scholarly journals Evaluation of Seismic Performance Factors in High Rise Steel Buildings with Dual Lateral Systems Consisting of Buckling Restrained Braced Frames and Intermediate Moment Frames

2016 ◽  
Vol 161 ◽  
pp. 680-686 ◽  
Author(s):  
Sipan Yavarian ◽  
Rais Ahmad
Keyword(s):  
Seismic Performance ◽  
Braced Frames ◽  
Steel Buildings ◽  
Moment Frames ◽  
Performance Factors ◽  
High Rise ◽  
Buckling Restrained Braced Frames

scholarly journals Evaluation of seismic performance factors for tension-only braced frames

2020 ◽  
Author(s):  
Shariati
Keyword(s):  
Seismic Performance ◽  
Seismic Energy ◽  
Lateral Force ◽  
Main Concern ◽  
Braced Frames ◽  
Steel Buildings ◽  
Performance Factors ◽  
R Factor ◽  
Non Linear ◽  
Margin Of Safety

The tension-only braced frames (TOBFs) are widely used as a lateral force resisting system (LFRS) in low-rise steel buildings due to their simplicity and economic advantage. However, the system has poor seismic energy dissipation capacity and pinched hysteresis behavior caused by early buckling of slender bracing members. The main concern in utilizing the TOBF system is the determination of appropriate performance factors for seismic design. A formalized approach to quantify the seismic performance factor (SPF) based on determining an acceptable margin of safety against collapse is introduced by FEMA P695. The methodology is applied in this paper to assess the SPFs of the TOBF systems. For this purpose, a trial value of the R factor was first employed to design and model a set of TOBF archetype structures. Afterwards, the level of safety against collapse provided by the assumed R factor was investigated by using the non-linear analysis procedure of FEMA P695 comprising incremental dynamic analysis (IDA) under a set of prescribed ground motions. It was found that the R factor of 3.0 is appropriate for safe design of TOBFs. Also, the system over strength factor (Ω0) was estimated as 2.0 by performing non-linear static analyses.

scholarly journals Seismic performance evaluation of high-rise steel buildings dependent on wind exposures

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983511
Author(s):  
Seonwoong Kim
Keyword(s):  
Seismic Performance ◽  
Response Spectrum ◽  
Slenderness Ratio ◽  
Lateral Force ◽  
Lateral Load ◽  
Seismic Load ◽  
Strong Wind ◽  
Steel Buildings ◽  
High Rise ◽  
Moderate Seismicity

The lateral load-resisting system of high-rise buildings in regions of low and moderate seismicity and strong wind such as the typhoon in the Korean peninsula considers the wind load as the governed lateral force so that the practical structural engineer tends to skip the evaluation against the seismic load. This study is to investigate wind-designed steel diagrid buildings located in these regions and check the possibility of the elastic design of them out. To this end, first, the diagrid high-rise buildings were designed to satisfy the wind serviceability criteria specified in KBC 2016. Then, the response spectrum analyses were performed under various slenderness ratio and wind exposures. The analyses demonstrated the good seismic performance of these wind-designed diagrid high-rise buildings because of the significant over-strength induced by the lateral load-resisting system of high-rise buildings. Also, the analysis results showed that the elastic seismic design process of some diagrid high-rise buildings may be accepted based on slenderness ratios in all wind exposures.

Ductility Enhancement in Reinforced Concrete Structure with Buckling Restrained Braced Frames

2016 ◽  
Vol 847 ◽  
pp. 281-289
Author(s):  
Erkan Senol ◽  
Ismail Kose ◽  
Bilge Doran ◽  
Pelin Elif Mezrea ◽  
Bulent Akbas
Keyword(s):  
Reinforced Concrete ◽  
Pushover Analysis ◽  
Design Procedure ◽  
Braced Frames ◽  
Base Shear ◽  
Moment Frames ◽  
Concentrically Braced Frames ◽  
Capacity Curve ◽  
Concentrically Braced ◽  
Buckling Restrained Braced Frames

Adding braces to moment frames is considered to be quite an efficient technique for increasing the global stiffness and strength of the structure. It has not only been used in steel moment frames, but also in reinforced concrete (RC) moment frames in recent years. It certainly can increase the energy absorption capacity of structures and also decrease the demand imposed by seismic ground motions. Steel braces are anchored firmly to boundary beams and columns. They are modeled as truss elements and increase earthquake resistance of the building. Buckling restrained braced frames (BRBFs) in which members yield under both tension and compression without significant buckling have been used in recent years in order to ensure the desired seismic performance of special concentrically braced frames. BRBFs are similar to the special concentrically braced frames in that seismic accelerations are resisted by a building-frame members and diagonal braces whereas the design procedure is different. BRBs should be designed to permit ductile yielding both in compression and tension. In this paper, flat-slab RC building with two different configurations of buckling restraint braces (BRBs) is studied. The buildings have 4-storey with 5 bays in both X-and Y-directions and have been designed according to Turkish Specification of Reinforced Concrete Design (TS 500). In order to explore overall behavior up to failure and lateral load resisting capacities for these buildings, nonlinear static analyses have then been performed using SAP 2000-V14.1. Pushover analysis under constant gravity loads and monotonically increasing lateral forces during an earthquake until a target displacement is reached is generally carried out as an effective tool for performance based design. The major outcome of a pushover analysis is the capacity curve which shows the base shear vs. the roof displacement relationship and represents the overall performance of the building. The results of the analyses are presented in terms of capacity curve and energy dissipation.

Code-Oriented Methodology for the Seismic Design of Regular Steel Moment-Resisting Braced Frames

2014 ◽  
Vol 30 (4) ◽  
pp. 1683-1709 ◽  
Author(s):  
Edgar Tapia-Hernández ◽  
Arturo Tena-Colunga
Keyword(s):  
Seismic Design ◽  
Time History ◽  
Federal District ◽  
Design Parameters ◽  
Braced Frames ◽  
Steel Buildings ◽  
Moment Frames ◽  
Concentrically Braced Frames ◽  
Design Spectrum ◽  
Moment Resisting

In order to help improve the seismic design of regular steel buildings structured with ductile moment-resisting concentrically braced frames (MRCBFs) using the general design methodology of Mexico's Federal District Code (MFDC-04), suitable design parameters were first assessed using the results of pushover analyses of 13 regular MRCBFs. In order to insure collapse mechanisms consistent with the assumptions implicit in a code-based design (strong-column/weak-beam/weaker-brace), it is proposed to relate the minimum strength ratio for the resisting columns of the moment frames and the bracing system. Improved equations are proposed for a more realistic assessment of ductility and overstrength factors. In a second stage, the effectiveness of the improved methodology was assessed with the design of six regular steel buildings with MRCBFs. Buildings were evaluated by performing both pushover and nonlinear time-history analyses under ten selected artificial ground motions related to the corresponding design spectrum.

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 FEMA P695 Study for the Proposed Seismic Performance Factors for Cold-Formed Steel Special Bolted Moment Frames

2013 ◽  
Vol 29 (1) ◽  
pp. 259-282 ◽  
Author(s):  
Atsushi Sato ◽  
Chia-Ming Uang
Keyword(s):  
Seismic Performance ◽  
Moment Frames ◽  
Acceptance Criteria ◽  
Performance Factors ◽  
Gravity Load ◽  
Cold Formed Steel

The objective of this study was to verify the adequacy of the proposed Seismic Performance Factors for the newly developed Cold-Formed Steel Special Bolted Moment Frames in the AISI S110 Seismic Standard. The FEMA P695 methodology, Qualification of Building Seismic Performance Factors, was used for this purpose. A total of 13 archetype designs, representing two seismicity and two gravity load levels, were designed and analyzed. The computed results from all individual archetypes and four performance groups showed that the proposed seismic performance factors met the acceptance criteria and could provide a sufficient margin against collapse under the maximum considered earthquake.

A Risk-Based Approach to Determine the Optimal Service Life of Steel Buildings in Seismically Active Zones

2013 ◽  
Vol 284-287 ◽  
pp. 1446-1449 ◽  
Author(s):  
Chien Kuo Chiu ◽  
Heui Yung Chang
Keyword(s):  
Service Life ◽  
Braced Frames ◽  
Steel Buildings ◽  
Eccentrically Braced Frames ◽  
Optimal Service ◽  
Probable Maximum Loss ◽  
Moment Resisting ◽  
Structural Fragility ◽  
Active Zones ◽  
Buckling Restrained Braced Frames

The object of this study is to propose, develop and apply a risk-based approach to determine the optimal service life for steel framed buildings in seismically active zones. The proposed framework uses models for seismic hazards, structural fragility and loss functions to estimate the system-wide costs owing to earthquake retrofitting and recovery. With the seismic risk curves (i.e. the expected seismic loss and probability of exceeding the loss), the optimal service life can be determined according to the probable maximum loss (PML) defined by the building’s owner. The risk-based approach is further illustrated by examples of 6- and 20-story steel framed buildings. The buildings have three kinds of different lateral load resisting systems, including moment resisting frames, eccentrically braced frames and buckling restrained braced frames. The results show that for the considered PML (i.e. 40% initial construction cost) and risk acceptance (e.g. 90% reliability), steel braced frames can effectively improve seismic fragility and lengthen service life for a low-rise building. However, the same effects cannot be expected in a high-rise building.

Incremental Dynamic Analysis of Shape Memory Alloy Braced Steel Frames

2014 ◽  
Vol 680 ◽  
pp. 263-266
Author(s):  
Saber Moradi ◽  
M. Shahria Alam
Keyword(s):  
Shape Memory Alloy ◽  
Dynamic Analysis ◽  
Shape Memory ◽  
Seismic Performance ◽  
Steel Frames ◽  
Incremental Dynamic Analysis ◽  
Braced Frames ◽  
Earthquake Excitation ◽  
Uniform Drift ◽  
Buckling Restrained Braced Frames

Incremental Dynamic Analysis (IDA) is a technique to determine the overall seismic performance of structures under varied intensities of earthquakes. In this paper, the seismic performance of four-story steel braced frames equipped with superelastic Shape Memory Alloy (SMA) braces is assessed by performing IDA. The seismic response of SMA-braced frames was compared to that of corresponding Buckling-Restrained Braced Frames (BRBFs). Based on the results of this comparative study, the SMA-braced frames were generally effective in reducing maximum interstory drifts and permanent roof deformations. In addition, the SMA-braced frames demonstrated more uniform drift distribution over the height of the building. As the intensity of earthquake excitation increases, a higher response reduction can be expected for SMA-braced frames.

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