Applied Mechanics and Materials Vols. 501-504

Abstract: The item 6.1.5 in Code for seismic design of buildings (GB50011-2010)^[ is for single span frame structure design requirements of regulations. But there may be a partial single long-span frame structure in the actual project. Therefore, it is necessary to study the seismic performance of the structure under rare earthquake, especially in high intensity area. This paper takes a hybrid structure which is in high intensity zone with partial single long-span concrete structures (31m) and the single long-span steel roof as an example, and the seismic performance of partial single long-span structures under rare earthquake is discussed. In the elastic-plastic analysis, reinforcement results of members are automatically merged by VBA program. Material parameters of the Elastic-plastic analysis model are compared to Pseudo-static collapse experiment results of reinforced concrete frame columns and the overall framework in Tsinghua University. Results show that: The partial single long-span frame structure reasonably designed based on the Chinese code can meet the requirement of No Collapsing With Strong Earthquake; The bearing type of the steel roof has certain influence on the inter-story displacement angle of supporting frame structures under rare earthquake.

Abstract: Ancient buildings have poor anti-seismic ability due to the long age of construction and lack of data materials. This paper seeks a scientific and quantitative evaluation method and predicts the earthquake damage of an ancient building by using fuzzy analogy approach. The example shows that this evaluation method has great meaningful of the existing ancient buildings under the earthquake intensity which likely to be encountered with the design life expectancy and provides a certain scientific basis of seismic estimation in ancient buildings.

Abstract: Shear wave splitting analysis is one of the most commonly used techniques in structural seismology. In this study, the splitting parameters of Moho converted P-to-S phase (Pms), the time difference between maximal energy of qS1 and qS2 and their amplitude ratio were obtained. The data were from 29 broad-band stations across the Longmenshan fault belt. Subsequently, the deformation features of the crustal structure beneath the east Tibetan margin and Sichuan basin were analyzed. Our results show that the time delay and the time difference between maximal energy of qS1 and qS2 in east Tibetan margin is obviously larger than Sichuan basin. However, the amplitude ratio between qS1 and qS2 beneath Longmenshan fault is much smaller than other tectonic sub-regions. These results may suggest the existence of fluid beneath the Longmenshan fault.

Abstract: With the increasing focus on the earthquake resistant problems of subway engineering, the response displacement method is used in the seismic design of subway structures. The determination method for coefficient of subgrade reaction in seismic design of subway structures is very important. Four typical determination methods including test method, Lis method, MIDAS method and finite element method are introduced. Based on the values of coefficient of subgrade reaction from four methods, models of the response displacement method are used to obtain the bending moment of the subway structures. The advantages and disadvantages of four determination methods for coefficient of subgrade reaction are compared. The results show that the test method is the preferred one for designers, the tangential coefficient should be in a range of one to two third of the normal coefficient, and the internal force of subway structures can be obtained by the test method and modified by a correction factor that is 1.05.

Abstract: Combining with specific engineering project, the author has researched the impact image method that was applied on inverse analysis of foundation structure of the buried pipeline. The author has also expounded the theory, method, process and conclusion of the impact image method in the detection of the buried pipelines basis. The results show that, it is a nondestructive testing method with high reliability and accuracy. Using this method, people could make sure whether there are boulders, empty or loose areas. Thus scientific basis could be provided to dispose the defect beneath the buried pipeline.

Abstract: People remained optimistic about the safety of the space grid structures, because the seismic damages of space grid structures were quite rare and rather light. However, two space grid structures got damaged in 2013 Lushan Ms 7.0 earthquake. The two structures are the double-layer reticulated shell structure and flatbed grid structure, namely Lushan Gymnasium and Lushan Middle School Gymnasium respectively. This paper briefly reviews the seismic damage phenomena of grid structures in historical earthquakes, and then focuses on the two damaged space grid structures in Lushan earthquake. The reason why the two space grid structures got damaged are derived from the force state analysis of the rods, ball joints and bearings. Finally, we come up with the effective advice for the seismic design and construction of the space grid structure.

Abstract: A two-dimensional finite differential model is established to find the variation of displacements and stresses of culvert components. The time-history analysis is performed and a wide range of parametric studies are carried out to investigate the influences of height of embankment, ground acceleration and the propagation angle of seismic wave on the responses of the junctions between the culvert components under seismic loads. The results show that the horizontal displacements, the peak values of internal forces under seismic loads increase considerably and nonlinearly with the increases of the height of embankment. The peak values of stresses are sensitive to minor variations of acceleration. And the stresses in the culvert structure are reduced, when the propagation angle of seismic wave increases.

Abstract: L-shaped plane structure in the common buildings cannot meet seismic requirements because of significant torsion. According to the analysis of the vibration characteristics, structural deformation and base shear of irregular L-shaped plane structure under frequent and rare earthquake, four arrangement plans of viscous dampers are proposed to adjust the stiffness of the structure. The layout principles of viscous dampers are obtained by comparing effects of different arrangements such as in the periphery, in the short sides, in the long sides and in both short and long sides.

Abstract: In order to study seismic behavior of double web-angle and top-seat-Angle connections, finite element methods, which included material, geometric and contact nonlinearity, were used to the model under cyclic loading. The effects of the angle length, the angle thickness, the bolt diameter and grade on strength, and the gauge distance from the edge of the angle to the center of bolt line on strength and hysteretic behavior of connections were studied. Finite element results reveal that the hysteretic behavior, initial stiffness and load bearing capacity are significantly affected by the gauge distance from the edge of the angle to the center of bolt line, the angle length, the angle thickness and the bolt diameter and grade.

Abstract: To ensure the safety of students during earthquakes, the Department of Education in Taiwan has been conducting a seismic evaluation and rehabilitation project on elementary and high-school buildings in recent years. In this project, column-jacketing is one of the most frequently used retrofit techniques due to its compatibility with existing building configurations. However, the seismic performance of column-jacketing often falls behind other retrofit techniques such as addition of shear walls. In order to enhance the seismic performance of column-jacketing, the addition of supplemental beams is proposed in this study. Analysis conducted on a typical school building based on nonlinear push-over analysis indicates that such addition could improve the seismic performance of column-jacketing for 38%, which would provide a great enhancement on the seismic safety of the retrofitted building.