Operation Of Bridge Research Articles

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.

Monitoring Bridge Dynamic Deformation Law Based on Digital Photography and Ground-Based RAR Technology

Dynamic deflection deformation is a crucial index which can reflect the healthy operation of bridges; due to their limitations, monitoring technologies (e.g., sensors, automatic total stations, and GPS) cannot perform high-frequency and whole-process non-contact dynamic deformation monitoring. Therefore, taking the Jinan Fenghuangshan Road Bridge as an example, this paper developed key low-cost and high-precision close-range photogrammetry technology and combined this with GB-RAR technology to remotely monitor bridge dynamic deformation. The results indicate that the measurement accuracy pertaining to the technology, which is based on an isometric virtual surface, is approximately 0.5 mm when the monitoring distance is 250 m, which can meet the accuracy requirements of bridge deformation monitoring. A vehicle’s dynamic load is transmitted in the form of a stress wave inside the bridge, and with regard to span, the wave is most significant in the 1/2 to 1/4 range. This study observes that the maximum deflection deformation of the bridge is 47.2 mm, which is within the allowable deformation range of the General Specifications for Design of Highway Bridges and Culverts. The research results herein provide technical support and data reference for safety monitoring, and for the reinforcement and maintenance of bridges such as the Fenghuangshan Road Bridge.

Design of Digital Twin System for Harbor Cranes Based on Unity 3D

Port container crane (shore bridge) is an important equipment for container loading and unloading in the port, and its working mechanism includes four parts: lifting mechanism, operating mechanism, operating system and equipment structure. In this paper, digital twin technology is integrated to realize the digital mapping of quay bridge operation, which is the basis for realizing predictive maintenance. As a link between the physical space and the digital space, the digital twin is based on a new generation of information technology, which can complete the mapping of the real space in the digital space, so as to reflect the whole life cycle process of the corresponding physical equipment, and can derive related other functions on this basis. Firstly, the bridge was constructed using 3D modeling software solid works, and the mapping and model format conversion were carried out using 3ds Max. Finally, the 3D model was imported into Unity and the port virtual environment was built. Combined with C#, the driving engine of the lifting mechanism and operating mechanism of the quayside bridge is developed, and the virtual and real synchronous operation of the quayside bridge is finally realized.

Case study: use of SHM to support bridge assessment, maintenance and operation

AbstractThe assessment of infrastructure conditions is at present a topic of great interest and importance, as well as great challenge. This paper presents a case study of the Samuel De Champlain Bridge (Montreal, QB, Canada), an outstanding stay cable bridge equipped with a comprehensive monitoring system (SHM). Among other SHM features, particular attention was paid to implementation of a strategic corrosion monitoring system. This paper intends to describe the concept design, implementation and data interpretation. Here corrosion sensors have been embedded during construction stage to monitor long term evolution of key electro‐chemical parameters for controlling deterioration of materials. Furthermore, these sensors measure stray current interference generated from the rail system that can cause corrosion. In both cases, abnormal values would warn the owner of the associated increased risk of corrosion. This gives them the possibility to take corrective measures to protect the structure before corrosion becomes a serious threat.

Measurements, Simulation, Analysis and Geolocation in a Digital Twin tool for bridge management

AbstractThis paper presents a digital‐twin based tool that can be used for bridge management. The tool offers various capabilities that include embedding BIM geometries, simulations, measurements, GIS location, and performance analysis. These features enable efficient and effective management of bridges by providing detailed information and analysis of the bridge's performance, which can help in identifying potential issues and implementing appropriate solutions. The methodology represents one of the outcomes of Ashvin, an H2020 project aimed to providing assistant solution for design, construction and management of infrastructure systems. The hitherto obtained findings include this digital tool which can be of practical and beneficial use for bridge owners and operators, as it can help them to organize and centralize the bridge data in a way it helps making informed decisions regarding the maintenance, repair, and replacement of bridges. Overall, this paper highlights the importance of embracing technology in the management of critical infrastructure such as bridges, which can significantly improve their performance and extend their lifespan.

Probability of detection curve for the automatic visual inspection of steel bridges

AbstractThe damage tolerant design philosophy is based on periodical inspections and provides safe bridge operation preventing fatigue cracks from growing up to a critical size. It is possible to optimize the management costs of a bridge throughout its life by designing the inspection frequency, which depends on the capabilities of the inspection method. However, such optimization requires knowledge about the performance of inspections that are envisioned to take place during the use of the bridge. Regular visual inspections is the most frequently applied type of inspection of bridge structures. Recent advances in computer vision technologies provide a strong basis for the development of automatic damage detection systems that can support regular visual inspection, thus increasing the reliability of the inspection. Several automatic crack detection systems have been developed in the past years. However, the performances of such systems have not been evaluated in the way as for traditional non‐destructive inspection methods, i.e. in terms of probability of detection curves and detectability limits. This restricts the applicability of automatic visual inspections for inspection planning and damage tolerant design. This paper proposes an encoder‐decoder neural network for segmentation of cracks on images of steel bridges. A probability of detection curve is calculated for this neural network.

Anatomical and symptomatic mid-term outcomes of patients with isolated anterior compartment defect repair or stress urinary incontinence

BackgroundAn evaluation of preoperative and postoperative 12th month Pelvic Organ Prolapse Quantification (POP-Q) and Lower Urinary Tract Symptoms (LUTS) changes in patients operated for the diagnosis of isolated anterior compartment defect (ACD) or Stress Urinary Incontinence (SUI).MethodPatients who were diagnosed with isolated ACD or SUI were retrospectively analyzed at urogynecology unit of our tertiary referral center. All pelvic examinations were performed by the same experienced urogynecologist. Pre-operative and post-operative 12th month POP-Q scores and the responses to a detailed LUTS questionnaire in the unit were assessed.ResultsOf the 90 patients with isolated ACD or SUI, midurethral sling with mini-sling and retropubic transobturator tape methods was applied in 24, iliococcygeal fixation in 28, trapezoid repair in 9 patients, anterior bridge operation in 14, and plication of pubocervicovaginal fascia to the cervical ring in 15. We compared the POP-Q score and pre and post-operative 12th month LUTS. Between pre and post-operative 12th month, there was a statistically significant difference at Aa and Ba points (p < 0.00, 0.001). Comparative LUTS questionnaire showed statistically significant differences in stress urinary incontinence, frequency, urgency, abnormal emptying, nocturia, pelvic pain (p: <0.001, p < 0.001, p: <0.001, p:0.001, p:<0.001, p:0.003, respectively).ConclusionAnatomical and symptomatic recovery is achieved with appropriate surgical intervention in women with isolated ACD or SUI. When LUTS were evaluated in terms of symptomatic recovery, they were found to be related not only to symptoms involving the anterior compartment, but also to symptoms involving other compartments.

Structural Stability Analysis of Bridge Structure Using FEA

In the current research, the dynamic analysis of bridge structure is conducted to determine the natural frequency and mode shape. The dynamic analysis is conducted using ANSYS FEA simulation package. The critical regions of high deformation and energy states are determined. The analysis revealed the presence of several dominant vibration modes, each associated with distinct deformation patterns and nodal patterns. These findings shed light on potential vulnerability zones and areas of concern that may be susceptible to resonance and excessive vibrations during bridge operation. Understanding these critical modes is vital for designing appropriate damping and vibration control measures to ensure the bridge's long-term stability and safety.

Study on the adaptability and optimization of boom replacement methods for suspension bridges

To ensure the safe operation of bridges, the study of methods and techniques for boom replacement has become a crucial aspect of the scientific maintenance of suspension bridges. This study focuses on analyzing the bridge responses and evaluating the applicability of three different boom replacement methods: single-point, three-point and five-point, using finite element calculations. A sea-crossing suspension bridge is taken as a case study to simulate the process of boom replacement using temporary booms. Consequently, the optimal replacement method for booms of varying lengths is determined. Meanwhile, this research proposes a quantitative basis for classifying boom lengths based on calculation data and analysis results to determine the suitable boom lengths for different replacement methods. Besides, a comparison of the relationship between the force transmission efficiency of temporary booms and boom length reveals that longer booms exhibit lower force transmission efficiency, with the efficiency decreasing at a faster rate as boom length increases. Overall, these findings provide a theoretical basis for the study of boom replacement in suspension bridges.

A Review on Damage Monitoring and Identification Methods for Arch Bridges

The damage monitoring and identification of arch bridges provide an important means to ensure the safe operation of arch bridges. At present, many methods have been developed, and the applicability and effectiveness of these methods depend on the damage type, structural configuration and available data. To guide the practical application of these methods, a systematic review is implemented in this paper. Specifically, the damage monitoring and identification methods of arch bridges are divided into the damage monitoring of local diseases and damage identification of overall performance. Firstly, the research on the damage monitoring of the local diseases of arch bridges is reviewed. According to the disease type, it is divided into four categories, including suspender inspection, void monitoring, stress detection and corrosion detection. For each disease, this paper analyzes the principles, advantages and shortcomings of various methods. Then, the damage identification methods of the overall performance of arch bridges are reviewed, including masonry arch bridges, steel arch bridges, reinforced concrete arch bridges and concrete-filled steel tubular arch bridges. And the commonly used damage indexes of damage identification methods are summarized. This review aims to help researchers and practitioners in implementing existing damage detection methods effectively and developing more reliable and practical methods for arch bridges in the future.

Study on dynamic impact factor of girder bridges due to vehicle load model

The dynamic effects of moving vehicle on bridge are generally treated as withstand static loads that are recommended an increment by dynamic impact factors (IMs) (or dynamic amplification factors) in many design codes, that are a function of either the span or the first flexural natural frequency of the bridge. The value of the IM will relate to safe and economical in new bridge designs, evaluate recommendation and operation of bridges. Due to the bridge-vehicle interaction model, previous studies have shown that the calculated IM from field measurements could be higher than the values specified in design codes. Currently, studies on IM often focus on using interaction models with multi mass vehicles move on bridge that are increasingly similar to real models. This study develops a 2D three-axle vehicle–bridge model to analysis the dynamic response of the girder bridge subjected to moving loads consider to some vehicle parameters with the each axle is modelled in two masses, each mass is connected to a spring and a damping corresponding to the suspension and tire. In addition, depending on the stiffness parameters of the suspension and tires of the analyzed vehicle model, the IM results of this study are different from those of some authors and the bridge design rules. Based on the dynamic analysis of the bridge under the vehicle loading consider the stiffness of tire and suspensions, the calculation of the IM needs to be considered more carefully in the process of designing new bridges or existing bridges.

Establishment and effect analysis of traffic load for long-span bridge via fusion of parameter correlation

Traffic flow is the main driver behind the dynamic response in operation of long-span bridges. To further improve the effectiveness of safety analysis for long span bridges, the bridge dynamic response should be analyzed under traffic flow. This paper investigated the simulation method of traffic flow and the bridge dynamic response under it. Firstly, the potential parameter correlation in the traffic flow was analyzed based on WIM data. Secondly, a refined simulation method of stochastic traffic flow that considers the correlation in vehicle arriving sequence and axle weight (AW) was proposed and validated. The Markov Chain Monte Carlo (MCMC) method and the correlation random sampling Monte Carlo simulation (CMCS) method were used to simulate the correlation of vehicle arriving sequence and axle weight, respectively. Finally, the constructed stochastic traffic flow is used to evaluate the influence of parameter correlation of traffic flow on dynamic response for long span suspension bridges. Results highlight the correlation of traffic flow. For the vehicle arriving sequence, those vehicles with a small quality rarely follow those with a large quality. The vehicles of different types follow certain transfer relationship. The correlation of vehicle arriving sequence can be effectively simulated that the vehicle type distribution and transition probability of the samples are both close to the WIM data. Meanwhile, the correlation of vehicle AW is mainly observed among multi-axle vehicles, and that in two- and three-axle vehicles is not significant. In the bridge application, the proposed method outperforms the MC method in the simulation of multi-axle vehicles. The parameter correlation of traffic flow has obvious influence on the response of the girder of long-span suspension bridge. The distribution of vertical displacement and bending moment of SC is closer to WIM data, and due to the small ratio of live load to dead load, some indexes such as the suspender force are less affected. The consideration of parameter correlation brings the load effect closer to the WIM data, the parameter correlation should be considered in the evaluation of the fatigue life of components, which can positively contribute to the long-term evaluation of bridge response under traffic flow.

Identification of the dynamic parameters of bridge elements using unmanned aerial vehicle

The condition of the bridge may deteriorate due to the traffic that passes over it, as well as weather and environmental conditions. To ensure the safety and structural stability of the bridges, regular inspections of the bridge elements should be carried out. Recent advances in unmanned aerial vehicles (UAVs) can provide tools for accurate and even autonomous inspection of bridge structures without interrupting normal bridge operations. In this paper, we focus on the determination of the dynamic structural parameters of a suspension bridge. The proposed method is based on the estimation of the natural vibration frequency of the bridge cables using the videos captured by the UAV. We provide a detailed theoretical description of the algorithm and an analysis of the simulation results and the data collected during the experiments in the laboratory and in the real case study. In addition to the vision based method for estimating vibration frequency, we tested the ability of the UAV’s on-board sensors to record structural oscillations when the UAV landed on the surface of the bridge.

Monitoring-based adaptive water level thresholds for bridge scour risk management

Riverbed scour is the leading cause of bridge failure worldwide. Recent developments in sensor technology for structures have resulted in more bridges being instrumented and monitored. However, alongside scour monitoring systems, there is a need of techniques to handle the data obtained and exploit them to inform the management of the bridge scour risk. This paper illustrates the development of a decision support system (DSS) for bridge scour risk management, which is based on a probabilistic framework for scour risk estimation, enhanced by real-time information from scour monitoring systems and in line with current risk procedures used by transport agencies. The proposed DSS provides bridge operators with adaptive measurement-informed water level thresholds triggering bridge closure to traffic under heavy floods. The application of the DSS is illustrated by considering a case study of three bridges at risk of scour managed by Transport Scotland. It is shown that information from scour sensors within the proposed DSS allows reducing the uncertainty in the scour estimates and yields adaptive water level thresholds triggering bridge closure to traffic that can differ significantly from those currently considered by transport agencies. This can ultimately result in a reduction of false alarms and unnecessary bridge closures.

Investigation of the Temperature Actions of Bridge Cables Based on Long-Term Measurement and the Gradient Boosted Regression Trees Method

Cable-stayed bridges have been commonly used on high-speed railways. The design, construction, and maintenance of cable-stayed bridges necessitate an accurate assessment of the cable temperature field. However, the temperature fields of cables have not been well established. Therefore, this research aims to investigate the distribution of the temperature field, the time variability of temperatures, and the representative value of temperature actions in stayed cables. A cable segment experiment, spanning over one year, is conducted near the bridge site. Based on the monitoring temperatures and meteorological data, the distribution of the temperature field is studied, and the time variability of cable temperatures is investigated. The findings show that the temperature distribution is generally uniform along the cross-section without a significant temperature gradient, while the amplitudes of the annual cycle variation and daily cycle variation in temperatures are significant. To accurately determine the temperature deformation of a cable, it is necessary to consider both the daily temperature fluctuations and the annual cycle of uniform temperatures. Then, using the gradient boosted regression trees method, the relationship between the cable temperature and multiple environmental variables is explored, and representative cable uniform temperatures for design are obtained by the extreme value analysis. The presented data and results provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.

Study on strain characteristic function for performance evaluation of high-speed railway steel truss bridge

From the data collected by bridge health monitoring systems, various indicators can be derived to evaluate the structural, environmental, and loading conditions. These indicators provide a basis for decision-making of bridge operations managers and administrators. In this paper, a new monitoring indicator called the Statistical Steady-State Static Effect Characteristic Function is proposed for railway bridges. A digital twin (DT) finite element model is developed in this study, which allows for real-time analysis of the structural effects during train travel. Using this model, the strain effects on key components of a high-speed railway steel truss bridge under dynamic loading conditions caused by random trains are simulated. Based on the characteristics of the simulation results, an extraction algorithm for the statistical steady-state strain characteristic function of the high-speed railway steel truss bridge is proposed in this study. By simulating the strain effects under multiple random train travel events, the strain characteristic functions at different locations of the structure are extracted, demonstrating the applicability of the proposed algorithm. Finally, by comparing these strain characteristic functions, the distribution pattern in the structural configuration space is revealed, suggesting the potential of the function as an indicator for assessing inherent structural characteristics, monitoring structural condition, and identifying damage.

Structure-borne noise of steel and concrete box girders in an urban metro system: A hybrid evaluation and parametric study

Metro systems provide an efficient, convenient, and expeditious way to travel around crowded routes. Because these systems are established in cities, residential buildings close to metro viaducts are significantly affected by structure-borne noise (SBN). Although most previous studies developed SBN prediction with a focus on the accuracy and computational efficiency of a specific bridge type, only limited studies on parameters for the SBN on bridges were carried out. Thus, eliminating SBN is still a challenging task for both the design and operation phases of bridge design. Therefore, this study integrates simplified experiments with numerical analyses to evaluate the influential parameters on the structure-borne noise level (SBNL) for two types of bridge girders, that is, the double-box pre-stressed concrete girder and the double-box steel girder. The present study also proposes an optimization method for reducing the SBNL in the bridge design and operation phases and identifies the sources of SBN for these two types of bridges. In this paper, the solutions to mitigating SBN are first reviewed and briefly introduced. Theories associated with SBN are then derived and experimentally verified using a concrete or steel plate with a unit area. A hybrid evaluation method is developed to integrate transient finite-element simulation with experimental results, and the main sources (e.g., plate thickness, train speed, fastener stiffness, and track irregularity) that induce SBN are examined by this hybrid method. Consequently, the approach to resolving the SBN problem can be optimally determined. As demonstrated in the results from the hybrid evaluation method, the track condition dominates the SBNL for both types of bridges, and the relationship between train speed and plate eigenfrequency should be carefully investigated to avoid the effect of plate resonance. The pre-stressed concrete box girder is the recommended bridge type for use in urban areas from the viewpoint of minimizing the SBNL.

Analysis of the Temperature Effect and Influence of Large Span Continuous Rigid Bridge in Mountainous Area

The temperature problem of large span bridges in mountainous areas is particularly prominent due to the large temperature difference. This paper addresses the problem of ambient temperature influence on the construction and operation of large span prestressed reinforced concrete continuous rigid frame bridges. Through finite element modeling and computational analysis of an example of a continuous rigid frame bridge, the simulation results reveal the law of temperature influence on large span continuous rigid frame bridges and provide reference for the subsequent analysis of temperature problems of continuous rigid frame bridges. Based on the force analysis of the model, a series of bridge temperature crack generation mechanisms are proposed in combination with the bridge construction process and concrete characteristics, and reasonable treatment measures are proposed for the control of temperature cracks during bridge construction to ensure the overall quality effect of bridge construction and operation.

Fatigue life evaluation on wire rope suspenders of the suspension bridge based on a time-varying degradation process

Suspenders are critical force transmission components of a suspension bridge and may be more prone to fatigue damage due to environmental aggression and repetitive live loads. To evaluate the safety of the suspender more accurately, a fatigue life evaluation framework of the rope suspender was proposed, where a time-varying fretting-corrosion-fatigue degradation process of the rope wire and probabilistic critical limit states based on failure area were integrated. A case study on the rope suspenders of a prototype suspension bridge was performed under the random vehicle and wind loads, and the reliability indices and fatigue life of the rope suspender were obtained. Results show that the fretting wear had an obvious effect on the degradation process of the wire rope in conjunction with corrosion fatigue, and the fatigue life of the rope suspender would be less than its design life. The proposed method can comprehensively evaluate the service life of wire rope suspenders and provide replacement suggestions more timely, ensuring the safety of the bridge operation.

Anomaly diagnosis of stay cables based on vehicle-induced cable force sums

Stay cables are one of the most critical load-carrying components for cable-stayed bridges. Cable damage or performance degradation can affect the normal operation of bridges. Therefore, it is essential to evaluate the service performance of cables in real time to ensure bridge safety. In this paper, an anomaly diagnosis method for stay cables based on vehicle-induced cable force sums (VICFS) of cable pairs (defined as two symmetric cables upstream and downstream) is proposed. First, the theoretical relationship between the vehicle load and VICFS was derived through mechanical analysis. Second, a new anomaly-sensitive warning index was established based on the above derivation, and the anomaly diagnosis for stay cables was achieved by combining it with the X-bar control chart. Then, according to finite element simulation, the variations in VICFS in different cases were analyzed to verify the rationality of the theoretical derivation and the established warning index. Finally, an engineering application to an in-service cable-stayed bridge was carried out to validate the feasibility and effectiveness of the anomaly diagnosis method. The results show that the proposed method can accurately detect and locate damaged cables, which can be successfully applied to monitor the long-term performance of stay cables.