Applied Mechanics and Materials Vols. 166-169

Abstract: The current underground structure seismic soil pressure was stated briefly in this paper first, as well as several commonly used quasi-statics calculation methods, and then based on the calculation mentioned above, various simplified calculation methods were applied to calculate the seismic pressure of tunnel structure, offering reference for future improvement of seismic pressure calculation methods and seismic design level of tunnel structure.

Abstract: The behavior of transmission line under three-dimensional seismic excitations is studied by numerical simulation. According to a practical engineering, the transmission towers are modeled by frame elements and the transmission lines are modeled by cable element account for the nonlinearity of the cable. The effects of single-dimensional, two-dimensional and three-dimensional ground motions on the responses of transmission line are investigated using nonlinear time history analysis method, respectively. The results indicate that the longitudinal maximum response of transmission lines can be obtained considering longitudinal ground motion excitation only. The transverse maximum response of transmission lines can be obtained considering transverse ground motion excitation only. Neglecting multiple nature of ground motion in analysis will significantly underestimate the vertical responses of the transmission lines. To obtain an accurate seismic response of transmission lines, three-dimensional ground motion inputs are required.

Abstract: A large number of rural housing data based on field identification of Gansu five surveys were compiled, and the paper analyses the housing situation of Gansu, points out that the technical defects of the current rural housing construction. The mathematical model is established by fuzzy theory which is used to predict the earthquake disaster that may occur under the appropriate intensity of the survey areas in the future. Purpose is to provide the basic data to fully carry out the rural residential seismic safety work, and provide advice and reference for the follow-up to the rebuilding of old housing. It may be beneficial to enhance and improve the areas of rural building seismic performance.

Abstract: Aiming at the problem of seismic response of the base isolation tanks, make the tanks simplify the mechanical model of three particles, considering the quality of continuous liquid that is in the tanks equivalent to convection quality, pulse quality and rigid quality and introducing isolation stiffness. According to the stiffness of each particle and quality calculate natural vibration period, making sure the power amplification coefficient, and analysis on the response spectrum of isolation vertical seismic response storage tanks. The results show that the response spectrum method calculating isolation vertical seismic response storage tanks tends to safety；With the site categories and isolation cycle's increasing, basal shear shock absorption rate gradually reduce , the change of shaking height of wave is not obvious, after isolating the earthquake , hydraulic pressure show linear change, hydraulic pressure increase as the increasing of the site categories and ratio of height to radius, along with the increasing of the isolation of the cycle increasing, hydraulic pressure decrease；ratio of height to radius exists certain optimization period, in the period of optimization , basal shear shock absorption rate is bigger, isolating effect is better.

Abstract: In this paper, the behavior of the structure of a pressurized water reactor (PWR) nuclear power plant (NPP) in China, is taken into consideration during a great earthquake especially beyond the design benchmark. The effects of earthquake energy absorption are analyzed using simplified multi-lumped mass system. The effects of site conditions, post yield stiffness, yield force on isolated reactor structure (IRS) are also discussed. The results show that isolation technology can significantly reduce seismic response of the reactor structure and achieve preferable earthquake energy absorption of the IRS beyond the design benchmark during a great earthquake. Earthquake wave characteristics and isolation layer parameters have direct effects on seismic response and the results of parameter analysis can provide reference for a correct and logical design of IRS.

Abstract: This paper investigates the coupled effect of the supporting soil flexibility and pounding between neighbouring, insufficiently separated buildings under earthquake excitation. Two adjacent three-storey structures, modelled as inelastic lumped mass systems with different structural characteristics, have been considered in the study. The models have been excited using the time history of the Kobe earthquake of 1995. A nonlinear viscoelastic pounding force model has been employed in order to effectively capture the impact forces during collisions. A discrete element model has been incorporated to simulate the horizontal and rotational movements of the supporting soil. Numerical simulations have been performed using developed software based on the Matlab code. The variation in storeys peak displacements, peak accelerations and peak impact forces for various gap sizes is presented in the paper and comparisons are made with the results obtained for colliding buildings with fixed-base supports. The results of the study indicate that the incorporation of the soil-structure interaction decreases both storey peak displacements and peak impact forces during collisions, whereas increase the peak accelerations at each floor level.

Abstract: In view of the lack of formal design, professional construction team and qualified building material in construction process of present country residential buildings, seismic survey in several villages in Guangzhou is carried out, aiming to know more about the seismic safety of country residential buildings. Three most commonly used country residential building structures are raw soil structure, brick-concrete structure and frame structure. By analyzing the common structure and recording the construction process, the general characteristics are summarized, the potential safety hazard is demonstrated and the seismic capacity is evaluated.

Abstract: The seismic response analysis model of a single-column pier surrounded by sea ice was established and it analyzed the nonlinear seismic response of the pier subject to different types of earthquakes. The results show that the maximum seismic responses of the pier occur when the mass of sea ice is about 5000~10000 ton, which should be used to design a pier. When the sea ice is considered, the curvature ductility demand coefficient，the maximum displacement and the maximum residual displacement of the pier are several times than those corresponding to without sea ice, and the M-Ø hysteretic curves of the cross-section of the pier subject to earthquakes present downfallen ‘S’ form significantly and the deformability and energy dissipation capability of the pier drop remarkably.

Abstract: In order to improve the accuracy of earthquake damage assessment of reinforced concrete structure, the earthquake damage assessment mutation model and four-dimensional model of seismic damage analysis are established using catastrophe theory. Firstly, internal damage index, number of inelastic cycles, maximum inter-storey drift and energy-concentrated quotient were taken as evaluation factors. Value assignment and standardization of each evaluation index is conducted. The appropriate mutation model is selected to calculate the total mutation value of seismic damage and comparison with the evaluation criteria of seismic damage of reinforced concrete structure, the extent of structural damage is differentiated. Secondly, comprehensive consideration of people's initiative and non-linear characteristics of the system, a four-dimensional seismic damage analysis model is build based on the mutation assessment of earthquake damage. Finally, four different structures are calculated and the results are compared with the ones of variable fuzzy set theory, set-pair theory to verify the reasonableness and effectiveness of the method.

Abstract: A method which gives the quantitative prediction for earthquake magnitude is proposed in this paper. By this method, after calculating the earthquake parameters and the astronomical time-varying parameters, an earthquake prediction model can be established to gives the quantitative prediction for earthquake magnitude in the future prediction period. In this research, the research object was the experimental areas, the prediction period was 6 months, and Linear Regression analysis and conventional BP (Back Propagation) Neural Network were used respectively in prediction. Through backtracking test, the RMSEs(root mean square error) of earthquake magnitude prediction are ±0.78 ML and ±0.61 ML. Then after summarizing the advantages and disadvantages of the two methods, an integrated model based on linear regression and neural network was proposed. Through backtracking test, the RMSE of earthquake magnitude prediction reaches ± 0.41 ML, results improving significantly.