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Zhou C.-D.,Beijing Jiaotong University | Tian T.,Film and Television Design and Research Institute
Gongcheng Lixue/Engineering Mechanics | Year: 2015

To study the seismic damage behavior of circular reinforced concrete columns strengthened with pre-stressed Carbon Fiber Reinforced Polymer (CFRP) strips, the Park-Ang damage model was modified by studying the test data of 13 RC columns, and then the seismic damage model of circular concrete columns strengthened with pre-stressed CFRP strips was established. According to the nonlinear regression analysis of axial load ratio, longitudinal reinforcement ratio and double transverse confinement from pre-stressed CFRP strips and stirrups, the experienced expression of the combination parameter of the recommended model was proposed. Based on the recommended model, damage indexes corresponding with the feature points of different damage statuses were calculated, and then the criteria for the classification of seismic performance levels for reinforced concrete circular columns strengthened with pre-stressed CFRP were concluded. The finite element analysis results of the damage indexes showed good agreement with the experiment results, which indicates the rationality of the recommended damage model and the classification standards for reinforced concrete circular columns strengthened with pre-stressed CFRP. ©, 2015, Tsinghua University. All right reserved. Source


Zhou C.,Beijing Jiaotong University | Li H.,GE CHENG & Co. | Zeng X.,Beijing Jiaotong University | Tian T.,Film and Television Design and Research Institute
Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering | Year: 2015

After strengthened with pre-stressed carbon fiber reinforced polymer(CFRP) strips, core concrete can be actively confined, stress hysteresis of CFRP strips can be reduced, and bearing capacity, ductility and seismic behavior of circular RC columns can be significantly improved. In order to obtain nonlinear response process of circular RC columns strengthened with pre-stressed CFRP strips in pseudo-static experiment, the nonlinear finite element models of circular RC columns were established by solid element in software ABAQUS, hysteretic curves and skeleton curves of them were analyzed and compared with test results, the strengthening effect of pre-stress degree, the axial compression ratio on hysteretic performance of circular RC columns strengthened with pre-stressed CFRP strips were observed. The results show that ABAQUS based finite element analysis can simulate hysteretic curves and skeleton curves of circular RC columns strengthened with pre-stressed CFRP strips well in cycling load. The seismic performance of circular RC columns strengthened with pre-stressed CFRP strips could be improved. ©, 2015, The Editorial Board of Journal of Basic Science and Engineering. All right reserved. Source


Li L.,CAS Institute of Automation | Li L.,Film and Television Design and Research Institute | Yuan C.,CAS Institute of Automation | Hu W.,CAS Institute of Automation | Li B.,CAS Institute of Automation
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

How to fuse static and dynamic information is a key issue in event analysis. In this paper, we present a novel approach to combine appearance and motion information together through a top-down manner for event recognition in real videos. Unlike the conventional bottom-up way, attention can be focused volitionally on top-down signals derived from task demands. A video is represented by a collection of spatio-temporal features, called video words by quantizing the extracted spatio-temporal interest points (STIPs) from the video. We propose two approaches to build class specific visual or motion histograms for the corresponding features. One is using the probability of a class given a visual or motion word. High probability means more attention should be paid to this word. Moreover, in order to incorporate the negative information for each word, we propose to utilize the mutual information between each word and event label. High mutual information means high relevance between this word and the class label. Both methods not only can characterize two aspects of an event, but also can select the relevant words, which are all discriminative to the corresponding event. Experimental results on the TRECVID 2005 and the HOHA video corpus demonstrate that the mean average precision has been improved by using the proposed method. © 2011 Springer-Verlag Berlin Heidelberg. Source


Zhou C.-D.,Beijing Jiaotong University | Zhou C.-D.,Tongji University | Tian T.,Film and Television Design and Research Institute | Lu X.-L.,Tongji University | And 2 more authors.
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2012

By lateral cyclic loading test, hysteretic behavior of seven circular RC columns confined by lateral pre-stress under high axial compression was studied. Using theoretical analysis and statistic regression analysis, the formula of calculated flexural capacity for columns is proposed. The three line restoring force model of circular RC columns under high axial compression confined by pre-stressed CFRP belts which is capable of considering the pre-stress of CFRP belts and axial load ratio is set up. Test results show that the hysteretic behavior of the columns with high axial load ratio is improved significantly after confined by pre-stressed CFRP belts. The diagonal shear cracks of columns can be effectively confined with the active lateral stress provided by pre-stressed CFRP belts, and the failure mechanism of the columns with high axial load ratio may be changed from shear to flexure with satisfactory ductility. The result of the recommended model shows good agreement with the test result. Source


Zheng Y.,Shandong University | Dai X.,Film and Television Design and Research Institute | Li L.,Shandong University
Applied Mechanics and Materials | Year: 2012

In order to promote the experience of applying O-cell pile test to determine the behavior of integral pile in Jinan, a case of O-cell pile test in Jinan was analyzed with proposed approach. The pile-soil system was simulated with FEM. The resistance parameters of piles, the load-displacement curves and the ultimate bearing capacity of integral pile were determined. Comparing with results obtained from load transfer method, it is found that the p-s curve of integral pile obtained from load transfer method is conservative. © (2012) Trans Tech Publications, Switzerland. Source

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