Applied Mechanics and Materials Vols. 166-169

Abstract: A method based on Ordinary Differential Equations (ODE) solver for free vibration analysis of tubular structures of tall buildings is developed, considering the deformation of the foundation soil as well as the interactions between the foundation and soil, by means of a three dimensional model with continuously distributed mass and stiffness. The nodal lines employed to discretize the computational model of the structures are one-variable functions defined on the nodal lines selected by the analyst to describe the dynamic behavior of the model. The unknown functions determined numerically herein are actual vibration modes that can be also recognized as the deformation functions of a set of conceptual structural components. By a Hamiltonian principle, the governing equations of the free vibration analysis can be obtained, which are a set of ordinary differential equations (ODE) of the vibration modes with their corresponding boundary conditions. The desired frequencies and corresponding vibration modes can be obtained by numerically solving the ODEs with boundary conditions. The method is applied to the tubular structures of tall buildings. The results from the illustration example show that the method is rational and powerful for the free vibration analysis of tall buildings.

Abstract: Cold-formed steel self-drilling screws connection are imitated to carry out numerical simulation analysis, in which geometric large deformation, materials nonlinear and contact problem are taken into account. From the comparison of computer analysis with experimental results, it comes out that the finite element numerical simulation method is accurate and feasible.

Abstract: Combined with canopy structure design of a old-man university, this paper introduces the selection of scheme, material selection and Load value of fan-shape variable height four pyramid grid structure. Using the software ANSYS, finite element model of grid structure is established, and internal force and deformation of the members are got, the bearing capacity of the members and structural deformation are checked, finally design and construction for the node of members and the detail of structure are given, these can provide references for the design of similar engineering.

Abstract: In combination with a distinctive grid design with six-point supporting, three kinds of calculation methods of the grid structure are compared. By finite element method the internal force of the bars and deformation of the whole structure are calculated, and specific design process is given. Finally design details of bolts ball nodes of grid are given, these can provide reference for the same kind of grid structure design.

Abstract: The steel bar connection is an important and inevitable work in civil engineering. The traditional overlapped connection method usually needs to place the transversal rebars in the overlapped splicing area to restrict the splitting cracks in concrete. The steel usage and labor cost are increased. An improved splice, which is the hybrid connection of welding and overlapping, was developed for mid-diameter bars, which is easy to install and has commendable mechanical behavior. A series of reinforcing rebar splice tests with steel-concrete interaction were conducted. The failure model of hybrid connection and the ultimate strength were acquired. Based on the tests, the failure mechanism of hybrid connections was analyzed. The results show that the ultimate load of the new splice is sufficient for the engineering application and the failure model is reasonable. The hybrid connection could be used in the engineering practice.

Abstract: According to the working mechanism of re-centring SMA damper, restoring force model is established. Based on the mechanical model, the re-centring SMA damper is modeled in finite element software SAP2000 by adding Multi-Linear element and Plastic (Wen) element. Time-history analysis method under different ground motion is used to analyze control parameters of re-centring SMA damper. The influence on damping effect and ability to re-centring of damper of several factors such as the ratio SR of initial stiffness of energy components and stiffness of corresponding structural layer, the ratio β of yield displacement of energy components and yield displacement of corresponding structural layer, the ratio α of the second stiffness and initial stiffness of energy components, the ratio Q of initial restoring force of re-centring group and yield force of corresponding structural layer, and the ratio λ of the second stiffness and initial stiffness of re-centring group were studied. Their reasonable numerical value range are obtained by numerical calculation, the reasonable ranges for SR, β, α, Q and λ are found to be 2~3, 0~0.05, 0~0.1, 0.05~0.10 and 0.05~0.15 respectively.

Abstract: Through theoretical analysis of a simplified model for web-core sandwich beam, a simple equation for predicting the deflection of such beam in the weak direction is deduced. The obtained equation is verifed by comparing the predicted deflection of a web-core sandwich beam with reported finite element result. It is found that the presented equation can provide reasonably accurate estimation in analyzing the static behaviour of web-core sandwich beam in weak direction. Additionally, it is also found that the deformation of a web-core sandwich beam is caused mainly by shear deformation while the flexural deflection is much smaller compared to the shear deformation

Abstract: Based on the test of 108 blocks with 150mm×150mm×300mm, 54 blocks with 150mm×150mm×150mm, elastic modulus of that of combined aggregate concrete is studied, and the influencing factors on it are discussed. The results show that the elastic modulus of combined aggregate concrete are very much affected by the ratio of common aggregate to lightweight aggregate, and it increases with the water-cement ratio decreasing. The calculation equation of combined concrete modulus is suggested.

Abstract: In this paper, wind tunnel test of a large-span roof structure is firstly introduced. Secondly, data processing on synchronous multi-spots pressure measurement test is given. Wind pressure distribution is calculated by using the method mentioned in this paper. Some results and conclusion are useful for design of large-span roof structure.

Abstract: Based on the limit equilibrium method and assumptions of vertical stiffener joint model, the stress mechanism of vertical stiffener joint model is analyzed for concrete-filled square steel tube and steel beam. The formula of bearing capacity for vertical stiffener joint of concrete-filled square steel tube and steel beam is established. The rationality of proposed formula is validated by comparing analytical results with experimental data. Moreover, some factors involved in the proposed bearing capacity formula of connection joints are discussed. The results can provide some theoretical references for the study of bearing capacity of annular plate joint.