Comparison of seismic force reduction factors used in U.S.A. and Japan

1991 ◽  
Vol 20 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Chia-Ming Uang
Keyword(s):  
Seismic Force ◽  
Force Reduction ◽  
Reduction Factors

Period-dependent seismic force reduction factors for short-period structures

1991 ◽  
Vol 18 (4) ◽  
pp. 568-574 ◽  
Author(s):  
W. K. Tso ◽  
N. Naumoski
Keyword(s):  
Reduction Factor ◽  
Structural Systems ◽  
High Ductility ◽  
Base Shear ◽  
Ductility Demand ◽  
Seismic Design Code ◽  
Short Period ◽  
Seismic Force ◽  
Force Reduction ◽  
Reduction Factors

The seismic force reduction factors proposed in the seismic provisions of the National Building Code of Canada 1990 (NBCC 1990) are examined using ground motion records from two recent Canadian earthquakes. The displacement ductility demands are analyzed for structural systems with different ductility capacity. It is found that the NBCC 1990 force reduction factors, which are period independent, lead to a very high ductility demand for short-period structural systems. To avoid this, two types of period-dependent force reduction factors for short-period structures are investigated. The results show that the linearly varying period-dependent reduction factor represents a viable means to resolve the high ductility problems associated with short-period structural systems. Key words: earthquake, seismic, design, code, response, spectra, ductility, reduction factor, base shear.

An Evaluation of Two-Level Seismic Design Procedure

1993 ◽  
Vol 9 (1) ◽  
pp. 121-135 ◽  
Author(s):  
Chia-Ming Uang
Keyword(s):  
Structural Damage ◽  
Limit State ◽  
Design Procedure ◽  
Reduction Factor ◽  
Performance Criteria ◽  
Ultimate Limit State ◽  
Seismic Codes ◽  
Seismic Force ◽  
Force Reduction Factor ◽  
Force Reduction

The two-level design philosophy is recognized by modern seismic codes. When this philosophy is implemented in the code, the intensities of the two design earthquakes, the structural performance criteria, explicit versus implicit design approach, and the effectiveness to achieve the performance criteria vary considerably from one code to the other. For the ultimate limit state, the UBC was compared with seismic codes of Canada, Japan, and Eurocode. It was found that a trend to deviate from the UBC approach of using a single seismic force reduction factor (i.e., Rw) is apparent. Instead, an approach using a compound force reduction factor which considers the contribution of structural ductility and structural overstrength is preferred. For the serviceability limit state, a comparison of the level of design earthquakes and performance criteria of the UBC, Tri-Services Manual, and the Japanese code indicates that the UBC produces the most flexible structure, and that UBC does not control structural damage. It is suggested that the UBC adopts an explicit serviceability design procedure.

Development of Seismic Force Reduction and Displacement Amplification Factors for Autoclaved Aerated Concrete Structures

2006 ◽  
Vol 22 (1) ◽  
pp. 267-286 ◽  
Author(s):  
Jorge L. Varela ◽  
Jennifer E. Tanner ◽  
Richard E. Klingner
Keyword(s):  
Reduction Factor ◽  
Test Results ◽  
Lateral Loads ◽  
Autoclaved Aerated Concrete ◽  
Laboratory Test Results ◽  
Seismic Force ◽  
Force Reduction Factor ◽  
Aerated Concrete ◽  
Hysteretic Characteristics ◽  
Force Reduction

This paper addresses the development and application of a rational procedure to select the seismic force reduction factor ( R) and the displacement amplification factor ( Cd) for the design of autoclaved aerated concrete (AAC) structures. The values of R and Cd are proposed based on a combination of laboratory test results and numerical simulation. The test results are obtained from 14 AAC shear-wall specimens tested under simulated gravity and quasi-static reversed cyclic lateral loads. Analytical responses are predicted using nonlinear analysis models whose hysteretic characteristics are based on the experimentally observed responses. Using an iterative procedure, typical AAC structures are designed using successively larger trial values of the factor, R, until the structure's response (either ductility or drift) exceeds the experimentally determined capacity. A lower fractile of those critical values, modified for probable structural overstrength, is taken as a reasonable value of 3 for R. Using an analogous procedure, a reasonable value of Cd is determined as 3. These values will undoubtedly be refined based on field experience, just as they have been for other structural systems.

scholarly journals Assessment of Response Reduction Factors Of Reinforced Concrete Buildings Using Response spectrum Analysis

2021 ◽  
Author(s):  
Natalie Simone Bryon
Keyword(s):  
Reinforced Concrete ◽  
Spectrum Analysis ◽  
Response Spectrum ◽  
Elastic Response ◽  
Reinforced Concrete Buildings ◽  
Response Spectrum Analysis ◽  
Concrete Buildings ◽  
Seismic Force ◽  
Comparative Review ◽  
Reduction Factors

This study provides an in-depth comparative review of the response reduction factors per NBCC 2015 code used to reduce the elastic response of the structure. An assembly of eight (8) reinforced concrete buildings of which four (4) different Seismic Force Resisting System (SFRS) types was included. The models were also categorized based on ductility and overstrength characteristics specifically ductile and conventional construction moment frames as well as ductile and conventional construction shear walls. All eight (8) models were analyzed using elastic Response Spectrum Analysis (RSA). Each SFRS was also analyzed as both a 12 storey and 40 storey building in order to explore the effects / restrictions of building height. The Equivalent Lateral Force Procedure was performed on the assembly of models for comparison to determine if the static procedure as per NBCC 2015 provisions resulted in overly conservative or similar results. The relevant structural response such as base reactions, storey drifts, storey forces, and member forces were recorded and analyzed.

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