Applied Mechanics and Materials Vols. 166-169

Abstract: Lateral seismic action on retaining wall along the height is a key parameter in the design of the wall against earthquake. Seismic responses of 6 gravity retaining walls with heights from 7 to 25 meters are analyzed by finite element method with considering the soil-structure interaction. A formula of the action on retaining wall is summarized from the response results with input acceleration time histories simulated for Intensity Ⅵ, Ⅶ, Ⅷ and Ⅸ.

Abstract: For the complex features in the form of a flat L-shaped reinforced concrete frame structure, the three dimensional FEM model of the structure was established in this paper, and the dynamic characteristics of the structure was analyzed, the participation equivalent mass of every mode’s order was obtained. Seismic response analysis for the structure was carried out with modal decomposition spectrum method and time history analysis method, the weak layer of the structure was pointed out and the reference for the structural design was provided.

Abstract: The different damaged characteristics of ancient masonry pagodas in earthquake should be reinforced by corresponding seismic strengthening methods with modern construction materials. Focusing on the long-term preservation of pagoda, investigates the strengthening technology and protective measures relative to durability of reinforcement materials and masonry structure. Combining with the analysis of typical pagoda strengthening projects after the Wen-chuan Earthquake, probes into the improving construction procedure and material formula for the durability of masonry pagodas based on the protective principle of cultural relics.

Abstract: Dam damaged is one of common forms about lifeline engineering after earthquake raids. Based on the analysis of the seismic damaged conditions of 825 dams in Mianyang City, this paper establishes a dam’s seismic vulnerability matrix that suite for the Chinese specification. Compares the Mianyang city’s earth-rock dam seismic vulnerability matrix with the ATC-13’s that based on Delphi method, the vulnerability of dams in the Wenchuan earthquake is quite different with ATC-13’s, earth-rock dams of Mianyang City appear to be more vulnerable during earthquake. Base on date of seismic vulnerability matrix in Mianyang city, vulnerability curves are established. The vulnerability curves that fitted by beta function can be used to predict Chinese earth-rock dam’ seismic damage.

Abstract: Among the long-span spatial structures, the grid shell has many advantages compared to the other spatial structures.Because of the combination of the reasonableness of mechanics and the economy production,and characteristics of the light-duty and the mature design methods,this structure has more wider application than the others.At present,the static stability problem of spatial grid shell structure has been well solved,but the research about dynamic properties and seismic performance is imperfect,especially about single-layered cylindrical grid shell.So this paper does some research about the seismic performance on the base of numerical analysis.

Abstract: The design process of the 100 m high reinforced concrete masonry building in China was firstly presented, deformation check calculation under earthquake action by mode-superposition response spectrum method and time-history analysis method were detailed and deformation under wind load was also checked. Then elastic-plastic deformation under earthquake action was checked by time-history analysis method and pushover analysis method with both under uniform load and reverse triangle load. The conclusion is construct 100 m high office building built in Fortification intensity 6 by reinforced concrete masonry is feasible. Then the building was redesigned as built in fortification 7, the same check was performed as that have been done in fortification 6, it is feasible too.

Abstract: In connection with the practical project of Kunminglu station of Tianjin subway Line 3 in soft soil sites, the finite element method model based on soil-structure interaction was established by using ANSYS program. Additionally, this paper analysed the static calculation and the dynamic interaction system of underground soil-structure, obtained the acceleration time histories of seismic response, and concluded that what are mechanical characteristics of subway station structure under the static and dynamic load. Possible damage to subway station brought about seismic response and seismic weak links of subway station structure under the action of horizontal earthquake is analyzed.

Abstract: The cumulative damage produced by severe earthquake is significant to the structural dilapidation and collapse. Most design methods based on force or displacement can’t reflect the effect of cumulative damage. Energy-based seismic design is known as a good alternative design. At present the research on the hysteretic energy of single-degree of freedom system(SDOF) is abundant, but real buildings can only be simplified as multi-degree of freedom systems(MDOF) mostly. Therefore how to acquire suitable equivalent single-degree of freedom system(ESDOF) is a key program. In this paper 12 equivalent system schemes(ESS) have been put forward, then the ratio of hysteretic energy(R_H) of 6-floors framework was calculated with 30 typical seismic waves. Based on the comparison and analysis between calculations of 3 typical ESS, by the way of envelope fitting, the expression of R_H related to earthquake characteristic value a/v was established.

Abstract: Underground structures have mechanical characteristics and seismic responses very different from common structures on the ground in the earthquake due to the constraints of the surrounding soil. Tunnel destruction has occurred many times in domestic and international earthquake. In order to study seismic factors and failure mechanism of tunnels in the earthquake, numerical simulation of the seismic responses of the circular shield tunnel is carried on. Harmonic P-waves and S-waves are entered to make the tunnel vibrate and deform. Viscous-spring artificial boundary condition is applied in the numerical simulation to consider the semi-infinity of soil. The elastic modulus of soil, the frequency of harmonic waves and the depth of the tunnel are regarded as the main factors. The seismic responses such as stress and relative displacement are analyzed in different parameters to get the failure mechanism of circular tunnel.

Abstract: Evaluation approach of occurrence probability for subduction-zone earthquakes adopted in “National Seismic Hazard Maps for Japan” is reviewed, especially for the area of the 2011 off the Pacific coast of Tohoku Earthquake (2011 Tohoku Earthquake in short). One problem is pointed that the occurrence probability of such a large earthquake cannot be predicted just from seismicity in a region small like Miyagi-ken-Oki area or southern Sanriku-Oki. The whole subduction zone in eastern Japan is suggested to be taken into account with the interaction between the energy released in quakes. Finally, a simple test to predict the next large earthquake in the subduction-zone by means of Artificial Neural Network is presented, and the result for the years of 2008-2018 shows there may be an earthquake with magnitude up to 8.8 in the zone.