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Li F.,Hunan University | Li F.,Hunan Provincial Architectural Design Institute | Xiao Y.,Hunan University | Xiao Y.,University of Southern California | And 4 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014

In design of a structure under accidental load action, it is important to understand the failure mechanism. Collapse tests of a 1/2 scale 3-bay and 3-story space reinforced concrete frame model with sudden side column removal were carried out to study the dynamic response, internal force redistribution, and failure model of frame by Hunan University, University of Southern California, University of California at Davis, and National Institute of Standards and Technology of USA together. The displacement response, acceleration response, reinforcement strain and crack distribution during the collapse of the frame were studied to reveal the progressive collapse resistance with sudden vertical element removal. Testing results show that the RC frame designed according to Chinese Seismic Code has good behavior against progressive collapse caused by sudden loss of a first floor side column and dynamic effect is not significant to the structure. Numerical simulation on displacement response and internal force redistribution of RC frame with sudden vertical element removal is also carried out using the finite element software SAP 2000. It is found that the analysis results agree well with the test results.

Tong L.,Tongji University | Xu G.,Tongji University | Liu Y.,Hunan Provincial Architectural Design Institute | Yan D.,China Architecture Design and Research Group | Zhao X.-L.,Monash University
Thin-Walled Structures | Year: 2015

A diamond bird-beak T-joint is similar to a conventional T-joint except that the brace member and chord member both rotates 45°. Previous research demonstrated that the diamond bird-beak joint has better static and fatigue behaviour than a conventional joint. Experimental testing has been reported by the authors to determine the stress concentration factors (SCFs) of diamond bird-beak SHS T-joints. This paper fills the knowledge gap through FE analysis, parametric study and proposed SCF formulae for such joints. Three-dimensional finite element (FE) models were developed and validated by experimental data. The FE model was utilized for parametric study on SCFs for diamond bird-beak SHS T-joints to investigate the influence of key non-dimensional geometric parameters β (ratio of brace width to chord width), 2γ (ratio of chord width to chord thickness) and τ (ratio of brace thickness to chord thickness). Finally SCF formulae were proposed for diamond bird-beak SHS T-joints under four loading cases, namely axial force and in-plane bending in the brace, as well as axial force and in-plane bending in the chord. © 2014 Elsevier Ltd.

Tong L.,Tongji University | Fu Y.,Tongji University | Liu Y.,Tongji University | Liu Y.,Hunan Provincial Architectural Design Institute | Zhao X.-L.,Monash University
Thin-Walled Structures | Year: 2014

T-joints made of hollow structural sections (e.g. circular hollow section (CHS) or square hollow section (SHS)) are often found in welded trusses that may be subjected to fatigue loading. The brace member of conventional T-joints (e.g. CHS-to-CHS, SHS-to-SHS and CHS-to-SHS T-joints) is perpendicular to the chord member. When the brace member and the chord member both rotates 45 a conventional SHS-to-SHS T-joint becomes a so-called "diamond bird-beak" SHS T-joint. Most of the research work on bird-beak joints has been focused on the static strength. Very limited information is available with regard to the fatigue strength of diamond bird beak joints. This paper will fill the knowledge gap in understanding the stress concentration factor (SCF) of this type of T-joints under brace loading (i.e. axial load in the brace and in-plane bending in the brace). A series of tests were conducted to measure the SCF of diamond bird-beak T-joints with a reasonable range of three key parameters, i.e. β (ratio of brace diameter to chord diameter), 2γ (ratio of chord diameter to chord thickness) and τ (ratio of brace thickness to chord thickness). It was found that the SCFs for the diamond bird beak T-joints are much lower than those for SHS-to-SHS and CHS-to-SHS T-joints, but just slightly smaller than those for CHS-to-CHS T-joints. © 2013 Elsevier Ltd.

Zhang H.,Chongqing University | Chen Z.,Chongqing University | Chen Z.,Key Laboratory of New Technology for Construction of Cities in Mountain Area | Chen F.,Hunan Provincial Architectural Design Institute
Applied Mechanics and Materials | Year: 2012

The time-history wind pressure records of the rigid model of an annular large-span cantilever roof of a stadium were obtained by the wind tunnel test. Considering the influence of the vortex shedding, the correlation coefficient and coherence function in along-wind and cross-wind directions were analyzed to get the characteristics of the external fluctuating pressure correlation of the stadium's roof. The coherence function curves were fitted and the related coherence function was present. The conclusion: These characteristics of coherence are all coincide with the correlation coefficient. Compared to the classical coherence function models, the present coherence function has the same form and a higher fitting accuracy for the cantilever roof. © (2012) Trans Tech Publications.

Chen Y.,Hunan University | Huang C.,Hunan University | Chen W.,Hunan Provincial Architectural Design Institute | Wei R.,Hunan University
Dianwang Jishu/Power System Technology | Year: 2012

To avoid the influence of current transformer saturation on bus-bar protection, a measured surge impedance based approach for busbar protection is proposed. The theoretical analysis on the faults occurred inside and outside the busbar protection zone shows that when the fault inside the protection zone occurs the polarity of all measured surge impedances of all transmission lines are negative and their amplitudes are approximately equal, when the fault outside the protection zone occurs the polarity of all measured surge impedance of all transmission lines are positive and their amplitudes are far less than the amplitudes of measured surge impedances of non-faulty transmission lines, thus by means of comparing the polarities and amplitudes of measured impedances of all transmission lines connected to the busbar the fault type occurred on busbar can be judged. Besides, the implementation of the proposed new approach for busbar protection is discussed and a feasible scheme to implement the proposed approach is achieved. Results of both theoretical analysis and simulation of EMTP show that the proposed approach based on measured surge impedance is basically not affected by fault types, transition resistance, fault position and initial phase angle by which the fault occurs, so this approach is reliable and effective.

Jin H.,Tongji University | Xue W.,Tongji University | Yang X.,Hunan Provincial Architectural Design Institute | Li P.,Hunan Provincial Architectural Design Institute
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2012

Based on tests of five specimens under low cyclic reversed loading, the failure pattern, hysteretic loops, skeleton curves, characteristic values of strength and deformation, ductility, deformation restoring capacity, rigidity degradation and energy dissipation capacity of connections between prestressed steel reinforced concrete (PSRC) beams and concrete-filled steel tubular (CFT) columns were systematically studied. The influences of prestressing force, axial compression ratio, drilling method including pre-drilling and post-drilling method and so forth on seismic performance of connections were studied. Experimental results show that the failure mode of connections between PSRC beams and CFT columns is shear failure in the panel zone. The hysteretic loops of the horizontal shear force versus shear deformation are plump, while pinching can be observed at large deformation stage. The ultimate shear deformations in the panel zone of the five specimens are between 28.60×10 -3 rad and 60.90×10 -3 rad, and the shear ductility coefficients in the panel zone of the five specimens are between 4.72 and 6.69. The degradation tendencies of shear stiffness of the five specimens are almost the same. Prestressing force and post-drilling methods have a little beneficial influence on the shear strength of connections, while prestressing force is unfavorable to the capacity of shear deformation and the ductility of shear deformation. The shear capacity of the specimens increases by 16.62% with the increase of axial compression ratio from 0.2 to 0.4. However, the shear capacity of the specimens increases only by 1.09% when the axial compression ratio increases from 0.4 to 0.6.

Yin J.,Central South University of forestry and Technology | Hu Q.-G.,National University of Defense Technology | Li P.,Hunan Provincial Architectural Design Institute
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012

The uncertainty generation of earthquake demand parameters (EDP) caused by a series of basic uncertain factors was analyzed. The advantages and limitations of FOSM method, Tornado Diagram method and mathematical statistics method were discussed for sensitivity analysis. Taking a typical frame structure as an example, the sensitivity of four kinds of earthquake demand parameters to a series of basic uncertainties was estimated using the three kinds of methods and the basic uncertainties were sorted according to their importance obtained by sensitivity analysis. The results show that EDP are the most sensitive to the intensity measure and the profile of ground motions, rather less sensitive to the viscous damp, the mass and the concrete compressive strength, but not sensitive to other basic uncertainties, which provides the evidence for the random response and probabilistic seismic demand analysis of structures efficiently.

Long Y.,Hunan Provincial Architectural Design Institute | Baran P.K.,North Carolina State University
Environment and Behavior | Year: 2012

Lynch has defined place legibility as the ease with which people understand the layout of a place. The concept essentially represents the composite mental image of a place. Alternatively, space-syntax literature has objectively defined the concept of intelligibility as the capacity of a space to give clues to the understanding of the system as a whole. This study contributes to understanding space-syntax theory as applied to spatial cognition by examining the effect of spatial configuration, measured by intelligibility, on place legibility, measured by sketch maps, recognition tests, and surveys. The results of the experimental study showed that the intelligibility of neighborhood layout influences place legibility. The findings of this study suggest that the space-syntax methodology could be used by urban designers and policy makers to understand and quantitatively manipulate one aspect of the environment, that is, intelligibility, which contributes to improved legibility. © The Author(s) 2012.

Li Y.,Central South University | Yang M.,Hunan Provincial Architectural Design Institute
Advances in Civil Engineering and Building Materials IV - Selected and Peer Reviewed Papers from the 2014 4th International Conference on Civil Engineering and Building Materials, CEBM 2014 | Year: 2015

The transfer matrix method has been used for analysing the steady-state forced vibrations of pierpile-foundation system in the paper. Based on the beam’s transfer matrix method, the dot matrixes of the spring damper and the lumped masses have been deduced to analyse the steady-state forced vibrations of simplified model of pier-pile-foundation system. The main contents of this paper include free vibration characteristics of the structural systems, the law of sectional elements change with the exciting forces’ frequency, and the vibration attenuation of pier-pile-foundation system under the steady-state forced vibration. Finite element analysis software ANSYS has been used to analyse the harmonic response of the same model to test the validity of the transfer matrix. © 2015 Taylor & Francis Group, London.

Li Y.P.,Central South University | Yang M.,Hunan Provincial Architectural Design Institute
Advanced Materials Research | Year: 2014

With the development of railway transportation, the traffic load increased continuously and it had the adverse effect on the system of pier-foundation. The quantitative analysis of the load supplied on the top pier is necessary for analyzing the dynamic response of pier-foundation system. Based on the theory of vibration inverse analysis and finite element method, the paper identified the dynamical load supplied on the top pier in vertical and the transverse direction. Combined with the vibration and acceleration history measured by the field test in Xiaolinhe Bridge, the vertical and transverse direction vibration-load history curves were calculated when the train speeds were 153 km/h and 206 km/h respectively. The results indicated that the amplitude of dynamic load increased with the higher speed of train. © (2014) Trans Tech Publications, Switzerland.

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