Comparison of eigenanalysis and Ritz vector approaches for response spectrum analysis of soil-pile-bridge systems

2021 ◽  
Vol 17 (3-4) ◽  
pp. 89-100
Author(s):  
M. Davidson ◽  
A. Patil ◽  
S.A. Rosenfeld ◽  
Z. Zhu
Keyword(s):  
Spectrum Analysis ◽  
Soil Structure ◽  
Response Spectrum ◽  
Active Regions ◽  
Ritz Vector ◽  
Response Spectrum Analysis ◽  
Fixed Base ◽  
Potential Benefits ◽  
Eigenvectors And Eigenvalues ◽  
Vector Approach

Frequency-based analysis techniques such as response spectrum analysis (RSA) are widely used for designing bridges in seismically active regions. Two well-known analysis procedures that underlie RSA are the solution of the eigenproblem and the approximation of the solution to the eigenproblem (i.e., approximation of eigenvectors and eigenvalues) through use of force-dependent Ritz vectors. While frequency-based methods have achieved widespread adoption in practice, certain simplifications remain common, such as neglecting soil-structure interaction (SSI) due to a fixed-base assumption. In the present study, frequency-based techniques packaged within a research version of a design-oriented computational tool are employed to analyze, assess, and compare results obtained from RSA with use of the eigenanalysis, and separately, Ritz vector approaches. Importantly, for the bridge configurations analyzed, SSI is taken into account. As outcomes, the potential benefits of the Ritz vector approach (as well as modeling strategies) are demonstrated. The study outcomes are intended to aid practicing engineers when the need to account for SSI is recognized as pertinent to a given bridge seismic design application.

scholarly journals Response Spectrum Analysis of Base Isolated Regular and Vertical Irregular Building in Different Types of Soil

2021 ◽  
Vol 9 (10) ◽  
pp. 1095-1103
Author(s):  
Priya Namdev
Keyword(s):  
Spectrum Analysis ◽  
Passive Control ◽  
Base Isolation ◽  
Response Spectrum ◽  
Soft Soil ◽  
Type I ◽  
Seismic Zone ◽  
Type Ii ◽  
Response Spectrum Analysis ◽  
Fixed Base

Abstract: These days earthquake is a major problem for development of high rise building in seismic zone areas. Researchers have developed devices to overcome these earthquake problems. So we need to design a structure which can withstand against the seismic loads. There for it became necessity to provide passive control device “base isolation” to resists large horizontal and vertical loads which lead the structure to collapse. In present workthe effectiveness of the fixed base and Base isolation (LRB) with different type of vertical irregularities in different type of soil (Hard, Medium, Soft soil) in plan are concerned the vibration of the structure. The present work G+10 story Building of different vertical irregularities ( Regular building, vertical irregular Type-I, vertical irregular Type-II, vertical irregular Type-III ) Situated in zone IV are analyzed under the various Loading such as dead load, live load and earthquake load. Free vibration analysis, response spectrum analysis have been carried out for these model of building with a fixed base and base Isolation Devices. It is observed that story displacement in response spectrum is significantly increases at top stories with the base isolated building. And this work shows that the response of building reduced by using base isolation (LRB) devices in all different typeof vertical irregularities building, but the same isolation device is more effectively work in Vertical irregular Type-II Building Keywords: Base isolation Techniques, LRB, Base Shear and Etabs etc.

scholarly journals A Literature Review on Seismic Response of Floating Column Building

2021 ◽  
Vol 9 (12) ◽  
pp. 68-72
Author(s):  
Deepak Jain
Keyword(s):  
Literature Review ◽  
Seismic Response ◽  
Spectrum Analysis ◽  
Response Spectrum ◽  
Seismic Loads ◽  
Seismic Zone ◽  
Response Spectrum Analysis ◽  
Promising Solution ◽  
Story Building ◽  
Shape And Size

Abstract: Floating column building is a new fascination for engineers. As floating column buildings provides more space and good aesthetics to the building. But have high structural challenges, when a floating column is provided in a multi-story building in a high seismic zone. This paper reviews several studies conducted on the floating column building and its behavior under seismic loads. This paper studies that floating column building are vulnerable to the high seismic zones. The risk of damage also depends on the shape and size of the buildings.The ductile detailing of the joints is the promising solution for immediate failure of such buildings. Keywords: Floating Column, Response spectrum analysis. Vulnerable, damage, multi-story

The Application of Harmonic Finite Elements in the Seismic Response Spectrum Analysis of a Skirt Supported Vessel

2010 ◽  
Author(s):  
Bikramjit Singh Antaal ◽  
Yogeshwar Hari ◽  
Dennis K. Williams
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Seismic Response ◽  
Spectrum Analysis ◽  
Degrees Of Freedom ◽  
Response Spectrum ◽  
Response Spectrum Analysis ◽  
Element Analysis ◽  
Structure Interaction ◽  
Input Response

This paper describes the finite element considerations employed in a seismic response spectrum analysis of a skirt supported, liquid containing pressure vessel. Like many axisymmetric cylindrical vessels, the gross seismic response to an input response spectrum can be categorized by a simplified lump mass model that includes both the mass of the vessel proper in combination with the associated mass of multiple fluid levels. This simplified response may be utilized to determine the initial sizing of the supporting configuration, such as a skirt, but lacks the ability to properly address the fluid-structure interaction that creates sloshing loads on the vessel walls. The most obvious method to address the fluid-structure interaction when considering the finite element method is to build a three-dimensional model of the vessel proper, including, but not limited to the shell courses, the top and bottom heads (for a vertical vessel), and the support skirt. The inclusion of the fluid effects may now be incorporated with a “contained fluid” finite element, however, for vessels of any significant volume, the number of finite elements can easily exceed 100,000 and the number of degrees of freedom can sore from as few as 300,000 to as many as 500,000 or more. While these types of finite element analysis problems can be solved with today’s computer hardware and software, it is not desirable in any analysis to have that volume of information that has to be reviewed and approved in a highly regulated nuclear QA environment (if at all possible). With these items in mind, the methodology described in this paper seeks to minimize the number of degrees of freedom associated with a response spectrum analysis of a liquid filled, skirt supported vertical pressure vessel. The input response spectra are almost always provided in Cartesian coordinates, while many, if not most liquid containing pressure vessels are almost always axisymmetric in geometry without having benefit of being subjected to an axisymmetric load (acceleration in this case) due to the specified seismic event. The use of harmonic finite elements for both the vessel structure and the contained fluid medium permit the efficiencies associated with an axisymmetric geometry to be leveraged when the seismic response spectrum is formulated in terms of a Fourier series and combined to regain the effects of the two orthogonal, horizontally applied accelerations as a function of frequency. The end result as discussed and shown in this paper is a finite element model that permits a dense mesh of both the fluid and the structure, while economizing on the number of simultaneous equations required to be solved by the chosen finite element analysis.

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