Bridge Model Research Articles

Bridge bottom crack detection and modeling based on faster R‐CNN and BIM

AbstractThe bridge bottom crack detection provides important state information for bridge disease control and safety assessment. This paper proposes a detection method based on deep learning Faster R‐CNN and BIM (Building Information Modeling). The UAV (Unmanned Aerial Vehicle) was used for close aerial photography to obtain high‐resolution crack images of the concrete surface at the bottom of a bridge. Through deep learning algorithms, a Faster R‐CNN model is trained and established for crack identifications. The crack identification accuracy rate and recall rate reach 92.03% and 96.54%, respectively. Crack images are mapped to a BIM model developed for the chosen bridge, and the box girder family with cracks and the three crack families of transverse cracks, longitudinal cracks and turtle cracks are established. The cracks are located and the visualization of the beam bridge with cracks was completed. In order to better assess the health condition of the bridge. The results show that the combination of UAV bridge crack detection and modelling solves the remote, visual and automated detection of cracks on the surface of bridge structures, which are difficult to reach manually, and has important scientific research and engineering application value.

Analytical Study Of Load Rating On RCC Box Girder Superstructure Under The Effect Of IRC Loadings

It is observed that over the course of time structural components weakens and their ability to carry the self weight along with the superimposed load decreases. Consequently, it becomes very much important and vital to periodically assess the strength, stability and the performance of the bridge and other structure in order to ascertain their remaining residual strength and to ensure safety. There are different experimental methods available which uses the concept of Non-Destructive testing in order to ascertain the performance and the condition of any structure at any point of time. There are numerous experimental method which are used to perform the Load Rating Analysis but there is no provision to perform the same rating analysis analytically as per the Indian code on bridge related software. This paper generally deals with providing an analytical solution which can be used in order to estimate the residual strength of the bridge structure and perform the Load Rating Analysis analytically on Midas Civil Software. The study basically involves the modelling and Analysis of 2 Reinforced Concrete Box Girder Superstructure, each of span length 40m situated in Lucknow analyzed as per the Indian Standard Codes. Both of the bridge model represents the condition of the bridge structure at a specific time period. The time gap between the analysis of the two models is assumed to be 70 years. The bridge model is modelled and analyzed with the help of Midas Civil Software and the Load carrying capacity of the structure is evaluated based on the different statistical parameters such as Vertical Displacement, Shear Force and Bending Moment. At last a comparative study is conducted between the two models. The analysis revealed that the Bridges Lose their load bearing capacity and strength after a time period of 70 years. A considerable increase in the value of vertical displacement and bending moment was observed beyond the safe and permissible limit of the structure. The analytical approach demonstrated in this study can be applied to various bridge structure such as RCC and PSC Tee Beam Bridge, I Girder bridge, cable stayed bridge etc.

Feasibility study on intelligent bridge combined with smart monitoring techniques

This article proposes an innovative concept of an intelligent bridge system that integrates sensors, a processing unit, and an actuator to maintain bridge safety and performance even in the face of unexpected environmental changes and disturbances. Although technically challenging, this system is an exciting prospect for young engineers who aspire to contribute to cutting-edge technological advancements. As a practical example, this article presents an ICT-based bridge remote monitoring system called the "Intelligent Bridge," which allows real-time monitoring and control during extreme events such as earthquakes and typhoons. The Intelligent Bridge comprises a stand-alone monitoring system and a web-based internet monitoring system for bridge maintenance, which is introduced as an intelligent structure integrated into the intelligent bridge system. To verify the validity of the proposed system, it is investigated the ability to adjust cable forces on a 2-span continuous cable-stayed bridge model to control its structural performance. The development of an intelligent bridge system represents a significant advancement in bridge engineering and has the potential to improve the safety and longevity of bridges, particularly in areas prone to extreme environmental events. The system proposed in this article has practical applications that can benefit both engineers and the general public.

Detection, localisation and quantification of stiffness loss in a bridge using indirect drive-by measurements

Drive-by health monitoring uses the measurements gathered on a vehicle while traversing a bridge to assess its condition. To date, drive-by monitoring has been mostly proposed as a pre-screening tool to detect damage under favourable conditions of low vehicle speeds and low road roughness. A major shortcoming is the potential degradation of the road profile, which is often indistinguishable from bridge damage. In this paper, the influence of vehicle dynamics, speed and road roughness is removed by applying cross-entropy optimisation to the response of individual crossings of the vehicle at different speeds. The proposed model-based algorithm locates and quantifies damage while remaining unaffected by changes in the road profile. In addition to providing the distribution of bending stiffness in the underlying bridge, the algorithm isolates the bridge deflections accurately making the reconstruction of the actual road profile on the bridge possible. The latter can be a useful feature for ensuring traffic safety as well as preventing a major dynamic amplification of the bridge response. The algorithm is successfully tested for a quarter-car driving on a 15 m simply supported beam bridge model at highway speeds of 30 m/s over a class ‘B’ road with a roughness coefficient of 64 × 10−6 m3/cycle.

Effect of a V‐shaped canyon on the seismic response of a bridge under oblique incident SH waves

AbstractTo elucidate the effect of canyon topography on dynamic response of a bridge, an analytical model for a simply supported bridge crossing a symmetric or non‐symmetric V‐shaped canyon in an elastic half‐space under SH waves is proposed. An exact solution to the dynamic canyon‐bridge interaction problem is derived using wave function expansion and verified by its comparison with past exact solution for a sole bridge model without a canyon. The wave propagation in the half‐space, wave scattering by the canyon and wave radiation from the bridge are all taken into account rigorously. Through a systematical parametrical study, it is found that the seismic response of the bridge beam and the wave‐facing side foundation will be significantly amplified. The degree of the topographic amplification is closely related to the geometry of the canyon, the mass and the stiffness of the bridge beam, and the frequency content and angle of the incident wave. The potential adverse effects of a V‐shaped canyon on a bridge should be considered in its seismic design.

Investigation of torsion angle measurement method in spatial cables of suspension bridges

Spatial cables in suspension bridges may twist between two adjacent suspension points due to transverse tension. To determine the spatial torsion angle of the cables, a scale-reduced suspender bridge model was fabricated and tested in this study. The cable torsion angles of the bridge model under different loading cases were obtained and presented. Theoretical methods (e.g., the coordinate method and the angle method) to calculate the spatial cable torsion angle in the suspender bridge were developed by analyzing the deforming characteristics of the suspender cables. The feasibility and predictive accuracy of the proposed methods were assessed using the experimental results. Results show that the proposed coordinate and angle methods produced similar torsion angles for the main cables, showing a maximum relative error of 10.4 %. Compared to the coordinate method's complex data transformation and measurement procedures, the angle method is more convenient, efficient, and easier to calculate the torsion angle of the main cable. Despite the capability of calculating the spatial cable torsion angles, the coordinate method also exhibits advanced capability in determining the geometric curves of the main cable under different spatial angles.

Calibration of finite element model of bridge with pier retrofitted using Fe-SMA strips

Calibration of finite element model of bridge with pier retrofitted using Fe-SMA strips

Study on vehicle-bridge coupling vibration response and impact factor of spatial Y-shaped tied arch bridge

The spatial Y-shaped steel arch bridge adopts a single and double arch rib composite structure, which has a complex spatial structure, and its structural dynamic characteristics are special, resulting in a more complex vehicle-bridge coupling vibration response law. To clarify the dynamic characteristics of the space Y-shaped steel arch bridge structure, this paper takes a space Y-shaped steel arch bridge under construction in China as the research object and uses ABAQUS to establish a vehicle-bridge coupling model. The correctness of the ABAQUS model is verified by the bridge model established by Midas Civil, and four grades of road roughness are established by using the ABAQUS kernel command. The influence of vehicle speed and road roughness on the spatial Y-shaped steel arch bridge is analyzed. The impact factor of the vehicle on the flat bridge deck at the design speed is calculated and compared with the current specification, which provides a reference for the design and maintenance of space Y-shaped steel arch bridge in the future.

Particle coating growth behaviors in a spray fluidized bed based on Gas-Liquid-Solid Quasi-Three-phase DEM numerical simulation

Wet granulation processes are widely used in chemical, food, pharmaceutical, and various other industrial processes. During the process of particle coating growth, particle fluidization state and liquid characteristics have an impact on the layer's thickness and homogeneity. In this study, discrete element, liquid bridge, and droplet motion models were combined to investigate the impact of injection gas velocity, droplet diameter and injection liquid viscosity on the particle growth ratio and coating thickness distribution, and the particle growth mechanism was investigated. The particle growth area, which is the area where the number of coated particles exceeds 0, was significantly expanded by decreasing the droplet diameter and increasing the gas velocity at appropriate ranges. The frequency of droplet and particle collisions increased, and average relative liquid content decreased with increasing particle growth area. By accelerating the injection of gas and reducing the viscosity of the injected liquid, the fluidization condition of the particles, which primarily affected the particle cycle frequency, could be enhanced. The improvement of particle growth area and particle cycle frequency allowed more particles to participate in growth and improved the quality of the grown particles. The proportion of small particles dramatically grew while the proportion of large particles reduced. The standard deviation of particle diameter decreased, and particle growth became more uniform.

Distributed bending stiffness estimation of bridges using adaptive inverse unit load method

Bending stiffness has important applications in bridge damage detection, model updating, and load bearing capacity assessment. However, accurately predicting bending stiffness is a challenging task. In this paper, a two-phase methodology named the adaptive inverse unit load method (AIULM) is developed for distributed reconstruction of bending stiffness from onboard deflection data. In the first phase, the bending stiffness is roughly estimated by uniform discretization. A global stiffness smoothing method is applied to eliminate nonphysical discontinuities of stiffness at interelement boundaries. Then, the smoothed results are applied in the second phase to define a node optimization function to adaptively adjust the element node distribution. An accurate bending stiffness distribution is provided by performing AIULM analysis again based on optimized discretization. Since only real bridge deflection influence lines (DILs) are utilized in the formulation, the AIULM provides a C0-continuous stiffness distribution without any information on internal force. The adaptive optimization of the node distribution allows the practical application of AIULM to different bridges, especially old bridges. Numerical and experimental validation cases, which demonstrate the excellent predictive capability and practical usefulness of the AIULM, have been performed.

Automated geometric digital twinning of bridges from segmented point clouds by parametric prototype models

Digital Twins (DTs) provide a promising solution for the maintenance and operation of bridges, thanks to their ability to mirror physical/structural conditions. A bridge DT generally consists of a geometric-semantic model whose creation, however, requires extensive manual effort. This paper presents an automated framework to generate the parametric model of bridges from their segmented point clouds. Following the concept of reverse engineering with parametric modeling, Parametric Prototype Models (PPMs) are proposed as tools to extract parameter values from point clouds. A local and global optimization problem is defined to adjust and assemble PPMs into an integrated model. The proposed approach has been validated by applying it to the point cloud of bridge components as well as point clouds captured from six concrete bridges in Bavaria, Germany. The results show that the proposed approach can generate the parametric model of bridges with a mean absolute error (MAE) of 8.71 cm.

Rapid damage assessment of regional beam bridges after earthquake based on simplified models and different seismic inputs

As the hub of the traffic network, the rapid damage assessment of bridges after earthquake is of great significance for post-disaster rescue. Traditional vulnerability-based method can only provide the probability of different damage states of structures under different earthquake intensity indicators, which confuses the selection of post-disaster rescue routes. Therefore, this paper proposes a post earthquake damage assessment technique for regional bridges based on nonlinear dynamic time-history response analysis. First, a simplified mechanical model for a single pier was established for a large number of beam bridges in the region, achieving standardized and batch rapid finite element model establishment. Secondly, using Kriging interpolation method and continuous wavelet transform technology, the surface seismic response of geological drilling points is calculated to obtain the seismic motion history of any bridge site in the region. Finally, using parallel computing technology, nonlinear dynamic time-history response analysis was conducted on the simplified beam bridge model, and the bridge damage status was quantitatively evaluated based on the calculation results. Eighty-five bridges in a specific area are considered as an example to verify the proposed method. The results show that the proposed method has high calculation efficiency and can consider the site characteristics and structural design parameters. Also, the calculation results can better reflect the actual earthquake damage distribution, providing strong technical support for post-disaster rescue.

Exploring the Cable-Stayed Bridge with Shifting the Cable Arrangement at Deck Level

Cable stayed bridges are becoming a more and more viable option for lengthy spans with the development of computer-based optimisation techniques. Additionally, because they are suspended structures, they can be constructed with ease in locations where it would be challenging to provide several foundations or piers. The pre-tensioning forces of the cables on Sikkim's Akkar Bridge have been determined through this investigation. CSiBridge software is the programme utilised for the investigation. A analysis of the bridge's several parameters concludes this work. The parametric analysis looks at the deck moment, the bridge's span-wise reaction, the height of the pylon, and the length of the span in relation to the girder thickness. Also investigated is the impact of superstructure modifications on substructure. Due to a lack of resources, particularly steel, cable stayed bridges were initially created in Germany in the years following World War II. The effective introduction of cable stayed bridges is made feasible by the development of welding processes, advancements in structural analysis, the use of high strength steel, orthotropic type decking, and the previously noted shortage of steel in the years following World War II. Cable stayed bridges were extremely statically indeterminate structures. Electronic computers were essential in determining the precise solution to these extremely indeterminate systems and in analysing the cable stayed bridge. The software CSi Bridge is used to perform the analysis. Three distinct models of cable-stayed bridges have been constructed, each taking into account identical cable configurations under varying situations. Since the cables are arranged on the deck at various angles and attachment locations, their effects may be thoroughly investigated. IRC Class 70R Vehicle load was taken into consideration when taking live loads in accordance with IRC: 6-2017. Key Words: Cable-stayed Bridge, CSiBridge Software, IRC - 6, Analysis.

A Stochastic Algorithm Based on Cable-stayed Bridges Model for Stochastic Optimization in Machine Learning

This paper takes the economic cost of road design as the objective function to study the optimization of road construction cost. It is well-know that stochastic optimization is widely regarded as one of the most important and difficult problems in optimization and machine learning. It is noted that various methods for stochastic optimization problems are sensitive to the learning rate (step-size), which is usually underestimated. Therefore, two new stochastic conjugate gradient algorithms are proposed in this paper. We adapt two modified line search techniques to set the stochastic optimization. One uses the modified Armijo line search technology, the other uses the modified weak Wolfe-Powell line search technology. The new search direction has the properties of sufficient descent and trust region, which makes the establishment of global convergence of the two algorithms very understandable and clear. Finally, numerical experiments show that the two new stochastic conjugate gradient methods are competitive compared with other classical methods.

Habitat utilization distribution of sika deer (Cervus nippon)

Habitat-specific and movement-related behavioral studies are essential for the development of sustainable biodiversity management practices. Although the number of studies on sika deer is increasing, habitat utilization distribution (UD)-related studies remain limited. In this study, we investigated the habitat UD behavior of sika deer (Cervus nippon) using a literature survey and an experimental study on Suncheon Bonghwasan Mountain, South Korea. We reviewed home range-related literature on sika deer published between 1982 and 2019 in order to assess their estimation methods, study region, and research background. We observed that the number of studies on sika deer has increased. The minimum convex polygon (MCP) has been utilized the most to estimate habitat UD, followed by the kernel density (KD), the Brownian bridge model, and a combination of these methods. The average home ranges (95 % utilization distribution) of sika deer from the literature survey were 236.99 ha and 1183.96 ha using the minimum convex polygon and kernel density approaches, respectively. The five female deer in our experimental study on Suncheon Bonghwasan Mountain had a mean home range of 66.831 ± 15.241 ha using the MCP approach and 78.324 ± 20.82 ha using the KD approach. The UD behavior of sika deer explored in this research is expected to benefit future scholars and policymakers when formulating deer management and wildlife conservation strategies.

Estimation of Mean Velocity Upstream and Downstream of a Bridge Model Using Metaheuristic Regression Methods

This study compares four data-driven methods, Gaussian process regression (GPR), multivariate adaptive regression spline (MARS), M5 model tree (M5Tree), and multilinear regression (MLR), in estimating mean velocity upstream and downstream of bridges. Data were obtained through multiple experiments in a rectangular laboratory flume with glass walls 9.5 m long, 0.6 m wide, and 0.6 m deep. Four different bridge models were placed at the 6th meter of the channel to determine the average velocities upstream and downstream. Different data-driven models were implemented with different combinations of effective parameters as input. They were evaluated and compared using root mean square error (RMSE), mean absolute relative error (MARE), and Nash–Sutcliffe efficiency (NSE). The results showed that the MARS had the best efficiency in estimating the mean velocity upstream of the bridge model. At the same time, the M5Tree provided the highest performance in estimating the mean velocity downstream. The MARS method improved the estimation accuracy of GPR, M5Tree, and MLR in the test phase by 23.8%, 45.1%, and 47.4% concerning the RMSE at the upstream. The M5Tree provided better RMSE accuracy of 31.8%, 70.4%, and 75.5% at the downstream compared to MARS, GPR, and MLR, respectively. The study recommends the MARS and M5Tree for estimating mean velocities upstream and downstream of the bridge.

Temperature Effect of Railway PC Part Cable-stayed Bridge Based on Long-term Monitoring

The natural environment in which bridges are located varies widely. In order to ensure the normal use of the pylon structure, it is necessary to study the influence of different external environmental factors on the temperature field and temperature effect of the pylon. The purpose of this paper is to study the temperature effect of a cable-stayed bridge in the PC part of the railway based on long-term monitoring. The relevant theories of temperature field and temperature stress analysis are summarized, and the main girder section temperature monitoring scheme is designed according to the interpolation fitting criteria. As the comparative weak radiation day temperature data, the temperature variation law of the box girder section is analyzed, and the temperature gradient fitting curve is obtained by the regression fitting method. The temperature boundary is established according to astrophysics and heat transfer theory, and the temperature field distribution and temperature stress state of the main beam are analyzed by ANSYS two-dimensional box girder section model and Midas/Civil full bridge model. The experimental results show that the solar short-wave radiation is a The main factor that causes the temperature difference of box girder section.

Bottom‐up analysis framework for the continuous multidirectional carbon fiber‐reinforced PEEK composite laminates

AbstractThe continuous carbon fiber‐reinforced polyether ether ketone (CCF/PEEK) composites have been widely utilized in aerospace structures due to their excellent properties. However, the main load‐bearing structure in the next‐generation aircraft needs to withstand high temperatures up to 200°C, and the mechanical properties of CCF/PEEK composites show significant time‐/temperature‐dependence due to the viscoelastic nature of the PEEK matrix. Therefore, accurate predictions of the mechanical performance of CCF/PEEK composites under high‐temperature service conditions are the key issue for structural safety and life assessments and have therefore become a recent research focus. To address these challenges, this study established a bottom‐up analysis framework for the CCF/PEEK composites and employed the theoretical model and the finite‐element representative volume element (FE‐RVE) method to investigate the anisotropic viscoelastic properties of CCF/PEEK composites. We first built an anisotropic viscoelastic model of the unidirectional CCF/PEEK composites by integrating the generalized Maxwell into the bridging model. Upon this foundation, we further developed a viscoelastic laminate model capable of accurately predicting the thermoviscoelastic properties of multidirectional laminates. To verify the developed model, different kinds of FE‐RVEs were built and analyzed. Overall, there is good agreement among the model predictions, the FE‐RVE simulations, and the experimental results within a temperature range of 25–250°C. The developed model can be used to design the high‐temperature performance of CCF/PEEK composites with different fiber volume fractions, laminated configurations, or loading directions.Highlights An anisotropic viscoelastic model of the unidirectional (UD) continuous carbon fiber‐reinforced polyether ether ketone (CCF/PEEK) composites is built. The viscoelastic laminate composite model is developed based on the UD CCF/PEEK composites model. The finite element representative volume element (FE‐RVE) simulation with fibers in a hexagonal or random array has better accuracy compared with the experimental results. The FE‐RVE simulation and the experimental results verified the developed model from 25°C to 250°C.

Evaluating the dynamic behavior of railway-bridge transition zone: numerical and field measurements

Short-span bridges are one of the most frequent infrastructures along railway tracks where railway track stiffness suddenly changes. The sudden variation in the vertical stiffness of railway tracks increases dynamic loads and causes numerous defects in ballasted railroads. Therefore, improving the dynamic performance of railway tracks can be conducted by constructing countermeasures along the transition zone. In this regard, the approach slab is a practical technique used in railway-bridge transition zones. As the dimensional shape of the approach slab plays a significant role in the dynamic response of transition zones, this study evaluated the effects of its main geometric parameters. A three-dimensional model of the railway portal bridge, including the approach slab, was built using the finite element method and analyzed by imposing moving wheel loads as a series of acting force points along rail elements. The model was validated with field-obtained results acquired through a laser/camera-based measuring technique. Then, some sensitivity analyses were performed to find optimized geometric dimensions of approach slabs to improve the dynamic behavior of railway-bridge transition zones. Obtained results of the geometrical sensitivity analysis show that when the geometrically optimized approach slab is used along the railway-bridge transition zone, the displacements of rail and ballast are decreased by 24% and 18%, respectively.

A novel bridge damage detection method based on the equivalent influence lines – Theoretical basis and field validation

This paper presents equivalent deflection as a new concept for bridge damage detection. The equivalent deflection is similar to the real deflection and can be inferred from bridge acceleration measurements (accelerometer). While calculating measured acceleration, the method essentially explores the static response of the bridge to load. It is laid on the premise that most of the deflection response is generally static rather than dynamic. By using the equivalent deflection from a group a trains without knowing their bogie weights, the average single bogie equivalent deflection response (ASBED) can be calculated and used as an indicator of structural damage. Initially, the theoretical procedure is described to find the equivalent deflection from an acceleration signal using a moving force identification algorithm. Then, numerical analyses are carried out to validate the algorithm. The results confirm that the equivalent deflection is close to the real deflection and contains only a small dynamic component. Then, a method to find the shape of influence line is developed. Using real acceleration data from a 26.8 m simply supported railway bridge (located over the West Coast Mainline in Staffordshire, UK), the shapes of equivalent influence lines are obtained from different groups of trains with very good repeatability. The ASBED response concept is introduced as the product of the ‘inferred bogie weight’ and the shape of the influence line. Good repeatability of the ASBED response is obtained from site with variability less than 1.5%. Theoretically, this ASBED response should be able to detect changes in the influence line when the average bogie weight at the site is repeatable. The last section explores the changes in the theoretical influence line due to different bridge damage conditions by using a 2D grillage bridge model. The results show that a 2% overall reduction in material stiffness or 20% local reduction (over 1.5 m) should be detectable using this method.