Localisation of a mobile robot for bridge bearing inspection

Bridge bearings are a critical component of a bridge and require regular visual inspection to ensure the safe operation of the bridge throughout its life. However, the bearings are often located in spaces that are difficult or hazardous to reach, which can impact how often the bearings are inspected. In addition, these spaces are small and offer significant challenges for tele-operation due to line-of-sight restrictions; hence, some level of autonomy is required to make robotic inspection possible. In this work, a robotic solution to bridge bearing inspection is presented, and localisation methods are assessed as the first, and most, important step towards automation. Robot localisation is performed in both a lab environment and a real bridge bearing environment. In this paper, Adaptive Monte-Carlo Localisation is considered for localisation in a known map and gave comparable results to Hector-SLAM, with all results less than a defined error threshold of 10 cm. A combination of both of these methods are proposed to give a more robust approach that gives errors lower than the defined threshold in the real bridge. The experiments also show the need to provide an accurate starting point for each inspection within the bearing, for which we notionally suggest the use of a docking station that could also be used for improved autonomy, such as charging. In addition, proof-of-concept approaches for visual inspection tasks, such as geometry changes and foreign object detection are presented to show some of the proposed benefits of the system presented in this work.     

Development of a bridge maintenance system for prestressed concrete bridges using 3D digital twin model

Abstract

Preventive maintenance is increasingly becoming an essential strategy in the bridge industry owing to its proactive advantage of maintaining the structural sustainability during its entire service life. Several in-use bridges lack an appropriate regular maintenance solution, leading to extra cost during the operation stage. This paper proposes a new generation of the bridge maintenance system by using a digital twin model concept for more reliable decision-making. A detailed solution is proposed in this work to enhance the bridge maintenance process using a parallel solution: a maintenance information management system based on a 3D information model in conjunction with a digital inspection system using image processing. Three-dimensional digital models are required to utilise information from the entire lifecycle of a project, including design and construction, operation, and maintenance, by continuously exchanging and updating data from each stakeholder. For the maintenance of prestressed concrete bridges, the twin models are defined and their uses are presented.     

论述道路桥梁工程的原材料检测

文章首先介绍了道路桥梁工程中进行原材料检测的重要性,然后分析了道路桥梁工程原材料检测过程中需注意的要点,之后分别介绍了道路桥梁工程中原材料的检测方法。最后,根据道路桥梁工程原材料检测工作中存在的问题提出了几点建议。     

基于有限元的桥梁垮塌场景模拟初探

为了科学而逼真地还原桥梁垮塌过程,辅助桥梁垮塌事故鉴定,本文在虚拟现实平台上对基于有限元数据的桥梁垮塌过程场景模拟进行了研究。基于桥梁垮塌过程的有限元模拟数据,本文在三维图形引擎OSG上实现了桥梁场景建模和垮塌动画模拟,并基于桥梁垮塌模型构建了具有一定真实感的场景漫游系统。通过场景模拟与有限元模拟的结果对比,证明了本文基于有限元的桥梁场景建模和垮塌动画控制方法的有效性。本文将有限元技术与虚拟现实技术相结合,为桥梁垮塌事故鉴定提供了科学而真实的虚拟场景。     

Beurteilung der Tragfähigkeit von geschädigten Stahlbetonbrücken auf der Grundlage der Ergebnisse einer Bauwerksprüfung

Structural Reliability Assessment of Damaged Reinforced Concrete Bridges on the Basis of the Results from a Bridge Inspection The regular bridge inspection is of high importance for the reliable use of the infrastructure. This paper describes and explains a method with supports the engineers of a bridge inspection in the assessment of the damaged bridges during or directly after the inspection. Based on this initial estimate the urgent measures i.e. a lower permitted bridge class can still be carried out before more detailed inspections and calculations have been done. The reliability analyses for the damaged bridges are carried out using first order and second order reliability method (FORM and SORM). The probability of failure, p_f or the safety index, of the system respectively are the main results of the calculation procedure. This paper shows the approach and the application with an example. Particularly in the communal sector the method can be helpful, because it can not be assumed that in all cases the regular bridge inspections and the appropriate maintenance have been carried out.     

Drone-enabled bridge inspection methodology and application

The field of Civil Engineering has lately gained increasing interest in Unmanned Aerial Vehicles (UAV), commonly referred to as drones. Due to an increase of deteriorating bridges according to the report released by the American Society of Civil Engineers (ASCE), a more efficient and cost-effective alternative for bridge inspection is required. The goal of this paper was to analyze the effectiveness of drones as supplemental bridge inspection tools. In pursuit of this goal, the selected bridge for inspection was a three-span glued-laminated timber girder with a composite concrete deck located near the city of Keystone in the state of South Dakota (SD). A drone, a Dà-Jiāng Innovations (DJI) Phantom 4, was utilized for this study. Also, an extensive literature review to gain knowledge on current bridge inspection techniques using drones was conducted. The findings from the literature review served as the basis for the development of a five-stage drone-enabled bridge inspection methodology. A field inspection utilizing the drone was performed following the stages of the methodology, and the findings were compared to current historical inspection reports provided by the SD Department of Transportation (SDDOT). Quantified data using the drone such as a spalled area of 0.18 m², which is identical to the measurement provided by the SDDOT (0.3 m by 0.6 m), demonstrated the efficiency of the drone to inspect the bridge. This study detailed drone-enabled inspection principles and relevant considerations to obtain optimum data acquisition. The field investigation of the bridge demonstrated the image quality and damage identification capabilities of the drone to perform bridge inspection at a lower cost when compared to traditional methods.     

消防监督检查创新模式研究

对消防监督检查的创新模式进行探索,对消防监督检查的三种工作模式进行对比研究,包括以政府为全核心的监督检查执法模式;由政府购买第三方服务辅助监督检查,政府执法的半社会化模式,以及以第三方为监督检查核心,政府执法的社会化 模式。进一步提出了“两查两评一公示两应用”模型。结合上海市奉贤区消防监督检查试点工作成果加以分析,对消防监督检查改革发展提供借鉴意义。     

urbanHIST: a multidisciplinary research and training programme on the history of European urbanism in the twentieth century

ABSTRACT

This paper introduces the Planning Perspectives readership to urbanHIST, a current Horizon 2020 European Joint Doctorate programme that focuses on the history of European urbanism in the twentieth century. Its concept is based on the inherent multidisciplinary approach of the research field and the ambition to gain a pan-European perspective on planning history. The paper delineates the underlying general research trends and the current responses of urbanHIST. Finally, it connects the programme's thematic orientation with both, its external contributions and its internal key activities that might bridge the gap between the protected environment of a PhD programme with the reality of academic life.     

基于虚拟现实技术的体积雾与能见度研究

在现有体积雾算法的基础上进行改进,基于消光公式在虚拟现实空间渲染烟雾,让消光效果接近现实中的非刺激性烟雾对人眼能见度减弱效果。为虚拟空间下进行应急逃生指示系统的模拟仿真提供有效支持。测试了1 080分辨率、1 440分辨 率头戴式VR显示器对人视敏度和能见度的影响。实验结果表明：低分辨率对人的视敏度有很大影响,但对能见度没有太大影响;在虚拟场景中,改进后的体积雾算法可以使能见度与烟雾消光系数的关系与现实中相符,因此可以测试人眼对火场烟气的视觉感知效果。此研究构建了能见度与火场消光系数的关系,有利于利用FDS的仿真结果在虚拟空间重建符合光学原理的烟气,改进在虚拟火场进行逃生演习的效果。     

A simplified management procedure for bridge network maintenance

Structural problems due to corrosion, ageing, durability, aggressive environments, materials defects, lack of ductility and unforeseen behaviour under seismic loads may significantly compromise the resistance and safety of bridges. Scheduled maintenance of bridges becomes important to ensure complete serviceability of the road network. Among existing bridge management systems (BMSs), this work is a contribution to the evaluation criteria of bridge condition by means of visual inspection, prediction of future structural condition and planning of maintenance intervention. After a brief review of some existing BMSs, a simple new procedure for evaluation of bridge condition by means of visual inspection, aimed at general planning of maintenance in a BMS framework, is presented in this paper. This procedure is applied to stock, including about 200 bridges and viaducts, of the Veneto region road network in the north-eastern part of Italy, and is then discussed.     

基于静载试验的某预应力混凝土简支板桥状态评估

我国目前阶段以及未来都有大量的桥梁需要进行检测和承载力评估.论文以国内某座预应力混凝土简支空心板梁桥为背景,介绍了基于静载试验的桥梁检测内容、过程和方法.在桥梁结构的试验测试数据和理论计算结果比较分析的基础上,对桥梁的横桥向连接性能、各板的弹性工作状况以及受力状态等方面进行了评价.同时该桥的测定和分析方法也可作为同类桥型设计和施工的参考.     

SHM-based F-AHP bridge rating system with application to Tsing Ma Bridge

This paper aims at developing a structural health monitoring (SHM)-based bridge rating method for bridge inspection of long-span cable-supported bridges. The fuzzy based analytic hierarchy approach is employed, and the hierarchical structure for synthetic rating of each structural component of the bridge is proposed. The criticality and vulnerability analyses are performed largely based on the field measurement data from the SHM system installed in the bridge to offer relatively accurate condition evaluation of the bridge and to reduce uncertainties involved in the existing rating method. The procedures for determining relative weighs and fuzzy synthetic ratings for both criticality and vulnerability are then suggested. The fuzzy synthetic decisions for inspection are made in consideration of the synthetic ratings of all structural components. The SHM-based bridge rating method is finally applied to the Tsing Ma suspension bridge in Hong Kong as a case study. The results show that the proposed method is feasible and it can be used in practice for longspan cable-supported bridges with SHM system.     

Improved visualization of infrastructure monitoring data using building information modeling

Abstract

With growing complex infrastructure, autonomous condition assessment of large-scale structures has garnered significant attention over the past few decades. Data-driven structural health monitoring (SHM) techniques offer valuable information of existing health of the structures, maintain the safety and their uninterrupted use under varied operational conditions by undertaking timely risk and hazard mitigation. Traditional approaches, however, are not enough to monitor a large amount of SHM data and conduct systematic decision making for future maintenance. In this article, building information modeling (BIM) is utilised as a promising computing environment and integrated digital representation platform of SHM that can organize and visualise a considerable amount of sensor data and subsequent structural health information over a prolonged period. A BIM-enabled platform is utilised to develop the proposed visualisation tool for a long-span bridge and enable automated sensor data inventory into the BIM environment. Such automated tool facilitates systematic maintenance and risk management, while avoiding manual errors resulting from visual inspection of the structures. The proposed method can be considered as a user-friendly and economic framework for condition assessment and disaster mitigation of structures from long-term monitored data.     

利用LIDAR数据测制城市大比例尺地形图的研究与实践

以南京市新港地区为例，研究利用LIDAR系统的影像数据与点云数据及相应数字摄影测量软件，测制城市大比例尺地形图的方法。本文给出其中的关键技术和生产流程，是激光点云及数码航空影像综合使用上的一次成功尝试。     

Development of methodology and virtual system for optimised simulation of road design data

Current virtual reality (VR) and augmented reality (AR) tools do not lend themselves well to the simulation of non-repetitive activities that could be involved in road construction and heavy civil engineering projects. Therefore it is argued in this paper that specialised functions are required to support the use of VR and AR tools to visually design and simulate such projects. The prime objective of this study is to develop visual design and simulation analysis functions to support optimum road design by extending the applicability of current virtual reality (VR) systems to the design phase of road construction projects. The VR simulation functions developed in this research enable visual inspection of road alignment and earthwork status, simulation of alternative routes, and selection of optimum design route. This study implements a methodology for configuring VR simulation functions and develops a VR system for optimising the road design data. The research results include an improved road design process as a result of the application of the VR functions developed.     

谈桥梁交工前的检查与清理

结合锡张高速公路无锡新区互通桥梁交工前的清理工作,分别介绍了桥梁交工前施工单位现场检查和清理的细节及注意事项,包括场地的清理和立柱、支座、桥台、上部结构及附属结构等不同部位的清理和检查,对今后桥梁交工前自检工作有一定指导意义。     

Identifying bridge structural condition development trends via categorical inspection condition rating with case studies

Inspection data in a bridge management system (BMS) may provide us with comprehensive information about a structure's condition history. Identification of bridge structural condition development trends from historic inspection data for maintenance planning has drawn more and more attention, particularly from bridge agencies, who prefer ‘worst-first’ maintenance and rehabilitation strategies. In this paper, rather than correlating inspection data with fundamental structural deterioration models, a statistical inspection data-based analysis was developed. To demonstrate the inspection data-based approach in identifying bridge structural condition development trends in practical scenarios, case studies of concrete deck slabs and steel beam girders were applied. The ANalysis Of VAriance (ANOVA) technique was adopted to identify the major factors considered by a BMS to have a significant influence on the condition index. As a result, three major factors, bridge construction year, inspection year and inspector, were identified when structures were exposed to the same environment. Associated with these major factors, statistical indicators were introduced to characterize the condition development trends of structures, and to detect signs related to the potential of threat to the structural integrity. The indicators were further applied to identify a specific subgroup, e.g. those bridges that were constructed in a certain period and experienced the most deterioration or the highest deterioration rate. The approach developed can be extended to look into more causal factors on how they may alter the structural condition development trends when their information is available within inspection records. The outcomes may offer useful information for maintenance planning. Furthermore, it was found that the inspector also had quite a considerable impact on the condition index. A difference in structural condition assessment among inspectors may occur regardless of the same structural condition scenarios. This difference was quantified and applied to identify inspectors who tended to underestimate deterioration in structural condition.     

Management of bridges with shallow foundations exposed to local scour

Abstract

The Serbian road network includes a large portion of bridges with shallow foundations vulnerable to local scour as tragically demonstrated during the extreme flooding in May 2014. Currently, the bridge management procedures in Serbia and worldwide do not comprehensively account for a risk of bridge failure due to flooding and fail to provide sufficient information for the decision-making. Thus, a novel methodology for quantitative vulnerability assessment is suggested as a tool to identify the most vulnerable bridges in a network. Herein, the essential task is evaluation of the conditional probability of a bridge failure due to local scour in a flooding event of a certain magnitude. To apply this approach on a network level, there is a dire need to establish precise practice-ready guidelines on an optimal set of information to be used and/or collected in situ, which is discussed on an example of the Serbian bridge database. The vulnerability of a bridge to local scour may be used as a comprehensive indicator of a bridge performance in a flooding event. For a network level, the vulnerability maps with respect to flooding of different magnitudes will give road operators crucial information to apply adequate quality control plans to vulnerable bridges.     

Multihazard resilience of highway bridges and bridge networks: a review

Abstract

Assessment of resilience for engineered systems has drawn ample attention from the engineering community in recent years. It has resulted in a significantly large body of literature focusing on pertinent areas of resilience. This article provides a systematic and comprehensive review of the literature addressing resilience assessment of bridges and bridge networks under single hazard and multihazard conditions. Though not much work been performed yet on multihazard resilience of bridges, relevant aspects including combinations of multiple hazards for bridge performance evaluation, methods for loss assessment and approaches taken for post-event recovery are discussed. Furthermore, maintenance is a key component if resilience is assessed in a life-cycle framework. Hence, available maintenance plans and strategies and their probable applications for bridges and bridge networks are discussed. The article concludes with a discussion on the need for further research in the focus area and challenges involved with the same.     

Methodology for development of live load models for refined analysis of short and medium-span highway bridges

Abstract

The accuracy of bridge system safety evaluations and reliability assessments obtained through refined structural and finite element analyses depends not only on the accuracy of the structural model itself but also on the proper modelling of the maximum traffic loads. While current code-specified live load models were calibrated to properly reflect the safety levels of bridge structures analysed using the simplified methods adopted in bridge design and evaluation manuals, these load models may not lead to accurate results when implemented during refined structural analysis procedures. This paper describes a method to calibrate appropriate live load models that can be used for advanced analyses of bridges. The calibration procedure is demonstrated using actual traffic data collected at a representative weigh-in-motion station in New York State. The proposed calibration methodology is applicable for developing live load models for different bridge service periods, bridge types and design/assessment codes or standards. Live load models obtained using the proposed calibration procedure are readily implementable for deterministic refined analyses of highway bridges to produce similar results to those of complex traffic load simulations. Examples are presented that describe how results of such calibrated live load models would be used in engineering practice.