冲击回波法检测装配式混凝土结构浆锚搭接灌浆饱满度的试验研究

针对目前装配式混凝土结构的浆锚搭接灌浆饱满度缺乏有效的无损检测技术,研究了基于冲击回波的无损检测方法测试单筋和钢筋集中束浆锚连接节点灌浆饱满度。介绍了扫描式冲击回波法检测混凝土结构缺陷的原理及方法。详细阐述了采用扫描式冲击回波法检测设有大、小直径波纹管试件及实际工程中装配式剪力墙波纹管浆锚搭接节点的测试结果,且总体测试结果良好;通过对冲击回波频谱图、名义厚度的分析,得出扫描式冲击回波法可较准确地判断金属波纹管内灌浆的饱满度的结论。     

冲击回波法检测装配式混凝土结构浆锚搭接灌浆饱满度的应用研究

针对目前装配式混凝土结构的浆锚搭接灌浆饱满度缺乏有效的无损检测技术,以某一装配式混凝土结构工程为背景,研究基于冲击回波的无损检测方法在工程中的应用及测试效果。详细阐述了冲击回波法现场检测某装配式混凝土工程剪力墙波纹管浆锚搭接节点灌浆饱满度的测试过程,分析了三种典型墙体波纹管连接节点测试结果的频谱图和名义厚度图;通过对频谱图、名义厚度图的分析,以及局部取芯验证,得出冲击回波法可准确判断金属波纹管内灌浆的饱满度,总体测试结果准确。     

冲击回波法检测预应力箱梁管道灌浆质量的室内试验研究

制作室内模型模拟预应力箱梁顶底板及腹板管道典型的灌浆状况,采用了冲击回波法进行检测。实测发现,管道材质对测试结果无明显影响,而腹板与顶底板有灌浆缺陷管道的冲击回波响应有较大不同,实验表明,冲击回波法可准确判别管道内缺陷及其位置。     

如何利用冲击回波法检测混凝土结构缺陷

正冲击回波法是一种建立在低频应力波传播特点基础上的无损检测方法,具有单面检测、检测精度高等特点。经试验证明冲击回波法可较准确地检测混凝土结构内部缺陷情况,适用于水利工程、建筑工程、隧道工程等。笔者以不同内部缺陷混凝土试件为基础,使用冲击回波法对其进行试验以获取相应的识别方法和缺陷测定方法。结果表明,冲击回波法具有较高的测量精度,且可通过单面测量进行,作为一种新型的无损检测技术,其应用价值较高。     

冲击回波法测量混凝土厚度

冲击回波法是基于瞬态应力波应用于无损检测的一种技术,它可以探测结构混凝土厚度及其内部缺陷的位置。本文阐述了该方法的基本原理,并列举了一些工程测试的实例     

冲击回波法检测预应力预留孔灌浆质量

预应力预留孔的灌浆质量一直是人们关心的问题 ,传统的超声波检测方法由于受测试条件、判断方法等因素的影响 ,往往难以对其进行检测。冲击回波法 (Impact echoMethod)是近 10年研究和发展起来的一项新的无损检测技术[1,2 ] 。该方法的优点是 :可单点测试 ,其结果反映的是测点处混凝土内部的质量情况 ;检测仅需 1个测试面 ,测试结果客观。为研究冲击回波法检测预应力孔灌浆质量 ,笔者进行了室内试验及工程实际检测。图 1　测试原理　1　测试原理冲击回波法检测预应力预留孔灌浆质量[3 ] 的原理如图 1所示。在预留孔位置的混凝土表面施加瞬…     

用冲击回波法检测混凝土质量的结构模型试验

介绍了冲击回波法在工程质量检测中的基本原理。通过模型试验研究了冲击回波法检测混凝土质量缺陷的可行性。模型试验结果表明冲击回波法可检测表面裂缝深度、板状体厚度以及探测混凝土浅部不密实体或架空等质量缺陷,是一种有效、快速的无损检测方法。     

装配式混凝土结构叠合构件结合面缺陷检测试验研究

采用冲击回波法、雷达法及超声CT对装配式混凝土结构叠合构件结合面缺陷检测进行试验研究.考虑缺陷深度、类型等参数,共设计制作了4个试验构件.采用IE-Scanner扫描式冲击回波仪、PS1000混凝土透视仪、A1040 MIRA混凝土超声断层扫描仪分别对4个试验构件结合面缺陷进行检测,并通过钻芯进行验证.试验结果表明,冲击回波法和超声CT均能检测叠合构件结合面的缺陷,其中超声CT还能准确定位缺陷的埋置深度,而雷达仅能检测到不位于钢筋下的结合面缺陷.实际叠合构件缺陷检测时,应首先采用扫描式冲击回波仪进行大范围快速检测,初步确定缺陷位置,然后采用超声CT对缺陷大小及埋深进行详细检测.     

冲击回波法检测翼墙面板混凝土内部缺陷研究

介绍了冲击回波法的检测原理,采用该方法检测了某水闸上游扶壁式翼墙面板混凝土内部缺陷,并通过超声法与钻孔法,验证了检测结果的准确性,指出冲击回波法是一种能应用于水利工程混凝土结构内部缺陷的无损检测方法。     

基于冲击回波法对混凝土预制箱梁梁板厚度及缺陷检测技术的应用

介绍了冲击回波法相对于其它无损检测手段的优越性,详尽的说明冲击回波法的检测原理,分析冲击弹性波的反射特性,并进行室内模型梁对比试验和实际工程验证试验。试验结果表明:冲击回波法能准确地检测出预制混凝土梁板厚度,可以有效评定预制混凝土梁的内部质量,冲击回波在边界、缺陷间的反射形成的频谱曲线与预制混凝土梁板结构内部缺陷的有无有很好的相关性。     

Modified SIBIE procedure for ungrouted tendon ducts applied to scanning impact-echo

The impact-echo method has been successfully applied to identify defects inside concrete. In addition, to detect ungrouted tendon ducts in a large concrete slab, a scanning impact-echo technique is developed. However, since resonant frequencies in the spectrum responsible for the travel paths via defects are only taken into account, the method could lead to erroneous results due to complicated spectra obtained in the tests. Consequently, Stack Imaging of spectral amplitudes Based on Impact-Echo (SIBIE) procedure has been developed to improve the data interpretation.Conventionally, SIBIE is applied to a single measurement data and a point information of defects is obtained at the area, where the impact test is performed. In this study, SIBIE is applied to scanning impact-echo data. Locations of ungrouted tendon ducts embedded in a large concrete specimen are investigated. In order to visualize the whole cross-section tested, the SIBIE analysis is modified, introducing an elliptical integration mode. It is demonstrated that ungrouted tendon ducts are successfully located by the modified SIBIE analysis, whereas results of the conventional B-scan analysis are not so good as the modified SIBIE analysis.     

On-site measurement of delamination and surface crack in concrete structure by visualized NDT

On-site measurement in concrete piers of a highway structure was conducted by visualized non-destructive testing (NDT). First, the radar technique was applied to identify delaminated areas between pre-stressed concrete (PC) panels covered and original concrete piers. By applying the impact-echo method, Stack Imaging of spectral amplitudes Based on Impact-Echo (SIBIE) procedure is developed as an imaging technique, which can visually display a cross-sectional view based on the impact-echo data. In order to identify voids in delaminated areas and depths of surface cracks, then the impact-echo tests were conducted. From these results, a superior applicability of the SIBIE procedure to on-site measurement is demonstrated in existing concrete structures.     

冲击回波法测量混凝土厚度

冲击回波法是基于瞬态应力波于无损检测的一种技术,它可以探测结构砼厚度及其内部缺陷。阐述了该方法的基本原理及在检测中应注意的若干问题,并列举了一些工程测试的实例。     

利用瑞利波频谱分析法无损检测混凝土结构

本文系统的阐述了瑞利渡频谱分析法的原理、试验设备、试验方法和检测混凝土结构的优越性，通过对瑞利波特性的分析表明瑞利波频谱分析法在检测大体积、层状混凝土结构质量和确定结构中半闭合或充有水的裂缝的深度比其他（冲击回波法和超声脉冲法）检测方法具有较高的精度。     

BEM analysis of dynamic behavior of concrete in impact-echo test

The impact-echo method is well known as a non-destructive testing for concrete structures. Taking out resonant frequencies responsible for locations of reflectors in frequency spectra, locations of reflectors are determined. In order to improve the impact-echo method and to visually identify locations of reflectors, a new procedure has been developed by applying an imaging procedure to the data, as stack imaging of spectral amplitudes based on impact-echo (SIBIE). Concrete slabs containing ungrouted tendon ducts were tested by applying SIBIE procedure. Reflectors near the duct can be visualized clearly by SIBIE. Here, the procedure is theoretically investigated by the boundary element method (BEM). Two-dimensional BEM analysis is conducted to investigate stress distributions and dynamic deformations at frequencies corresponding to the resonances. Results show that by changing frequencies, stress distributions and deformation modes change. The cross-section deforms like a plate, generating other resonant frequencies of in-plane modes.     

混凝土结构内部缺陷的两步诊断法

针对混凝土结构内部缺陷构建了一种两步诊断评价方法.该方法先采用探地雷达对结构物进行整体评价,再结合冲击回波技术对雷达检测异常区域进行定位,进而对结构内部缺陷类型和位置加以判定.试验研究和工程应用结果表明:该诊断方法在混凝土内部结构缺陷的定性和定位评价中,具有全面、高效、准确的优点,在实际工程检测中取得了良好的效果.     

联肢钢板-混凝土组合剪力墙性能化设计方法及静力弹塑性分析

为代替传统的钢筋混凝土剪力墙,充分发挥组合剪力墙结构体系的良好抗震性能,使其易于满足9度抗震设防的设计要求,同时控制墙肢的厚度,以便获取更大的建筑使用面积,钢板-混凝土组合剪力墙被设计应用于9度区高层建筑结构中。根据LEELATAVIWAT等提出的塑性设计方法,并结合对应的内力调整措施,对基于能量平衡的组合联肢剪力墙结构塑性设计方法进行了相关梳理和推导。并且在9度抗震设防条件下,基于此方法设计了12个联肢组合剪力墙结构算例,采用ABAQUS有限元软件对12个算例进行静力弹塑性分析及抗震性能研究。同时对各个结构算例的静力推覆曲线、结构整体屈服、墙肢内力、连梁剪力发展规律以及结构耦连比指标发展规律进行讨论分析。结果表明,12个结构算例中,耦连比的发展规律在单向推覆分析中符合理论和设计的基本预期,说明联肢组合剪力墙结构的"双重抗震防线"机制目标在基于能量平衡的塑性设计方法中能够较好地得到实现。     

Prediction of rebar profile in a earth retaining RCC structure using cover meter survey

Reinforced concrete retaining walls are generally used for the construction of underground structures, such as coal handling systems, underground subways and railway stations. In some exceptional cases, the retaining walls are used as structural walls for supporting other structures besides retaining the earth. The retaining wall construction is a highly specialized job requiring multidisciplinary activities. One of the major problems is to make a good quality construction ensuring good integral concrete and adequate cover thickness to the rebar cage. In many projects, construction deficiency in the form of exposure of reinforcement and lack of cover occurred at the excavated face of a retaining wall, which posed a challenging problem of determining the actual available cover thickness at the soil face. This problem was addressed by carrying out cover thickness survey and concrete surface profile at the excavated face, based on which a prediction can be made on the rebar cage profile and the available cover thickness at the soil face. This approach and methodology are highlighted in this paper.     

城市隧道混凝土墙火灾行为数值模拟研究

为探究火灾作用下城市隧道混凝土墙的火灾行为规律,用有限元软件ABAQUS 建立三维混凝土墙数值模型,对其结构温度场分布进行数值模拟,分析得到墙体厚度、保护层厚度、火灾荷载比等因素对墙体变形的影响规律。结果表明：在火灾高温作用下,城市隧道混凝土墙受火面温度迅速升高,且由于混凝土的热惰性,内部会形成较大的温度梯度;混凝土墙体单面受火时的挠度变化规律可分为三个阶段,且火灾高温作用引起材料性能急剧劣化造成的截面中和轴偏移是影响墙体挠度变化的主要原因;混凝土墙体厚度、保护层厚度及火灾荷载比等因素对混凝土墙的火灾行为及其耐火性能均有一定影响,同时墙体挠度随火灾持续时间的增加而增大。     

Seismic performance analysis and evaluation of tall structures using grille-type steel plate composite shear walls

Grille-type steel plate composite (GSPC) shear wall is an innovative wall system consisting of concrete cores, steel faceplates, steel tie plates, and steel channels with more advantages than conventional reinforced concrete (RC) walls, including better ductility, higher bearing capacity, and easy-modular characteristics. This paper mainly discusses the seismic performance and damage resistance of GSPC walls to the entire structure from the aspect of the structural level. Three nonlinear numerical models of high-rise structures with different structural heights and types were established by PERFORM-3D software to study the influence of GSPC walls on the change in structural internal forces and deformations compared with RC walls. One of these structures was selected to conduct the seismic fragility analysis based on the incremental dynamic analysis and to assess the structure's seismic performance with GSPC walls. Finally, the seismic damage prediction method was used to evaluate the damage levels of the GSPC wall structure. Results indicate that the structures with GSPC walls suffer more significant seismic forces than those with RC walls, although they experience lesser structural deformations. Moreover, GSPC walls can effectively improve the structure's collapse and seismic damage resistance.