Applied Mechanics and Materials Vols. 204-208

Abstract: To ravel out the difficulty in the expression and measurement of Non-subjected Information in earthquake emergency decision-making under fuzzy environmental conditions, a ranking method was put forward for earthquake emergency events on Intuitionistic Fuzzy Sets. Via the explanation about the concept of Intuitionistic Fuzzy Sets, intuitionistic fuzzy matrix and its interval estimation was established for the set of the earthquake emergency events, and the positive and negative ideal intuitionistic fuzzy earthquake emergency was determined; Through defining the distance calculation about subjected, non-subjected and hesitated degree, and respectively comparing the distance from the emergency to the positive and negative ideal event, the superiority degree model was established for the earthquake emergency events, which further gained the sequence of the emergency event collection. Case showed that model effectively solved the ranking problem about earthquake emergency events, which provided one theory and method for scientific decision-making practice in shock resistance and disaster relief.

Abstract: Complicated and variational relation among the factors of the pregnant environment, resulted that, it was hard to orderly sentence the connection from the pregnant risk factors to the overall slope safety. Through differentiating risk relational factors into the extreme variation, same directional matrix was established for the pregnant environment safety of earthquake-induced underground engineering slope. Gray relation Analysis Model was established on the pregnant environment of earthquake-induced underground engineering slope, which was integrated with entropy information of same directional matrix. Model calculated out the gray relation degree and variation coefficient among the sample data sequence of the observed units, and finally sentenced the overall safety of underground engineering slope systemically. Example showed that toward the multi-objective decision-making problem for the safety assessment of underground engineering slope, model possessed with a scientific, simple, practical feature, whose outcome revealed the full status of the slope pregnant environment.

Abstract: Two curved bridges with typical line shapes: C shaped curved bridge and S shaped curved bridge were selected to study the influence of line shapes on the dynamic parameters of the curved bridge. Spatial finite element analysis models were established and the seismic responses of the two bridges in different earthquake input directions were studied by the elastic dynamic time history method. Results show that: except for the first natural period, the rest natural periods of the two bridges are basically the same; the earthquake resistant capability of the C shaped curved bridge is worse than that of the S shaped curved bridge; under earthquake, the control input direction is Y-direction, and the control internal force is the axial force-Fx, shear Fy, and the moment Mz; relative to the horizontal seismic inputs, the internal force produced by the vertical seismic input is very small, and it can be resisted by structural measures in seismic design.

Abstract: 2008 Ms8.0 Wenchuan earthquake produced Strong surface rupture and deformation, triggered geological disasters: collapse and landslide, and brought about serious buildings damage and casualties. Wenchuan earthquake surface rupture, secondary geological disasters and buildings damage were investigated on-site. Disasters characteristics of the earthquake were discussed, and relationship between buildings damage distribution and seismogenic fault of Wenchuan earthquake was discussed. In light of seismic protection and the Code for Seismic Design of Buildings, typical buildings damage and its causes are analyzed and discussed from following respects of buildings location, seismic design and buildings construction. Corresponding seismic measures are suggested.

Abstract: In order to reduce the hazards of earthquake disasters on human, basic principle of reducing vibration is discussed by establishing passive vibration isolation model. The calculation results show vibration can be reduced by isolation materials whose deformation modulus (stiffness) should be smaller and damping should be appropriate. Light reinforced soil is a good man-made material, its all physical mechanical parameters can be changed, and anti-pull capacity of soil can be increased. According to the basic principle of reducing vibration, reducing vibration idea using light reinforced soil is brought forward, and the idea has a very important significance for research on reducing earthquake disasters from the angle of ground and foundation.

Abstract: Based on the energy analysis of a multi-degree-of-freedom (MDOF) system, a mode decomposition method for the input seismic energy is proposed, which substitutes a MDOF system with equivalent single-degree-of-freedom (SDOF) systems. The input seismic energy is obtained, using the actual earthquake data. The influence of ground motion parameters is analyzed. The results show that the seismic input energy increases proportionally with the square of ground motion acceleration peak. The bigger the predominant period is, the more the input seismic energy is.

Abstract: With the increasing importance of urban disaster prevention, the earthquake disaster prediction has gained more and more attention. Based on the investigation data of one multi-story masonry building in Yinchuan City, which located in the North-South seismic belt of China, the earthquake disaster prediction has been done by using of vulnerability analysis.

Abstract: Joints are the forces cross points of members, and the bearing modes are more complex than other members, especially under earthquake action, so the rationality of joints are directly related to the safe reliability of structure. By the pseudo-static test of 4 concrete-filled square steel tubular column and steel beam joint with outer stiffened ring, this paper discusses the failure characteristics, failure mechanism and seismic behavior of joints under different axial compression ratio. The analysis of the testing results shows: the energy dissipation capacity of joints is much better, the degradation of strength and stiffness are slowly when reached the ultimate strength, and the ductility is also good.

Abstract: The intake tower of the hydropower station is a high-rise underwater hydraulic building whose seismic safety is enormously important. Taking the effect of foundation and hydrodynamic pressure into account, we apply the ANSYS for the static and dynamic analysis which evaluate the seismic behavior of the intake tower. The result which provides the basis for the improvements shows that the rigidity of intake tower meets the requirement. After taking some engineering reinforcement measures, the strength also meets the requirement.

Abstract: The reinforcement technique with strengthening geogrid has been widely used in modern seismic design of 200m high rock-fill dams. However, how to evaluate accurately the effects of reinforcement in seismic design and safety evaluation has become a key problem. As compared with the minimum safety factors which are conventionally employed as the evaluation criteria, the earthquake-induced deformation can better reflect the characteristics of rock-fill materials, input motion and the performance of reinforced dams for the earthquake loading. In the improved Newmark sliding method, the effects of reinforcement in enhancing the stability of slope in high rock-fill dams and restricting the permanent deformation of dams are investigated. Firstly, the limit tensile intensity and limit coordinating strain of reinforcement is determined based on the stress-strain relationship of reinforcement-composite and rock-fill materials. Secondly, the location of critical failure face is determined via a combination of ant colony algorithm and Holland method. The yielding acceleration of potential sliding bodies, which considers the limited stress of reinforcement layers and time-history vertical acceleration, is obtained. Finally, the transient movements are accumulated for all the overloadings. It is guaranteed that the reinforcement can reduce the permanent deformation up to 80% and improve the seismic design and safety evaluation of high rock-fill dams subjected to strong ground motion effectively.