The development of a mobile manipulator imaging system for bridge crack inspection

A mobile manipulator imaging system is developed for the automation of bridge crack inspection. During bridge safety inspections, an eyesight inspection is made for preliminary evaluation and screening before a more precise inspection. The inspection for cracks is an important part of the preliminary evaluation. Currently, the inspectors must stand on the platform of a bridge inspection vehicle or a temporarily erected scaffolding to examine the underside of a bridge. However, such a procedure is risky. To help automate the bridge crack inspection process, we installed two CCD cameras and a four-axis manipulator system on a mobile vehicle. The parallel cameras are used to detect cracks. The manipulator system is equipped with binocular Charge Coupled Devices (CCD) for examining structures that may not be accessible to the eye. The system also reduces the danger of accidents to the human inspectors. The manipulator system consists of four arms. Balance weights are placed at the ends of Arms 2 and 4, respectively, to maintain the center of gravity during operation. Mechanically, Arms 2 and 4 can revolve smoothly. Experiments indicated that the system could be useful for bridge crack inspections.     

Testing in harsh conditions: Tracking resources on construction sites with machine vision

When tracking resources in large-scale, congested, outdoor construction sites, the cost and time for purchasing, installing and maintaining the position sensors needed to track thousands of materials, and hundreds of equipment and personnel can be significant. To alleviate this problem a novel vision based tracking method that allows each sensor (camera) to monitor the position of multiple entities simultaneously has been proposed. This paper presents the full-scale validation experiments for this method. The validation included testing the method under harsh conditions at a variety of mega-project construction sites. The procedure for collecting data from the sites, the testing procedure, metrics, and results are reported. Full-scale validation demonstrates that the novel vision tracking provides a good solution to track different entities on a large, congested construction site.     

Application of GA in optimal robot selection for bridge restoration

This paper further expands and tests a method for optimising construction robot's kinematic parameters using a genetic algorithm (GA) technique as a tool, proposed earlier by Navon and McCrea [J. Comput. Civ. Eng. 11 (1997) 175]. The approach to selecting an optimal robot is demonstrated on a steel bridge restoration robot. Optimising a robot's kinematic parameters is divided into a two-stage problem. Distinctions among the criteria, different ways of assessing the robot's behaviour according to these criteria and ranking the criteria according to their importance lie at the base of this division. The robot's parameters: (i) major configuration, (ii) minor configuration, (iii) optimal division of the unit length between both links in RRR (revolute configuration) option, (iv) determination of the joints' movement ranges, (v) determination of joints' velocities and accelerations are optimised simultaneously, based on: (i) collision avoidance including arm and wrist singularity avoidance, (ii) percentage of coverage, (iii) dexterity, and (iv) productivity. The procedure for analysis of the inter-relation between the task characteristics and robot design characteristics enables extensions to disparate structures. The GA general function optimisation software is customised here, to be used as the optimisation tool. Comments on the effectiveness of the method and quality of the outcome conclude the paper.     

Unmanned aerial vehicle inspection of the Placer River Trail Bridge through image-based 3D modelling

Unmanned aerial vehicles (UAV) are now a viable option for augmenting bridge inspections. Utilising an integrated combination of a UAV and computer vision can decrease costs, expedite inspections and facilitate bridge access. Any such inspection must consider the design of the UAV, the choice of cameras, data acquisition, geometrical resolution, safety regulations and pilot protocols. The Placer River Trail Bridge in Alaska recently served as a test bed for a UAV inspection methodology that integrates these considerations. The end goal was to produce a three-dimensional (3D) model of the bridge using UAV-captured images and a hierarchical Dense Structure-from-Motion algorithm. To maximise the quality of the model and its benefits to inspectors, this goal guided UAV design and mission planning. The resulting inspection methodology integrates UAV design, data capture and data analysis together to provide an optimised 3D model. This model provides inspection documentation while enabling the monitoring of defects. The developed methodology is presented herein, as well as analyses of the 3D models. The results are compared against models generated through laser scanning. The findings demonstrate that the UAV inspection methodology provided superior 3D models with the accuracy to resolve defects and support the needs of infrastructure managers.     

柳州双拥大桥缆索体系转换

柳州双拥大桥跨越柳江,主桥为三跨连续钢箱梁悬索桥,采用单主缆重力式锚碇悬索结构。主桥采用主缆架设和箱梁顶推同步,最后通过吊杆张拉实现体系转换的方式进行施工。独特的主桥结构和新颖的施工程序,为该桥建设过程增加了亮点。     

基于多旋翼无人机的桥梁外观检测技术及工程应用研究

针对传统桥梁外观检测手段在实践中存在的诸多不足,提出基于多旋翼无人机的桥梁外观检测技术。该技术利用无人机搭载摄像头近距离提取桥梁表面图像,采用图像处理技术的方法检出表面缺陷。结合厦门海沧大桥工程,应用结果表明该技术能够高效、全面和准确地完成桥梁外观检测作业。     

Robot-aided tunnel inspection and maintenance system by vision and proximity sensor integration

This article describes an unprecedented alternative to manual procedures for the application of advanced composite materials, such as Fiber Reinforced Polymer (FRP) and epoxy resins. A complete mobile integrated system is presented for the inspection and maintenance of concrete surfaces in tunnels. It allows performance of operations with minimum interference on passing traffic. The core of this system resides in a specially designed light-weight robotic tool, which is sensed and automated for processes. Sensing includes vision and a laser telemeter to assure precise inspection, superficial preparation, and composite application. The designed interconnection flange allows simple and robust attachment of the tool to a robotic arm's tip. The robot-tool set is to be mounted on a standard articulated lift platform. Therefore, an operator can direct the platform and the robot-tool set's operations from a control station placed at ground-level, in a wheeled vehicle on which the articulated lift platform is mounted. A graphical Human-Machine Interface (HMI) has been developed for the system. It allows the operator to identify fissures for the injection of epoxy resin, and weakened surfaces for FRP adhesion. Actual procedures are planned and performed by the system's automatic components.     

巡视系统在泵站中的应用探讨

结合山西禹门口黄河提水工程实际情况,提出采用考勤机作为巡视终端设备,根据管理需要对系统数据库等进行开发,着重介绍了系统的实现过程,对加强值班巡视管理,综合提升泵站管理水平能起到积极的指导作用。     

潮白河大桥的结构体系

潮白河大桥为三塔单索面预应力混凝土部分斜拉桥。本文主要介绍了该桥的结构体系和结构特点，并结合本桥的特性闸述了部分斜拉桥的结构优势、现状和发展。     

市政工程检测公司软件管理系统应用研究

对市政工程检测公司开发的检测管理软件系统进行了介绍,明确了该系统的技术特点,主要对该系统在实践中的应用流程作了阐述,并提出了该软件系统的改进方向,体现其在检测工作中信息化、智能化、自动化的优势。     

海内关外--港珠澳大桥澳门口岸交通配套工程设计实践

本文通过对港珠澳大桥澳门口岸交通配套工程项目的规划、设计和工程建设方面进行阐述和思考。提出了如何通过高效集约、功能整合及群体逻辑等来探讨解决澳门口岸交通换乘复杂性与地域的特殊性的问题、也通过在澳门项目中以国际模式进行工程实践的经验和总结,为我们今后深入实施建筑师负责制初步探索。     

气体灭火系统消防监督检查技术要点探析

文章主要研究了当前气体灭火系统中防火监测管理技术以及其中存在的弊端,深入挖掘分析了气体灭火部件的基本原理,为防火监测工作提供一些建议,有效提升防火监测管理技术的针对性和高效性。     

住宅性能认定中期检查指标体系建立的研究

介绍了住宅性能认定过程中中期检查的定义、意义、程序和内容,根据中期检查性能评价的审查内容,提出了建立起一套完整的定性、定量的住宅性能认定中期检查指标体系要点。     

部分斜拉桥的结构体系及斜拉索索力影响分析

分析新型部分斜拉桥的结构体系,以福州市浦上大桥为工程背景结合有限元结构计算的结果,分析斜拉索的结构体系及其在桥梁整体结构中的受力特点,并分析桥梁施工和运营中斜拉索的索力变化对部分斜拉桥结构的影响。     

浅谈JG-1型激光三维路面状况检测系统的应用

结合潭邵高速公路检测的情况,介绍了JG-1型激光三维路面状况检测系统路面破损检测和车辙检测的原理以及应用,可为日后养护管理系统的建立和路面日常管理提供依据,同时,探讨了激光三维路面状况检测系统应用中的注意事项。     

OVM拱桥吊杆体系在艾溪湖大桥的应用

南昌艾溪湖大桥主桥为30m+108m+30m三跨连续外倾式四索面下承式钢箱系杆拱桥,其吊杆采用OVM拱桥吊杆体系。该体系是在原有吊杆的基础上发展的新型吊杆体系,采用新型PES(FD)低应力防腐体系、新型防水结构体系和可偏摆的球铰装置等多项新技术、新结构,从整体上解决HDPE护套短时间开裂、下段进水和短杆适应变形的问题,从而提高吊杆的安全性和耐久性。介绍该吊杆体系的结构及施工工艺。     

Visual inspection and bridge management

This paper estimates visual inspection quantitatively prior to its implementation in a Bridge Management System using a Value of Information (VoI) approach employing a Bayesian pre-posterior analysis. Information from a significant number of real bridges from Ireland and Portugal are considered in this regard following existing commercial practices. The variation of different parameters on the estimated VoI is investigated including the assumed probabilistic models of the prior bridge state, the likelihood of inspector assigned condition ratings and the economic setting surrounding the cost matrix for maintenance decision alternatives. The values of no information, perfect information and imperfect information are presented and the change in the optimal strategy based on such information is assessed. The effect of human imperfections in assessment and difference in condition rating scale are also estimated. The studies and findings of this paper are expected to allow a better insight for practising engineers and researchers working in bridge management.     

基于计算机视觉的结构系统识别

结构系统识别是土木工程结构健康监测的重要组成部分,传统的结构系统识别通过有线或无线的测量系统进行数据采集,布置传感器以及数据采集设备的过程繁琐、费时。为了提高结构系统识别的效率,提出一种无需人工靶点、基于计算机视觉的非接触式测量方法,以消费级相机为采集设备,采用基于点匹配的特征光流技术实现目标的运动跟踪,获得目标的位移时程,进而实现结构系统识别。使用消费级摄像机对振动台试验中的结构模型进行测量,与传统拉线式位移传感器的测量结果进行对比。研究结果表明,采用基于计算机视觉的非接触式测量方法,在频域中具有较高的测量精度,并且能够准确识别出结构的自振频率、振型等动力特性,具有良好的应用前景。     

浅谈建筑工程的质量检查

详细地阐述了质量检查是质量管理中不可缺少的重要环节,质量检查能够促进工程质量的提高,提出了落实“三检制度”是项目施工质量管理的核心工作,并对其进行了深入探讨,以保证建筑工程的质量。     

厦门海沧大桥预应力锚碇体系设计

简述了厦门海沧大桥的工程概况及桥型方案，着重介绍其预应力锚碇体系的设计要点及特点。