Modified complex mode superposition design response spectrum method and parameters optimization for linear seismic base-isolation structures

2013 ◽  
Vol 4 (4) ◽  
pp. 341-363 ◽  
Author(s):  
Dong-Mei Huang ◽  
Wei-Xin Ren ◽  
Yun Mao
Keyword(s):  
Base Isolation ◽  
Response Spectrum ◽  
Parameters Optimization ◽  
Response Spectrum Method ◽  
Complex Mode ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Design Response Spectrum ◽  
Seismic Base Isolation

Mode Superposition Response Spectrum Method Combined with Continuum Method for High-Rise Energy Dissipation Structure

2011 ◽  
Vol 94-96 ◽  
pp. 799-802
Author(s):  
Li Yan Gao ◽  
Yu Kun Feng ◽  
Wen Feng Liu
Keyword(s):  
Architectural Design ◽  
Design Method ◽  
Response Spectrum ◽  
New Method ◽  
Response Spectrum Method ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Damping Rate ◽  
Adjustment Factors ◽  
Spectrum Curve

Response spectrum curve is the base of seismic design of structures, and mode-superposition response spectrum method is a practical design method of structures. Damping adjustment factors and shape parameters have been adjusted in the new Chinese code (2010) for damping rate is not equal to 0.05. Then, a new mode superposition response spectrum method combined with continuum method is introduced in this paper. Finally, the earthquake shear of a shear-wall structure’s bottom is calculated, and the results of the new method are compared with that of traditional method implemented in PM-SATWE software which is widely used in architectural design institute. The contrast results show that the new method is available and has a good accuracy.

Theoretical Model of Suspended Floor under the Seismic Effect

2015 ◽  
Vol 713-715 ◽  
pp. 26-29
Author(s):  
Yu Xin Zhang ◽  
Wen Jin Zhang ◽  
Jin Ru Zhu
Keyword(s):  
Theoretical Model ◽  
Basic Assumption ◽  
Response Spectrum ◽  
Seismic Effect ◽  
Response Spectrum Method ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Floor System

This paper proposes a new idea about damping of suspended floor in huge frame constructions. By using mode-superposition response spectrum method, the inner force and displacement in theory was obtained. Suspended floor system has economical, theoretical, social and humanistic benefits, but is not mature technically. Thus in the end, the paper proposes subsequent researching directions about damping of suspended floor system based on the basic assumption in the program.

The Application of Mode-Superposition Response Spectrum Method in Seismic Calculation of the Boiler Steel Structure

2012 ◽  
Vol 594-597 ◽  
pp. 1645-1651 ◽  
Author(s):  
Shu Wei Li ◽  
Wen Zhao ◽  
Jia Xu Jin
Keyword(s):  
Response Spectrum ◽  
Steel Structure ◽  
Normal Operation ◽  
Engineering Practice ◽  
Correction Coefficient ◽  
Response Spectrum Method ◽  
Boiler Steel ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Formula Method

The boiler steel structure is the main parts of the boiler, its stability directly determines the normal operation of the boiler and the security of the surrounding environment. For analyzing the boiler steel structure, first respectively using matrix displacement method, energy method and the empirical formula method to calculate the periodic of the boiler steel structure; then using the bottom shear method and the mode-superposition response spectrum method to calculate the shear and the axial force of the boiler steel structure in same situation, and through comparing the results to gain the correction coefficient of the mode-superposition response spectrum for the engineering practice and discussing the calculation of the boiler steel structure under earthquake using mode-superposition response spectrum method. Providing the theoretical basis for the seismic design, the reinforcement and the maintenance of the boiler steel structure.

Insights Gleaned From NRC-BNL Benchmark Evaluation of Seismic Analysis Methods for Non-Classically Damped Coupled Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 75-84 ◽  
Author(s):  
J. Xu ◽  
G. DeGrassi ◽  
N. Chokshi
Keyword(s):  
Normal Mode ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Computer Programs ◽  
Coupled Systems ◽  
Response Spectrum Method ◽  
Complex Mode ◽  
Spectrum Method ◽  
Mode Response

Under the auspices of the US Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) developed a comprehensive program to evaluate state-of-the-art methods and computer programs for seismic analysis of typical coupled nuclear power plant (NPP) systems with non-classical damping. In this program, four benchmark models of coupled building-piping/equipment systems with different damping characteristics were developed and analyzed by BNL for a suite of earthquakes. The BNL analysis was carried out by the Wilson-θ time domain integration method with the system-damping matrix computed using a synthesis formulation as presented in a companion paper [Xu, J., 2003, Nuclear Eng. Des. These benchmark problems were subsequently distributed to and analyzed by program participants applying their uniquely developed methods and computer programs. This paper presents the insights gleaned from the participants’ analyses, and the comparison of their results to the BNL time history solutions. The participant’s results established using complex modal time history methods showed close agreement with the BNL solutions, while the analyses produced with either complex-mode response spectrum methods or classical normal-mode response spectrum method, in general, produced relatively conservative results, when averaged over a suite of earthquakes. However, when coupling due to damping is significant, complex-mode response spectrum methods performed better than the classical normal-mode response spectrum method. Furthermore, as part of the program objectives, a parametric assessment is performed aiming at evaluating the applicability and sensitivity of various analysis methods to problems with different dynamic characteristics unique to coupled NPP systems. It is believed that the findings and insights learned from this program are useful in developing new acceptance criteria and providing guidance for future regulatory activities involving licensing applications of these alternate methods to coupled systems.

The Seismic Analysis of Cooperative Grid with Prestressed Upper and Lower Chord Cables

2012 ◽  
Vol 446-449 ◽  
pp. 961-965
Author(s):  
Shi Dong Nie ◽  
Guo Xin Dai ◽  
Gang Xiong ◽  
Wei Fu Zhang ◽  
Xiao Hua Sun ◽  
...  
Keyword(s):  
Mechanical Characteristics ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Response Spectrum Method ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Earthquake Action

This document advances a concept of Cooperative grid with prestressed upper and lower chord cables, and points out its characteristics by comparing with different structure forms. Through an example of the Cooperative grid, the analysis is carried out by means of mode–superposition response spectrum method, and the mechanical characteristics of the Cooperative grid under earthquake action are researched.

scholarly journals Seismic soil-structure interaction analysis of wind turbine support structures using augmented complex mode superposition response spectrum method

2021 ◽  
Author(s):  
Masaru Kitahara ◽  
Takeshi Ishihara
Keyword(s):  
Wind Turbine ◽  
Soil Structure ◽  
Response Spectrum ◽  
Soil Structure Interaction ◽  
Support Structures ◽  
Complex Mode ◽  
Structure Interaction ◽  
Mode Superposition ◽  
Spectrum Method ◽  
Seismic Loadings

Abstract. In this study, the seismic soil-structure interaction (SSI) of wind turbine support structures is investigated using response spectrum method (RSM) based on the complex eigenmodes. Seismic loadings on wind turbine support structures are newly derived by complex mode superposition RSM. To improve the prediction accuracy of the shear force acting on footings, this method is augmented by introducing the upper limit of modal damping ratios of 10 %. In addition, the bending moment at the hub height due to the mass moment of inertia of rotor and nacelle assembly is considered as an additional loading. The proposed method is validated by comparison with time history analysis (THA) accounting for different types of foundations and different tower geometries. Seismic loadings acting on the towers and footings by the proposed method show favourable agreement with the mean results by THA of several input acceleration time histories, while the original complex mode superposition RSM strongly underestimates shear forces acting on footings.

Seismic response analysis of steel–concrete hybrid wind turbine tower

2021 ◽  
pp. 107754632110075
Author(s):  
Junling Chen ◽  
Jinwei Li ◽  
Dawei Wang ◽  
Youquan Feng
Keyword(s):  
Wind Turbine ◽  
Response Spectrum ◽  
Ground Motions ◽  
Time History ◽  
Seismic Action ◽  
Response Spectrum Method ◽  
Spectrum Method ◽  
Wind Turbine Tower ◽  
Ground Types ◽  
Nonlinear Time History

The steel–concrete hybrid wind turbine tower is characterized by the concrete tubular segment at the lower part and the traditional steel tubular segment at the upper part. Because of the great change of mass and stiffness along the height of the tower at the connection of steel segment and concrete segment, its dynamic responses under seismic ground motions are significantly different from those of the traditional steel tubular wind turbine tower. Two detailed finite element models of a full steel tubular tower and a steel–concrete hybrid tower for 2.0 MW wind turbine built in the same wind farm are, respectively, developed by using the finite element software ABAQUS. The response spectrum method is applied to analyze the seismic action effects of these two towers under three different ground types. Three groups of ground motions corresponding to three ground types are used to analyze the dynamic response of the steel–concrete hybrid tower by the nonlinear time history method. The numerical results show that the seismic action effect by the response spectrum method is lower than those by the nonlinear time history method. And then it can be concluded that the response spectrum method is not suitable for calculating the seismic action effects of the steel–concrete hybrid tower directly and the time history analyses should be a necessary supplement for its seismic design. The first three modes have obvious contributions on the dynamic response of the steel–concrete hybrid tower.

Comparative Evaluation of Mode Combination Methods in Seismic Analysis Using Response Spectrum Method for Tank Structure Using FEA - Seismic FEA

2011 ◽  
Vol 110-116 ◽  
pp. 5240-5248
Author(s):  
Sujay Shelke ◽  
H.V. Vankudre ◽  
Vinay Patil
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Initial Step ◽  
Relative Displacement ◽  
Geometrical Parameters ◽  
Response Spectrum Method ◽  
Spectrum Method ◽  
Combination Methods ◽  
Eigen Values ◽  
Modes Of Vibration

Typical seismic analysis using response spectrum method involves several steps from the initial step of extracting the modes. At the initial stage Eigen values are extracted corresponding to the modes of vibration. These give us Eigen vectors which are a series of relative displacement shapes; however these do not correspond to real displacements or stresses. Participation factors asses these Eigen vectors and grades them according to contribution they will have to the overall solution. Based on the spectral seismic acceleration, participation factor is used to calculate the mode coefficient, which is more of a scaling factor to give physical meaning to the values. Once the modes are extracted, the key issue is of combining these modes to obtain the seismic response. The modes cannot be added algebraically in reality as all the modes do not occur at the same time. Hence we employ methods which can add the modes in a more realistic manner. The objective of this paper is to do a comparative study of various mode combination methods with a focus on tank structures and study the effect of various geometrical parameters on the combination methods

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