Automated crack evaluation of a high‐rise bridge pier using a ring‐type climbing robot

This article proposes a deep learning‐based automated crack evaluation technique for a high‐rise bridge pier using a ring‐type climbing robot. First, a ring‐type climbing robot system composed of multiple vision cameras, climbing robot, and control computer is developed. By spatially moving the climbing robot system along a target bridge pier with close‐up scanning condition, high‐quality raw vision images are continuously obtained. The raw vision images are then processed through feature control‐based image stitching, deep learning‐based semantic segmentation, and Euclidean distance transform–based crack quantification algorithms. Finally, a digital crack map on the region of interest (ROI) of the target bridge pier can be automatically established. The proposed technique is experimentally validated using in situ test data obtained from Jang–Duck bridge in South Korea. The test results reveal that the proposed technique successfully evaluates cracks on the entire ROI of the bridge pier with precision of 90.92% and recall of 97.47%.     

桥梁加固综述

一、桥梁的结构性能桥梁结构是典型的不可逆结构,受自然因素如腐蚀、冲刷、预应力损失等,非自然因素如意外损伤、超载、开裂等的影响,一旦建成,其结构性能会随运营时间的增长而不断下降,若采取适当加固或提高等级等措施,则其结构性能会提高,桥梁寿命会延长。     

差异进化算法中影响进化过程的参数研究

通过对四个DeJong典型函数最小值问题的数值分析，系统地研究了差异进化算法中变异因子和交叉因子两个关键参数对整个进化过程的影响，为运用差异进化算法进行优化运算时的参数定值提供了参考。     

浅谈桥梁加固

阐述了桥梁加固的意义,分析了桥梁需要加固的原因,并详细介绍了加大截面加固法、粘贴钢板加固法、粘贴碳纤维增强塑料加固法等几种常用的桥梁加固方法,以使桥梁能更好地、及时地为现代交通运输服务。     

浅谈桥梁的加固施工

根据公路旧桥加固方面的实践经验，按桥梁的组成介绍了旧桥上部及下部结构的加固技术措施，并总结了桥梁的常见加固方法，通过加固方法的实施，从而达到提高桥梁承载能力的目的。     

Structural optimization of hollow-section steel trusses by differential evolution algorithm

This paper deals with the weight minimization of planar steel trusses by adopting a differential evolution-based algorithm. Square hollow sections are considered. The design optimization refers to size, shape and topology. The design variables are represented by the geometrical dimensions of the cross sections of the different components of the truss, directly involving the size of the structure, and by some geometrical parameters affecting the outer shape of the truss. The topology is included in the optimization search in a particular way, since the designer at different runs of the algorithm can change the number of bays keeping constant the total length of the truss, to successively choose the best optimal solution. The minimum weight optimum design is posed as a single-objective optimization problem subject to constraints formulated in accordance with the current Eurocode 3. The optimal solution is obtained by a Differential Evolutionary (DE) algorithm. In the DE algorithm, a particular combination of mutation and crossover operators is adopted in order to achieve the best solutions and a specific way for dealing with constraints is introduced. The effectiveness of the proposed approach is shown with reference to two case-studies. The analysis results prove the versatility of the optimizer algorithm with regard to the three optimization categories of sizing, shape, topology as well as its high computational performances and its efficacy for practical applications. In particular useful practical indications concerning the geometrical dimensions of the various involved structural elements can be deduced by the optimal solutions: in a truss girder the cross section of the top chord should be bigger than the one of the bottom chord as well as diagonals should be characterized by smaller cross sections with respect to the top and bottom chords in order to simultaneously optimize the weight and ensure an optimal structural behaviour.     

浅谈拱桥加固方法

分析了拱桥加固的必要性,详细地介绍了几种拱桥加固的方法,指出各种维修加固技术各有其优缺点和适用性,应根据桥梁现状进行选择,以达到缩短工期、节省加固费用、满足加固要求的目的.     

试析桥梁结构检测与加固处理

当前桥梁建设施工的建筑材料质量逐渐下降,桥梁建筑施工的程序逐步简化,同时受到监督不利等因素的影响,导致目前桥梁建设事业遭受到了发展瓶颈,为此,笔者结合多年的桥梁理论经验和实际数据考察,对桥梁结构的检测和加固处理问题进行了深入的分析。     

梁板桥加固综述

根据我国桥梁技术的应用现状，明确了旧桥加固的目的，介绍了工程实践中常用的梁式桥加固方法，并对部分重要加固方法的优缺点做了详细分析，以恢复和提高旧桥的承载能力及通行能力，延长使用年限。     

桥梁加固与桥梁拓宽施工技术分析

以莱州某桥梁工程项目建设情况为例,对桥梁拓宽改建的模式进行了阐述,基于桥梁工程改扩建施工技术,从增加钢筋混凝土悬臂挑梁量、增加桥梁边梁等方面,分析了桥面扩宽改建的施工方式,并介绍了墩台位置拓宽改建的施工方式。     

Schedule-dependent evolution of site layout planning

The appropriate layout of temporary facilities on a construction site has a large impact on construction safety and productivity. For the duration of a project the site layout may need to be efficiently re-organized at various intervals to satisfy the schedule requirements and to maintain site efficiency. This paper presents a practical model for schedule-dependent site layout planning in construction. The proposed model uses a combination of artificial intelligence tools (knowledge-based systems, fuzzy logic, and genetic algorithms) to generate, optimize, and re-organize the site layout plan at frequent intervals during the project. The model incorporates flexible representation of irregular site shapes and several options for placing facilities. Based on the proposed model, an automated system is developed, fully integrated with widely used scheduling software. At each schedule interval, the system recalculates the space requirements and, for the convenience of congested sites, can utilize parts of the constructed space to accommodate temporary facilities. Details of the schedule-dependent model are described, and its application in an actual case study project is presented to demonstrate its capabilities.     

Concrete bridge surface damage detection using a single‐stage detector

Early and timely detection of surface damages is important for maintaining the functionality, reliability, and safety of concrete bridges. Recent advancement in convolution neural network has enabled the development of deep learning‐based visual inspection techniques for detecting multiple structural damages. However, most deep learning‐based techniques are built on two‐stage, proposal‐driven detectors using less complex image data, which could be restricted for practical applications and possible integration within intelligent autonomous inspection systems. In this study, a faster, simpler single‐stage detector is proposed based on a real‐time object detection technique, You Only Look Once (YOLOv3), for detecting multiple concrete bridge damages. A field inspection images dataset labeled with four types of concrete damages (crack, pop‐out, spalling, and exposed rebar) is used for training and testing of YOLOv3. To enhance the detection accuracy, the original YOLOv3 is further improved by introducing a novel transfer learning method with fully pretrained weights from a geometrically similar dataset. Batch renormalization and focal loss are also incorporated to increase the accuracy. Testing results show that the improved YOLOv3 has a detection accuracy of up to 80% and 47% at the Intersection‐over‐Union (IoU) metrics of 0.5 and 0.75, respectively. It outperforms the original YOLOv3 and the two‐stage detector Faster Region‐based Convolutional Neural Network (Faster R‐CNN) with ResNet‐101, especially for the IoU metric of 0.75.     

刚架拱桥结构检测和加固

通过对某斜腿刚架拱桥的详细检测,对桥梁运营的技术性能进行了准确评估;在此基础上经结构验算,拟定了以更换微弯板构件、加强桥面铺装、封闭裂缝等针对性的加固措施,提高了桥梁运营安全性,延长了桥梁使用寿命。     

双曲拱桥加固与数值模拟分析

详细分析了双曲拱桥的主要病害及相关治理方案,运用有限元软件ADINA进行数值建模,得出采用有限元软件计算拱桥实际荷载与边界条件,可以更为科学的计算出拱圈的变形和应力分布及其他各项物理力学指标。     

桥梁加固的新技术新方法

桥梁质量关系到该路段的路程安全以及过往行人的人身和财产安全,通过分析桥梁改造的设计原理,结合桥梁加固的新技术方法和应用实例,最终得出了桥梁加固对于提高桥梁承载力、延长桥梁使用寿命有重要作用的结论。     

桥梁结构检测与加固处理

随着桥梁崩塌事故的增多，针对桥梁的结构进行科学的检测与及时的加固处理已经成了绝大多数劣质桥梁不出现坍塌事故的唯一解决之道。此外，年久失修的桥梁也必须进行适时的结构检测与加固处理。     

某栈桥的检测与加固

通过对一大跨度栈桥在使用过程中局部开裂的检测,分析了该栈桥局部开裂的原因,提出了对该栈桥进行加固处理的措施,工程实践表明：加固效果明显,提高了结构的安全性和耐久性。     

某四类梁桥采用体外预应力法加固后试验分析

为了研究采用体外预应力加固后的桥梁实际工作状况,以实际工程为背景,采用Midas civil 2013三维有限元软件建立了结构计算模型,并对加固后桥梁进行了荷载试验,经过分析说明采用体外预应力加固方法可使该桥的承载能力满足要求,为今后类似情况的桥梁加固提供了参考依据。     

石拱桥加固技术浅析

以古北公路石河桥为例，对石拱桥病害进行了综合分析，介绍了加固修复措施，从而对加固修复全市的旧石拱桥，提高旧桥承载力，延长桥梁使用寿命，具有重要的现实指导意义。