Papers by Keyword: Earthquake

Abstract: Different from the other distribution center location methods, there are new characteristics in distribution center location during earthquake disaster responses. In this paper, we investigate the factors impacting the location of distribution center during earthquake responses, and propose a decision-making model based on improved AHP framework for this issue. The improved AHP is extended to automatically calculate large scale judgment matrices by the crosstie model. This decision-making model was successfully applied in the simulation case of Yushu earthquake responses in 2010. The results show that the proposed decision-making model is reasonable.

Abstract: According to the recent earthquakes, the asymmetric buildings suffer from severe damages caused by increased torsional response. The new seismic codes try to take into account this effect and during the modeling it is difficult to assess all the parameters that have an influence on the behavior of this kind of structures. In this work, a study on the influence of the effects of torsion on the behavior of structure is done. The proposed structures consist of an irregular 3-storey reinforced concrete frame with infinitely rigid slabs. The uncertainties of input parameters, such as seismic Arias intensity, peak ground acceleration, predominant period and output ones such as, inter-story Drift, and dynamic eccentricity upon the torsion is investigated. Using a finite element code, dynamic linear and non linear time analysis and pushover analysis have been performed, based on 116 seismic records with a magnitude varying between 6.2 and 7.7.

Abstract: There are a large number of concrete dams worldwide. Some of the dams are in areas prone to seismicity and were built many years ago with minimal consideration to seismic loads. Dam safety during and after an earthquake, is the aim of the present study. The failure of a dam during an earthquake will be catastrophic in terms of human life and financial losses. In the present work, an analytical fragility analysis was performed in order to characterize the seismic vulnerability of concrete gravity dams by using a probabilistic method to model sources of uncertainty that could impact dam performance. The assessment of the seismic vulnerability of concrete gravity dams under near-fault ground motions was performed to assess their performance against seismic hazards. A case study was considered, it is about the dam of Oued el Fodda on the Oued Chelif River, West Algeria. This dam was designed in the early 1930s.

Abstract: The disaster-related epidemic is the secondary disaster after serious earthquake. By comparing the epidemic situations and prevention work in Tangshan and Wenchuan earthquakes, this paper summarized the successful factors and deficiencies. Some countermeasures are proposed for disaster epidemic prevention, such as integration of the epidemic prevention system, perfection of disease prevention standard, establishment of hygienic evaluation system, planning of material reservation and development of epidemic prevention equipment.

Abstract: Liquefaction properties of large diameter long pile in medium dense sand under earthquake was investigated based on finite difference method. Dynamic property of foundation soil was modeled with equivalent linear model, three peak acceleration of 0.2g, 0.15g and 0.1g was studied. Numerical calculation results show that: peak acceleration affects large pore pressure zone and maximum pore pressure, when peak acceleration increase from 0.1g to 0.2g, large pore pressure zone moved from middle to bottom of pile, maximum pore pressure raised from 45 kPa to 350 kPa; liquefaction zone of foundation has a heart shape, and expanded with increase of peak acceleration, peak acceleration increase from 0.1g to 0.2g, depth of liquefaction zone bottom increase from 27% to 41% pile length, width of liquefaction zone increase from 34% to 41% pile length, peak acceleration reached to 0.2g, liquefaction zone extended to ground surface.

Abstract: Three level seismic fortification theory is seismic design theory of the bearing capacity,which can not really realize that no damage under minor earthquake, repairable under moderate earthquake and no collapsing under strong earthquake. In order to overcome this deficiency, American earthquake engineering and structural engineering experts have profound conclusion after the previous earthquakes, improved bearing capacity design method, put forward the theory of performance-based design.Firstly,the origin of performance-based design theory is introduced in the paper.Secondly,the main content of performance-based design theory is illustrated,which include Earthquake Hazard Levels,performance levels of building structure,target building performance levels and performance- based design methods.Finally,the paper pointes out that performance-based design theory has attracted extensive attention of Chinese researchers and engineering designer,a series of research work has been carried on,and some achievement has been made.

Abstract: Soft-storey mechanism is characterized by a sudden reduction of lateral stiffness in one or more levels of a structure. Soft-storey is often observed in the ground level due to the absence of wall or cladding. With recent develop of energy dissipation systems, soft-storey mechanism can be corrected by addition of a damper-brace assembly. In particular, this paper investigates the effect of toggle-damper-brace systems on such situations. Governing equations including the magnification factor and lateral stiffness contributed by a toggle-damper-brace are formulated. It was found that a toggle-damper-brace system, if proportioned correctly, will significantly increase the travel in the damper and overall stiffness of structure can be enhanced. An illustrative example is presented using nonlinear time history analysis implemented on MATLAB.

Abstract: Concrete arch dams are critical structures, the failure of which would lead to catastrophic effects on a regional scale. Considering the uncertainty characteristics of earthquake and the self-adjustment of inner force of arch dams, it’s necessary to investigate the seismic performance index of arch dam for holistically evaluating the seismic safety of arch dam-foundation system subjected to high intensity seismic excitations. By considering the contraction joints movement and concrete material nonlinearity, a series of dynamic response-history analyses of arch dam were carried out under increasing levels of earthquakes. Based on these analyses, the performance index of crest deformation is recommended for the seismic safety assessment of arch dam. And several performance stages of seismic response including the opening of contraction joints and the distribution of concrete damage are also investigated.

Abstract: Based on the theory of soil-structure interaction, the underground structure and surrounding soil as a system, and the finite element analysis model is established, and finite element dynamic analysis method is implemented, the three seismic acceleration time history of the different spectrum characteristics is inputted, the seismic effect on the surrounding ground of underground structure is analyzed. The results show that the effect on dynamic response is the limited range and not significant, when seismic design of structures on the surrounding sites is implemented, additional dynamic response on surrounding sites does not need to consider.

Abstract: After the Wenchuan earthquake, a large number of infilled frame structure of underlying weak layer (the bottom of non-filled walls, the upper wall of clouds filling) of the housing system did not appear "weak beam strong column" of the failure mode. Established pure frame structure of finite element model which considered the quality of in filled wall without taking into account of its stiffness and strength and the frame of finite element model which contains filler wall, and carried out elastic-plastic time-history analysis with established finite element model of two under earthquake, through analysis and comparison understand reasons which infilled frame structure of underlying weak layer did not achieve the "weak beam strong column" ductile failure mechanism, and further explored how to achieve "weak beam strong column" failure mechanism for infilled frame structure of underlying weak layer, raised a number of assurance measures.