Qin Q.-B.,Guangzhou Design Institute |
Fang Y.-Q.,Guangzhou Design Institute |
Luo X.-W.,CAS Wuhan Institute of Rock and Soil Mechanics |
Huang N.-H.,Guangxi Anke Ltd Liability Company of Geotechnical Engineering
Yantu Lixue/Rock and Soil Mechanics | Year: 2012
Based on successful reinforcement projects of the sliding zone of the ancient debris landslide with applying deep high pressure grouting method, and combined with various detection measures and elastoplastic finite element analysis, the mechanism of deep high pressure grouting to reinforce sliding zone, physico-mechanical parameters of the soil in sliding zone before and after grouting, the remnant sliding force and safety factors of the landslide have been studied. Electron microscopy experiments show that, The filling replacement rate of cement slurry to rock and soil in sliding zone is 5%~10%. The soil tests results indicate that the soil cohesion increase from 20.20 kPa to 39.54 kPa and its internal friction angle from 16° to 21.30°. The sound wave CT scanning experiments show that the sound wave velocity of the soil in the sliding zone increases about 31%. The finite element analysis show that pressure grouting could make the unstable landslide go into the basic stable state and the remnant sliding force reduces a lot. These can provide optimization basis for retaining structure design. Tests and calculation results show that high pressure grouting method for enhancing the rock and soil in sliding zone is feasibility. The mechanical performance of the rock and soil in sliding zone has been significantly improved and the safety of the slope has been enhanced.
Zhou G.-W.,Nanjing Southeast University |
Zhou G.-W.,Guangzhou Design Institute |
Zhang Z.-Q.,Nanjing Southeast University |
Li A.-Q.,Nanjing Southeast University |
Xu J.-J.,Internal Trade Engineering Design and Research Institute
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012
There are two main problems in the study of damping effect of composite structures: the first is how to calculate the damping ratio of the whole structure when adopting different materials; the second is how to modify the low damping material after obtaining the integral damping ratio of the whole structure. Taking the high-rise building with steel tower on top as an example, a construction method of non-classical damping matrix was proposed. The result shows the damping ratio based on this matrix can reflect the energy dissipation of 4 orders of modes which play the most important influence on the main structure and the steel tower on top. By the response spectrum method, the inaccuracy of the steel tower's result due to using the calculated integral damping ratio was deduced and a modification equation was provided. The comparison with the accurate result shows the modification factor obtained by the equation has certain reference value to the earthquick response calculation.
Xu Z.-D.,Nanjing Southeast University |
Weng C.-H.,Nanjing Southeast University |
Weng C.-H.,Guangzhou Design Institute
Journal of Zhejiang University: Science A | Year: 2013
Vibrations inherently generated by on-board disturbance sources degrade the performance of the instruments in an on-orbit spacecraft, which have stringent accuracy requirements. The Stewart platform enables both track-positioning and vibration control. The strut of the Stewart platform is designed as a piezoelectric (PZT) element in series with a voice coil motor (VCM) element and a viscoelastic element. The track-positioning system uses a VCM as the main positioning control driver and a PZT as the positioning compensator. The vibration control system uses the characteristics of struts including active and passive control elements to attenuate the vibration. Simulation results indicate that the Stewart platform with the designed struts has good performance in tracking and vibration attenuation with different interference waves. © 2013 Zhejiang University and Springer-Verlag Berlin Heidelberg.
Wang X.,China Academy of Building Research |
Fu J.,Chongqing University |
Zhu A.,China Academy of Building Research |
Liu C.,Chongqing University |
And 2 more authors.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2011
Based on the numerical simulation analysis of the behavior of tested RC columns with HRB500 longitudinal reinforcement, it is verified that the FEAP, a nonlinear finite element analysis software, can be used to conduct systematic parametric analysis on seismic behavior of RC columns. With this software, seismic behavior of 162 columns reinforced with HRB500 longitudinal steel bars were studied, considering different hoop characteristic values, different longitudinal bar ratios and different axial compression ratios. Simulation analysis and experimental results show that the column displacement ductility factor decreases exponentially with the increase of axial compression ratio, while increases linearly with the increase of the hoop distribution characteristic values. Under constant hoop distribution characteristic values, the displacement ductility coefficient decreases with the increase of longitudinal reinforcement ratio when the axial compression ratio is small, while increases slightly with the increase of longitudinal reinforcement ratio when the axial compression ratio is large. An equation for the calculation of the displacement ductility of columns considering these three parameters was obtained by the regressive analysis based on the simulation results.
Xu G.-L.,Wuhan University |
Zhang X.-L.,Guangzhou Design Institute |
Wang C.-Y.,Wuhan University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010
It is of great importance to precisely appraise the mechanical characteristics and to provide credible design parameters of soils for the design of foundation engineering. At present, the strength and deformation parameters are tested by different test methods whose precisions differ from each other, and the soils are disturbed inevitably to some degree, so do the stresses in the soils. The self-boring in-situ shear pressuremeter test, namely SBISP, adopts the self-boring technique. Its unique structure and loading method make it possible to directly attain many mechanical parameters, such as the strength and deformation parameters, earth pressure at rest, coefficient of subgrade shear reaction and pile friction. The SBISP test is a testing technique in the drilling boreholes, so it can obtain the mechanical parameters of the soils at different depths. The results of the field tests show that SBISP can obtain the strength and deformation parameters at the same time by one test, and that the values tested by SBISP can be used as the corresponding ones.
Ye M.,Guangzhou University |
Cao B.,Guangzhou University |
Pi Y.,Guangzhou Design Institute |
Ren M.,Guangzhou University
Journal of Vibroengineering | Year: 2015
Increasingly ancient ruins are subjected to higher levels of vibrations induced by rail due to urbanization. In this way, to better understand and preserve ancient ruins against train-induced vibrations, vibration measurements and FE analysis were conducted on the Hangu Pass, Luoyang, China, located adjacent to the Longhai railway line. Firstly, damage descriptions of the Hangu Pass are conducted, and train-induced vibrations were recorded at several points on the ground and the ruin. Then, attenuation characteristics of vibration in the ground and on the ruin were examined. Secondly, based on the FE analysis, the stress distributions of the Hangu Pass are present when the train crossed the nearby railway line. The results showed that the maximum stress distribution from the result of the FE analysis is similar to crack distribution of the Hangu Pass, which confirmed that the train-induced vibration is a significant factor to deteriorate the Hangu Pass. Thirdly, in order to protect the Hangu Pass against train-induced vibrations, an anti-vibration system, isolation trench, is introduced. The FE model of the Hangu Pass with isolation trench is established. The effect of the trench's width, depth, location and filling materials on decreasing the train-induced vibrations of the Hangu Pass are studied. The results showed that the set isolation trench can protect the ancient ruin against environmental vibration. © JVE INTERNATIONAL LTD.
Xu X.,Guangzhou University |
Huang G.,City University of Hong Kong |
Liu H.,Guangzhou Design Institute |
Chen L.,Guangzhou Design Institute |
Liu Q.,Guangzhou University
Energy and Buildings | Year: 2015
The energy-saving optimization control strategies of central air-conditioning system widely used now is according to the operation parameters of the cold source side to adjust the load supply. But the operation parameter describes the centralized and hysteresis effect about the central air conditioning system in current load. The effects can't well reflect the actual change about the user load and ensure the comfort of all users. It will be better if directly regulate the cold source of central air conditioning load according to the needs of the terminal users. Based on this idea, the study calculates the load of the terminal air-conditioning equipment according to its operating parameters, and then the dynamic load forecasting methods is used to establish the forecasting model that can forecast in real-time the load demand in the next time. The load forecasting methods do not need to analyze the factors that directly affect indoor load changes and to establish the load changes physical model. It use "the degree of load changes" to describe the load variation influence so to avoid the randomness and uncertainty about the change of the air-conditioning system load. The experimental results show that the forecasting model has well prediction effect. With the support of network control technology, all the terminal user load demand can be got, so the total load about the central air-conditioning based the terminal user forecasting load can be got. The better energy-saving optimization control strategies of central air-conditioning system will be get to use the forecasting load as the basis of the energy saving control for the central air conditioning cold source system. © 2015 Elsevier B.V. All rights reserved.
Li Q.,Hunan University |
Li Q.,City University of Hong Kong |
Li Y.,Hunan University |
Chen F.,Hunan University |
And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011
Pearl River Tower(PRT) with a height of 309.6 m and located in Guangzhou was designed to activate four wind turbines for electricity power generation. Wind load plays a key role in the structural design of this building. Based on the wind tunnel test results of the PRT, the overall equivalent static wind load of the building, the wind pressure distributions on the facades and near the holes for installation of the wind turbines, the enhancement effect of wind speed inside the holes, and the feasibility of power generation by the wind turbines are studied. Some of these results are compared with those of a smaller scale model test, which shows that the overall equivalent static wind load are different while using different scale models. The four holes opened in the building for installation of the wind turbines will actually reduce the wind load on the building, but when the wind turbines are running, the minimum peak pressure of the tap in a hole will increase by 65%. Wind power generation in the super-tall building is an innovative strategy, but there is a need to conduct in-depth studies to make full use of wind power in super tall buildings.
Liang F.,Guangzhou Design Institute |
Han J.,Guangzhou Design Institute |
Gan H.,China Construction Fifth Engineering Division Co. |
Luo Q.,Guangzhou Design Institute |
And 2 more authors.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2016
With reference to the Nanhai Glory IFC Project, the measured vertical deformation difference between the frame column and core tube from the commencement of construction to 258 days after finishing of top story, was obtained through observation points at the 12th, 23th, 35th floor, roof (169.75 m) and the tip of tower (179.50 m). By conducting curve fitting analysis on the data obtained, the vertical deformation difference of the structure two years later after finishing of top story can be predicted. The elastic deformation difference was obtained by using the finite element program SATWE. Considering the creep and shrinkage and the effects of steel ratio, the CEB-FIP 1990 model of the finite element software MIDAS/GEN was used to simulate construction process and analyze the vertical elastic deformation difference of the structure at time up to two years after finishing of top story. By comparing the measured and FEA data, the adjustable range of additional moment at the frame beam end caused by the deformation of vertical members was analyzed. Results show that in the super high-rise frame-core tube building, the measured deformation difference with the concrete shrinkage and the creep taken into account is 70% less than the elastic deformation difference and the additional moment at the joint of the frame beam end caused by the deformation difference of vertical members is far less than the FEA results. The adjustment of the limit of additional bending moment was put forward from an economical perspective. Based on studies, the adjustable range of additional moment at the frame beam end of the high-rise building in article 5.2.4 of DBJ 15-92-2013 'Technical specification for concrete structures of tall building' can be increased to 40%. © 2016, Editorial Office of Journal of Building Structures. All right reserved.
Wu B.,South China University of Technology |
Luo Z.,South China University of Technology |
Luo Z.,Guangzhou Design Institute
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2016
Mechanical properties of fifteen composite slabs with profiled steel sheet casted using demolished concrete blocks (DCBs) and fresh concrete (FC) have been experimentally studied, including nine slabs without studs and six slabs with studs, and the influences of some parameters (i.e., replacement ratio of DCBs, shear span, thickness of slab, and arrangement of studs) on the specimens' longitudinal shear behavior and flexural behavior have been investigated. Based on the combined strength of fresh concrete and demolished concrete, the values of two coefficients used in the calculation of the specimen's longitudinal shear capacity have been determined, and the validity of current formulas in predicting the specimen's flexural capacity has been checked. It is found that: when the replacement ratio of DCBs ranges from 21% to 36%, the difference between the longitudinal shear capacity of the specimen without studs casted using DCBs and FC and that of the specimen without studs casted using FC alone is within a range of -13.1%~11.7%, but this difference does not change monotonically with the increase of the replacement ratio of DCBs; when the replacement ratio of DCBs ranges from 11% to 31%, the initial stiffness of the specimen with studs casted using DCBs and FC is almost the same as that of the specimen with studs casted using FC alone, and the flexural capacity of the former is not lower than that of the latter; and the safety margin of the predicted flexural capacity using CECS 273-2010 for the specimen with studs casted using DCBs and FC is not less than that for the specimen with studs casted using FC alone. © 2016, Editorial Office of Journal of Building Structures. All right reserved.