Papers by Keyword: Seismic Response

Abstract: This paper carried on the numerical analysis about the impact on soft soil ground seismic effect according to the buried depth and thickness of the soft interlayer, which took Jiangsu typical stratigraphic distribution and some engineering field as the prototype. In order to analyze the impact of buried depth and thickness of soft soil interlayers on the surface of the ground motion parameter, this paper combined with the formation parameters and calculated 3 sections which the thickness of soft soil interlayers were respectively 3m, 5m and 9m, in condition of the buried depth of the soft soil interlayer was constant. Choose ElCENTRO process curve for site seismic response analysis. The results showed that the influence of soft soil interlayer thickness on ground surface acceleration peak value was related with the location of weak interlayer. The influence of soft interlayer thickness on earthquake peak acceleration A_max and the eigenperiod T_g was more obvious; When the thickness of the soft interlayer increased, the earthquake peak acceleration decreased, the maximum speed decreased, and the maximum displacement increase; When the thickness of the soft interlayer increased, The maximum response spectrum decreased, the cycle of response spectrum peak increased, and the eigenperiod increased.

Abstract: In order to study the vibration and seismic performance of K8 triangular cone partial double layer spherical reticulated shell and analyze the factors that impact its self-vibration and seismic performance, this paper used parametric design language APDL of ANSYS to establish the shell model,then used 3D El-Centro seismic waves to analyze the influencing factors of its self-vibration and seismic performance by changing the ratio of rise to span, the ratio of thickness to span, bar section area and other parameters. Therefore this paper get some conclusions with engineering significance.

Abstract: The shaking table tests of a 1:7 scale model of three-floor steel frame base-isolated building was completed to study the seismic responses of base-isolated buildings under near-fault ground motions. Under the action of the typical near-fault seismic wave, the seismic responses of base-isolated structures increase with the increase of PGA. The maximum story displacements of super-structure decrease with increase of story. The velocity pulse has an adverse effect to acceleration responses of base-isolated structures. The isolation effect of base-isolated super-structures is still favorable under near-fault ground motions, but it will be necessary to add damping in isolation system or limit the displacement of bearings to prevent the excessive deformation of isolation layer.

Abstract: With the extensive use of HSC in the tall building and super high-rise building, the harm of HSC subjected to fire has also been increasing. For the concrete structure in the seismic region after fire, its seismic performance after repair directly relates to the structure safety under the action of possible earthquake in the future. Based on the experimental data in the preliminary research, seismic response analysis on the repaired HSC structure after fire was made according to the principle of uniform section. The results indicate that the seismic performance of HSC frame structure repaired by the principle of uniform section can be restored to the level before fire. But we should pay more attention to the interlaminar maximum displacement of fire storey, which should be partly strengthened when necessary.

Abstract: This paper summarized the current research situation and development direction of the storey adding structure all over the country. On the basis of the situation, combined characteristics of light steel storey adding structure, the article analyzed adding structure's damping distribution regularity. Based on the complex damping theory, through the mode-superposition method, there was established the correction formula of the earthquake response spectrum of light steel storey adding structure considered the effects of damping. All above, the article provides the basis for the study on the dynamic properties of light steel storey adding structure.

Abstract: The seismic response of 4-span continuous bridges with different configurations has been investigated. In the series of bridges studied, the height of the central pier varies from 5 m to 100 m, while the heights of all the other piers remain the same. Using non-linear time history analysis, the internal forces at the bottom of individual piers have been predicted for each case. The correlation between the relative stiffness of adjacent piers and the ratio between the seismic response at the bottom of adjacent piers has been studied. Based on the results, in order to guarantee approximately balanced seismic response among all piers of a given bridge, a range of the relative column stiffness of two adjacent piers has been proposed.

Abstract: With the rapid development of underground space exploration in Chinese cities, the construction scale of underground subway structures expands continuously. This thesis elaborates the development history of seismic research on underground subway structures, summaries the seismic response characteristics of the structures, and analyzes the seismic research methods of underground subway structures including the prototype observation, theoretical analysis, numerical simulation and experimental research and discusses the characteristics and usages of each research method. At last, several important problems have been proposed for seismic research and seismic design of underground subway structures in China.

Abstract: Focusing on a complicated metro station with shallow depth, its three-dimensional calculation model was established, which includes not only the main station structure, but also includes the subsidiary structure such as the entrances and detailed structures such as the holes in the floor. The Davidenkov model was employed to simulate the nonlinear characteristics of the soil. The three-dimensional nonlinear seismic responses were analyzed. it can be shown from the calculation that: (1) the metro station structure can satisfy the demand under given seismic motion; (2) it is more important for structural concept design and structural measures design than the strength and deformation design for complicated underground structures.

Abstract: In order to point out the main factors in MDOF pseudo-dynamic test design of high-rise flexible, the key points in pseudo-dynamic test design using equivalent MDOF system were analyzed based on the theoretic derivation and numerical simulation, and the problems to notice in test design were pointed out, the pseudo-dynamic test results validity of high piers based on equivalent SDOF system was discussed, and the impact of high mode to the earthquake response of high-rise flexible structure was acquired. The results of numerical simulation of lumped-mass model prove that the contribution of high mode to the displacement of high flexible structure is little, and the displacement is mainly provided by the first-order mode, which is nothing to do with the selection of seismic waves. However, the high mode have great influence on seismic base shear and base moment of high flexible structure, and the influence level is associated with the properties of seismic wave spectrum. Under one specific earthquake wave, the second-order vibration may play a main contribution to seismic base shear and base moment of high-rise flexible structure. Therefore, it is proper to use equivalent two-degree of freedom system in pseudo-dynamic test of high piers. However, if using equivalent SDOF system, the structural displacement response is correct while the strain data and experimental phenomenon may be untrue. The conclusion proposed is significant in guiding the pseudo dynamic test design of high-rise flexible structure and ensuring the rationality of test.

Abstract: The motion of strong earthquakes causes nonlinear deformation and damages to the structure. For structural systems of buildings, domestic and European (EC8) regulation apply algorithm of seismic design based on reference linear-elastic methods that are carried out in two phases. Phase I includes determination of dynamic characteristics of structure, which are then used in phase II for calculation of seismic effects. In this study, parametric analysis of influence of dynamic characteristics of structure was done on multiple numerical examples, according to domestic and EC8 regulations and comparison of results.