Selection of Input Motion for Seismic Analysis of Scoured Pile-Supported Bridge with Simplified Models

2018 ◽  
Vol 144 (8) ◽  
pp. 04018099 ◽  
Author(s):  
Yu Shang ◽  
Alice Alipour ◽  
Aijun Ye
Keyword(s):  
Seismic Analysis ◽  
Simplified Models ◽  
Input Motion ◽  
Selection Of

scholarly journals Approach for Selection of Rayleigh Damping Parameters Used for Time History Analysis

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
R. E. Spears ◽  
S. R. Jensen
Keyword(s):  
Seismic Analysis ◽  
Time History ◽  
System Response ◽  
Piping System ◽  
Nuclear Facilities ◽  
Rayleigh Damping ◽  
Modal Damping ◽  
American Society ◽  
Selection Of ◽  
Civil Engineers

Nonlinearities, whether geometric or material, need to be addressed in seismic analysis. One good analysis method that can address these nonlinearities is direct time integration with Rayleigh damping. Modal damping is the damping typically specified in seismic analysis Codes and Standards (ASCE 4-98, 1998, “Seismic Analysis of Safety-Related Nuclear Structures and Commentary,” American Society of Civil Engineers, Reston, Virginia and ASCE/SEI 43-05, 2005, “Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities,” American Society of Civil Engineers, Reston, Virginia.). Modal damping is constant for all frequencies where Rayleigh damping varies with frequency. An approach is proposed here for selection of Rayleigh damping coefficients to be used in seismic analyses that is consistent with given modal damping. The approach uses the difference between the modal damping response and the Rayleigh damping response along with effective mass properties of the model being evaluated to match overall system response levels. This paper provides a simple example problem to demonstrate the approach. It also provides results for a finite element model representing an existing piping system. Displacement, acceleration, and stress results are compared from model runs using modal damping and model runs using Rayleigh damping with coefficients selected using the proposed method.

Maximizing Human Power Output by Suitable Selection of Motion Cycle and Load

1970 ◽  
Vol 12 (3) ◽  
pp. 315-329 ◽  
Author(s):  
J. Y. Harrison
Keyword(s):  
Mechanical Properties ◽  
Experimental Work ◽  
Power Output ◽  
Factors Affecting ◽  
Human Power ◽  
Input Motion ◽  
Ergometer Cycling ◽  
Selection Of

In this paper various factors affecting human power output are discussed, including the mechanical properties of muscle, the geometry of the input motion and the kinematics of the input motion. A mulitpurpose ergometer, designed and built to take account of these factors is described. Two basic motions are possible on the ergometer: cycling and rowing. The rowing motions may be made with any combination of seat and feet either sliding or fixed. In the rowing motions, during a single to and fro cycle, prescribed variations in velocity of the input links can be forced on a subject. Experimental work, which is described, showed that there are considerable differences in the effectiveness of the various ways of working, and that one in particular, a modified rowing motion, allowed the production of greater average amounts of power for periods up to two minutes than have so far been recorded and published (to the author's knowledge).

A Note on Selection of Time-Histories for Seismic Analysis of Bridges in Eurocode 8

2009 ◽  
Vol 13 (8) ◽  
pp. 1125-1152 ◽  
Author(s):  
Iunio Iervolino ◽  
Giuseppe Maddaloni ◽  
Edoardo Cosenza
Keyword(s):  
Seismic Analysis ◽  
Eurocode 8 ◽  
Time Histories ◽  
Selection Of

scholarly journals Eliminating Conservatism in the Piping System Analysis Process Through Application of a Suite of Locally Appropriate Seismic Input Motions

2009 ◽  
Author(s):  
Anthony L. Crawford ◽  
Robert E. Spears ◽  
Mark J. Russell
Keyword(s):  
System Analysis ◽  
Seismic Analysis ◽  
Interaction Analysis ◽  
Department Of Energy ◽  
Piping System ◽  
Total Uncertainty ◽  
Seismic Input ◽  
Nuclear Systems ◽  
Computationally Intensive ◽  
Input Motion

Seismic analysis is of great importance in the evaluation of nuclear systems due to the heavy influence such loading has on their designs. Current Department of Energy seismic analysis techniques for a nuclear safety-related piping system typically involve application of a single conservative seismic input applied to the entire system [1]. A significant portion of this conservatism comes from the need to address the overlapping uncertainties in the seismic input and in the building response that transmits that input motion to the piping system. The approach presented in this paper addresses these two sources of uncertainty through the application of a suite of 32 earthquake realizations with equal probability of occurrence whose collective performance addresses the total uncertainty while each individual motion represents a single variation of it. It represents an extension of the soil-structure interaction analysis methodology of SEI/ASCE 43-05 [2] from the structure to individual piping components. Because this approach is computationally intensive, automation and other measures have been developed to make such an analysis efficient. These measures are detailed in this paper.

scholarly journals Editorial

2018 ◽  
Vol 2 (3) ◽  
pp. 1
Author(s):  
Raimundo Delgado
Keyword(s):  
Structural Dynamics ◽  
Civil Engineering ◽  
Seismic Analysis ◽  
Doctoral Program ◽  
Seismic Loading ◽  
Extended Version ◽  
Special Issue ◽  
Training Process ◽  
Interesting Paper ◽  
Selection Of

This special issue of U. Porto Journal of Engineering includes a selection of papers that were presented at the Symposium on Civil Engineering held during the 1st Doctoral Congress in Engineering (DCE 2015). A set of very interesting papers were presented at that session and their authors were invited to submit an extended version of their papers for inclusion in a special issue of this journal. After the reviewing process five papers have been selected covering mainly two different topics: transport infrastructures and structural dynamics and seismic analysis. The first topic is raised in an interesting paper entitled Freeway geometric design comparison between Mexico and Portugal. The second is brought up in four papers which cover very important and updated subjects, such as structural analysis, seismic loading characterization and losses’ estimation. All papers selected include original contributions and I´m strongly convinced that they will be a very interesting tool for the study of the referred subjects. Finally, I would like to congratulate all authors of the published papers and emphasize that the main objectives of this congress have been achieved, namely in what concerns the training process of the students enrolled in the Doctoral Program in Civil Engineering at FEUP.

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