期刊文献+
共找到19篇文章
< 1 >
每页显示 20 50 100
Analytical Study of Mechanism of Concrete Cracking and Its Propagation Due to Corrosion of Reinforcement in RCC
1
作者 A. M. Jadhav H. K. Munot 《Open Journal of Civil Engineering》 2016年第2期286-294,共9页
The experimental results which were carried out by different researchers on corrosion of RCC beam were validated in ABAQUS. A finite element (FE) model similar to experimental condition was generated in ABAQUS. The mo... The experimental results which were carried out by different researchers on corrosion of RCC beam were validated in ABAQUS. A finite element (FE) model similar to experimental condition was generated in ABAQUS. The model with different percentages of corrosion and with varying load conditions was also generated. The deflections of RCC beam for different corrosion percentages and for varying load conditions were then validated. The model is then used to explore the effects of bar radial expansion, due to formation of corrosion products, on the cracking of cover concrete. The predictions are compared with tests results from reinforced concrete accelerated corrosion specimens. The aim of the analytical investigation was to reveal the mechanism for the development of concrete cracking due to corrosion of reinforcement. Further the finite element model will be used to explain qualitatively the experimentally determined relationship between amount of corrosion for concrete cracking and ratio of concrete cover to bar diameter, as well as that between reinforcement bond strength and amount of corrosion. 展开更多
关键词 Corrosion of Reinforcement cracking of concrete Finite Element ABAQUS
下载PDF
A numerical case study on the long-term seismic assessment of reinforced concrete tunnels in corrosive environments 被引量:1
2
作者 Maria Antoniou Antonios Mantakas +1 位作者 Nikolaos Nikitas Raul Fuentes 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第3期551-572,共22页
The paper investigates the long-term seismic behaviour of an underground reinforced concrete(RC)metro tunnel in Santiago,Chile,considering the combined effects of chloride-induced corrosion and cumulative,low-amplitud... The paper investigates the long-term seismic behaviour of an underground reinforced concrete(RC)metro tunnel in Santiago,Chile,considering the combined effects of chloride-induced corrosion and cumulative,low-amplitude seismic shaking on the structure’s performance.The soil-tunnel response is evaluated with the aid of transient,nonlinear finite element analysis using a two-dimensional(2D)plane strain numerical model that adopts advanced nonlinear models for the simulation of soil and concrete plasticity and the dynamic stiffness behaviour.The effects of corrosion deterioration are demonstrated in terms of time-dependent loss of rebar area and cover concrete stiffness and strength.The study illustrates the influence of ageing and repeated seismic shaking on lining deformation,crack development,and the modal characteristics of the intact and degrading systems.The results indicate that multiple lowamplitude events drive the non-degrading RC tunnel beyond its elastic regime without significant structural response consequences.A noticeable impact of corrosion deterioration on the structure’s seismic performance is revealed,increasing with the number and intensity of earthquake events.Two different tunnel embedment depths are comparatively assessed.The analyses demonstrate larger coseismic section convergence in the case of the deeper tunnel,yet a less pronounced effect of ageing and successive seismic loading compared to the shallow section,which is evident in the RC lining cracks at the end of shaking. 展开更多
关键词 TUNNELS Reinforcement corrosion Ageing EARTHQUAKES Numerical modelling Long-term performance concrete cracking behaviour
下载PDF
Simulation of the Cracking and Ablation Behavior of Ferrosiliceous and Siliceous Nuclear Sacrificial Concretes
3
作者 蒋金洋 YU Yingjun +3 位作者 CHU Hongyan SUN Wei GAO Yun SHE Wei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第5期982-988,共7页
We investigated the simulation of the cracking and ablation behavior of ferro-siliceous and siliceous nuclear sacrificial concretes. To this end, four type of sacrificial concretes were fabricated, i e, the ferro-sili... We investigated the simulation of the cracking and ablation behavior of ferro-siliceous and siliceous nuclear sacrificial concretes. To this end, four type of sacrificial concretes were fabricated, i e, the ferro-siliceous(F) and siliceous(S) plain concretes, and the polypropylene fiber reinforced concretes of the above two(FF, SF). The cracking and ablation behaviors of the sacrificial concretes were investigated by simulation tests, and the simulated elevated temperature was obtained by means of thermite powder. The number and the width of the cracks were compared and the pore size distribution of sacrificial concretes was measured. In addition, the interface and chemical composition of melt at different positions were analyzed, and the ablation depth of the sacrificial concrete crucibles was also measured. It was found that the siliceous concrete shows to be more prone to cracking than the ferro-siliceous concrete due to the higher content of fly ash and lower water to binder ratio; though the ablation depth of siliceous concrete is found to be slightly larger, no clear difference can be detected for the basemat ablation rate. 展开更多
关键词 sacrificial concrete cracking ablation MCCI high temperature
下载PDF
Evaluation method of cracking resistance of lightweight aggregate concrete 被引量:7
4
作者 季韬 张彬彬 +1 位作者 陈永波 庄一舟 《Journal of Central South University》 SCIE EI CAS 2014年第4期1607-1615,共9页
The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship betw... The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack. 展开更多
关键词 ceramsite type cracking resistance lightweight aggregate concrete evaluation index evaluation method
下载PDF
Cracking Propagation of Hardening Concrete Based on the Extended Finite Element Method 被引量:2
5
作者 朱振泱 CHEN Weimin ZHANG Guoxin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第5期1132-1139,共8页
Self-deformation cracking is the cracking caused by thermal deformation, autogenous volume deformation or shrinkage deformation. In this paper, an extended finite element calculation method was deduced for concrete cr... Self-deformation cracking is the cracking caused by thermal deformation, autogenous volume deformation or shrinkage deformation. In this paper, an extended finite element calculation method was deduced for concrete crack propagation under a constant hydration and hardening condition during the construction period, and a corresponding programming code was developed. The experimental investigation shows that initial crack propagation caused by self-deformation loads can be analyzed by this program. This improved algorithm was a preliminary application of the XFEM to the problem of the concrete self-deformation cracking during the hydration and hardening period. However, room for improvement exists for this algorithm in terms of matching calculation programs with mass concrete temperature fields containing cooling pipes and the influence of creep or damage on crack propagation. 展开更多
关键词 concrete crack self-deformation loads extended finite element method
下载PDF
Analysis of Concrete Crack Treatment Technologies in Buildings
6
作者 Wenyu Zheng 《Journal of Architectural Research and Development》 2023年第4期57-63,共7页
With the continuous development of civil engineering,concrete crack treatment technology has become an important research field.This paper proposes treatment techniques for different types of cracks,including the prev... With the continuous development of civil engineering,concrete crack treatment technology has become an important research field.This paper proposes treatment techniques for different types of cracks,including the prevention and repair of surface cracks,the reinforcement and grouting of structural cracks,and the design and construction of controlled cracks through the analysis of the causes and classification of concrete cracks.The methods and suggestions proposed in this paper are practical and can improve the quality and safety of buildings. 展开更多
关键词 Civil engineering concrete cracks Construction treatment technology Structural damage Safety hazards
下载PDF
Model of the Bearing Capacity of Concrete Little Eccentric Compressive Flexural Members Affected by Rebar Corrosion
7
作者 张克强 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第z1期108-111,共4页
The assessment for bearing capacity of corroded RC members is one of the main component of durability study on RC structure. But few researches had been developed for the study of corroded RC eccentric especially litt... The assessment for bearing capacity of corroded RC members is one of the main component of durability study on RC structure. But few researches had been developed for the study of corroded RC eccentric especially little eccentric compressive members. By discussing the effect of factors, such as decrease of concrete strength in biaxial stress condition during pre-cracking stage and torsion buckling of local cracking concrete during post-cracking stage, on the bearing capacity of little eccentric RC members, the model of bearing capacity is established respectively, which the cracking damage coefficient of concrete k is suggested to be 0.15 in post-cracking stage. The experimental certification shows: model calculation fits well with experimental result, which proves the effectiveness of the model in this paper. 展开更多
关键词 little eccentric compressive flexure members biaxial stress concrete cracking torsion buckling
下载PDF
Effect of Concrete Cracks on Dynamic Characteristics of Powerhouse for Giant-Scale Hydrostation 被引量:2
8
作者 田子勤 张运良 +1 位作者 马震岳 陈婧 《Transactions of Tianjin University》 EI CAS 2008年第4期307-312,共6页
With the increase of capacity and size of the hydro-generator unit, the spiral case becomes a more super-giant hydraulic structure with very high HD value, where H and D denote water head and maximum intake diameter o... With the increase of capacity and size of the hydro-generator unit, the spiral case becomes a more super-giant hydraulic structure with very high HD value, where H and D denote water head and maximum intake diameter of spiral case, respectively. Due to the induced lower stiffness by the more giant size and adverse operation conditions, dynamic performances of the powerhouse and the supporting structure for the giant units have become more important and attracted much attention. If the manner of steel spiral case embedded directly in concrete is adopted, on some locations of the concrete surrounding the spiral case, distributed and concentrated cracks will emerge due to high tensile stress. Although the concrete is reinforced well to control the maximum crack width, definitely these cracks will reduce the local and entire stiffness of the powerhouse. Under dynamic loads such as hydraulic forces including water pressure pulsation in flow passage acting on the structure, effect of the cracks on the dynamic characteristics of the local members and entire structure needs to be evaluated. However, research on this subject is few in hydroelectric engineering. In this paper, Three-Gorge Project was taken as an example to evaluate effect of such cracks on natural frequencies and the vibration responses of the powerhouse under hydraulic and earthquake forces in detail. Results show that cracks only reduce the local structural stiffness greatly but have little effect on the entire powerhouse especially the superstructure; vibrations of powerhouse with cracks in concrete surrounding the spiral case are still under the design limits. Results in this paper have been verified by practice of Three-Gorge Project. 展开更多
关键词 giant-scale hydrostation POWERHOUSE concrete crack dynamic characteristics numerical simulation
下载PDF
Chloride diffusivity in flexural cracked Portland cement concrete and fly ash concrete beams 被引量:1
9
作者 陆春华 崔钊玮 +1 位作者 刘荣桂 刘奇东 《Journal of Central South University》 SCIE EI CAS 2014年第9期3682-3691,共10页
In order to examine the effect of load-induced transverse cracks on the chloride penetration in flexural concrete beams, two different concretes, Portland cement concrete(PCC) and fly ash concrete(FAC), were tested wi... In order to examine the effect of load-induced transverse cracks on the chloride penetration in flexural concrete beams, two different concretes, Portland cement concrete(PCC) and fly ash concrete(FAC), were tested with various crack widths. Total 14 reinforced concrete(RC) beams, ten of which were self-anchored in a three-point bending mode, were immersed into a 5% NaCl solution with the condition of dry-wet cycles. Then, the free chloride ion contents were determined by rapid chloride testing(RCT) method. Based on the proposed analytical models of chloride penetration in sound and cracked concrete subjected to dry-wet cycles, the apparent chloride diffusion coefficient and chloride diffusivity of concrete were discussed. It can be found that the performance of chloride diffusivity in both concretes will be improved with the increase of crack width, and that the influence of convection action will also be augmented. Based on the two samples obtained in sound concrete after 15 and 30 cycles, the time-exponent, m, for chloride diffusion coefficient was determined to be 0.58, 0.42, 0.62 and 0.77 for PCC1, PCC2, FAC1 and FAC2 specimens, respectively. Finally, two influencing factors of fly ash content and crack width on chloride diffusivity were obtained by regression analysis of test data, and it can be seen that factors kf and kw can be expressed with quadratic polynomial functions of fly ash content, f, and crack width, w, respectively. 展开更多
关键词 flexural cracked concrete fly ash chloride dry-wet cycle equivalent chloride diffusion coefficient
下载PDF
Fracture characteristics and ductility of cracked concrete beam post-strengthened with CFRP Sheet 被引量:1
10
作者 易富民 董伟 +1 位作者 赵艳华 吴智敏 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2011年第3期5-10,共6页
The present paper concerns the fracture characteristics and ductility of cracked concrete beam externally bonded with carbon fiber-reinforced polymer (CFRP) sheet as well as the integration behaviors between CFRP/conc... The present paper concerns the fracture characteristics and ductility of cracked concrete beam externally bonded with carbon fiber-reinforced polymer (CFRP) sheet as well as the integration behaviors between CFRP/concrete interfacial debonding and concrete cracking.Three-point bending tests were carried out on the CFRP-strengthened cracked concrete beams with varying specimen depth and initial crack length.A straingauge method was developed to monitor the crack initiation and propagation in concrete,and the CFRP/concrete interfacial bonding behaviors,respectively.Clip gauges were used to measure crack mouth opening displacement (CMOD) and the deflection at midspan.Experimental results revealed that CFRP-strengthened specimen shows a higher load capacity under the same deformation level and a better inelastic deformation capacity compared with the unstrengthened one.For there are two manifest peak values in the obtained load versus displacement curve,the ductility of CFRP-strengthened concrete beams were investigated using index expressed as area ratio on the load versus displacement curve.The calculated results indicated that the contribution from CFRP sheet to the ductility improvement of specimen is notable when the deflection at midspan exceeded 10.5 times the first-crack deflection. 展开更多
关键词 FRP composites cracked concrete beam fracture characteristics DUCTILITY
下载PDF
Hydration Process and Crack Tendency of Concrete Based on Resistivity and Restrained Shrinkage Crack 被引量:1
11
作者 MUAZU Bawa Samaila 魏小胜 WANG Lei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第5期1026-1030,共5页
Hydration process, crack potential and setting time of concrete grade C30, C40 and C50 were monitored by using a non-contact electrical resistivity apparatus, a novel plastic ring mould and penetration resistance meth... Hydration process, crack potential and setting time of concrete grade C30, C40 and C50 were monitored by using a non-contact electrical resistivity apparatus, a novel plastic ring mould and penetration resistance methods, respectively. The results show the highest resistivity of C30 at the early stage until a point when C50 accelerated and overtook the others. It has been experimentally confirmed that the crossing point of C30 and C50 corresponds to the final setting time of C50. From resistivity derivative curve, four different stages were observed upon which the hydration process is classified; these are dissolution, induction, acceleration and deceleration periods. Consequently, restrained shrinkage crack and setting time results demonstrated that C50 set and cracked the earliest. The cracking time of all the samples occurred within a reasonable experimental period thus the novel plastic ring is a convenient method for predicting concrete's crack potential. The highest inflection time(t_i) obtained from resistivity curve and the final setting time(t_f) were used with crack time(t_c) in coming up with mathematical models for the prediction of concrete's cracking age for the range of concrete grade considered. Finally, an ANSYS numerical simulation supports the experimental findings in terms of the earliest crack age of C50 and the crack location. 展开更多
关键词 concrete electrical resistivity restrained shrinkage crack setting time finite element simulation
下载PDF
Characterisation of Bacteria⁃Based Concrete Crack Rejuvenation by Externally Applied Repair
12
作者 Jie Yuan Xin Chen +2 位作者 Mohamed Alazhari Bo Yang Guorong Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2020年第4期20-30,共11页
Microbiologically⁃induced calcite⁃precipitation(MICP)has been increasingly studied in structural repair including self⁃healing and external applications.Among various MICP pathways,enzymatic urea hydrolysis is suggest... Microbiologically⁃induced calcite⁃precipitation(MICP)has been increasingly studied in structural repair including self⁃healing and external applications.Among various MICP pathways,enzymatic urea hydrolysis is suggested to be applied as external repair instead of self⁃healing.This study comprehensively characterised the enzymatic urea hydrolysis pathway in physical,impermeable,and mechanical rejuvenation of concrete cracks.The visual quality of repaired structures was presented,and the importance of humidity in the remediation of cracks was demonstrated.Moreover,this study investigated the differences in the effectiveness of repair between premixing bacteria with urea and without any premixing.With premixing,there was a concern that the accelerated reactions would precipitate calcite in the shallow spaces of the cracks and impede deeper healing.However,the observed results indicated that neither physical nor impermeable rejuvenation of concrete cracks repair would be detrimentally affected.The results obtained from this study will allow further development in commercialisation since the effectiveness of repair has been confirmed with an improvement in its efficiency. 展开更多
关键词 concrete crack REJUVENATION BACTERIA repair agent relative humidity IMPERMEABILITY chloride penetration flexural strength
下载PDF
Effect of Pulse Parameters on Deposition in Concrete Crack using Pulse Current Electro-deposition
13
作者 储洪强 WANG Tingting +4 位作者 JIANG Linhua XU Yi SONG Zijian XU Ning ZHAO Sujing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第4期908-914,共7页
To evaluate the effect of pulse parameters on the formation of electrodeposits in concrete cracks, five different types of pulse current were set up, and ZnSO_4 and MgSO_4 solutions were used as the electrolytes. The ... To evaluate the effect of pulse parameters on the formation of electrodeposits in concrete cracks, five different types of pulse current were set up, and ZnSO_4 and MgSO_4 solutions were used as the electrolytes. The rate of weight gain, rate of surface coating, rate of crack closure and crack filling depth were measured. Scanning electron microscopy was used to assess the morphology of the electrodeposits, and energy dispersive spectroscopy was used to analyze the mineral composition of the electrodeposits in the cracks. The experimental results demonstrate that, among five different pulse parameters, when T_(on)/T_(off)=0.8 ms/0.8 ms, the healing effect of electro-deposition is the best. The pulse mode hardly affects the mineral composition of the electrodeposits but changes the micromorphology. In addition, for both ZnSO_4 and MgSO_4 solutions, when T_(on)/T_(off)=0.8 ms/0.8 ms, the crystal structure of the electrodeposits is the most uniform and the densest. 展开更多
关键词 pulse electro-deposition repair of concrete cracks pulse parameters healing effect
下载PDF
Research on Concrete Beam Crack Recognition Algorithm Based on Block Threshold Value Image Processing
14
作者 Wenting Qiao Xiaoguang Wu +1 位作者 Wen Sun Qiande Wu 《Structural Durability & Health Monitoring》 EI 2020年第4期355-374,共20页
To solve the problem that the digital image recognition accuracy of concrete structure cracks is not high under the condition of uneven ill umination and complex surface color of concrete structure,this paper has prop... To solve the problem that the digital image recognition accuracy of concrete structure cracks is not high under the condition of uneven ill umination and complex surface color of concrete structure,this paper has proposed a block segmentation method of maximum entropy threshold based on the digital image data obtained by the ACTIS automatic detection system.The steps in this research are as follows:1.The crack digital images of concrete specimens with typical fea-tures were collected by using the Actis system of KURABO Co,Ltd,of Japan in the concrete beam bending test.2.The images are segmented into blocks to dis-tinguish backgrounds of different grayscale.3.The max imum interclass average gray difference method is used to distinguish the sub-blocks and screen out the image blocks that need to be segmented.4.Segmentation is made to the image with 2D max imum entropy threshold segmentation method to obtain the binary image,and the target image can be obtained by screening the connected domain features of the binary image.Results have shown that compared with other algo-rithms,the proposed method can effectively decrease the image over-segmentation and under segmentation rates,highlight the characteristics of the target cracks,solve the problems of excessive difference between the identified length and actual length of cracks caused by background gray level change and uneven ilumnination,and effectively improve the recognition accuracy of bridge concrete cracks. 展开更多
关键词 concrete crack block segmentation maximum entropy segmentation algorithms maximum interclass variance(Otsu)method
下载PDF
Thermal and Stress Analysis of Early Age Concrete for Spread Footing
15
作者 丁红岩 张磊 +1 位作者 张浦阳 朱奇 《Transactions of Tianjin University》 EI CAS 2015年第6期477-483,共7页
The early age performance of spread footing, especially the growth of cracks, is deeply influenced by the heat of hydration of cement. In this paper, 3D finite element method(FEM)models are set up to analyze the tempe... The early age performance of spread footing, especially the growth of cracks, is deeply influenced by the heat of hydration of cement. In this paper, 3D finite element method(FEM)models are set up to analyze the temperature distribution and thermal stresses of the spread footing during the first seven days after concrete placement. The mechanical properties of early age concrete are calculated, which are further used in the FEM models. The possibilities of crack growth are estimated by the method of crack index. The crack indexes of quite a number of points are very close to the allowable limit of 1.0 during the last three days. It is also indicated that the influence of foundation ring on the thermal stresses of concrete can be neglected. 展开更多
关键词 mass concrete heat of hydration early age concrete thermal crack crack index
下载PDF
Stress on Ballast-Bed and Deterioration of Geometry in a Railway Track
16
作者 Konstantinos Giannakos 《Journal of Civil Engineering and Architecture》 2010年第6期27-42,共16页
In Greece extended cracking of twin-block concrete sleepers (ties) and fouling of the ballast-bed were observed with implied problems of gauge widening and deterioration of track's geometry. This led to a ten-year ... In Greece extended cracking of twin-block concrete sleepers (ties) and fouling of the ballast-bed were observed with implied problems of gauge widening and deterioration of track's geometry. This led to a ten-year investigation program, during which a new method was developed for the estimation of actions on track panel as well as of the pressures / stresses that develop under the seating surface of the sleeper on the ballast-bed. Results from the tests performed on the ballast used in the Greek network are also presented, conducted in laboratories in France, Austria, and Greece. The influence of the actions -static and mainly dynamic- on the track response and the stress and strain of the ballast-bed are also discussed as derived from the tests and theoretical analysis. 展开更多
关键词 Railway ballast ballast hardness actions on track mean stress on ballast bed cracked concrete ties.
下载PDF
Water presence detection in a concrete crack using smart aggregates 被引量:5
17
作者 Qingzhao Kong Qian Feng Gangbing Song 《International Journal of Smart and Nano Materials》 SCIE EI 2015年第3期149-161,共13页
Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent resear... Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent research on water presence detection in concrete cracks using piezoceramic-based smart aggregate(SA)transducers.The active sensing approach,in which one piezoceramic transducer is used to generate stress waves and others are used to detect the stress wave responses,is adopted in this research.Cracks formed in concrete structures act as stress reliefs,which attenuate the energy of the signals received by the SAs.In case of a crack being filled with liquid,which changes the wave impedance,the piezoceramic transducers will report higher received energy levels.A wavelet packet-based approach is developed to provide calculated energy values of the received signal.These different values can help detect the liquid presence in a concrete crack.A concrete beam specimen with three embedded SAs was fabricated and tested.Experimental results verified that the SA-based active sensing approach can detect a concrete crack and further detect the liquid presence in the concrete crack. 展开更多
关键词 water detection concrete crack smart aggregate active sensing piezoceramic sensors and actuators2
原文传递
Abnormality diagnosis of cracks in the concrete dam based on dynamical structure mutation 被引量:18
18
作者 GU ChongShi LI ZhanChao XU Bo 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1930-1939,共10页
A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bi... A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the downstream face of a concrete gravity arch dam is analyzed with the proposed method. Two distinct mutations are discovered to indicate that the abnormality diagnosis of cracks in the concrete dam is achieved dynamically through this method. Furthermore, because it can be directly utilized in the measured crack opening displacement series to complete abnormality diagnosis, it has a good prospect for practical applications. 展开更多
关键词 dynamical structure mutation cracks in the concrete dam method of the fuzzy cross-correlation factor exponent indynamics abnormality diagnosis of cracks
原文传递
Computer-vision-guided semi-autonomous concrete crack repair for infrastructure maintenance using a robotic arm 被引量:1
19
作者 Rui Chen Cheng Zhou Li-li Cheng 《AI in Civil Engineering》 2022年第1期133-148,共16页
Engineering inspection and maintenance technologies play an important role in safety,operation,maintenance and management of buildings.In project construction control,supervision of engineering quality is a difficult ... Engineering inspection and maintenance technologies play an important role in safety,operation,maintenance and management of buildings.In project construction control,supervision of engineering quality is a difficult task.To address such inspection and maintenance issues,this study presents a computer-vision-guided semi-autonomous robotic system for identification and repair of concrete cracks,and humans can make repair plans for this system.Concrete cracks are characterized through computer vision,and a crack feature database is established.Furthermore,a trajectory generation and coordinate transformation method is designed to determine the robotic execution coordinates.In addition,a knowledge base repair method is examined to make appropriate decisions on repair technology for concrete cracks,and a robotic arm is designed for crack repair.Finally,simulations and experiments are conducted,proving the feasibility of the repair method proposed.The result of this study can potentially improve the performance of on-site automatic concrete crack repair,while addressing such issues as high accident rate,low efficiency,and big loss of skilled workers. 展开更多
关键词 Computer vision concrete crack repair Robotic construction Semi-autonomous Knowledge base system Human decision making
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部