scholarly journals Response modification factors for dual moment-resisting frames with vertical links: Multilevel approach

2021 ◽  
pp. 136943322110262
Author(s):  
Vahid Mohsenian ◽  
Nima Gharaei-Moghaddam ◽  
Iman Hajirasouliha
Keyword(s):  
Demand Response ◽  
Earthquake Hazard ◽  
Performance Based Design ◽  
Response Modification Factor ◽  
Seismic Reliability ◽  
Moment Resisting Frames ◽  
Before And After ◽  
Moment Resisting ◽  
And Performance ◽  
Hazard Level

Despite the growing applications of the performance-based design concepts for seismic design of structures, the response modification factors for structural systems proposed by the current design codes and standards do not generally consider different hazard and performance levels. Therefore, these factors are not directly applicable for performance-based design purposes. As a step to address this shortcoming, the present study aims to propose multilevel response modification factors for multistory dual moment-resisting frames equipped with eccentric braces and vertical links corresponding to different seismicity levels and performance targets. The concept of demand and capacity response modification factors is introduced, and these parameters are calculated for moment-resisting frame structures with 3-, 5-, and 7-stories before and after the addition of vertical steel shear links. It is shown that the calculated capacity response modification factors for the dual frames equipped with vertical links are generally higher than the demand response modification factors proposed by the design code for such systems under the design basis earthquake hazard level. This indicates the efficiency of the eccentric braces with the vertical links in improving the seismic reliability and performance of the moment-resisting steel frames. Based on the results of this study, the demand response modification factor for the studied dual lateral load-resisting system is calculated to be in the range of 7–10.

scholarly journals Evaluation Of Response Modification Factor For Moment Resisting Frames

10.29007/q8wl ◽  
2018 ◽  
Author(s):  
Nirav K. Patel ◽  
Prutha Vyas
Keyword(s):  
Nonlinear Response ◽  
Seismic Analysis ◽  
Nonlinear Static Analysis ◽  
Elastic Response ◽  
Systematic Evaluation ◽  
Elastic Behaviour ◽  
Response Modification Factor ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Modification Factor

Conventional seismic analysis of structure incorporates only elastic response of the structure. To understand nonlinear response of the structure, Performance Based Design (PBD) approach is widely used. PBD includes Pushover analysis i.e. nonlinear static analysis, which shows the post-elastic behaviour of the structure. IS 1893-2002 incorporates the nonlinear response of a structure considering response reduction factor (R) so that a linear elastic force based approach can be used for design. The response modification factor plays a key role in the seismic design of new buildings. However, the Indian code does not provide information on the components of R factor. The values assigned to this factor is based on engineering judgment. The study includes the calculation of value R based on different components as per ATC-19 and compares values of R for Special Moment resisting frame (SMRF) and Ordinary Moment resisting frames (OMRF) for two different seismic zones. An improvement in the reliability of modern earthquake-resistant buildings will require the systematic evaluation of the building response characteristics, which mostly affects the values assigned to the factor.

A new performance based design approach for moment resisting frames

2012 ◽  
Vol 39 (4) ◽  
pp. 473-483 ◽  
Author(s):  
Mark Grigorian ◽  
Carl E. Grigorian
Keyword(s):  
Design Method ◽  
Seismic Loading ◽  
Performance Based Design ◽  
Equilibrium Conditions ◽  
Future Behavior ◽  
Straight Line ◽  
Before And After ◽  
Moment Resisting ◽  
Strength And Stiffness ◽  
Constituent Elements

This paper proposes a simple, relatively new elastic–plastic design method for earthquake resisting frames that enables the engineer to directly control the essential aspects of the future behavior of certain structural forms, through basic statics and imposition of predetermined modes of behavior. The method is particularly applicable to the preliminary design of low to mid-rise buildings where the fundamental period of vibrations dominates the response of the system to seismic loading. The focus of this paper is directed towards simplified but accurate manual design rather than sophisticated structural analysis. The premise of the proposed solution is that the constituent elements of the system can be selected in such a way as to cause both the elastic as well as the plastic drift functions to follow linearly varying straight line profiles during all phases of loading. Frameworks designed by this method act not only as structures of uniform response (UR), i.e., uniform strength and stiffness, where the demand/capacity ratios of its members remain the same, both before and after formation of plastic hinges, but they also result in unique solutions, satisfying the prescribed yield criteria, the boundary support, as well as the of static equilibrium conditions.

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