Wang T.,Southwest Jiaotong University |
Shen R.-L.,Southwest Jiaotong University |
Li H.,Chongqing Architectural Design Institute
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013
The concept of cable-beam vibration was defined as forced vibration and parametric vibration of cables under the excitation of end displacements. The nonlinear finite element dynamic time-history integration method was combined with cable nonlinear vibration equations for studying cable-beam vibration. A numerical calculation model was built with programming, the characteristics of cable-beam vibration based on the numerical results were discussed. The computing results indicated that the cable local vibration has a distinct relationship with the global structural vibration. The results were close to practical situations. The proposed method could be used for building and investigating a global bridge finite element model.
Yuan Y.,Chongqing Architectural Design Institute |
Jiang T.,Tongji University |
Liu F.,Shanghai Xiandai Architectural Design Group
Advances in Environmental Vibration - Proceedings of the 5th International Symposium on Environmental Vibration, ISEV 2011 | Year: 2011
By discussing of several problems encountered in-situ measurement on a section perpendicular to a subway line in Shanghai, some meaningful results related to evaluation and analysis of environmental vibration were obtained as follows: (1) To the same measuring point, the vibration level(VL) analyzed by JGJ/T170-2009 was higher than GB100704988. According to the statistic analysis, the difference of two standards for the measuring points in building was higher than that in tunnel and on ground; (2) Sampling frequency should be 2. 5 times as high as the maximum analysis frequency and approximately equal to the number of 2m. It can avoid distortion induced by data cut off as well as artificial reduction of VL; (3) In process of one-third octave band spectrum (1/3 OCT)analysis, when the sampling time period takes one second, the VL may be zero in some lower 1/3 OCT center frequencies. Longer sampling time is suggested in analysis of 1/3 OCT analysis; (4)The method using overlapping time has little effect on VL. So it is not necessary to use the method of overlapping time.
Cao A.-Y.,China University of Mining and Technology |
Dou L.-M.,China University of Mining and Technology |
Jiang H.,Chongqing Architectural Design Institute |
Lv C.-G.,China University of Mining and Technology |
And 2 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011
In this paper, we theoretically analyze characteristics of stress drop, the strain energy release, and seismic radiation pattern associated with the rock tensile fracture and shear failure to reveal the corresponding burst risk ranks of coal-rock mass in various failure modes. The results show that the stress required to fail the rock and the associated energy released by rock failure are different, mainly depending on the fracture mode within the rock mass. In case of the same physical and mechanical properties, the energy released increases with the increase of fracture radius. Given the same fracture radius, the stress drop and energy released associated with shear failure are significantly greater than that of tensile fracture. In addition, in case of the same energy released, the fracture radius decreases with the increase of uniaxial compressive strength of the rock mass. Meanwhile, the seismic displacements and energy radiation patterns of different mining-induced tremors vary with different components of the moment tensors. The seismic waveforms of tensile fractures are always characterized by clear P-wave arrivals and the ratio of S- to P-wave energy or amplitude is relatively small, while the shear failures always present weak P-wave arrivals and the ratio of S- to P-wave energy or amplitude is much greater.
Zheng N.,Chongqing University |
Li Y.,Chongqing University |
Zhao J.,Chongqing Architectural Design Institute |
Chen Z.,CPECC Northwest Electrical Power Design Institute
Advanced Materials Research | Year: 2012
The seismic action effects of tower structures for ultra-high-voltage(UHV, upon 750KV) overhead transmission lines are much greater than those of 500KV and below, it is necessary to inspect the control load in structural design and specify the seismic design scope of tower structures for these UHV transmission lines. In this paper, the current regulations of seismic design and non-seismic design of tower structures for overhead transmission line were contrasted firstly; then, a series of typical towers including large-crossing towers and cup-towers at soft sites, on the zone of earthquake fortification intensity region of 8, were analyzed. The ratios of seismic action effects and wind load effects for characteristic value were calculated and the control load in structural design of tower structure was investigated. The results show that, although the height and the weigth of tower structures for UHV transmission lines are increasing, the control load in structural design is still the wind load on the zone of earthquake fortification intensity region of 8 and below. © (2012) Trans Tech Publications, Switzerland.
Liu X.,Tongji University |
Sang Y.,Tongji University |
Bao H.,Chongqing Architectural Design Institute
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2013
Loading tests on two 1:1 tunnel lining specimens reinforced by umbrella arch with 1/3 and 2/3 crack depth/lining thickness ratios were conducted. The specimens were tested to obtain the cracking patterns within the arch reinforcement area and the causes of such damages. The deformation of the specimens reinforced by stacked umbrella arch can be separated into three stages, namely, load-specimen crack stage, "specimen crack-adjoining plane crack" and "adjoining plane crack-specimen fail". Occurrence of adjoining plane crack may significantly decrease the lining stiffness. Specimen with prefabricated 1/3 crack depth/lining thickness ratio was 3.19%, 23.58%, 19.35% less than undamaged member in bending moment of cracking, short-term stiffness and bending bearing capacity, respectively. While the specimen with prefabricated 2/3 crack depth/lining thickness ratio was 14.39%, 54.37% and 37.78% less than the theoretical value, respectively, and it was observed that prefabricated crack extended diagonally in fragile failure mode. Finally, based on test results, computational methods are proposed for the cracking-moment, short-term stiffness and bending capacity of stacked umbrella arch.
Fang J.,Chongqing University |
Zhang C.,Chongqing University |
Zhang M.,Xiamen Municipal Engineering Design Institute Co. |
Cai P.,Chongqing Architectural Design Institute
Asian Journal of Chemistry | Year: 2014
The seed sludge and the anaerobic sludge for a two-phase anaerobic process that is used for the treatment of N-phenylglycinonitrile wastewater were analyzed by PCR-TGGE technology. Furthermore, the structural differences of the seed sludge and the anaerobic sludge were investigated and compared. Moreover, the Shannon diversity index, an important parameter for studying microbial community diversity, was calculated for each sample. The results showed that the sludge's microbial community structure was significantly different before and after domestication. The microbial species and structure in the different stages of a two-phase anaerobic reactor were also obviously different. The acidogenic sludge's diversity index was the highest. Finally, the sludge diversity index of the secondary methanogenic reactor was higher than that of the primary methanogenic reactor and its degradation efficiency of pollutants was also higher. © 2014, Chemical Publishing Co. All rights reserved.
Liu R.,Chongqing University |
Wang M.,Chongqing University |
Chen X.,Chongqing University |
Zhu W.,Chongqing Architectural Design Institute |
Fu J.,Chongqing University
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2016
Small-span-to-depth-ratio coupling beams of shear wall can be formed with a crack in the middle to prevent from shear failure and improve the seismic performance. Three coupling beams with same small-span-to-depth-ratio were tested under cyclic loading. Comparing the results of slotted coupling beams with other coupling beams of different forms of reinforcement, we analyzed the seismic behavior of the slotted coupling beam, including failure pattern, hysteresis loop, strength degradation, stiffness degradation, ductility and energy dissipation. We simulated skeleton curve of specimens' hysteresis curve by using ABAQUS and compared the simulation result mith the experiment result. The results show that slotted coupling beams with small-span-to-depth-ratio have good performance of bearing capacity and deformation. They can be constructed conveniently and economically. Besides, with the good seismic performance, small-span-to-depth-ratio coupling beams could prevent from shear failure effectively and be applied well in practical engineering. © 2016, China National Publications Import and Export (Group) Corporation. All right reserved.
Chen Z.,Chongqing University |
Sun Y.,Chongqing University of Science and Technology |
Zhang H.,China Third Design and Research Institute of Machinery Industrial |
Zhang Z.,Chongqing Architectural Design Institute
International Journal of Structural Stability and Dynamics | Year: 2016
A wind tunnel test on a large-span cantilevered elliptical annular roof was carried out. The time series of wind pressures were tested simultaneously on the upper and lower surfaces of a roof structure rigid model, that was exposed to open and suburban boundary layer air flows in various wind directions. The spatial correlation characteristics of fluctuating pressures on the roof structure were analyzed. Both the analyzing results of the correlation coefficient in time domain and the coherence function in frequency domain indicated that the correlation structure of the fluctuating pressure of a large-span roof is sensitive to the location of the investigated taps, the roof geometry, the wind direction, and the inflow turbulence. Therefore, the simulation methodology, using a single coherence function, based on the spatial interval of two taps, ignoring the geometry characteristics and the particular tap locations on the roof, a method commonly used in wind load simulations for high-rise and flat roof structures, is shown to not be appropriate for large-span cantilevered roof structures. This quasi-steady approach cannot be employed to evaluate large-span roof structures. © 2016 World Scientific Publishing Company.
Bai X.,Chongqing University |
Luo T.,Chongqing University |
Cheng K.,Chongqing Architectural Design Institute |
Chai F.,Capol International And Assotes Group
Applied Thermal Engineering | Year: 2014
Fouling in the heat exchangers plays a key role on the performance of surface water heat pumps. It is also the basement for the system design criteria and operation energy efficiency. In this paper, experimental measurements are performed both in the field and the laboratory with different water qualities, temperatures and velocities. The research will focus on the dynamic growth characteristics of fouling and its main components. By studying the variation rules of fouling resistance, the fouling resistance allowance for certain water condition is recommended. Furthermore, a fouling prediction model in surface water heat pump will be developed and validated based on elaborating with fouling principle under specified water conditions. © 2014 Elsevier Ltd. All rights reserved.
Wu Y.,Chongqing University |
Li Y.,Chongqing University |
Zhang Q.,Chongqing Architectural Design Institute |
Fan J.,Chongqing University
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2011
In this paper, the seismic design method of the hybrid coupled wall structure in the United States is introduced based on the California Building Code and its referencing design standards and the Recommendations for Seismic Design of Hybrid Coupled Walls presented by the ASCE Committee on Composite Construction. The seismic design method described in this paper includes the earthquake action demand calculation, the seismic design performance levels, yielding mechanism design, the component design and check following the prescribed yield mechanism. It is suggested that the first stage seismic design of the hybrid wall be based on the design earthquake level instead of frequent earthquake level. This paper is helpful for developing a rational seismic design method for hybrid coupled walls in China.