Advanced Materials Research Vols. 1065-1069

Abstract: Due to the interference of strong vibration signal, a big error exists in modal parameter identification based on traditional ARMA model. In order to solve this problem, a new method for modal parameter identification based on natural excitation technique (NExT) and ARMA model is presented. Firstly, NExT is used to obtain cross-correlation function of different response sequences. Then, ARMA model of cross-correlation function is established, and the parameters of ARMA model are estimated by least squares method. Finally, the modal parameter identification is achieved using the relationship between the ARMA parameters and structural modal parameters. Experiment shows that the identification results of our method are more accurate than the traditional ARMA model.

Abstract: Assembled monolithic structure is a common structure in the process of housing industrialization, among which the composite plate is an indispensable element. The thickness of the precast slab of composite plate is small so special measures have to be adopted to prevent the excessive deformation even destruction occurred during hoisting or transport. A novel removable stiffness increasing device for precast slab is presented in this paper. The device consists of steel truss, upper steel plate and steel base plate and can effectively improve the performance of the slab during hoisting and transport. The device has the advantages of simple construction and no special equipment is necessary. The device can be removed after being hoisted and saving cost. The performance of the slab with the device during hoisting and transport is analyzed and appropriate shape parameters are suggested.

Abstract: Based on the double member model of wall-frame structure and the corresponding transfer matrix method, the concept of frequent impedance of rigid foundation is introduced so that SSI can be taken into account. This method is more convenient and efficient compared to finite element method because of fewer structural parameters and faster calculation speed. Necessary structure parameters include 7 parameters of each storey, geometry size and total mass of foundation and elastic parameters of site soil. Totally 39 examples were calculated for 13 values of foundation mass and 3 kinds of soil, which are compared to the result of fix bottom model of upper structure. Results show that SSI does not always deduce a decrease of seismic response. Sometimes SSI may increases structural displacement evidently. The simplified method would provide structure designers an efficient tool to understand seismic behavior of wall-frame structures with various foundation and site soil.

Abstract: This paper is about a new steel tubular columns filled with concrete.

Abstract: This paper is a seismic response study on a vertical irregular frame structure which has a cantilevered top floor. Aimed to analyze the features of seismic response for a vertical irregular frame and scaled model, dynamic time history analysis and shaking table test have been carried out by use of the earthquake waves recorded in WENHUAN earthquake. It shows that the results of dynamic time history analysis and shaking table test are in good agreement, and the earthquake influence coefficients obtained by dynamic time history analysis and shaking table test are larger than the value according to Code, which indicates that the results would be not secure if the simplified methods specified in Code only in the sight of the calculation of earthquake loads.

Abstract: This article briefly analyzes the European norms EN 1992-1-1 design of concrete provisions , oblique shear capacity force section of concrete beams without stirrups calculation method, the factors affecting beams without stirrups carrying capacity, such as longitudinal reinforcement ratio, shear span ratio , concrete strength , compared to the Central European norms consider different ways . Through comparative analysis, some differences between China and the EU to get concrete oblique section design methods , but also pointed out the Chinese norms factors longitudinal reinforcement ratio is not considered.

Abstract: This paper presents functional and structural possibilities of Class B greenhouses, which has a film covered, for areas with extreme winter temperatures and heavy snow loads, which are typical of a Class A model (glass or rigid film covered). This greenhouse study covers from its analysis in the design phase to its correct operation after construction, breaking patterns set by European standard, due to the structural design of the greenhouse, providing new possibilities for this type B, restricted to a specific geographical area so far.

Abstract: For decades attention has been paid to interaction of foundation structures and subsoil and development of interaction models. Currently there are several software that, can deal with the interaction of foundations and subsoil. The purpose of this paper is to compare resulting deformation of the slab, subsidence of the subsoil, bending moments and contact stress calculated by two different software based on FEM calculations. Calculated deformation of the slab is compared with deformation measured during experiment.

Abstract: Since 2001, ACI 319 adopted the CCD equation for the concrete breakout capacity and a modified equation was recently included in 2011. In this study a new equation to predict the concrete breakout capacity of CIP anchor under shear loading was proposed. The equation was derived from multi-variable regression on the test results conducted by the authors and other researchers. It was found that the proposed equation could consistently predict the shear breakout capacity from small to large diameter anchors and edge distances.

Abstract: The dynamic response process for the reinforced concrete frame under different peak value of explosion load was simulated by the general finite element software SAP2000, followed by the comparative analysis on the displacement of the beams and columns under each condition. The analysis results show that the displacement of the beams and columns suffering the explosion load directly is ten times or even dozens of times more than those far away from the explosion load, which makes it clear that the explosion load influence on frame structure has a certain locality.