Papers by Keyword: Response Spectrum

Abstract: In order to break through the limitation of the width of river, depth of water, channel and etc., it is an optimal choice to construct a long-span suspension bridge. In a suspension bridge, the main cable is the major bearing member; and the use of super high strength cable wire can lighten the dead weight and obtain an economical design. 1960 Mpa cable wire is adopted by an under-construction suspension bridge, namely Ni-Zhou Channel Bridge, for the first time in China. In this paper, taking the Ni-Zhou Channel Bridge as a case-study, comparative analyses on dynamic characteristic and seismic response of long-span suspension bridge with 1960 Mpa cable wire are performed. Firstly, dynamic calculating model for Ni-Zhou Channel Bridge is built and its dynamic characteristics are studied; then by using response spectrum and time history analysis method, seismic response of Ni-Zhou Channel Bridge is investigated on the basis of design response spectrum and artificial seismic ground motions; finally, the energy dissipation performances of a seismic protection devices (viscous damper) are also discussed. The results show that long-span suspension bridge with 1960 Mpa cable wire has a longer natural vibration period; the use of viscous damper can effectively reduce the peak value of bending moment in stiffening girder. This paper can provide references for the project’s construction.

Abstract: Structure under long-term load, environmental erosion, material aging, especially under the seismic action can cause damage accumulation and bearing capacity decrease. In order to make sure its safety and reliable, avoid extreme cases of catastrophic accident, it is necessary to carry out the engineering structural health diagnosis. Using SAP2000 software, seismic response analysis for a two layer reinforced concrete frame structure is carried out. The laws of the acceleration response time history and spectrum under different seismic action were found out by discussing structure in no damage and different damages. The results showed that no matter where the damage located, the top node response increment is bigger than the middle node, the peak of acceleration response spectrum changes little with the beam damage degrees changing. Selecting the acceleration response peak of the top node as a structural damage index is feasible in the damage detection and identification of engineering structures, but analyzing the response spectrum for damage detection is unpractical.

Abstract: In order to verify that the +20m platform hoist for Qinshan Nuclear Power Plant can withstand safe shutdown earthquake (SSE) without any damage, that is during or after SSE, completeness of structure and operation can be ensured, finite element analysis software, ANSYS Workbench is applied to analysis on model building and seismic analysis for the platform hoist (including hoisting mechanism, base plate,drum).

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 influential factors on synthetic seismic waves and seismic codes in China are described in detail in this paper. And the evolution of synthetic seismic waves is overviewed. The methods of synthetic ground motion in the earthquake engineering field are summarized in order to provide references for the synthetic ground motion. Based on the study situation over the world, the issues and trend are presented. Some suggestions are provided for improving the codes and standards.

Abstract: Submitted paper presents brief information about structural dissipative design of a power plant boiler structure. The main attention is paid to the selection of material solution. Several material combinations of materials for dissipative members and other structural elements have been evaluated. As a measure of material combination effectiveness has been chosen a ratio between structural stiffness of primary and secondary lateral load resisting system. Probabilistic analysis of the structural sub-section has been carried-out for the most common material combination with steel S235 used for seismic links. Probabilistic analysis has been performed for the evaluation of the risk of material hardening in links and probabilistic distribution of material properties.

Abstract: The dynamic characteristics of 80 m single-layer spherical lattice shell structure are analyzed to control its vibration under seismic load. Through the response spectrum curve of current design specification, the analyses for the vertical and horizontal seismic responses of the single-layer spherical lattice shell structure are made by CQC, and the displacement response of the nodes and internal force of the rods unit are calculated respectively. The calculation results show that the vertical and horizontal seismic responses of the long-span lattice shell structure are in great difference, and should be performed in vibration control at the same time, which could provide certain references for the seismic design and vibration control of single-layer spherical lattice shell structure.

Abstract: According to the Chaoyang town east bridge design data, build the model with finite element analysis method. Based on two levels fortification, two stage design ideas of seismic design, modal response spectrum and seismic response of the nonlinear time history analysis method are used respectively. The nonlinear effect of the boundary conditions are considered in the analysis process, and the seismic response of the cable-stayed bridge is obtained, providing bases and presenting methods for aseismic design of Chaoyang town east bridge.

Abstract: In order to further regulate the vertical earthquake action in seismic design specification, to overcome the unreasonable and inconvenient flaws in certain conditions by using vertical to horizontal spectra ratio function, the feasibility of stipulating vertical design response spectrum with the same way of horizontal one is deal with in this paper. 1513 sets of three component records during 64 earthquakes from NGA-west1 database are selected and grouped by magnitude, distance and site conditions. Average acceleration response spectrum of each group is generalized to get the corresponding mean maximum amplitude and effective peak acceleration EPA. Furthermore, some groups with EPA in an interval are merged into one. Once again, the parameters, such as maximum amplitude and characteristic periods of each final grouping are acquired by the same way. The former is divided by the corresponding horizontal value for site category, to obtain the site coefficient for vertical action. Finally a preliminary suggestion of vertical site coefficient and characteristic period are presented. Comparison of observed data with results from the new suggestion and those from spectral ratio shows that the improvement of this study is obvious.

Abstract: The seismic response of the Wusong bridge was analyzed though the response spectrum method and the time-history method by adopting the MIDAS/CIVIL. The analysis results show that the longitudinal displacement of the main girder is much larger under longitudinal seismic input, so some inhibiting device or dampers should be used to avoid impacting. There is not coupling between longitudinal and lateral seismic excitations, while the seismic response of moment and shear force at the bottom of the main tower is much larger. On the contrary the seismic response of main beam and the main cable should be calculated under the longitudinal and vertical seismic excitations because of the coupling between the both of them. Furthermore, the artificial seismic wave fitting standard response spectrum was generated to conduct the time-history analysis and the results are much larger than the results from the response spectrum method.