing technology and other advanced technologies could help bridge managers review structural conditions and deteriorations through bridge inspection. This paper proposes an artificial intelligence-based methodology to solve the condition assessment of regional bridges and optimize their maintenance schemes. It includes data integration, condition assessment, and maintenance optimization. Data from bridge inspection reports is the main source of this data-driven approach, which could provide a substantial amount og condition-related information to reveal the time-variant bridge condition deterioration and effect of maintenance behaviors. The regional bridge condition deterioration model is established by neural networks, and the impact of the maintenance scheme on the future condition of bridges is quantified. Given the need to manage limited resources and ensure safety and functionality, adequate maintenance schemes for regional bridges are optimized with genetic algorithms. The proposed data-driven methodology is applied to real regional highway bridges. The regional inspection information is obtained with the help of emerging technologies. The established structural deterioration models achieve up to 85% prediction accuracy. The obtained optimal maintenance schemes could be chosen according to actual structural conditions, maintenance requirements, and total budget. Data-driven decision support can substantially aid in smart and efficient maintenance planning of road bridges.

Based on the 16–32 m simply-supported beam bridge on Shanghai-Kunming high-speed railway, a collision model of CRTS II track system was established. The model considered the longitudinal, horizontal as well as vertical nonlinear constraints among structural layers, and the Kelvin element was used to simulate the pounding effect of the gaps. The seismic response of the CRTS II track system was firstly analyzed and then the influences of different cases of damaged track plate, base plate, and mortar layer were discussed. The study revealed that: (1) The rail, track plate, and base plate all bear large longitudinal force and their stress envelope curves are all anti-symmetric. (2) The broken track plates result in a sharp decrease in track plate stress and an extreme increase in rail stress and base plate stress near the gap. The broken base plates result in a sharp decrease in base plate stress and an extreme increase in rail stress and track plate stress near the gap. (3) Both the pounding frequency and pounding force between broken slabs are relatively large and will decrease after some time. (4) The broken slabs near ends of the first bridge span greatly increase the pounding force of stoppers close to the abutment. (5) The gap width has a huge influence on the pounding force and times of stoppers and gaps. (6) The debonding of mortar layer has a great influence on the vertical displacement of rail, track plate, and the base plate.

In this study, the seismic performance of a precast bridge substructure from an urban viaduct is investigated via shake table tests. A simple beam bridge is formed by using two precast bri...

China is shifting from the stage of large-scale bridge construction to the stage of equal emphasis on the construction and maintenance of bridges. The problems of low efficiency and high cost in bridge inspection are becoming more and more prominent, which threaten people’s life safety. In this paper, the deterioration state prediction model of concrete beam bridge under Boosting DT C5.0 was established as the basis, and optimization suggestions were put forward in terms of bridge inspection standards and processes, which aims to perfect the bridge inspection mechanism, realize the fine management of the bridge and prolong the service life of the bridge. Research shows that: first, the bridge inspection standard with a single index should be improved into the bridge inspection standard with multiple indexes, so as to scientifically determine the bridges that need to be inspected and optimize the allocation of maintenance resources. Second, the bridge deterioration state prediction model is used to add a screening mechanism for the bridge in the inspection plan, which can effectively reduce the workload of bridge inspection and enhance the inspection efficiency. Third, the deterioration phenomenon of coexistence between adjacent traffic assets should be fully considered and the linkage inspection mechanism of adjacent traffic assets should be established to improve the effect of bridge inspection.

Natural vibration characteristics serve as one of the crucial references for bridge monitoring. However, temperature-induced changes in the natural vibration characteristics of bridge structures may exceed the impact of structural damage, thus causing some interference in damage identification. This study analyzed the influence of temperature on the natural vibration characteristics of simply supported beams, which is the most widely used bridge structure. The theoretical formula for the variation of the natural frequency of simply supported beams with temperature was proposed. The elastic modulus of simply supported beams in the range of −40 °C to 60 °C was acquired by means of the falling ball test and the theoretical formula and was compared with the elastic modulus obtained by the three-point bending test at room temperature (20 °C). In addition, the Midas/Civil finite-element simulation was carried out for the natural frequency of simply supported beams at different temperatures. The results showed that temperature was the main factor causing the variation of the natural frequency of simply supported beams. The linear negative correlation between the natural frequency of simply supported beams and their temperature were observed. The natural frequency of simply supported beams decreased by 0.148% for every 1 °C increase. This research contributed to the further understanding of the natural vibration characteristics of simply supported beams under the influence of temperature so as to provide references for natural frequency monitoring and damage identification of beam bridges. Published version