scholarly journals Evaluation of NSP and MPA Methods to Optimize Special Truss Moment Frames (STMF) Using Island Genetic Algorithm

2021 ◽  
Author(s):  
Mohaddese Sadeghpour ◽  
VahidReza Kalatjari ◽  
Hossein Pahlavan
Keyword(s):  
Genetic Algorithm ◽  
Time History ◽  
Accurate Method ◽  
Moment Frames ◽  
Moment Frame ◽  
Response Modification Factor ◽  
Design Variables ◽  
Modification Factor ◽  
Dynamic Time ◽  
Special Truss Moment Frames

The purpose of the present study is to evaluate the Pushover (NSP) and Modal Pushover (MPA) analysis methods in optimizing Special Truss Moment Frames (STMF) using island genetic algorithm. For this purpose, the optimization program is written and developed in Matlab software, and OpenSees software is used for structural analysis. The design variables of truss arrangement, cross section of members, truss height values and length of special zone of truss moment frame are considered. The constraints of the optimization problem are based on the rules and restrictions of AISC341-16. Case studies were performed on five frames of 3, 6, 9, 12 and 15 stories with a story height of 3 meters and span length of 18 meters with the aim of minimizing weight and maximizing the response modification factor. The results of these analyses are compared with nonlinear dynamic time history analyses as the most accurate method available, which could be used to finally identify and introduce the most efficient method in these structures. The MPA method was able to show better performance than the NSP method in estimating the maximum response of the structure. Despite the excellent performance of this method, Evaluation of numerical results of this study indicates the non-economic nature of MPA method for low-rise structures, and the acceptable efficiency of this method for medium-height to high-rise structures.

Response modification factors for steel buckling restrained braced frames designed as per the 2010 National Building Code of Canada

2016 ◽  
Vol 43 (8) ◽  
pp. 702-715 ◽  
Author(s):  
Moniruzzaman Moni ◽  
Saber Moradi ◽  
M. Shahria Alam
Keyword(s):  
Time History ◽  
Building Code ◽  
Braced Frames ◽  
Response Modification Factor ◽  
Building Frames ◽  
Modification Factor ◽  
Design Values ◽  
Nonlinear Static ◽  
Buckling Restrained Braced Frames ◽  
Dynamic Time

This paper evaluates the overstrength, ductility, and response modification factors for low to mid-rise buckling restrained braced frames (BRBFs) designed as per the 2010 National Building Code of Canada. In addition to nonlinear static pushover analyses, dynamic time history analyses are performed to assess the seismic performance of four-, six-, and eight-story BRBFs. Different bracing configurations, including chevron (inverted-V) and split-X braces, are considered for the building frames with varied frame span lengths of 6 m and 8 m. The results confirm that the prescribed design values for overstrength and ductility factors provide reasonable estimations of the lower bound for these factors. The response modification factor obtained in this study ranged from 4.8 to 6 for different frames. The results also indicate that the response modification factor decreases with the increase of story height and span length. Moreover, bracing configurations may slightly affect the response modification factor for BRBFs.

Multi-story truss moment frames equipped with friction dampers and self-centering system for enhanced seismic performance

2019 ◽  
Author(s):  
Keyhan Faraji ◽  
Robert Tremblay
Keyword(s):  
Seismic Performance ◽  
Structural Damage ◽  
Linear Time ◽  
Time History ◽  
Moment Frames ◽  
Moment Frame ◽  
Friction Energy ◽  
Hazard Level ◽  
Residual Deformations ◽  
Dynamic Time

<p>In this article, two new truss moment frame (TMF) systems exhibiting enhanced seismic performance are examined: truss moment frames with friction energy dissipation dampers between the truss bottom chord and the columns (F-TMFs) and F-TMFs with tendons added to achieve self-centering response (FT-TMFs). In both cases, all steel components of the systems are expected to behave essentially elastically to eliminate structural damage. The second system is also expected to have negligible residual lateral deformations. To compare and investigate the seismic performance of the proposed TMF systems, a 5-story commercial steel building located in Vancouver, BC, is designed in accordance with the National Building Code of Canada 2015 (NBCC) and it is subjected to a series of nonlinear static and dynamic time history analyses. The earthquake records, employed in non-linear time history analyses, are scaled for a hazard level corresponding to a probability of 2% in 50 years. The analytical results show that structural damage does not occur in neither of the two proposed systems . Meanwhile, FT-TMF system showed notably better seismic response and negligible residual deformations due to its self-centering capacity provided by the tendons.</p>

Investigation of Damages in RC Frames Under Near Field Earthquakes Using a Damage Index

2016 ◽  
Vol 16 (02) ◽  
pp. 1450094 ◽  
Author(s):  
Seyed Morteza Zinati Yazdi ◽  
Mohammad Taghi Kazemi
Keyword(s):  
Near Field ◽  
Damage Index ◽  
Time History ◽  
General Rule ◽  
Nonlinear Time History Analysis ◽  
Far Field ◽  
Moment Frames ◽  
Moment Frame ◽  
Rc Frames ◽  
Nonlinear Time History

Heavy damages on structures caused by near field earthquakes in recent years has brought serious attention to this problem. An examination of previous records has shown significant differences for near field earthquakes, including a large energy pulse, unlike far field earthquakes. But as a general rule, the effects of near field earthquakes have been ignored in most building codes. The purpose of this paper is to investigate the effect of near field earthquakes on reinforced concrete (RC) moment frames. To achieve this goal, the Erduran damage index, an efficient way to calculate damage, was employed to analyze two 4- and 8-story RC moment frame buildings. The buildings with moderate and high ductility were designed by the strength criteria. Seven pairs of near field and far field earthquakes were scaled and used for dynamic nonlinear time history analysis. Using Erduran’s beam and column damage index, respectively, based on rotation and drift, the results from both near and far field earthquakes were compared. Moreover, for better assessment, 4-story buildings were evaluated from the performance based viewpoint of design. We observe from the results that most of the components of the structures under near field earthquakes sustained severe damages and in some cases even component failure. Components of the structures under near field earthquakes suffered from 30% more of damage, on average, than that under far field earthquakes.

scholarly journals Seismic Performance and Evaluation of Controlled Spine Frames Applied in High-rise Buildings

2018 ◽  
Vol 34 (3) ◽  
pp. 1431-1458 ◽  
Author(s):  
Xingchen Chen ◽  
Toru Takeuchi ◽  
Ryota Matsui
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Evaluation Procedure ◽  
Equivalent Linearization ◽  
Stiffness Ratio ◽  
Moment Frames ◽  
Moment Frame ◽  
High Rise ◽  
Frame System ◽  
Frame Stiffness

A controlled spine frame system consists of moment frames and spine frames with concentrated energy-dissipating members. This system guarantees the continuous usability of buildings against Japanese Level-2 earthquake events (similar to DBE events in California), and the authors have confirmed its excellent performance in preventing damage concentration in low-rise buildings. This study further investigates the effect of diverse structural properties on the seismic performance of controlled spine frames applied in high-rise buildings. The effect of building height, yield drift of dampers, spine-to-moment frame stiffness ratio, and damper-to-moment frame stiffness ratio are illustrated in detail, and optimal values are discussed. Also, a segmented spine frame system is proposed for high-rise buildings. The simple evaluation procedure proposed by the authors for low-rise buildings, based on equivalent linearization techniques and response spectrum analyses, was modified to include higher-mode effects for high-rise buildings based on modal analysis. The modified evaluation method was verified by modal pushover and time-history analyses.

A More Rational Approach to Capacity Design of Seismic Moment Frame Columns

1996 ◽  
Vol 12 (3) ◽  
pp. 395-406 ◽  
Author(s):  
K. Dirk Bondy
Keyword(s):  
Seismic Moment ◽  
Response Spectrum ◽  
Time History ◽  
Rational Approach ◽  
Elastic Analysis ◽  
Moment Frames ◽  
Capacity Design ◽  
Moment Frame ◽  
Maximum Credible Earthquake ◽  
Existing Structures

Inelastic time history analyses typically indicate that the traditional sub-assembly “capacity” approach used in the design of ductile moment frames grossly underestimates the maximum moments experienced by the columns during a maximum credible earthquake. In addition, these analyses predict that the maximum column demand moments often occur near the mid-height of concrete structures, whereas a conventional elastic analysis predicts maxima at the lowest levels of these structures. Incremental displacement analyses using modal properties and displacements predicted by a maximum credible response spectrum should be used to more accurately predict the maximum anticipated column demand moments in the analysis of existing structures or the design of new structures.

Seismic Behavior of Steel Moment Frames with Mechanical Hinge Beam-to-Column Connections

2020 ◽  
Vol 20 (06) ◽  
pp. 2040005
Author(s):  
Han Peng ◽  
Jinping Ou ◽  
Andreas Schellenberg ◽  
Frank Mckenna ◽  
Stephen Mahin
Keyword(s):  
Seismic Behavior ◽  
Shaking Table Test ◽  
Plastic Hinge ◽  
Time History ◽  
Shaking Table ◽  
Base Shear ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Moment Frame ◽  
Steel Moment Frame

This paper presents an investigation on the seismic behavior of steel moment frames with mechanical hinge beam-to-column connections. The connection uses a mechanical hinge to carry shear force and a pair of buckling-restrained steel plates bolted to the beam flange to transfer bending moment. The moment-rotation behavior of the connection was theoretically studied. A nonlinear numerical model for steel moment frames under strong earthquakes was developed and validated using a shaking table test of an 18-story steel moment frame at the E-Defense facility. Then, nonlinear static and time-history analyses were conducted to compare the seismic behavior of a conventional steel moment frame and three innovative steel frames equipped mechanical hinge connections in terms of roof displacement, base shear, inter-story drift ratio, and plastic hinge rotation.

scholarly journals Numerical study of the effect of geometric arrangement of the truss on the response modification factor of the special truss moment frame (STMF)

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
M. Sadeghpour ◽  
V. R. Kalatjari ◽  
H. Pahlavan
Keyword(s):  
Static Analysis ◽  
Numerical Study ◽  
List Type ◽  
Moment Frame ◽  
Response Modification Factor ◽  
Non Linear ◽  
Modification Factor ◽  
Geometric Arrangements ◽  
The Given ◽  
Linear Static Analysis

Abstract The purpose of the present study was to investigate the effect of the geometric arrangement of the trusses on the response modification factor of the special truss moment frame. For this purpose, six different geometric arrangements for the three types of trusses (Vierendeel, multiple Vierendeel panels, and X-diagonals) were considered. The results were obtained based on non-linear static analysis of two- and three-span frames for 4- and 8-story structures with the given geometric arrangements. According to the results obtained, different truss arrangements can affect the response modification factor by about 4 to 10%. Additionally, using multiple Vierendeel panels and the X-diagonals can increase the response modification factor by 1.06 and 1.74 times, respectively. Article Highlights Different truss arrangements do not have a significant effect on the coefficient of behavior. The addition of several Vierendeel panels does not have much effect on the behavior of these structures. Adding cross diameters almost doubles the coefficient of behavior and significantly improves the performance of the structure.

Non-linear behavior of ground-supported circular reinforced concrete tanks

2021 ◽  
Author(s):  
Maryam Rafieeraad ◽  
M. Reza Kianoush ◽  
Mehdi Moslemi
Keyword(s):  
Seismic Behavior ◽  
Current Practice ◽  
Time History ◽  
Response Modification Factor ◽  
R Factor ◽  
Linear Behavior ◽  
History Analysis ◽  
Earthquake Frequency ◽  
Modification Factor ◽  
Nonlinear Static

This study aims to investigate the effect of various parameters on the seismic behavior of concrete tanks. A finite element method using pushover and time-history analysis is developed to investigate the seismic behavior of circular ground-supported tanks. The response modification factor (R) is evaluated based on nonlinear static and time-history analyses. R factor is one of the key parameters in seismic design. In liquid containing structures, R-Factor in current codes and standards are based on empirical values. Therefore, a justifiable guideline to accurately determine these values is yet to be developed. This study shows that the effect of tank size, material non-linearity, base condition, and earthquake frequency content is significant. Also, fixed based and shallow tanks have higher R values compared to hinged based and tall tanks, respectively. Based on the results of this study, it is found that the value of R specified in current practice is not appropriate.

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