Wang C.-L.,Nanjing Southeast University |
Chen Q.,Nanjing Southeast University |
Zeng B.,The MCC Group |
Meng S.,Nanjing Southeast University
Engineering Structures | Year: 2017
For the immediate damage evaluation of a buckling-restrained brace (BRB) after earthquakes, a novel brace with partial buckling restraint was proposed. In the novel brace called the partially buckling-restrained brace (PBRB), only the edge parts of the core member are restrained, and the middle portion of the core member, the unrestrained part, is designed for visual inspection. This paper focuses on the partial restraining mechanism of the PBRB, and three PBRB specimens were tested and compared with two conventional BRB specimens. The unrestrained ratio of the width of the unrestrained part to the thickness of the same part was studied as one of the key parameters that affects the behaviour of the PBRB. Even if the PBRB shows relatively lower fatigue properties and higher compression strength adjustment factors compared with the conventional BRB, the behaviour of the PBRB is still acceptable. The PBRB with a large unrestrained ratio fails at the end of the yielding core plate, where the unrestrained buckling deformation of the core plate is significant, but the fracture of the PBRB with a small unrestrained ratio occurs around the stopper, similar to the failure mode of the BRB. Numerical results show that the maximum plastic strain concentrates in the wave valley of the ends of the yielding core plate for the PBRB with the large unrestrained ratio. To make sure that the behaviour of the PBRB is comparable to that of the conventional BRB, it is recommended that the unrestrained ratio should be less than 5. © 2017
Zhang C.,Taiyuan University of Technology |
Chen L.,Beijing Forestry University |
Jiang J.,Taiyuan University of Technology |
Zhou S.,The MCC Group
Trees - Structure and Function | Year: 2012
Root tensile strength plays an important role in soil stabilization and fixation. Testing and separating the different factors that affect root tensile strength are important. In the present study, the effects of four factors, namely, gauge length, strain rate, species, and root diameter, on root tensile strength were studied. Uniaxial tensile tests were conducted to acquire the root tensile strength of five tree species commonly growing in the mountains of northern China, namely, Chinese pine (Pinus tabulaeformis Carr.), Larch (Larix principis-rupprechtii Mayr.), White birch (Betula platyphylla Suk.), Mongolian oak (Quercus mongolicus Fisch.), and Elm (Ulmus pumila L.). Based on the results, Elm and White birch roots were the most resistant to tension, followed by Mongolian oak and Chinese pine roots. Larch roots were found to be the least resistant to tension. A power relationship was established between root diameter and root tensile strength. Based on linear regression analysis, gauge length was negatively correlated with root tensile strength. Tensile strength decreased with increasing gauge length. In addition, an unexpected variation of tensile strength was observed between two strain rates (10 and 400 mm min -1). The present study can serve as a basis for further studies on mechanical properties of root system and root reinforcement under different test circumstances, although this should be done with caution. © 2012 Springer-Verlag.
Ding D.-W.,University of Science and Technology Beijing |
Li X.,University of Science and Technology Beijing |
Yin Y.,University of Science and Technology Beijing |
Xie X.-P.,The MCC Group
Information Sciences | Year: 2012
This paper investigates the stabilization problem of discrete-time two-dimension (2-D) Takagi-Sugeno (T-S) fuzzy systems. Based on a novel non-parallel distributed compensation (non-PDC) control scheme combined with a new non-quadratic Lyapunov function, less conservative stabilization conditions are developed. The proposed non-quadratic Lyapunov function is homogeneous polynomially parameter-dependent on membership functions. As the degree of the Lyapunov function increases, the conservatism of the obtained stabilization conditions is gradually reduced. By exploiting the algebraic property of membership functions, the stabilization conditions approach to exactness in the sense of convergence. Compared with the existing methods, no slack variables are introduced in control synthesis, and hence the same or less conservative results can be obtained with a lower computational cost. A numerical example is given to illustrate the effectiveness of the proposed method. © 2011 Elsevier Inc. All rights reserved.
Li M.,The MCC Group |
Xin H.-B.,The MCC Group
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2015
The seismic stability of earth-fill hill is one of the key problems in the process of design and construction, and has not been understood properly. The seismic permanent displacement of earth-fill hill is studied by means of the equivalent linear method and Newmark sliding block analysis. The influences of heights, average gradients and input ground motions on permanent displacement are investigated. When the slope is gentle, there are significant differences in size and sliding surface between the maximum displacement sliding mass and the most dangerous sliding block discriminated by the pseudo-static Bishop's method. Finally, using the yield acceleration of earth-fill hill, a simple method to estimate the seismic permanent displacement of earth-fill hill is proposed. © 2015, Chinese Society of Civil Engineering. All right reserved.
Yang Y.X.,The MCC Group |
Lian J.,The MCC Group
Advanced Materials Research | Year: 2011
In this paper, mechanical performances of 480 specimens are tested and influences of basalt fiber ratio, slenderness, soakage material are studied. Results indicate that mechanical properties of BFRC are better than plain concrete. It can be found that the best mechanical performance may be get when the basalt fiber soaked by water-solubility material and its ratio at 8.4 to 14 kg per square meter as well as slenderness at 600 to 800. © (2011) Trans Tech Publications.
Wang J.,The MCC Group
Applied Mechanics and Materials | Year: 2013
Fiber reinforced polymers (FRP) can be used to restore the stiffness and bearing capacity of the damaged steel structures and improve their fatigue resistance. The reinforcement technology has the advantages of fast construction, short cycle, environmental protection and can greatly reduce the cost of the projects. Because there is a large number of steel structure need reinforced in our country, the market potential is tremendous. With localization of FRP and technology advancement of material production, the reinforcement technology will have a stronger competitiveness. Combined with material properties, comprehensive cost, construction method, maintenance and other aspects of FRP, a comprehensive technical and economic analysis has been done for FRP reinforcement and repair technology of steel structure. It could be provided a theory basis and application reference for existing steel repair reinforcement technology. © (2013) Trans Tech Publications, Switzerland.
Shang R.,The MCC Group |
Jiang F.,The MCC Group
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2015
The width of the rib and thickness of the flange were found to be the main factors influencing the shear capacity of cast-in-situ concrete hollow floor slab in transverse direction based on the analysis of equilibrium and the shear failure mechanism. 18 specimens of class A and class B were designed to be tested. In class A, the influence of the rib widths on the shear capacity was studied keeping the hollow diameters and thicknesses unchanged with the rib widths of 50 mm, 75 mm and 100 mm respectively. In class B, the influence of the thickness of the flange on the shear capacity was studied keeping the thickness unchanged and bigger rib width and with the thicknesses of upper and lower flanges of 40 mm, 60 mm and 80 mm respectively. Experimental study shows that the shear failure occurs on the rib when the rib width is small. The crack is found first on the inner wall of the hollow at the point of larger principal tensile stress, and the crack is developed to the adjacent hollow nearly horizontal. The shear capacity is increased with the increase of the rib width. The shear failure occurs on the upper and lower flanges when the rib width is bigger. The crack is found first on the inner wall of the hollow near the upper or lower flange, and gradually extended to the upper or lower surfaces of the plate. The shear capacity is positively correlated with the thickness of the flange. The shear capacity calculation formula of double control in transverse direction of cast-in-situ concrete hollow floor was given based on the experimental results and theoretical analysis. ©, 2015, Science Press. All right reserved.
Zou D.-F.,The MCC Group
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013
Based on the comparison and analysis of the static load tests on the experimental ultra-long bored piles of CCTV Tower and World Trade Center Tower (third stage) in Beijing, the behaviors of the pile tip resistance and the shaft resistance are studied. The results show that the deformation of pile top is mainly from its compression under loads. The tip resistance makes minor contribution to the bearing capacity relative to the shaft resistance. The pile shaft resistance exhibits a softening phenomenon in clay layer and a hardening phenomenon in sandy soil layer, and its play exhibits depth effect. The bearing capacity distribution of piles estimated according to the specifications is greatly different from the test results. Both the effective cleaning residue process and the post grouting means are proposed to be necessary measures for the ultra-long bored piles.
Das R.,The MCC Group |
Tripathy A.,The MCC Group
Medical Microbiology and Immunology | Year: 2014
We have characterized the NK/NKT-like cells in patients with self-limiting hepatitis E infection. The distribution of peripheral NK/NKT-like cells, expressions of activation receptors, cytotoxic potential and effector function of NK/NKT-like cells from fresh peripheral blood mononuclear cells of 86 acute patients, 101 recovered and 54 control individuals were assessed. Activated NKT-like (CD16+ CD56+ CD3+) cells were high in the patient groups. On CD56+ CD3− cells, NKp44 and NKp46 expressions were high in the acute patients, whereas NKp30, NKp44, NKp46 and NKG2D were high in the recovered individuals. On CD56+ CD3+ cells, NKp44, NKp46 and NKG2D expressions were high in the recovered but NKp30 was low in both the patient groups. Collectively, the current study elucidates the role of NK/NKT-like cells demonstrating phenotypic alterations of activated NKT-like cells and activation receptors, lack of CD107a expression and functional impairment of peripheral NK/NKT-like cells in self-limiting hepatitis E infection. © 2014, Springer-Verlag Berlin Heidelberg.