Applied Mechanics and Materials Vols. 405-408

Abstract: Spring-damper units were set on the boundaries to absorb incident waves and reflected scattering waves to realize viscoelastic artificial boundary (VAB). The equivalent node load input method was used to simulate the VAB and viscoelastic boundary element wave input. Programming is based on APDL secondary development language with ANSYS finite element software. Considering the interaction between chamber structure and the surrounding soil, docking chamber structure dynamic model is established based on the VAB. The linear elastic model was used for concrete structure. The D-P nonlinear model was used for the back soil calculation. Docking chamber structure dynamic analysis under conditions of fixed boundaries and viscoelastic boundaries were conducted. The result indicated that under the viscoelastic boundary conditions, dynamic acceleration response is significant on the top of the lock wall, which is approximately 2.5 times of the value on the bottom of the lock wall. The maximum response stress appears near the cross point of the lock wall and the bottom floor with value of approximately 5620 kPa;.The chamber bottom floor is subjected to tension and maximum stress with the value of approximately 6180 kPa. Usually, the structure response under the fixed boundary conditions is higher than the structure response under the viscoelastic boundary conditions.

Abstract: Using seismic analysis theory of CFRD, the numerical calculation of dynamic response of a high CFRD on alluvium deposit in strong earthquake zone subjected to strong seismic excitations of different transcendental probabilities was carried out, with emphasis on the seismic safety evaluation by permanent deformation. The influence of dynamic mechanical properties of the alluvium deposit on the dam's permanent deformation was also analyzed. The results show that permanent deformation will increase gradually with the increasing of peak value of seismic acceleration. The seismic safety of dam is in a normal range under the earthquake with transcendental probability of 2% in 100 years. The alluvium deposit has significant influence on the dam's dynamic response.

Abstract: The dam will interact with the foundation during earthquakes. The numerical seismic response of dam by FEM will be significantly influenced by the reasonable computational domain and dynamic boundary. Viscous-spring boundary, viscous boundary, fixed boundary, fixed boundary with massless foundation were compared one another on the dam's seismic response. Due to the radiation damping of foundation reflected by viscous-spring boundary, the peak value of dynamic response can be reduced 50% approximately at most compared with the traditional fixed boundary of massless foundation.

Abstract: The rotational seismic inputs for building design were discussed. The free ground rotations and the relation between free ground rotations and basement rotations were derived. The results show that the relation depends on the basement size, site and seismic frequency. For most building, the differences between the free ground rotations and the basement rotations are small. The suggestion is that for tall buildings the free ground rotations can be taken as the seismic input, but for low-rise building with large basement, the response spectra in short period region should be reduced.

Abstract: The article through to free vibration column experiment research to soft soil of Binhu new district of Hefei, The data and curves are given for four types of soil dynamic shear modulus and damping ratio with shear strain and draw rules of different size of confining pressure on the dynamic shear modulus and damping ratio of soil. For hefei binhu new area soft soil of the physical and mechanical characteristics, select the optimal soft foundation treatment scheme, practical design calculation model is set up, and perfect the construction technology measures, the article has some reference value.

Abstract: The Wenchuan earthquake occurred on May 12, 2008 (Beijing Time) caused great casualty and economic losses, a large number of masonry buildings were damaged in various degrees in this earthquake. The masonry residential buildings are widely used in China, and the study on them is significant. Although the masonry residential building discussed in this paper which was located in the highly intensity region was damaged severely, it hasnt collapsed and has very typical earthquake damage. The story comprehensive seismic capacity indexes are developed to anti-collapse capacity index which are used to calculate anti-collapse capacity of the building, and the results are also used for comparative analysis with the results calculated by means of structure vulnerability analysis. The earthquake resistant capacity of masonry residential buildings are discussed and analyzed. Finally, some reasonable suggestions on the seismic strengthening and reconstruction of this kind of building after disaster have been given.

Abstract: The brick-timber structures have a long history and are still used widely in Chinese rural area at present. A large amount of structures were damaged in Wenchuan earthquake occurred on May 12, 2008, and the brick-timber structures in different intensity regions were investigated in detail. Based on the investigate data of Wenchuan earthquake and other previous seismic data, the typical damage of brick-timber structures are summarized and the earthquake resistant design methods and research status are discussed, the earthquake resistant capability of brick-timber structure are also analyzed. Combined with current country codes, the constructional measures for earthquake resistance and construction technology of brick-timber structures are studied. Finally, some reasonable suggestions on the seismic strengthening and reconstruction of this kind of structure after disaster have been given.

Abstract: This paper first introduces two kinds of structural strengthening methods: direct method and indirect method. It is suggested that use frictional energy dissipation braces to reinforce the structure. Taking the reinforced concrete brace with steel-rubber frictional device as an example, the author discusses its strengthening design method. The applications of frictional energy dissipation brace in both domestic and international seismic strengthening are also introduced.

Abstract: In the tall building frame structure, the traditional frame joints which are usually constructed with the high strength concrete of the columns bring many difficulties to the construction. The frame joints concreted with beams low grade concrete (named as sandwich joint) is urged intensively by the engineers. The paper introduces the experiment of two full-scale sandwich boundary joints in the middle floor under cyclic load. Based on the test result, the specimens seismic behavior on performance of load-carrying capacity, node deformation, ductility, energy dissipation capacity etc are studied. Through comparison with traditional frame boundary joints, comprehensive seismic performance of sandwich boundary joints does not significantly reduce. The engineering applications of these sandwich frame joints are proved to be feasible, and some suggestions for the engineering application of this joint are proposed.

Abstract: The aqueduct bridge carries a large amount of water (fluid). How to model fluid is a basic issue in the seismic analysis and design of aqueduct bridges. This paper discusses and summarizes computational methods of fluid for the three-dimensional seismic response analyses. The result of this paper provides a reference for the researchers and engineers, who are interested in seismic-resistance computations of aqueduct bridges.