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The frequently conventional assumption that bridge temperature is uniformly distributed on long-span bridges could lead to uncertainty when analyzing temperature effects. This study investigated the surface temperature of steel box girders on a long-span suspension bridge, emphasizing the distribution characteristics in the longitudinal (spanwise) direction. The girder surface temperature distribution was monitored using the long-term structural health monitoring system (SHMS). First, the probability density functions (PDF) of the girder surface temperature were analyzed. The results showed that the PDFs had bimodal characteristics and could be well-fitted using the weighted superposition of two normal distributions. Meanwhile, there was an obvious difference between the PDFs of the measuring points at different longitudinal sections of the bridge, which is inconsistent with the assumption that the temperature was uniformly distributed in the longitudinal direction. Subsequently, the longitudinal distributions of the girder surface temperature were statistically analyzed, and polynomial functions were introduced to fit the distribution curves along the left and right sides of the mid-span. A correlation analysis was then performed, highlighting the variability in temperature in the longitudinal direction. Additionally, the longitudinal temperature distribution pattern could be summarized as (i) the highest in the mid-span, the lowest in the tower, and increasing along the side span; (ii) there were also significant differences between the left and right sides of the mid-span. Finally, the time- and space- distributions of the temperature were studied, and a contour map was displayed. The results showed that the girder surface temperature had significant three-dimensional spatial characteristics and was not only non-uniformly distributed in space but also in time. This work is useful for a more accurate analysis of temperature effects on long-span bridges.

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

Curved pedestrian bridges are important urban infrastructure with the desired adaptability to the landscape constraints and with aesthetic benefits. Pedestrian bridges feature thin cross-sections, which provide sufficient load capacities but lead to low natural frequencies that make the bridges susceptible to vibration under pedestrian excitation. This study investigates the lateral vibration of a curved bridge with a small radius down to 20 m, proposes an approach to mitigate the lateral vibration of bridges with large curvatures using distributed multiple tuned mass dampers (MTMD), and conducts in-situ bridge tests to evaluate the vibration mitigation performance. The lateral vibration was investigated through in-situ tests and finite element analysis as well as the code requirements. The key parameters of the distributed MTMD system were improved by strategically selecting the mass ratio, bandwidth, center frequency ratio, and damper number. The results showed that the curved bridge was subjected to significant lateral vibration due to the coupling of torque and moment, and the recommended design parameters for the studied bridge were derived, i.e., the total mass ratio is 0.02, bandwidth is 0.15, center frequency ratio is 1.0, and damper number is 3. The proposed approach effectively improves the deployment of MTMD for lateral vibration control of the curved bridge. The field tests showed that the vibration was reduced by up to 82% by using the proposed approach. [ABSTRACT FROM AUTHOR]

Qingshan Yangtze River Bridge is a cable-stayed bridge with a main span of 938 m, which is the fifth largest cable-stayed bridge in the world. In order to cope with challenges such as long span, wide bridge deck and heavy load, the girder of the main span adopts integral steel box girders, while the side span adopts steel box-concrete composite girders. The interface of the two types of structure is located on the middle span, 18 m to the bridge tower. The main girder is 4.5 m in height and 48 m in width. The main tower is an A-shaped concrete tower with a height of 279.5 m. The stay cables are arranged in a fan shape. The main girder section near the tower is supported by No.0 cable instead of a lower beam to achieve an optimum architectural effect. The foundation of the main tower adopts a rotary bored concrete pile. The bridge adopts a fully floating structure system. A restraint system of viscous damper + limit block is adopted in the longitudinal direction, while a system of separated c-section steel dampers with shear clip tenon + vibration reduction and wind resistant supports are adopted as horizontal restraints. [ABSTRACT FROM AUTHOR]

The shear lag effect of the steel box girder section in a self-anchored suspension bridge was investigated in this study. Finite element analysis software Midas Civil was used to discretize the girder under analysis into space plate elements and establish a plate element model. The law of shear lag in the longitudinal direction of the girder in the construction and completion stages was determined accordingly. The shear lag coefficient appears to change suddenly near the side support, middle support, side cable anchorage area, and near the bridge tower support of the steel box girder under the imposed load. The most severe shear lag effect is located near the side support and near the side cable anchorage area. Steel box girder sections are simulated before and after system conversion to analyze the shear lag coefficient in the bridge construction stage. The results show that the shear lag coefficient markedly differs before versus after system conversion due to the different stress mechanisms. The finite element analysis results were validated by comparison with the results of an analysis via analogous rod method.

This paper proposes an autonomous inspection method for steel box girders that uses a wall-climbing robot instead of human workers. According to the 3D operating environment inside the steel box girder, the method proposes a 3D path for the robot to traverse positions to be inspected. The path comprises two alternate sections of the lane's centerline and U-shaped steering. To realize the robot's tracking of the desired path, kinematics analysis based on different poses during the inspection was carried out. Corresponding path tracking algorithms were adopted to ensure that the robot moves accurately and efficiently. In addition, for the smooth transition of the two path sections, this method adopts an algorithm of cooperatively controlling the lifting mechanism and the wheel speeds to achieve stable crossing of a 90° concave corner. Finally, experiment results show that the robot can steadily cross 90° concave corner and can steer to the adjacent lane and complete lane inspection along the desired path. The method can realize autonomous inspection for steel box girders using the wall-climbing robot. [ABSTRACT FROM AUTHOR]

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

This paper mainly explores the distribution of welding residual stress of U-rib stiffened plates of steel box girders and examines the influence of welding residual stress over the natural frequencies of these plates. The research focuses on two aspects, namely, the distribution of welding residual stress, and the dynamic behavior of U-rib stiffened plates in the context of that distribution. Firstly, we build two finite element models to analyses the welding process and study the dynamic behavior. Next, the authors discussed how different geometric parameters, as well as welding parameters, affect the residual stress distribution. In addition, the welding residual stress curves were fitted for steel box girders of varied sizes, and a simplified formula was deduced for the distribution of welding residual stress. After that, the simplified formula was applied to analyze the natural frequencies of stiffened plates in multiple sets of models. Through the analysis of natural frequency under different boundary conditions, it was learned that the welding residual stress has a remarkable influence on the natural frequencies of stiffened plates.

In order to obtain the characteristics of train winds and wind-induced bridge vibrations during the under-passing of high-speed trains, a fly-over steel box girder cable-stayed bridge with a single tower and no back cable is selected as the background engineering. The CFD simulation is used to analyze the train wind loads applied on different panels of the steel box girder. Furthermore, the bridge dynamic analysis models are built to explore wind-induced vibrations in the construction and operation stages. Results show that the surface wind pressures applied on the flange plate, web and bottom plate of the steel box girder exhibit obvious "head wave" and "tail wave" characteristics due to the under-passing of high-speed trains. With the increase of train-bridge distance and the distance to track centerline, the extreme wind pressures decrease continuously, and the attenuation rates at the bottom plate and the web are faster than that at the flange plate. At the location that is 20 m away from the track centerline, the lift force, drag force and torque force applied on the steel box girder are about 28%, 23% and 11% of those at the track centerline. When the train speed is 350 km/h and the distance between track surface and bridge bottom is 7. 25 m, the maximal displacement and acceleration at the beam-end are 9. 89 mm and 164. 58 mm/s² respectively before the bridge closure; while during the operation stage, the maximal displacement and acceleration at mid-span are 3.24 mm and 91. 95 mm/s² respectively. [ABSTRACT FROM AUTHOR]

Zhengzhou - Ji'nan High-speed Railway crosses the Beijing - Shanghai High-speed Railway, Tianjin - Pukou Railway and Shuitun - Baimashan Railway near Ji'nan, and it is in a three-level interchange structure. It is necessary to study the structural form, structure and construction plan of the site in order to prevent the impact of the construction of the newly-built Zhengzhou-Ji'nan High-speed Railway on the existing high-speed railway and other railway lines below. Based on the conditions of the construction site, the comparison and selection of bridge schemes, bridge deck structure forms and construction schemes are carried out, and the research and application results of the weathering steel at home and abroad are summarized. It is determined that this work site adopts coating-free weathering steel box girder and UHPC+orthogonal special-shaped plate bridge deck structure, and detailed requirements for weathering steel, rust stability, waterproof and drainage design, and maintenance are proposed. This scheme has the advantages of low weight, low impact on existing railways, fast construction speed, good durability and less post-maintenance. It is one of the competitive bridge types for new railways to cross over existing lines. [ABSTRACT FROM AUTHOR]

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

Uneven temperature distribution in a structural element constitutes one of its load factors. Temperature fields occurring in structural elements lead to stresses and strains. The values of internal stresses are directly related to temperature distribution and degree of freedom for element deformation. The best way to get information about temperature distribution in an element is to take measurements on a real object. Such measurements have been run or are still taken over decades in various parts of the world, e.g. in Western Europe, USA, China, South America. In a number of cases, such examinations were carried out for objects constructed in warm or hot climate. It is a lot harder to find the results of measurements made in the countries with moderate and transitional climate, like in the Central or East-Central Europe. This paper presents measurement methodology and results gained for a large steel bridge located in the East European Plain, about 52.5° N northern latitude. Permanently installed contact sensors, temporary sensors, as well as pyrometry and thermography were used. An attempt was made to determine temperature distribution in a steel box girder of a bridge using thermovision technique. Approximate temperature distribution patterns in the main span girder were determined from thermal photographs taken. The most important results of examinations are the images of temperature fields in the main span girder related to solar radiation that first and foremost directly affects the bridge deck.

Metal magnetic memory testing (MMMT) is a nondestructive testing technique that can detect early signs of damage in components. Many scholars have studied the effect of uniaxial stress on the self-magnetic-leakage field (SMLF)’s strength. Nevertheless, there is still insufficient research on the combined action of bending and shear. We studied the law of distribution of the magnetic signal, ΔHSF(y), at different stress parts of a steel box girder and the quantitative relationship between the magnetic characteristic parameters and the external load. The results showed that the MMMT could accurately detect the early stress concentration zone (SCZ) and predict the final buckling zone of steel box girders. It could be judged that the corresponding parts of the steel box girder had entered the elastic-plastic working stage by the reverse change of the ΔHSF(y)-F and |HSF(y)|a -F curve trends, this feature could be used as an early warning sign before the steel box girder was deformed or destroyed. The fitted |HSF(y)|ave -F linear expression could be used as the expression between the magnetic signal and the shear capacity. All the evaluation methods were expected to provide a basis for effectively evaluating the stress state of steel box girders with the MMMT method.

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

Curved pedestrian bridges are important urban infrastructure with the desired adaptability to the landscape constraints and with aesthetic benefits. Pedestrian bridges feature thin cross-sections, which provide sufficient load capacities but lead to low natural frequencies that make the bridges susceptible to vibration under pedestrian excitation. This study investigates the lateral vibration of a curved bridge with a small radius down to 20 m, proposes an approach to mitigate the lateral vibration of bridges with large curvatures using distributed multiple tuned mass dampers (MTMD), and conducts in-situ bridge tests to evaluate the vibration mitigation performance. The lateral vibration was investigated through in-situ tests and finite element analysis as well as the code requirements. The key parameters of the distributed MTMD system were improved by strategically selecting the mass ratio, bandwidth, center frequency ratio, and damper number. The results showed that the curved bridge was subjected to significant lateral vibration due to the coupling of torque and moment, and the recommended design parameters for the studied bridge were derived, i.e., the total mass ratio is 0.02, bandwidth is 0.15, center frequency ratio is 1.0, and damper number is 3. The proposed approach effectively improves the deployment of MTMD for lateral vibration control of the curved bridge. The field tests showed that the vibration was reduced by up to 82% by using the proposed approach.

A novel copula-based probabilistic model is proposed to establish the temperature difference analysis model for a long-span suspension bridge's steel box girder. The key idea is to express a two-dimensional function of the temperature difference in flat steel box girder by using copulas. The maximum and minimum values of daily temperature difference model was developed using long-terms structural health monitoring data. Then, the correlation between adjacent temperature differences is investigated using five types of copulas. Akaike information criterion (AIC) is used to select an optimal model from five types of copulas, and the optimal joint function (two-dimensional function) for steel box girder's temperature difference is established. Finally, the structure's temperature gradient model is extrapolated for the service life of the structure by using Monte Carlo method. Moreover, this paper discusses the temperature gradient models using five types of common copulas and four types of time-varying copulas. The result shows that the t-copula is the optimal function to build the two-dimensional functions for steel box girder's temperature difference, and the temperature model along the transverse direction can offer useful information that is not available in the design codes. [ABSTRACT FROM AUTHOR]

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

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

This paper proposes an autonomous inspection method for steel box girders that uses a wall-climbing robot instead of human workers. According to the 3D operating environment inside the steel box girder, the method proposes a 3D path for the robot to traverse positions to be inspected. The path comprises two alternate sections of the lane’s centerline and U-shaped steering. To realize the robot’s tracking of the desired path, kinematics analysis based on different poses during the inspection was carried out. Corresponding path tracking algorithms were adopted to ensure that the robot moves accurately and efficiently. In addition, for the smooth transition of the two path sections, this method adopts an algorithm of cooperatively controlling the lifting mechanism and the wheel speeds to achieve stable crossing of a 90° concave corner. Finally, experiment results show that the robot can steadily cross 90° concave corner and can steer to the adjacent lane and complete lane inspection along the desired path. The method can realize autonomous inspection for steel box girders using the wall-climbing robot.

Uneven temperature distribution in a structural element constitutes one of its load factors. Temperature fields occurring in structural elements lead to stresses and strains. The values of internal stresses are directly related to temperature distribution and degree of freedom for element deformation. The best way to get information about temperature distribution in an element is to take measurements on a real object. Such measurements have been run or are still taken over decades in various parts of the world, e.g. in Western Europe, USA, China, South America. In a number of cases, such examinations were carried out for objects constructed in warm or hot climate. It is a lot harder to find the results of measurements made in the countries with moderate and transitional climate, like in the Central or East-Central Europe. This paper presents measurement methodology and results gained for a large steel bridge located in the East European Plain, about 52.5° N northern latitude. Permanently installed contact sensors, temporary sensors, as well as pyrometry and thermography were used. An attempt was made to determine temperature distribution in a steel box girder of a bridge using thermovision technique. Approximate temperature distribution patterns in the main span girder were determined from thermal photographs taken. The most important results of examinations are the images of temperature fields in the main span girder related to solar radiation that first and foremost directly affects the bridge deck. [ABSTRACT FROM AUTHOR]

The 55-km-long Hong Kong–Zhuhai–Macao Bridge (HZMB) is the world's longest sea-crossing bridge, connecting Hong Kong with Zhuhai and Macao at the mouth of the Pearl River Estuary in China, comprising 22.9-km-long steel bridges. HZMB is the leading steel bridge in China, with top-level manufacturing and installation technology. This paper outlines the steel bridge construction experiences of HZMB to provide comparisons for the construction of other long sea-crossing steel bridges at home or abroad. The main considerations of construction constraints, scheme selection, structural and aesthetic design of HZMB are presented, and the following points related to new strategies in the steel bridge construction of HZMB are elaborated: (1) construction quality assurance, (2) automatic manufacturing technology, (3) large segment offshore installation, (4) eco-friendly paint (content limitation of volatile organic compounds) and new multifunctional inspection gantry, and (5) Guss Mastic Asphalt steel deck pavement system. The successful implementation of those strategies shows that the steel bridge construction of HZMB promotes improvement in the overall construction and management level of the Chinese bridge industry. The advanced experience of HZMB has opened up broad prospects for the design and construction of offshore bridge engineering in China. [ABSTRACT FROM AUTHOR]

Super-long span bridges demand high design requirements and involve many difficulties when constructed, which is an important indicator to reflect the bridge technical level of a country. Over the past three decades, a large percentage of the new long-span bridges around the world were built in China, and thus, abundant technological innovations and experience have been accumulated during the design and construction. This paper aims to review and summarize the design and construction practices of the superstructure, the substructure, and the steel deck paving of the long-span bridges during the past decades as well as the current operation status of the existing long-span bridges in China. A future perspective was given on the developing trend of high-speed railway bridge, bridge over deep-sea, health monitoring and maintenance, intellectualization, standard system, and information technology, which is expected to guide the development direction for the construction of future super long-span bridges and promote China to become a strong bridge construction country. [ABSTRACT FROM AUTHOR]

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

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

Summary: This article presents the dynamic reliability prediction method of the existing steel box girder considering the time‐variant nonlinear correlations among the performance functions for the failure modes at the multiple control monitoring points. Firstly, the multivariate Bayesian dynamic linear model (MBDLM) considering the nonlinear correlations among the multiple variables is built to predict the extreme stresses at the different control monitoring points; secondly, based on the predicted covariance matrix of MBDLM, the dynamic correlation coefficients between any two performance functions can be accurately predicted; and finally, multivariate Bayesian dynamic Gaussian copula model through combining MBDLM with Gaussian copula technique is proposed to predict the dynamic reliability of the steel box girder, and the monitoring extreme stress data of an actual bridge are provided to illustrate the feasibility and application of the proposed method. The results show that predicted dynamic reliability of the bridge girder with considering the time‐variant nonlinear correlation of failure modes at the multiple control monitoring points is bigger than that without considering the time‐dependent nonlinear correlation. It is illustrated that the predicted results without considering the dynamic nonlinear correlation of failure modes at the multiple control monitoring points are more conservative. [ABSTRACT FROM AUTHOR]

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

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

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

This article studies the relationship between the target reliability index and the design life of the main girder of a long-span cable-stayed bridge to provide a theoretical basis for the design of steel girders for such an application. The changes of the bending section modulus under atmospheric corrosion and the residual ultimate stress of the section of a steel box girder under alternating loads are discussed. A resistance attenuation function for a steel girder of a cable-stayed bridge to predict the resistance change of a steel box girder over the service period is proposed, and the change characteristics of the time-varying reliability index of a steel box girder of a cable-stayed bridge are studied. By analysing the relationship between the time-varying reliability index and the evaluating benchmark value of the reliability index, the time point of maintenance and reinforcement is predicted. Based on the change over time of the difference between the time-varying reliability index and the evaluating benchmark value of the reliability index, the relation function between the target reliability index and the service lifetime of a bridge considering resistance attenuation are provided. [ABSTRACT FROM AUTHOR]

For the integral prefabricated steel-concrete composite girder bridge, an optimized design model for the section parameters of the steel box girder is established based on the combination of area matching and full stress method. By using MATLAB to optimize the steel box girder of the composite continuous girder bridge, a preliminary optimization value corresponding to the cross-section design parameters of different span steel box girder is proposed. The results show that this algorithm uses discrete steel box girder cross section dimensional variables to generate an area database. The embedding the area matching process in the iterative process can effectively improve the calculation efficiency, and the convergence speed is faster. [ABSTRACT FROM AUTHOR]

This study conducts crack identification from real-world images containing complicated disturbance information (cracks, handwriting scripts, and background) inside steel box girders of bridges. Considering the multilevel and multi-scale features of the input images, a modified fusion convolutional neural network architecture is proposed. As input, 350 raw images are taken with a consumer-grade camera and divided into sub-images with resolution of 64 × 64 pixels (67,200 in total). A regular convolutional neural network structure is employed as baseline to demonstrate the accuracy benefits from the proposed fusion convolutional neural network structure. The confusion matrix is defined for prediction performance evaluation on the test set. A total of six additional entire raw images are used to investigate the robustness and feasibility of the proposed approach. A binary conversion process based on the optimal entropy threshold method is applied and closely followed to identify the crack pixels in the sub-images. The effect of the super-resolution inputs on accuracy is investigated. Results show that the trained modified fusion convolutional neural network can automatically detect the cracks, handwriting, and background from the raw images. The recognition errors of the fusion convolutional neural network in both the training and validation processes are smaller than those of the regular convolutional neural network. The super-resolution process hurts the general identification accuracy. [ABSTRACT FROM AUTHOR]

Transverse block of a steel box girder viaduct can decrease the shear connection between the upper part and the lower part. As a consequence, deflection and deflection difference between blocks are significant, and the performance of weld seams and finished viaduct can be affected. To decrease the deflection of steel box blocks with an open section after transverse discretization, a piecewise uniform arrangement of temporary shear braces is proposed on condition that the total shear stiffness of the shear braces remains unchanged. First, the formulas for slip, axial force and deflection with a piecewise uniform arrangement of temporary shear braces are given, and the accuracy is verified by comparing the results with finite element method. The proposed formulas are applied to two field studies and the results show good agreement with measured data. Finally, the optimal arrangement of temporary shear braces was explored by the sequential quadratic programming optimization method. The deflection and the deflection difference at welding position are reduced significantly after bracing, and the optimal shear braces arrangement is to arrange the braces more at the ends of the blocks. [ABSTRACT FROM AUTHOR]

On the basis of massive data collected by the Weigh-in-motion (WIM) system of XiHouMen Bridge, analysis of fatigue-loaded vehicle models and theoretical fatigue life of U ribs butt weld of steel box girder are discussed in this paper. Firstly, basic vehicle information can be obtained from preliminary statistics of various types of vehicles data and the vehicles passing XiHouMen Bridge are divided into seven types based on the number of axles and axle groups. Secondly, the statistical distribution functions of gross vehicle weight under different loading conditions and wheelbase for each type of vehicle are developed to obtain the equivalent fatigue vehicle load. Then, the parameters of various types of fatigue-loaded vehicles are determined by combining the mathematic expectation of gross vehicle weight distribution with Palmgren-Miner fatigue damage accumulation theory. Finally, the seven types of fatigue-loaded vehicles are applied to the component-coupled finite element model of the steel box girders in XiHouMen Bridge and the theoretical fatigue life of the U ribs butt weld can be estimated. This research provides a reference to define the vehicle models for fatigue loading on steel box-girder bridges based on WIM data. [ABSTRACT FROM AUTHOR]

Started in 2014, the works on tramway Line D, awarded to Compagnie des Transports Strasbourgeois (CTS) by Strasbourg Eurometropole (EMS), are intended to extend the Strasbourg transport network into Germany and facilitate the development of cross-border links. Crossing the Rhine, this extension requires the construction of an iconic tied-arch bridge. The key design criteria and constructions are reviewed and discussed in this report. [ABSTRACT FROM AUTHOR]

The main bridge of Zhuankou Changjiang River Highway Bridge is a semi-floating system steel box girder cablestayed bridge with double pylons, double cable planes and with a main span of 760 m. The steel box girder sections in the tower area and on the top of the piers are erected on the bracket, and the other sections are cantilever erection constructed by the deck crane. Temporary hinge restraint is set between tower and beam during construction. The middle span closure section adopts unilateral lifting and pushing auxiliary closure construction. The one time tensioning method of segmental cycle construction technology and the techniques of geometric control in whole construction process are adopted. The utility model effectively saves the construction time, ensures the smoothness of the main beam alignment, and achieves good effect. [ABSTRACT FROM AUTHOR]

The steel box girders' production and installation play a great role in construction of the Hongkong-Zhuhai-Macao Bridge. We develop an early/tardy scheduling model for the production of steel box girders. And then an improved genetic algorithm based on heuristic rules has been proposed. A tardiness job filtering rule has been integrated to the genetic algorithm on the basis of the optimal time algorithm, which effectively solves the early/tardy problem without ex ante sequencing the jobs. The numerical study from Hongkong-Zhuhai-Macao examples proves that our proposed algorithm can improve the cost and to speed up the convergence. [ABSTRACT FROM AUTHOR]

Owing to its light self-weight, low heat capacity and large thermal expansion coefficient, the application of the curved steel box girder bridge with small and medium spans has gained popularity for the construction of urban infrastructure. However, sun exposure could easily increase the maximum temperature difference at the bottom of steel box beam by 25°C. With the effect of nonuniform temperature field and overloaded vehicles, the edge inside the curved steel box girder bridge may be separated from the remaining structure, resulting in overturning. Thus, more attention needs to be paid in order to prevent the separation. In this paper, an overturning resistance analysis of a three-span curved steel box girder bridge located in Hangzhou, China was performed. A model was proposed based on the measurement of temperature field to the steel box girder. The separating displacement due to temperature variations was predicted and verified by the measurement results. As a result, changes in supporting reactions due to the effect of the nonlinear temperature field and self-weight and offset vehicle load were determined, and the overturning stability of the bridge was analyzed via the trial and error method. The balance weight method was employed to diminish the risk of overturning of bridges. Finally, the method proposed in this paper was applied to a bridge under construction, which results in an increase in stability safety factor from 0.63 to 2.58. [ABSTRACT FROM AUTHOR]