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.

Seismic Performance Evolution of Tube-in-Tube Diagrid Structure Using Non Linear Static Analysis

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
M. K. Laghate ◽  
M. K. Laghate
Keyword(s):  
Static Analysis ◽  
Seismic Performance ◽  
Lateral Displacement ◽  
Pushover Analysis ◽  
Lateral Load ◽  
High Rise ◽  
Load Carrying ◽  
Non Linear ◽  
Diagrid Structure ◽  
Linear Static Analysis

Diagrid structures are evolved as one of the best structural system for high rise buildings. In this study seismic performance of 36 stories Tube-in-Tube Diagrid Structure with various diagonal slopes is evaluated by Non Linear Static Analysis. Tube-in-Tube diagrid structures are modified Diagrid structures in which gravity core is replaced with Diagrid core. Single tube diagrid structure is also studied for comparison. The structure is pushed gradually proportional to fundamental Mode shape. The analysis results shows that Tube-in-Tube structure possess higher stiffness and Lateral Load resisting capacity. The pushover analysis demonstrates that diagrid core can perform better by hardening the structure. According to analysis results, the Tube-in-Tube diagrid structure shows higher non-linear lateral displacement. It was observed that as the diagrid angle increases the stiffness and lateral load carrying strength decreases.

scholarly journals Seismic Performance Assessment of Existing RC Frames with Different Ultimate Concrete Strains

2018 ◽  
Vol 4 (6) ◽  
pp. 1273
Author(s):  
Rishath Sabrin ◽  
Mohammad Al Amin Siddique ◽  
Md. K. Sohel
Keyword(s):  
Seismic Performance ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Performance Criteria ◽  
Seismic Performance Assessment ◽  
Seismic Region ◽  
Response Modification Factor ◽  
Rc Frames ◽  
Moment Resisting ◽  
Modification Factor

In recent years, because of the older version code, inadequate design, lacks of construction supervision, change in loading pattern, damages and casualties of earthquakes or environmental degradation, buildings at risk need to be investigated frequently for safety purpose. To increase the strength and ductility capacities of deficient reinforced concrete (RC) beams, columns and beam-column joints, retrofitting may require. In this paper, a numerical investigation using nonlinear static pushover analysis is conducted to assess the seismic behavior of existing moment resisting RC frames. In numerical modeling, different plastic hinge lengths as well as different concrete ultimate strain conditions of RC members are considered. Pushover analysis has been carried out with the commercial software ETABS v.9.6.0 to evaluate structural behavior of RC frames located in a seismic region. Hinge properties simulating moment-rotation behavior of frame members considering different plastic hinge lengths as well as concrete ultimate strains are evaluated. Pushover curves are compared with each other to determine the plastic hinge length and strain values which provide better agreement with that of the default properties. Seismic performance criteria in terms of ductility, overstrength as well as response modification factor for frames are determined from pushover curves. From the analyses in general, the load carrying capacity as well as displacement at maximum lateral load and interstory drift index at any floor level of RC frames is assessed.

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 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.

scholarly journals Nonlinear Static Pushover Analysis of Medium Rise and High-Rise Building

2019 ◽  
pp. 255-561
Author(s):  
M Keshava Murthy ◽  
Ashwini L K
Keyword(s):  
Pushover Analysis ◽  
Performance Level ◽  
Base Shear ◽  
High Rise ◽  
High Rise Building ◽  
Non Linear ◽  
Nonlinear Static ◽  
Static Pushover Analysis ◽  
Different Levels ◽  
Nonlinear Static Pushover Analysis

Pushover analysis is an elegant tool to visualise the performance level of a building under a given earthquake. The purpose of the paper is to summarize the Non Linear static Pushover analysis of medium rise RC bare frame and high rise RC infilled structure with soft stories at different levels using ETABS software. Results concluded that due to the introduction of soft stories in the higher level the intensity of hinge formation becomes lower and lower and at the same time displacement and base shear increases

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 Assessment of plastic hinge in RC structures with and without shear walls applying pushover analysis

2020 ◽  
Vol 1 (1) ◽  
pp. 11-18
Author(s):  
Jean Pierre Lukongo Ngenge ◽  
Abdallah M. S. Wafi
Keyword(s):  
Plastic Hinge ◽  
Pushover Analysis ◽  
Computer Software ◽  
Shear Walls ◽  
Span Length ◽  
Base Shear ◽  
Rc Structures ◽  
High Rise ◽  
Moment Resisting Frames ◽  
Moment Resisting

This paper gives a brief presentation about different types of analysis, plastic hinge, moment-resisting frames (MRFs) and shear walls (SWs) in reinforced concrete (RC) Structures. ETABS computer software is employed to model and analyse the structures applying the pushover. The performances of the modelled structures are also evaluated considering different parameters such as the number of stories, spans length, shear walls, reinforcement yield strength and characteristic strength of concrete. The study includes two cases, which are moment-resisting frames with and without shear walls (i.e. MRFs and MRF-SWs, respectively). Each case covers low-, mid- and high-rise buildings. In this regard, a comparative study has been performed for the results obtained from all models. It was observed that the stiffness of MRFs compared to MRF-SWs was less and also the stiffness of low-rise frames was higher than that of mid-rise and high-rise frames. Technically this means that a low-rise building is stiffer than a mid-rise building and a mid-rise building is stiffer than a high-rise building. Additionally, when the span length increases, the stiffness of the building decreases. Therefore, it can be concluded that the span length is inversely proportional to the stiffness. Finally, all stiffness values were calculated taking into consideration the displacement and base shear at the first hinge formation on the pushover curve of each model.

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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