Canal Automation for Irrigation Systems: American Society of Civil Engineers Manual of Practice Number 131

2017 ◽  
Vol 67 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Brian Wahlin ◽  
Darell Zimbelman
Keyword(s):  
Irrigation Systems ◽  
Canal Automation ◽  
American Society ◽  
Civil Engineers

Chinese Contractors in the United States

2013 ◽  
Vol 05 (03) ◽  
pp. 67-75
Author(s):  
Catherine Yap CO
Keyword(s):  
United States ◽  
The United States ◽  
Economic Benefits ◽  
Exciting Opportunity ◽  
Engineering Firms ◽  
American Society ◽  
Civil Engineers

A 2009 American Society of Civil Engineers report indicates significant underinvestment in the maintenance and upgrading of US infrastructure. The group estimates a five-year investment of US$2.2 trillion is required. This presents an exciting opportunity for Chinese construction and engineering firms. Because infrastructure work provides long-term economic benefits, if done without controversy, they might generate goodwill towards China and may even help advance Chinese commercial interests in the United States.

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.

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