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.

Response Modification Factor for Y-Eccentric-Braced Steel Frame Structures Designed Based on Chinese Code

2014 ◽  
Vol 580-583 ◽  
pp. 1449-1457
Author(s):  
Wen Xia Yang ◽  
Qiang Gu ◽  
Ping Zhou Cao ◽  
Rong Jin Shi
Keyword(s):  
Pushover Analysis ◽  
Design Procedure ◽  
Response Spectra ◽  
Elastic Response ◽  
Base Shear ◽  
Response Modification Factor ◽  
Linear Elastic ◽  
Elastic Response Spectra ◽  
Modification Factor ◽  
Steel Frame Structures

In current seismic design procedure, structure base shear is calculated according to the linear elastic response spectra divided by the response modification factor, which accounts for ductility and overstrength of a structural system. In this paper, the response modification factors of Y-eccentric braced steel frames (YECBF) designed based on Chinese Code were evaluated by an improved pushover analysis on 12 examples with various stories and spans lengths. According to the analysis results, the effects of fundamental periods, storey numbers, and spans of frames on the behavior factor were studied. In the end, an appropriate response modification factor was proposed for YECBF designed base on Chinese Code.

scholarly journals Effect of Standard No. 2800 Rules for Moment Resisting Frames on the Elastic and Inelastic Behavior of Dual Steel Systems

2017 ◽  
Vol 7 (6) ◽  
pp. 2139-2146 ◽  
Author(s):  
H. Veladi ◽  
H. Najafi
Keyword(s):  
Steel Structures ◽  
Lateral Load ◽  
Nonlinear Static Analysis ◽  
Inelastic Behavior ◽  
Braced Frame ◽  
Moment Resisting Frames ◽  
Seismic Design Code ◽  
Moment Resisting ◽  
Bracing System ◽  
Steel Braced Frame

According to most valid Design Codes including the Iranian Seismic Design Code (Standard No. 2800), moment resisting frames in dual systems must have the ability of resisting the 25% of the total lateral load of the dual system independently. This study is conducted to investigate the implementation of this rule for dual steel structures with two types of steel braced frame. Also, its effect on the strength of the structure and the distribution of lateral load between the frames and the bracing system is evaluated. In order to investigate the effect of that rule, structural models with 5, 10 and 15 floors are modeled. Nonlinear static analysis is employed and results are discussed. Following the Standard No. 2008 seems to increase the structure’s lateral resistance and decrease the number of elements entered into the inelastic behavior stage. In general, the structure has a more desirable inelastic behavior.

RESEARCH INTO THE DEVELOPMENT OF A RESPONSE MODIFICATION FACTOR FOR DIAGRID STRUCTURES

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yasser Salem ◽  
Devindar Aulakh ◽  
Giuseppe Lomiento
Keyword(s):  
Pushover Analysis ◽  
Lateral Loads ◽  
Response Modification Factor ◽  
Ground Shaking ◽  
High Rise ◽  
Non Linear ◽  
Moment Resisting ◽  
Inelastic Behaviour ◽  
Modification Factor ◽  
Diagrid Structure

The diagrid structure system has recently gained popularity as an effective structural system for high rise buildings. The effectiveness of the system relies on the truss action developed by the perimeter diagrid system to resist lateral loads. In active seismic zones, ductile performance of the lateral resisting system is highly desired to dissipate energy developed in the structure from the ground shaking. In this study, the seismic performance of the diagrid system is investigated. Non-linear static pushover analysis followed by non-linear dynamic analysis were conducted to study the inelastic behaviour of diagrid systems. Through methods of analysis, the response modification factor of the modelled system was calculated. The results indicate that the reserve strength of a diagrid system is comparable to and often greater than that of many other lateral structure systems, such as steel special truss moment resisting frames and other structural systems as prescribed by the ASCE 7-10.

Behaviour of dual eccentrically braced steel frames with short and long seismic links

2019 ◽  
Author(s):  
Ivan Lukačević ◽  
Tomislav Maleta ◽  
Darko Dujmovic
Keyword(s):  
Energy Dissipation ◽  
Plastic Hinge ◽  
Seismic Energy ◽  
High Strength ◽  
Elastic Behaviour ◽  
Braced Frame ◽  
Moment Resisting Frames ◽  
Collapse Mechanisms ◽  
Moment Resisting ◽  
Flexible Part

<p>Dual structures obtained by combining moment resisting frames with innovative bracing systems such as replaceable shear panels or seismic links have significant advantages among conventional solutions. The major advantages of such systems are energy dissipation in the specific locations and re-centring capability which significantly reduces repair costs. On the other hand, design of such systems is driven with specific requirements such as combining different steel grades to ensure elastic behaviour of the flexible part of the system. This paper deals with comparative behaviour analyses of two dual systems combining moment resisting multi-storey frames with eccentric bracing systems. The steel frame consists of three bays with central braced frame and two adjacent moment resisting frames. The bracing system contains either long or short seismic link. Seismic energy dissipation of these systems is completely different. Long seismic links are characterised with a classical plastic hinge in which energy is dissipated through bending while in case of short seismic links seismic energy is dissipated through shear. Multi-linear plastic diagrams for both links have been defined and pushover analyses are performed. The behaviour of the analysed systems based on collapse mechanisms, overstrength ratio, target displacement and possible solutions for re-centring capabilities are discussed. Analysed system with short seismic links despite more complicated modelling and requirements for high strength steel in MRFs, results in higher overstrength ratio regarding the system with long seismic links. It is also far easier to dismantle system with short seismic links, due to the bolted connection of links with the adjacent members.</p>

The Effects of Various Slippage Loads on the Response Modification Factor of Steel Structures Equipped with Frictional Dampers

2015 ◽  
Vol 15 (06) ◽  
pp. 1450080
Author(s):  
Hamid Rahmani Samani ◽  
Masoud Mirtaheri ◽  
Mojtaba Rafiee
Keyword(s):  
Structural Control ◽  
Steel Structures ◽  
Earthquake Excitation ◽  
Response Modification Factor ◽  
Steel Moment Resisting Frames ◽  
Optimum Energy ◽  
Seismic Design Code ◽  
Moment Resisting ◽  
Modification Factor ◽  
Code Procedure

A common and successful way of structural control is to dissipate the seismic kinetic energy via frictional dampers. Response of a friction damped frame during an earthquake excitation is heavily dependent to the slippage limit of the frictional dampers. Low values of slippage load may lead to excessive deformations while large slippage loads may prevent sliding. Therefore, selecting appropriate values for slippages loads of the dampers is very important in order to have optimum energy dissipating system. Utilizing a response modification factor, the standard seismic design code procedure can be applied to the frames equipped with frictional dampers to determine the value of slippage loads. In this investigation, the response modification factor of steel moment resisting frames equipped with frictional dampers is evaluated considering the effects of various slippage loads. The response modification factor is calculated for two bay widths of 5 m and 7 m in length. It is shown that the optimum slippage load that results in the maximum response modification factor is in the range of 8% to 20% of the total weight of the structure. The taller the structure is, the less the optimum slippage load will be. Finally, an equation is proposed for the response modification factor as a function of the slippage load.

scholarly journals Seismic Response Modification Factorof Reinforced Concrete Frames Basedon Pushover Analysis

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Amira Elyamany Mohamed ◽  
Walid A Attia ◽  
Wael M. El-Degwy
Keyword(s):  
Reinforced Concrete ◽  
Seismic Analysis ◽  
Pushover Analysis ◽  
Fundamental Period ◽  
Concrete Frames ◽  
Reinforced Concrete Frames ◽  
Response Modification Factor ◽  
R Factor ◽  
Modification Factor ◽  
The Given

Response modification factor is an essential factor in seismic analysis to provide economic design of reinforced concrete structures. Base shear force is divided by the response modification factor to consider the ability of the structure to dissipate energy through plastic hinges. The current study investigates the effects of changing some parameters on response modification factor (R-factor). Four groups of reinforced concrete frames were studied with different number of bays, number of stories, load pattern, and fundamental period of vibration. All reinforced concrete frames were analyzed using SAP 2000 then the straining actions results were used at specific excel sheets which are developed to design reinforced concrete members according to the Egyptian code of practice ECP-203 and ECP-201. Frames were analyzed by nonlinear static analysis (pushover analysis) using SAP2000. A sum of thirty two systems of frames was analyzed. According to the results, every frame has its unique value of R-factor. Accordingly, many parameters should be mentioned and considered at code to simulate the actual value of R-factor for each frame. Response modification factor is affected by many factors like stiffness, fundamental period of vibration, number of bays, frame height, geometry of the structure, etc. The given values of R-factor at ECP-201 can be considered conservative; as the accurate values of R-factor is higher than the given values.

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