Applied Mechanics and Materials Vols. 580-583

Abstract: Aiming at the horizontal connection joint of the precast shear wall structure, this paper presents a new-type horizontal wall-to-wall connection. Based on the ABAQUS finite element analysis platform, an accurate finite element model of shear connection joints was built. By quasi-static numerical tests, the seismic behavior of the proposed connection of the precast shear wall system was analysed and compared with that of the traditional cast-in-place connection. The numerical results show that the seismic performance of the presented connection, such as deformability and energy-dissipation capacity, is slightly lower than that of its cast-in-place counterpart.

Abstract: The seismic response of the base-isolated structure can be reduced significantly in the far-field region compared to the conventional seismic structure. However, near-fault ground motions with velocity pulse may cause the adverse influence on the seismic performance of the base-isolation building, which needs to be investigated deeply. In this paper 6 ground motions with velocity pulse are selected as the input, and the seismic response of a 9 layers conventional seismic RC frame building and comparative base-isolation building with lead-core rubber bearings are obtained by nonlinear time history analysis. The result indicates that base-isolation building with lead-core rubber bearings are of good aseismic performance under the near-fault ground motions with velocity pulse.

Abstract: Submarine pipelines are described as the lifeblood of offshore oil and it is crucial to ensure the seismic safety of the submarine pipelines. Based on the fluid-structure interaction numerical analysis method and by using finite element software ADINA, the analysis models of the free long-span submarine flexible pipelines under earthquakes were established. By employing dynamic time-history method, the influences of fluid-structure interaction on the seismic response of the submarine pipelines were researched. The results showed that the peak normal stress and the peak displacement of submarine pipelines’ mid-span considering the influences of the fluid-structure interaction are greater than those without considering the influences, and the influences of the fluid-structure interaction on the seismic response of the submarine pipelines will increase with the increase of the submarine pipelines‘ diameter.

Abstract: To study Steel reinforced concrete frame-reinforced concrete core wall (SRC frame-RC core wall) hybrid structure earthquake damage evolution and collapse mechanism, this paper holds the earthquake collapse mechanism, seismic collapse analysis and collapse control strategies as the mainline, establishes performance degradation and collapse criterion characterization based on structure dynamic characteristics, adopts incremental dynamic analysis (IDA) method to complete the prototype structure collapse-resistant test and quantitative assessment of seismic collapse analysis and determine the main factors that affect the structure collapse-resistant properties. Through numerical analysis to reveals the mechanism of the earthquake collapse and obtains optimal collapse model, and proposes methods and measures of collapse-resistant design for such structure, which has practical significance for enhancing the ability of high-level hybrid structure to earthquake.

Abstract: According to the code and technical regulation, a irregular RC frame with specially shaped columns have been designed, which situated at the area of fortification intensity 7. Subsequently, the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results, this paper have examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it achieves the predetermined seismic aims. It indicates that the structure designed the codes can achieve the predetermined seismic aims under the rare earthquake.

Abstract: The seismic response of step-terrace frame structure is affected by the slope. Considered soil parameters of slope, the floor numbers and span numbers of layers below the scarp, 45 step-terrace frame example structures were designed, and three excitations at bedrock were selected to analyze the example structures response with dynamic time-history analysis method. The research indicates that when the other conditions are the same, the soil becomes softer, or structure's span numbers on the slope becomes larger or the slope becomes higher, the dynamic interaction between slope and step-terrace frame structure becomes more obvious. When the inputted ground motion at slope foot is adopted and the slope soil is soft, the seismic response of structure without soil-structure interaction is smaller than that of with soil-structure interaction.

Abstract: A radius of curvature 20 times greater than the deck width of the bridge (R≥20b) is required as a specification in the regular bridge simplification conditions of the seismic response of curved girder bridges. Selecting benchmark bridges and employing parameter analysis method, this article studies on the effect of R/B value of the curved girder bridge on the response ratio of the seismic response calculated using the finite element model and that using a regular girder bridge. This study shows that on conditions that the deck width of the bridge is constant, the smaller the radius of curvature and the larger the B/R value (i.e., the smaller the R/B value) of the curved girder bridge are, the greater the difference between the seismic response of the curved girder bridge and the result calculated with a regular girder bridge is, and the difference is more significant under traverse seismic effect than that of longitudinal seismic effect. On conditions that the radius of curvature is constant, the impact of the change of B/R value due to the deck width change of the bridge on the difference between the seismic response of the curved girder bridge and the result calculated with a regular girder bridge is insignificant. Compared with the deck width of the bridge, the difference between the seismic response of the curved girder bridge and the result calculated with a regular girder bridge is more sensitive to the radius of curvature.

Abstract: Rare study is done on floor response spectrum of super-high rise building, but it is an important condition for the seismic response analysis of floor subsidiary structure. Therefore, based on the early calculation model of China Financial Information Mansion, the floor response spectrum is calculated under different input ground motion. The floor and ground response spectrum is compared with each other from the seismic coefficient, dynamic amplification coefficient, characteristic period and the form of response spectrum. The results shows that: the floor seismic coefficient and the magnification coefficient are greater or smaller than the ground ones, the biggest difference of which is nearly 1 times; all the floor character period are greater than the ground ones, the biggest difference of which is over 60%; there are obvious differences between the floor and ground dynamic magnification factor spectra form under some conditions, of which the second peak of the former one is probably very large, even near to the peak of the first one, while the latter has no such phenomenon. Therefore, during the process of calculating the seismic response of floor subsidiary structure, it is necessary to consider the change of floor seismic coefficient, dynamic magnification factor, characteristic period and spectra form based on the main structure.

Abstract: In this paper, MEMD-based scalogram and coscalogram, and instantaneous frequency spectral are proposed to characterize the data derived from the multivariate non-stationary process. The scalogram and instantaneous frequency spectral capture spectral evolution of each component while the coscalogram reveals embedded intermittent correlation between two components. Compared with scale-based scalogram and coscalogram, frequency-based instantaneous frequency spectral provides more detailed portrayal for multivariate data. The effectiveness of the proposed MEMD-based time-frequency analysis framework is validated by numerical examples of uniformly and generally modulated ground motions.

Abstract: In this paper, the power spectral density method based on ANSYS is carried out to study the intake tower finite element model under an earthquake. A power spectral density function is obtained and disposed to be smooth. Then it is used to study the intake tower when the seismic wave occurs in the direction of flow and perpendicular to the direction of flow .This study provides theoretical basis for reinforce and transform of the intake tower structure.