Friction-Damped Moment-Resisting Frames

1996 ◽  
Vol 12 (3) ◽  
pp. 623-633 ◽  
Author(s):  
Douglas Way
Keyword(s):  
Energy Dissipation ◽  
Analytical Methods ◽  
Northridge Earthquake ◽  
Inelastic Behavior ◽  
Earthquake Energy ◽  
Moment Resisting Frames ◽  
Full Penetration ◽  
Energy Accounting ◽  
Moment Resisting

Friction-Damped Moment-Resisting Frames are discussed as an alternative to steel ductile moment-resisting frames. The design involves replacing all full penetration welds with bolted friction connections, thereby eliminating the problem of failures at welded connections as exhibited during the Northridge earthquake. Energy dissipation is achieved at the friction interface in lieu of inelastic behavior of the frame. Analytical methods that perform an energy accounting are discussed.

Identifying Critical Connections for the Global Performance of Steel Moment Resisting Frames

2018 ◽  
Vol 763 ◽  
pp. 165-173
Author(s):  
Paul Steneker ◽  
Lydell D.A. Wiebe ◽  
Andre Filiatrault
Keyword(s):  
Local Deformation ◽  
System Level ◽  
Single Type ◽  
Northridge Earthquake ◽  
Component Level ◽  
Moment Resisting Frames ◽  
Global Performance ◽  
Moment Resisting ◽  
Rbs Connections ◽  
Level Performance

The investigations following the unacceptable performance of moment resisting frames (MRFs) in the 1994 Northridge Earthquake led to the development of a variety of alternative ductile connections. Tests have shown that these connections have reliable component-level performance, leading to them being recommended in standards worldwide as pre-qualified for MRFs. Current design practice consists of applying a single type of ductile connection, often the reduced beam section (RBS), uniformly throughout an entire frame. These connections are detailed and inspected to ensure that each connection has a similar minimum deformation capacity throughout the building, regardless of local deformation demands.This paper examines the potential design implications of identifying local areas within a MRF having the greatest joint rotational demands. Once identified, the connections at these locations are deemed critical to the global performance of the frame. First, the collapse analysis of a six-storey MRF with well-detailed RBS connections was conducted to quantify an upper bound system-level performance. Thereafter, a lower bound system-level performance was determined by considering a frame constructed using only connections with a lowered rotational capacity. Subsequent series of analyses were conducted to identify critical locations within the frame where RBS connections must have a high reliable rotational capacity to ensure adequate system-level performance.

scholarly journals Strengthening of the Panel Zone in Steel Moment Resisting Frames

2019 ◽  
Author(s):  
Masoud Abedini ◽  
Sudharshan N. Raman ◽  
Azrul A. Mutalib ◽  
Ebrahim Akhlaghi
Keyword(s):  
Structural Engineering ◽  
Steel Structures ◽  
Inelastic Behavior ◽  
Linear Deformation ◽  
Rigid Zone ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Panel Zone ◽  
Standard Design ◽  
Moment Resisting

Rehabilitation and retrofitting of structures designed in accordance to standard design codes is an essential practice in structural engineering and design. For steel structures, one of the challenges is to strengthen the panel zone as well as its analysis in moment-resisting frames. In this research, investigations were undertaken to analyze the influence of the panel zone in the response of structural frames through a computational approach using ETABS software. Moment-resisting frames of six stories were studied in supposition of real panel zone, different values of rigid zone factor, different thickness of double plates, and both double plates and rigid zone factor together. The frames were analyzed, designed and validated in accordance to Iranian steel building code. The results of drift values for six stories building models were plotted. After verifying and comparing the results, the findings showed that the rigidity lead to reduction in drifts of frames and also as a result, lower rigidity will be used for high rise building and higher rigidity will be used for low rise building. In frames with story drifts more than the permitted rate, where the frames are considered as the weaker panel zone area, the story drifts can be limited by strengthening the panel zone with double plates. It should be noted that higher thickness of double plates and higher rigidity of panel zone will result in enhancement of the non-linear deformation rates in beam elements. The resulting deformations of the panel zone due to this modification can have significant influence on the elastic and inelastic behavior of the frames.

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.

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>

Cyclic behaviour of locally web-stiffened W-shape beams

1995 ◽  
Vol 22 (1) ◽  
pp. 121-134
Author(s):  
R. M. Korol ◽  
M. L. Daali
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Steel Frames ◽  
Earthquake Response ◽  
Lateral Loads ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Cyclic Behaviour ◽  
Rotation Capacity ◽  
Moment Resisting

A series of tests on W-shaped beam-to-column connections subjected to quasi-static cyclic loading was conducted to assess their ductility and energy dissipation capabilities. The specimens represent beams in ductile moment resisting frames undergoing alternating lateral loads. The aim of this study was to assess and compare the rotation capacity and energy absorption of locally web-stiffened beams with unstiffened beams. Of direct relevance to seismically designed moment resisting steel frames, the experimental results of this research clearly highlight the superiority of herring-bone style web-stiffened specimens over vertically web-stiffened or unstiffened specimens. Key words: earthquake, response, steel, moment resisting frames, stiffener, cyclic loading.

Performance Evaluation of Passive Damping Systems for the Seismic Retrofit of Steel Moment-Resisting Frames Subjected to Near-Field Ground Motions

2001 ◽  
Vol 17 (3) ◽  
pp. 427-456 ◽  
Author(s):  
André Filiatrault ◽  
Robert Tremblay ◽  
Assawin Wanitkorkul
Keyword(s):  
Near Field ◽  
The United States ◽  
Viscous Damping ◽  
Northridge Earthquake ◽  
Steel Moment Resisting Frames ◽  
Brittle Behavior ◽  
Moment Resisting Frames ◽  
Crustal Earthquakes ◽  
Moment Resisting ◽  
Damping Systems

Passive friction and viscous damping systems for retrofitting steel moment-resisting frames located along the west coast of the United States are considered. First, preliminary design procedures are presented for friction as well as linear and nonlinear viscous damping systems. Thereafter, nonlinear dynamic analyses are performed on a six-story moment-resisting frame designed according to seismic provisions for California prior to the 1994 Northridge earthquake. A flexural strength degradation model is considered to account for the brittle behavior of pre-Northridge welded beam-to-column connections. The structure was subjected to three different earthquake ensembles including near-field records developed for major crustal earthquakes in California. The results of a parametric study indicate that, although both friction and viscous damping systems reduce significantly the response of the structure, they are unable by themselves to prevent fracture of welded beam-to-column joints. Connection retrofit measures of the types elaborated after the Northridge earthquake would still be required.

Performance-based assessment of seismic-resilient steel moment resisting frames equipped with innovative column base connections

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 1646-1664
Author(s):  
Elena Elettore ◽  
Annarosa Lettieri ◽  
Fabio Freddi ◽  
Massimo Latour ◽  
Gianvittorio Rizzano
Keyword(s):  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Performance Based Assessment ◽  
Moment Resisting ◽  
Base Connections ◽  
Column Base
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