混凝土结构火灾损伤检测

通过介绍混凝土结构火灾损伤的特点,提出混凝土损伤的检测方案,并介绍了传统火灾混凝土损伤检测方法和近几年发展起来的火灾混凝土损伤检测新技术,还分别指出它们的特点和局限性。     

大型桥梁结构损伤识别方法研究

结构损伤识别是大型桥梁综合监测系统的重要任何之一。本文介绍利用结构振动实测数据并借助于有限元模型修正技术进行桥梁结构识别的方法，包括几种用于结构损伤识别的模型修正算法，并给出解决实测自由度不足问题的两种方法，然后通过对一试验模型的模拟损伤试验，调查各理论方法的有效性和在实际结构检测中的运用情况。     

混凝土结构火灾损伤检测方法研究

分析了混凝土结构火灾损伤的特点.对国内外火灾后混凝土结构损伤的常规检测方法的研究进行了综述,系统地总结和评价这些方法的基木原理、优点和使用范围,并指出了该领域的发展方向.     

混凝土结构构件火灾损伤后的检测与加固修复

详细介绍了火灾后混凝土结构的检测内容和方法,并对火灾受损的混凝土梁板及柱提出了几种加固修复的方案,以完善钢筋混凝土结构加固补强方法,为同类工程的处理提供了参考。     

混凝土结构损伤神经网络评估方法

利用BP网络的高精度模拟特性，以评估因素的评分值作为输入建立了混凝土结构损伤评估的神经网络模型，从而得出结构损伤的评估结果；然后根据给定的标准，确定结构的损伤等级，并可据此采取相应的工程对策。     

基于振动的结构损伤识别研究综述

提供了结构基于振动的损伤识别现状综述,并结合国内现状总结出一般建筑的通用框架.首先介绍了损伤识别的基本原理并总结出基于振动的损伤识别对应于损伤响应、损伤定位、损伤量化以及损伤预测的一般流程.接下来按照损伤识别流程分别介绍了各个步骤的最新进展及应用方法.最后讨论了基于振动的损伤识别的研究方向.     

混凝土桥梁结构损伤原因分析

根据工程调查并结合前人的研究成果，系统地分析了我国混凝土桥梁结构损伤的原因，目的是为桥梁结构的规划、设计、施工和管理工作提供有针对性的建议，以确保桥梁结构的安全和正常使用。     

火灾后混凝土结构损伤检测方法探讨

分析了混凝土结构在高温作用下影响混凝土材料性质变化的因素,对近年来国内外关于混凝土受火损伤检测方法的研究进行了简述,并指出了存在的问题和今后的发展方向。     

桥梁结构损伤振动测试的识别方法

介绍了基于动测法进行结构损伤识别的不同方法，并对相关方法进行了总结和评述，探索了其他方法在结构损伤识别中的应用，提出了损伤识别中有待解决的问题及其发展前景。     

拔出法检测结构混凝土强度

混凝土强度的压力试验法数十年来已为国内外工程界奉为公认的标准。但是,这种试验方法并不尽人意,最明显的缺点是立方体或圆柱体试件的压力试验结果往往不能真实地反映结构混凝土的实际强度。因此,人们一直在寻找可靠和便捷的检测结构混凝土强度的新方法,其中有些测试方法,诸如回弹法、超声法、射入法以及各种综合法,已不同程度地得到应用。混凝土强度的拔出试验     

土木工程结构损伤诊断研究现状与展望

阐述了结构损伤诊断技术在土木工程结构中的重要性，在综述结构损伤诊断研究现状的基础上，重点介绍了用于土木工程结构的各种损伤诊断方法，并对相关问题进行了讨论和评述，最后对土木工程结构损伤诊断的未来研究方向提出了建议与展望。     

土木工程结构损伤检测的研究概述

介绍了基于振动的损伤识别方法的研究现状,根据响应数据种类的不同,将基于观测响应的结构损伤识别方法作了综述,同时指出了损伤识别方法还需要进一步解决的问题,从而推广土木工程结构损伤检测技术的应用。     

谈基于结构动力响应的结构损伤检测

结合结构当前的服役状况,分析了对结构进行损伤检测的必要性和重要性,并对基于结构动力响应的结构损伤检测方法进行了介绍,探讨了该方法的优缺点和适用范围,指出了该方法的应用前景和需进一步研究的方向。     

New method for structural damage detection based on generalised displacement

In this paper, a new structural damage detection approach based on changes in the generalised displacement is presented. The generalised displacement is first introduced, its curvature and change are then used to detect structural damage location. Compared with the conventional approach using the original displacement, the generalised displacement method is more effective and is more robust to the noise factors in this new approach. Finally, a numerical example for two-span beam is used to illustrate the effectiveness of this proposed method.     

高混凝土面板堆石坝地震损伤机理研究

以紫坪铺面板堆石坝为例,基于堆石料的黏弹性模型和地震残余应变模型计算分析了高混凝土面板堆石坝的地震响应,并结合震害调查结果分析了高混凝土面板堆石坝的地震损伤机理。研究表明,输入地震加速度在坝顶附近和坝坡表面显著放大,呈现出显著的鞭梢效应,导致坝顶和下游坝坡上部堆石体松动滚落。地震导致大坝堆石体产生显著剪缩,坝体断面整体向内收缩,刚性混凝土面板与垫层料之间脱空,脱空后面板与垫层料之间的摩擦力大幅减小甚至消失,面板在自重和地震惯性力联合作用下向下滑动,致使面板水平施工缝发生错台,面板表面产生裂缝。地震还导致岸坡附近左右坝段堆石体向河谷中央位移,致使岸坡附近面板垂直接缝发生拉伸破坏,河床中部垂直接缝及附近混凝土面板发生挤压破坏。数值计算和震害调查结果均表明,高混凝土面板堆石坝的地震损伤现象主要与其堆石体地震残余变过大,以及堆石体与防渗系统之间变形不协调密切相关,故强震区修建高面板坝应尽可能提高堆石体压实密度,以减小坝体的地震残余变形。     

模态应变能法结构损伤检测研究

结合摄动理论，通过分析结构参数修改量高阶项的影响，推导了基于单元模态应变能的结构损伤评估方法；经数值仿真结果表明，其损伤定位准确、程度评估可靠，具有实际应用价值。     

水工混凝土常见损伤及检测方法

水工混凝土是水利工程主要建筑材料之一。受外界荷载及水环境影响,水工混凝土内不可避免会出现裂缝等损伤危及结构安全。本文对混凝土内常见损伤进行分类,对目前水工混凝土损伤检测技术进行总结,以期指导水利工程健康检测,从而提高其安全性能并延长服役寿命。     

Experimental evaluation of a vibration-based leak detection technique for water pipelines

Conventional water pipeline leak detection surveys employ labour-intensive acoustic techniques, which are usually expensive and not amenable for continuous monitoring of distribution systems. Many previous studies attempted to address these limitations by proposing and evaluating a myriad of continuous, long-term monitoring techniques. However, these techniques have difficulty to identify leaks in the presence of pipeline system complexities (e.g. T-joints), offered limited compatibility with popular pipe materials (e.g. PVC), and were in some cases intrusive in nature. Recently, a non-intrusive pipeline surface vibration-based leak detection technique has been proposed to address some of the limitations of the previous studies. This new technique involves continuous monitoring of the change in the cross-spectral density of surface vibration measured at discrete locations along the pipeline. Previously, the capabilities of this technique have been demonstrated through an experimental campaign carried out on a simple pipeline set-up. This paper presents a follow-up evaluation of the new technique in a real-size experimental looped pipeline system located in a laboratory with complexities, such as junctions, bends and varying pipeline sizes. The results revealed the potential feasibility of the proposed technique to detect and assess the onset of single or multiple leaks in a complex system.     

An efficient method for structural damage detection using a differential evolution algorithm-based optimisation approach

An efficient method employing the differential evolution algorithm (DEA) as an optimisation solver is presented here to identify the multiple damage cases of structural systems. Natural frequency changes of a structure are considered as a criterion for damage occurrence. The structural damage detection problem is first transformed into a standard optimisation problem dealing with continuous variables, and then the DEA is utilised to solve the optimisation problem for finding the site and extent of structural damage. In order to assess the performance of the proposed method for structural damage identification, some illustrative examples are numerically tested, considering also measurement noise. All the numerical results demonstrate the effectiveness of the proposed method for accurately determining the site and extent of multiple-structural damage. Also, the performance of the DEA for damage detection compared to the standard particle swarm optimisation is confirmed by a test example.     

Novel vibration-based technique for detecting water pipeline leakage

Exacerbating the imbalance between demand for freshwater and available water resources is the sub-optimal performance of water distribution systems, which are plagued with leaks that cause significant losses of treated freshwater. This paper presents an approach for leak detection that involves continuous monitoring of the changes in the correlation between surface acceleration measured at discrete locations along the pipeline length. A metric called leak detection index is formulated based on cross-spectral density of measured pipe surface accelerations for detecting the onset and assessing the severity of leaks. The proposed non-invasive approach requires minimal human intervention and works under normal operating conditions of the pipeline system without causing any operational disturbances. The approach is demonstrated on a 76 mm diameter polyvinyl chloride pipeline test system considering varying leak severities. The preliminary results presented in this paper seem promising and lead to several interesting questions that will require further research.