Advanced Materials Research Vols. 446-449

Abstract: The research of large amplitude vibration of simply supported beams can be dated back to 1950; many achievements and some evolution were accomplished by many researchers over hundred and fifty years. The development of nonlinear vibration formulations for beams has gone through distinct phases–earlier continuum solutions, development of appropriate forms, extra-variational simplifications, debate and discussions, variationally correct formulations and finally applications. A review of work in each of these phases is very necessary in order to have a complete understanding of the process of evolution of this field. This paper attempts to achieve precisely this objective.

Abstract: The ductility of primary lateral resisting member, i.e. Core wall is analyzed using finite element program ADINA. The influencing factors like aspect ratio, concrete grade, axial compression ratio, reinforcement ratio,boundary confinement and reinforcement ratio of boundary element etc. are considered in the analysis. Based on the aforementioned research, some suggestions for the design of core wall in hybrid structure are proposed.

Abstract: The program by Fortran to determine softening curve of concrete by inverse analysis was developed based on the wedge splitting test and Fictitious Crack Model (FCM). The four-linear softening curves were obtained by the inverse analysis program for the wedge splitting (WS) specimens which size are all 200mm×300mm×300mm with different coarse aggregate size. The approach of refining element mesh was presented for the inverse analysis calculation. It is shown that the three control parameters of softening curve, which are the tensile strength f_t, maximum crack width w_c and fracture energy G_F, increase with increase of the maximum coarse aggregate size d_max.

Abstract: Based on the nonlinear bending theory of double-deck reticulated shallow shells, the nonlinear buckling problem of cylindrical double-deck reticulated shallow shells under wind pressure is studied. An analytic solution for simply supported edges is obtained by using Galerkin’s method. The results of numerical calculations are presented in diagram and table, which show the influence of geometrical parameters on the buckling behavior.

Abstract: Castellated beam is a kind of holed web plate structural beam, since it has many advantages: savings in steel, light self-weight, resists bending and easy to deploy, the application of this structural beam becomes more and more widely. Due to its weakened web plate, castellated beam would be affected by shear effects greatly. The deformation of components increased under the affects of external loads. Therefore, in order to improve the accuracy of finite element analysis model, by consideration of the shearing effects and the bending stiffness affected under opened structure, this issue made improvement based on the theory of curved beams. By compare the results from this issue and the result from the analytical model of shell elements; we verify the feasibility of this method.

Abstract: In order to study the effect of rock fracture distributions on stability of tunnel, the effect of joints with different strike dip, the size and density was considered by using probability and statistics method. Based on the Monte Carlo random simulation, the statistical network model of 2D jointed rockmass was established to describe and characterize jointed rock mass. On the basis of this, the numerical code RFPA2D is employed to analyze effect of fracture dip angle on the tunnel stability. Numerical results show that the fracture distribution has a little effect on tunnels failure mechanism and failure type of tunnel because the failure of tunnel in the jointed rockmass is similar to the one without joints and fissures. However with the change of the fracture dip angle, the loading capacity of the tunnel in the jointed rockmass varies accordingly.

Abstract: Using the common classical turbulence model, k-ε turbulence model which has fairly common usability，CFD simulations for group high-rise building and wind-induced static interference between tall buildings, are conducted. Based on the comparison between the CFD and relative wind tunnel test ,it shows that: the method of numerical simulation have better accuracy, could be used for group high-rise buildings study of static interference.

Abstract: Based on the experimental study of normal-section bearing capacity of four steel reinforced high-strength concrete (SRHC) L-shape short pier shear walls with two-way eccentric compressive load, this thesis discussed the failure pattern and working mechanism and get some general laws about normal-section baring capacity of this kind of specimens. The research results show that: the failure pattern of SRHC L-shape short pier shear wall with two-way eccentric compressive load is classified into two types-large eccentric compression and small eccentric compression; the sectional strain basically fit the plane-section assumption; steel and concrete can practically work cooperatively until the specimens are damaged and the steel of compressive region yielded; the normal section baring properties of the perforated frame member and the trussed frame member were fairly close to each other and the trussed frame has no advantage compared with the perforated one.

Abstract: To improve the accuracy of describing the nonlinear behavior of long concrete-filled tubes (CFT) and make the nonlinear reliability analysis method more valuable for engineering application, based on the response surface and nonlinear finite element method, the reliability analysis model for the nonlinear carrying capacity of concrete-filled steel tube structure is made, with the help of consistent mode imperfection method to consider the initial geometric defects of the structure. After a parametric analysis of the diameter-thickness ratio and the slenderness ratio, the application scope is examined. The numerical results show that as the slenderness ratio increases, the influence of the initial geometric defects on the reliability of carrying capacity increases gradually. It is suggested that when the slenderness ratio is bigger than 15, the effect of initial geometric defects on the reliability index should be included. Moreover, when the diameter-thickness ratio is smaller, influence of geometric nonlinearity on the reliability index of the carrying capacity is obvious.

Abstract: As a new type of structural system, the cast-in-situ reinforced concrete grillage shear wall system has functions of formwork, strength and heat preservation at the same time. It is suitable for residential buildings in seismic and non-seismic areas. The results of quasi-static tests on 20 specimens of small and large grid size grillage shear walls with different shear span ratios show that: both of small and large grid size grillage shear walls have excellent seismic performance; shear or bending deformation of horizontal and vertical limbs dissipate seismic energy so the elastic-plastic deformability of grillage shear walls meet the requirements of shear wall structure under strong earthquakes; the bearing capacity of grillage shear wall was calculated with formulas used for solid RC shear walls. The equivalent thickness of grillage shear wall equalized as solid shear wall is determined by elastic finite element analysis.