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Tang M.,Guangzhou Institute of Building Science Co. | Chen X.,Central South University | Yang Z.,Guangzhou Institute of Building Science Co.
Chemical Engineering Transactions | Year: 2016

In view of the characteristics of erosion environment of underground concrete structure in Guangdong, this paper researched the chloride ion transmission characteristics in concrete under different conditions of water cement ratio, mineral admixtures, and ion concentration and soaking, then analysed the impact on chloride ion transmission speed and comprehensive revealed chloride ion infusibility in concrete in these conditions. Through the analysis of experimental results, the complex mixtures of fly ash and silicon ash is beneficial to the durability of urban underground structure. Especially when the proportion of silicon ash is 5% and fly ash is 30%-40%, which is the most favourable to the improvement of the durability of concrete. Copyright © 2016, AIDIC Servizi S.r.l.


Tang M.,Guangzhou Institute of Building Science Co. | Chen X.,Central South University | Yang Z.,Guangzhou Institute of Building Science Co.
Chemical Engineering Transactions | Year: 2016

The article is synthetically revealed the erosion deterioration law of concrete under double-factor erosion condition in complex environment, research results indicate: within a short period of time, the combined action of double factors which are chlorine ion and sulphate ion changed the change laws of single factor effect of chloride ion or sulphate ion. Under the combined action of double factors, there does not appear simple superposition of concrete's erosion effect, while there appears drag effect each other in short time, crush resistance, fracture resistance and anti-erosion coefficient appear the change law of decreasing after increasing, at the early stage of being in erosion for the city underground structure, the role of double factors delayed the decreasing of erosion resistance coefficient. Copyright © 2016, AIDIC Servizi S.r.l.


Zheng X.H.,South China University of Technology | Huang P.Y.,South China University of Technology | Chen G.M.,Guangdong University of Technology | Tan X.M.,Guangzhou Institute of Building Science CO.
Construction and Building Materials | Year: 2015

In subtropical coastal regions, fiber reinforced polymer (FRP) strengthened concrete bridge structures are typically subject to harsh environmental attack such as temperature and humidity variations during their service (i.e. under cyclic vehicle loading). For such FRP strengthened concrete structures, fatigue performance of the FRP-to-concrete bond (referred to as interface hereafter for simplicity) is extremely important to the durability of the strengthened structures. In order to investigate the fatigue performance of the interface subjected to temperature and humidity variations, 17 double shear test specimens with carbon fiber laminate (CFL) were prepared, and experimental study was carried out on the fatigue performance of the interface in a simulated environment with constant temperature and relative humidity (RH) (60°C, 95%). The results showed that the adopted temperature and RH adversely affected the bond behavior of CFL-concrete interface. In particular, the fatigue life of specimens under the above temperature and RH is significantly less than that of reference specimens without hygrothermal pretreatment. The test results also showed that the fatigue life can be reduced by a higher stress level. Based on the analysis on the bond-slip behavior of the interface, a three-phase fatigue damage model was presented to describe the fatigue damage process of the CFL-to-concrete bond under fatigue load while exposure to a certain hygrothermal environment. © 2015 Elsevier Ltd. All rights reserved.


Patent
Guangzhou Institute of Building Science Co. | Date: 2014-08-27

The present invention relates to a quick coupling for pipe pile, comprising an upper end plate, a lower end plate and a screw hook made of spring steel for coupling the upper and lower end plate, a plurality of tapped holes are uniformly provided on the upper end plate, a plurality of holes corresponding to the tapped holes are provided on the lower end plate, a lock hole is positioned at the lower portion of the hole, while the cross-section area of the lock hole is bigger than the cross-section area of the hole. One end of the screw hook is provided with a screw end mating with the tapped hole on the upper end plate, while the other end is provided with a hook end mating with the lock hole on the lower end plate, whereby the upper and lower end plate can be coupled firmly.


Tang M.-X.,Guangzhou Institute of Building Science Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

Considering the interaction between basement rock and pile, a procedure for computing uplift capacity of uplift pile with constant section is deduced according to power function slip surface premise and based on limit equilibrium method. Based on the report of skin friction experiment of pile in soft rock, it is taken that the power function slip surface of pile is close to experiment when the coefficient N = 0. Meanwlile the comparison between theoretical predictions and experimental data indicates the accuracy of the computing formula. According to this computing formula, it is proposed that the coefficient of interaction between soft rock and pile should take 0.7-0.8 discount of coefficient of rock's internal friction angle φ and cohesion c. The relation between the internal friction angle φ, cohesion c and uplift capacity of short uplift pile in soft rock is revealed, where the uplift capacity is enhanced with increasing of the internal friction angle φ, cohesion c of soft rock and cohesion c is more efficient. ©, 2015, Academia Sinica. All right reserved.


Jun R.,Shenzhen Institute of Building Science Co. | Wang P.,Guangzhou Institute of Building Science Co. | Jiang X.Y.,Guangzhou Institute of Building Science Co.
Applied Mechanics and Materials | Year: 2013

The Paper, based on the theory of technical and economic assessment, puts forward to make financial assessment (on net present value, payback time, risk-benefit ratio, etc.) as the economic control index in accordance with the ideology of entire life cycle during the energy-saving reconstruction of public buildings. Then the Paper makes analysis on cost-benefit ratio of energy-saving reconstruction measures taken on various parts and equipment of outer protective structure, finds out approaches to energy-saving reconstruction with high efficiency, and finally adopts the method of sensitivity analysis on individual energy-saving reconstruction measures to further optimize reconstruction plan, thus improving economic benefits of energy saving. © (2013) Trans Tech Publications, Switzerland.


Xu M.-J.,Guangzhou Institute of Building Science Co. | Wei D.-M.,South China University of Technology
Gongcheng Lixue/Engineering Mechanics | Year: 2011

The paper derives dynamic governing equations for unsaturated soils by adopting Bishop's effective stress formula and van Genuchten's capillary pressure function. These equations consider the compression of solid grain and pore fluids, the viscous-coupling interactions and the inertial forces of fluids. By introducing the displacement function and making use of Cauchy-Reimann conditions, the 3D wave equations in rectangular coordinates are transformed into two uncoupled governing differential equations. Then, with the help of double Fourier transform, general solutions of displacement and stress as well as pore pressure are obtained. With boundary conditions imposed, dynamic responses of unsaturated half-space under arbitrary distributed harmonic loads are solved. The influence of saturation on dynamic shear modulus is considered in numerical calculations, and an empirical formula is raised here to describe the relations between saturation and shear modulus. Numerical results show that (1) with the increase of saturation, the displacement of ground surface increases firstly, then decreases when soils are nearly saturated; (2) permeability of pore and drainage conditions of ground surface have insignificant effects on the displacement when soils are nearly saturated.


Hu H.S.,Guangzhou Institute of Building Science CO. | Tang M.X.,Guangzhou Institute of Building Science CO. | Zhang C.L.,Guangzhou Institute of Building Science CO.
Applied Mechanics and Materials | Year: 2013

Based on the experiment of frictional resistance between concrete short pile and lightly weathered silty mudstone, the frictional resistance of concrete short pile on uplift loading was analyzed and the ultimate friction resistance was obtained. Considering the site geotechnical investigation report and relative standards, the safety factor of side friction of uplift bored piles in soft rock was defined according to the testing of frictional resistance between concrete short pile and lightly weathered silty mudstone. Achievements in this research are already applied into engineering practice. © (2013) Trans Tech Publications, Switzerland.


Tang M.,Guangzhou Institute of Building Science Co. | Hu H.,Guangzhou Institute of Building Science Co. | Zhang C.,Guangzhou Institute of Building Science Co.
Progress in Civil, Architectural and Hydraulic Engineering - Selected Papers of the 4th International Conference on Civil, Architectural and Hydraulic Engineering, ICCAHE 2015 | Year: 2016

Comparisons between the hyperbolic model and exponential model prediction effect have been made and the exponential model is selected to analyze P-S curve of rock anchor test data. Ultimate bearing capacity of anchor is predicted by exponential model firstly then the bond strength of rock anchor is calculated and these results are classified according to the hardness degree of rock. It is shown that bond strength of rock anchor recommended in the code is larger than 20% the statistic on the soft rock condition and both are in agreement on the hard rock condition. © 2016 Taylor & Francis Group, London.


Zhang C.-L.,South China University of Technology | Zhang C.-L.,Guangzhou Institute of Building Science Co. | Zhou X.-W.,South China University of Technology
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015

The mechanical properties and characteristics of sand are significantly affected by particle shape. This paper is mainly aimed to quantify and build the grain shape. A new method based on ODEC (overlapping discrete element cluster) method is proposed. Firstly, the two-dimensional roundness of a particle in three projection planes is extracted through photography, and the weighted average roundness is calculated. Then the weighted average roundness is employed of particles to generate particles with various irregular shapes in numerical model through Matlab code and clump block function of PFC3D. ©, 2015, Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering. All right reserved.

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