Applied Mechanics and Materials Vols. 580-583

Abstract: This research investigated the influence of mortise-tenon joint before and after damage on seismic performance of ancient lifted-beam timber structure. Dynamic responses of an ancient timber structure under various earthquake intensities were analyzed by ANSYS to extract the M-θ hysteresis loops of mortise-tenon joints before and after damage. The area of the largest hysteresis loop was taken as quantitative indicator to measure energy dissipation of mortise-tenon joints. The results shows that if some mortise-tenon joints were damaged, they dissipated much less earthquake energy decreasing by 31.8%-38.5%, and top displacement of structures increased by 1.79%-5.96% correspondingly. Moreover, the displacement under 8-degree-fortification, 7-degree-rare earthquake intensity increased most obviously. Therefore, energy dissipation of mortise-tenon joint is a main indicator to the assessment of seismic performance of a damaged ancient timber structure.

Abstract: During recent years, an increasing number of studies advocate the application of the capacity spectrum method based demand diagrams computed directly from inelastic response spectra, as an alternative to the basic formulation of the method, which uses elastic spectra computed for single degree-of-freedom oscillators with modified characteristics to account for inelastic behavior. When demand diagrams are based on the code-specified elastic spectrum, inelastic spectra are typically determined by dividing the elastic spectrum by strength reduction factors. The paper presents the application of the method, based on strength reduction factors computed with a unified analytical expression, deduced by the author in previous studies. The expression and is valid both for broadband and narrow band ground motions. Taking as a starting point the newly-enforced elastic design spectra in the 2013 edition of the Romanian seismic design code, the method is exemplified for the capital city, Bucharest. It is shown that, for the analyzed case, the use of the proposed strength reduction factors leads to results that are very close to those obtained by the “classical” nonlinear static procedure used in the code. This suggests a good potential for the implementation of the capacity spectrum method in the Romanian code, based on these factors.

Abstract: This paper states the comparison research of calculation results from program LSSRLI-1 and program SHAKE2000, with the strong seismic records as well as the site soil conditions by using borehole arrays. The analytical results show that the site soil conditions have an amplification effect on the seismic PGA and response spectrum values, however, the actual seismic records are not consistent with the program calculations on the amplification effect. Besides, the site soil conditions also have an altering effect on the predominant period of seismic response spectrum, where actual seismic records and program calculation results of the altering effect are not the same either.

Abstract: By research of the functional classification, seismic fortification performance objectives and quantified targets of non-structural components, according to the case of earthquake destruction in non-structural components, analyzed the reasons for the destruction . proposed three functional classification;Based on performance-based seismic design theory, proposed four level seismic performance objectives division and quantify seismic indicators of inter story displacement angle.

Abstract: This paper mainly discusses seismic damage of RC frame buildings in Beichuan county based on the investigation on the spot. The building damage forms are classified and component failures are analyzed. Applying finite element analysis software, the performance of RC frame buildings under severe earthquake is simulated and the components plastic hinge development is researched. The analysis results are made a comparison with real damage of buildings in this paper and some suggestions are proposed to seismic design.

Abstract: In recent years, with the development of high-speed rail in China,bridge has a higher proportion in the lines. Every year earthquake occurs many times accidentally in China. In order to ensure the target performance of bridges under earthquake action, we need to be based on the seismic analysis. Only have a deep knowledge of seismic effect discipline, can we enable to guide seismic design economically and reasonably and achieve predetermined target performance. Our study shows that the main vibration mode is a combination of the longitudinal or lateral translation or the revolution around Z axis. Under high-level earthquake, the maximal displacements of side piers and the fixed pier are larger, the maximal longitudinal pier shaft moment of the fixed pier (No.3) or No.5 pier in lateral direction is larger. But the value that exceeds the yield moment is small, which indicates that the development of plasticity is little. The longitudinal shear force of the bearings on the same pier are the same, bearings fixed longitudinally own the largest value. Even bearings whose lateral directions are fixed on the same pier own larger forces. Seen from average maximum values of bearings, all bearings are at the second stage, meeting the requirements that we don’t need to repair or slightly repair the bridge to make it act normally once after an earthquake.

Abstract: The steel frame with wedge devices is a kind of shock structure based on the node energy consumption. The seismic performances of steel frame with wedge and ordinary steel frame model under low cycle reciprocating load simulation analysis and time history analysis under earthquake loads are analyzed by using finite element software, compared the respective energy dissipation performance and seismic performance, the results show that the wedge spring damping device can effectively control story drifts of structure, reduce the seismic response of structure, and well consume the seismic energy, so the structure of the new column bases with wedge spring devices show better seismic performance.

Abstract: This paper presents a technology of sliding damping which could resist ground frost heaving. In the technology, setting the low-grade mortar bond of the upper and lower ring beams to achieve slip shock absorption, and setting the rubber beams to achieve shear deformation limiting. By rubber beam shear performance test, the shear strength of the rubber beam has been acquired. In the paper, the finite element software has been adopted to simulate the seismic performances of common wall and sliding damping wall structures under low cyclic reversed loading, the hysteretic curves between the bottom shear and the top displacement of the walls. The research results show that sliding damping ring beam has the very good function on dissipating seismic energy and reducing seismic action.

Abstract: This article focuses on the effect of viscous damper on seismic performance of steel-concrete hybrid structure under strong earthquake. The result shows that viscous damper has effect on seismic reduction and control. The story lateral displacement, story drift rotation and energy dissipation-seismic can be reduced effectively by viscous dampers. The maximum value of vibration-reduction ratio is 36.0%, 67.9%, 36.9%. It is different effect on seismic reduction by different earthquake ground motion. Response of earthquake amplifies under Pasadena earthquake wave than the others.

Abstract: In the simulation of the rotational seismic ground motion, the apparent velocity of Love wave is always assumed to be equal to the S wave velocity of top layer of the site approximately, with the dispersion of surface wave not being fully considered. In this paper, the effect of the velocity structure to the Love wave dispersion is discussed based on the stiffness matrix theory. It shows that to assume the velocity to be equal to the S wave velocity of the top layer may greatly overestimate the low frequency rotational seismic motion. A simplified dispersion curve, is suggested for rotational seismic ground motion simulation. The shape of the bilinear curve is shaped by 3 parameters. They are the corner frequency, the minimum phase velocity and the velocity ratio. The parameters are affected by the velocity structure of the site.