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In this research work several high rise buildings were analyzed using CSI ETABS under the influence of the response spectrum analysis over it. Several different shaped high rise buildings such as H shaped, O shaped and C shaped buildings were taken into consideration for carrying out the research work. All three shaped buildings were of different storey that is of 12 storey and of 16 storey. For proper seismic analysis of all the above discussed buildings, response spectrum method of seismic analysis were taken into consideration. The results of all the buildings for response spectrum analysis were quite different from one another and it was found that the H-shaped building showed better results as compared to the other shaped buildings. It was also seen that the 12 storey building results were quite impressive as compared to the results of the 16 storey building. With the transference of heavy mass, very little effect was seen in latera sway i.e. variation in maximum displacement was negligible. Again, for 16 storey building, maximum displacement was found in the case L-Shaped 16 storey building with the value of 87.804 mm. Again, the transference of heavy masses had a minimal effect on total quantity and cost of the 16 Storey building. In the gist, it was concluded that, bending moments and shear forces were increased from 1.17% to 1.84%. Maximum variation in B.M and S.F. can be seen in O-shaped Building. L-shaped Building produces maximum displacement from all the three irregular shapes i.e. H-shape, L-shaped and O-shaped.

Through the years, the seismic resistance of underground structures has attracted more and more attention, and dynamic characteristics of metro station is one of the most important issues. In this article, the 3D numerical model of Zhang Wangqu metro station along Metro Line 5 in Xi'an is established to study on seismic dynamic response of roof, floor, columns and beams in the island platform metro station. Compared with the earthquake damage of Dakai metro station in the Kobe M7.2 Earthquake and the shaking table test of metro station in loess area, results reveal that horizontal acceleration can reflect seismic wave characteristics under the horizontal seismic wave; the maximum relative displacement of roof and floor, the maximum axle force and shear force at transfer node are bigger than the standard section and reduce with the increase of buried depth; the maximum axle force and shear force of columns increases from top to bottom. The island platform metro station should focus on the structural settings of transfer node, and the columns and beams here must select materials with greater strength.

Due to low design standard, and poor construction quality, Wangwu reservoir, which was built in the fifties, has been running in sub-health for a long time. The dam safety grade is evaluated as Class III, so it must to be reinforcement. The dam foundation anti-seismic reinforcement is one of the main contents. In the paper, the authors introduce the basic method of dam anti-seismic dynamic analysis, combining with the Wangwu reservoir reinforcement project.

The inelastic seismic behavior of two reinforced concrete buildings of 15-story and 25-story is compared with and without shear-walls. The resistance-seismic design and vertical loads is made according to the requirements of the Mexico City Building Code, RCDF-2004, satisfying the limit states of service and resistance: compressible seismic area, group B. Inelastic dynamic seismic responses are determined with step-by-step analysis under SCT-EW-85 record with the nominal resistance and over-resistance effects. Results show the importance of the participation of the shear-walls to help to reduction of the magnitude of structural damages during severe seismic future events. The shear walls located in adequate form inside the structure provide an excellent additional lateral stiffness to solve the common flexibility problems in the soft soil zone of the Valley of Mexico and therefore to avoid severe additional torsion problems. In the shear wall constructions we should pay special attention to the foundation design. It was verified that the shear strengths of the structural elements selected were higher than the seismic demands. In the cases of over-strengths considered, it can be concluded that had a minor incursion in the interval of inelastic performance compared with the inelastic performance presented in the cases of nominal strengths.

For the engineering background of subway tunnel with initial defects caused by the construction of new down-through tunnels, the aseismatic performance of the existed tunnel is studied so as to reveal the mechanism of seismic dynamic response by using finite difference method. Numerical simulation shows that the tunnel is deforming in its entirety since such physical variables as velocity, displacement and stress in its all key weak points have same dynamic tendency under influence of approaching construction of tunnels, and these variables are much larger than those without any influence. After down-through construction, much influences of aseismatic performance are mainly taking place at both the side wall and the upper arch, and the shearing damage are mainly doing in surrounding soil mass. Due to widely shearing damage after down-through construction, it is suggested that grouting reinforcing should be applied so as to make them much stiffness as a whole.

In this paper, the bond-slip effect has been applied to the numerical equations in the process of nonlinear dynamic analysis of reinforced concrete frames. The formulation is similar to that of the layer section theory, but the perfect bond assumption has been removed. The precision of the proposed method in considering the real nonlinear behavior of reinforced concrete frames has been compared to the precision of two other suggested methods for considering bond-slip effect in layer model. Among the capabilities of this method for seismic analysis are its ability of modeling the embedded lengths of bars within joints and nonlinear modeling of bond-slip. The precision of the analytical results were compared with the experimental ones achieved from a one bay two storey frame under seismic loading on the shaking table. According to the numerical results, the presence or absence of bond effect in numerical modeling and analysis will bring about considerable different results, including results for deformation and forces. All the studied methods for inserting the bond-slip effect into the layer model can relatively improve the accuracy of analytical results compared to experimental ones. The proposed method of this study has proved to enjoy the highest accuracy with regard to time-history seismic analysis of reinforced concrete frames. Among the capabilities of the proposed method, we may refer to its ability to model beam-column and joint element's nonlinear behavior separately.

The seismic vulnerability of bridges may be reduced by the application of Geotechnical Seismic Isolation (GSI) below the foundations of the columns and the abutments. However, the role of GSI on the seismic response of bridges has been limitedly examined in literature. Therefore, this research has been conducted to study the effect of applying GSI on the seismic response of bridges to address the aforementioned gap in knowledge. Advanced nonlinear dynamic three-dimensional finite element analyses have been conducted using OpenSees to study the influence of the GSI. The cases of traditional and isolated bridges subjected to earthquakes have been considered to assess the GSI effects. The results showed that the GSI reduces the seismic effect on the column while its effect seems to be less significant for the abutments. In addition, fragility curves for the traditional and isolated cases have been developed and compared to provide insights with a probabilistic-based approach. The results of this paper provide a useful benchmark for design considerations regarding the use of GSI for bridges.

The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the finite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave field on the nodes of the substructure composed of elements that contain artificial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artificial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplified by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verified by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.

Earthquakes represent one of the most catastrophic natural events affecting mankind. At present, a universally accepted risk mitigation strategy for seismic events remains to be proposed. Most approaches are based on vibration isolation of structures rather than on the remote shielding of incoming waves. In this work, we propose a novel approach to the problem and discuss the feasibility of a passive isolation strategy for seismic waves based on large-scale mechanical metamaterials, including for the first time numerical analysis of both surface and guided waves, soil dissipation effects, and adopting a full 3D simulations. The study focuses on realistic structures that can be effective in frequency ranges of interest for seismic waves, and optimal design criteria are provided, exploring different metamaterial configurations, combining phononic crystals and locally resonant structures and different ranges of mechanical properties. Dispersion analysis and full-scale 3D transient wave transmission simulations are carried out on finite size systems to assess the seismic wave amplitude attenuation in realistic conditions. Results reveal that both surface and bulk seismic waves can be considerably attenuated, making this strategy viable for the protection of civil structures against seismic risk. The proposed remote shielding approach could open up new perspectives in the field of seismology and in related areas of low-frequency vibration damping or blast protection.

The geological structure and stratum lithology have important roles in the seismic stability of complex slopes; however, their roles complicate engineering construction. Four three-dimensional, layered granite slope models with infinite boundaries were modeled via the finite element method. The seismic response characteristics of slopes are systematically analyzed in the time–frequency domain. A frequency-domain analysis method of complex slopes, including modal and spectrum conjoint analysis, is proposed. Modal analysis can directly display the main vibration modes of slopes. The combination of modal and spectral analysis can clarify the inherent characteristics of slopes and reveal the interaction mechanism between the inherent frequency of slopes and their dynamic characteristics. The results illustrate that structural planes have significant effects on the propagation characteristics of waves within rock masses, and complex refraction/reflection phenomena occur near these discontinuities, thus leading to different dynamic response characteristics in the slope. Layered slopes have an apparent magnification effect of slope surface and altitude. The directions of seismic excitation and structural plane types affect the dynamic response of slopes. Horizontal waves mainly affect the middle and upper parts of high-steep slopes, while vertical waves have an obvious influence on the slope crest. Additionally, Fourier spectral analysis shows that structural planes have filtering effects on high-frequency waves. Combined with modal analysis, this finding further explains that the high-frequency section of waves mainly triggers local deformation of slopes, while the low-frequency component controls their overall deformation. The instability regions and evolution process of slopes were predicted based on time–frequency conjoint analysis.