New Directions in Structural Seismic Designs

The code stipulated seismic force requirements for buildings from the historical point of view are described first. This is followed by examples of the emerging criteria of inelastic seismic spectra for displacement ductility, and number of yield reversals as a function of building period and strength. Novel spatial representations of seismic input energy and hysteresis energy, interpreted as damage energy, are given next. The available structural resistance countering the imposed seismic demand is illustrated by the ductile behavior of steel moment resisting frames (MRFs) and eccentrically braced frames (EBFs). A discussion of a practical and versatile frictional energy dissipating connection is given at the end.

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Seismic force reduction factor for steel moment resisting frames with supplemental viscous dampers

Earthquakes and Structures ◽

10.12989/eas.2014.7.6.1171 ◽

2014 ◽

Vol 7 (6) ◽

pp. 1171-1186 ◽

Cited By ~ 6

Author(s):

M. Hassanien Serror ◽

R. Adel Diab ◽

S. Ahmed Mourad

Keyword(s):

Reduction Factor ◽

Viscous Dampers ◽

Steel Moment Resisting Frames ◽

Moment Resisting Frames ◽

Seismic Force ◽

Moment Resisting ◽

Force Reduction Factor ◽

Force Reduction

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IMPACT OF INTRODUCING SEMI-RIGID MOMENT FRAMES ON SEISMIC RESPONSE OF BRACED FRAMES

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2019.88 ◽

2019 ◽

Vol 6 (1) ◽

Author(s):

Mahmoud Faytarouni ◽

Onur Seker ◽

Bulent Akbas ◽

Jay Shen

Keyword(s):

Braced Frames ◽

Seismic Evaluation ◽

Moment Frames ◽

Moment Frame ◽

Braced Frame ◽

Shear Connections ◽

Seismic Force ◽

Steel Building ◽

Story Drift ◽

Moment Resisting

Maximum seismic inelastic drift demand in a steel building with braced frames as primary seismic-force-resisting (SFR) system tends to concentrate in few stories without considering inherent participation of designed gravity-force-resisting (GFR) system in actual structural stiffness and strength. The influence of GFR system on stiffness and strength can be taken into account by considering the composite action in beam-to-column shear connections that exist in modern steel building construction to form actual semi-rigid moment-resisting frames. Therefore, modeling semi-rigid moment frames as an equivalent to the GFR system in braced frame buildings could be utilized as a representative to the strength provided by gravity frames. This paper presents a seismic evaluation of a six-story chevron braced frame, with and without semi-rigid moment frame. Four different cases are investigated under a set of ground motions and results are discussed in terms of story drift distribution along the height. The results pointed out that the current findings lay a foundation to conduct further investigation on the seismic performance of braced frames as designed SFR system together with GFR system.

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Failure progression resistance of a generic steel moment-resisting frame under beam-removal scenarios

International Journal of Structural Integrity ◽

10.1108/ijsi-02-2016-0008 ◽

2017 ◽

Vol 8 (3) ◽

pp. 308-325 ◽

Cited By ~ 3

Author(s):

Farshad Hashemi Rezvani ◽

Behrouz Behnam ◽

Hamid Reza Ronagh ◽

M. Shahria Alam

Keyword(s):

Progressive Collapse ◽

Structural Response ◽

Safety Level ◽

Content Type ◽

Steel Moment Resisting Frames ◽

Beam Elements ◽

Structural Resistance ◽

Moment Resisting ◽

A Chain ◽

Design Earthquake

Purpose The purpose of this paper is to determine the failure progression resistance of the steel moment-resisting frames subjected to various beam-removal scenarios after application of the design earthquake pertinent to the structure by investigating a generic eight-story building. Design/methodology/approach The structure is first pushed to arrive at a target roof displacement corresponding to life safety level of performance. To simulate the post-earthquake beam-removal scenario, one of the beam elements is suddenly removed from the structure at a number of different positions. The structural response is then evaluated by using nonlinear static and dynamic analyses. Findings The results show that while no failure is observed in all of the scenarios, the vulnerability of the upper stories is much greater than that of the lower stories. In the next step, the structural resistance to such scenarios is determined. The results confirm that for the case study structure, at most, the resistance to failure progression in upper stories is 58 percent more than that of lower stories. Originality/value Failure and fracture of beam-to-column connections resulting in removal of beam elements may lead to a chain of subsequent failures in other structural members and eventually lead to progressive collapse in some cases. Deficiency in design or construction process of structures when combined by application of seismic loads may lead to such an event.

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Damage Avoidance Self-Centering Steel Moment Resisting Frames (MRFs) Using Innovative Resilient Slip Friction Joints (RSFJs)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.726 ◽

2018 ◽

Vol 763 ◽

pp. 726-734 ◽

Cited By ~ 3

Author(s):

Ashkan Hashemi ◽

Pouyan Zarnani ◽

Farhad Mohammadi Darani ◽

Armin Valadbeigi ◽

George Charles Clifton ◽

...

Keyword(s):

Experimental Tests ◽

Steel Moment Resisting Frames ◽

Residual Drift ◽

Moment Resisting Frames ◽

Moment Resisting ◽

Gap Opening ◽

Ductile Behavior ◽

Design Earthquake ◽

Determining Factor ◽

Damage Avoidance

Higher seismic performance can be achieved by localizing the inelastic deformation in the connections (fuses) and minimizing the residual drift that are often a determining factor in whether a structure can be repaired or re-occupied after an earthquake. This paper introduces the self-centering damage avoidance steel Moment Resisting Frames (MRFs) using innovative Resilient Slip Friction Joints (RSFJs). The RSFJ provides self-centering and energy dissipation in one compact package requiring no post-event maintenance. In this concept, the beam is connected to the column through a pinned joint at the top, an RSFJ at the bottom and a slotted web plate for transferring the shear forces, when required. The RSFJ allows for gap opening in the connection upon loading and then re-centers the system when unloading. Furthermore, a secondary fuse within the RSFJ is considered to keep maintaining a ductile behavior in the system in case of an earthquake larger than the design earthquake. The conducted experimental tests confirmed the outcomes of this study.

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Steel structures damage from the Christchurch earthquake series of 2010 and 2011

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.44.4.297-318 ◽

2011 ◽

Vol 44 (4) ◽

pp. 297-318 ◽

Cited By ~ 34

Author(s):

Charles Clifton ◽

Michel Bruneau ◽

Greg MacRae ◽

Roberto Leon ◽

Alistair Fussell

Keyword(s):

Steel Structures ◽

Braced Frames ◽

Concentrically Braced Frames ◽

Eccentrically Braced Frames ◽

Satisfactory Performance ◽

Concentrically Braced ◽

Earthquake Series ◽

Moment Resisting ◽

Industrial Storage ◽

Storage Racks

This paper presents preliminary field observations on the performance of selected steel structures in Christchurch during the earthquake series of 2010 to 2011. This comprises 6 damaging earthquakes, on 4 September and 26 December 2010, February 22, June 6 and two on June 13, 2011. Most notable of these was the 4 September event, at Ms7.1 and MM7 (MM as observed in the Christchurch CBD) and most intense was the 22 February event at Ms6.3 and MM9-10 within the CBD. Focus is on performance of concentrically braced frames, eccentrically braced frames, moment resisting frames and industrial storage racks. With a few notable exceptions, steel structures performed well during this earthquake series, to the extent that inelastic deformations were less than what would have been expected given the severity of the recorded strong motions. Some hypotheses are formulated to explain this satisfactory performance.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.1446 ◽

2013 ◽

Vol 284-287 ◽

pp. 1446-1449 ◽

Cited By ~ 1

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.

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Experimental and numerical investigation of axial load effects on the seismic behavior of steel moment-resisting frames and buckling-restrained knee-braced frames

Asian Journal of Civil Engineering ◽

10.1007/s42107-019-00209-y ◽

2019 ◽

Vol 21 (3) ◽

pp. 449-461

Author(s):

M. TahamouliRoudsari ◽

M. Torkaman ◽

F. Soroush

Keyword(s):

Numerical Investigation ◽

Axial Load ◽

Seismic Behavior ◽

Braced Frames ◽

Steel Moment Resisting Frames ◽

Moment Resisting Frames ◽

Moment Resisting ◽

Load Effects

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Seismic Retrofitting of Eccentrically Braced Frames by Rocking Walls and Viscous Dampers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.1105 ◽

2018 ◽

Vol 763 ◽

pp. 1105-1112 ◽

Cited By ~ 1

Author(s):

Francesca Barbagallo ◽

Melina Bosco ◽

Aurelio Ghersi ◽

Edoardo Michele Marino ◽

Pier Paolo Rossi

Keyword(s):

Damping Ratio ◽

Design Procedure ◽

Seismic Retrofitting ◽

Braced Frames ◽

Viscous Dampers ◽

Equivalent Viscous Damping ◽

Eccentrically Braced Frames ◽

Displacement Ductility ◽

Displacement Capacity ◽

Rocking Walls

A design procedure for seismic retrofitting of eccentrically braced frames (EBFs) by rocking walls and viscous dampers is proposed. The design procedure is founded on the displacement-based approach. The top displacement capacity of the building is evaluated based on the displacement ductility capacity of links and on a rigid lateral deformed configuration of the structure promoted by the rocking walls. The equivalent viscous damping ratio capacity of the EBFs with rocking walls is calculated by semi-empirical relationships specifically calibrated for EBFs with links characterized by mechanical length lower than 2.0. Additional damping is provided by linear viscous dampers. The design internal forces of the rocking walls are evaluated based on the seismic effects of more than one mode of vibration. The effectiveness of the design procedure is verified by means of a case study.

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Practical design (aseismic) of steel structures

Canadian Journal of Civil Engineering ◽

10.1139/l79-030 ◽

1979 ◽

Vol 6 (2) ◽

pp. 292-307

Author(s):

Henry J. Degenkolb

Keyword(s):

Structural Design ◽

Shear Walls ◽

Steel Structures ◽

Braced Frames ◽

Moment Frame ◽

Steel Moment Resisting Frames ◽

Elastic Resistance ◽

Moment Resisting ◽

The Stability ◽

Stability Of Structures

Structural design to resist earthquakes is different from structural design for the more usual forces in that the loads are uncertain but much larger than the elastic resistance of the structure; consequently, the engineer must be concerned with cyclic postelastic performance of materials and systems, ductility, and the stability of structures near ultimate loads.Cyclical tests on members and connections for steel moment-resisting frames indicate very stable hysteresis in the plastic range, a very desirable characteristic. Moment-frame structures, however, are subject to large deflections with consequent damage to the point where secondary effects such as P-delta may become critical. Some observations have indicated that better performance can be obtained by combining the ductile steel frame with concrete shear walls or with steel-braced frames. Tests, both in Japan and California, suggest that large amounts of energy can be absorbed and large ductilities can be achieved by using eccentric connections with steel-braced frames.

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