Braced Frame Symmetrical and Asymmetrical Friction Connection Performance

2018 ◽  
Vol 763 ◽  
pp. 216-223 ◽  
Author(s):  
Robin Xie ◽  
Jose Chanchi Golondrino ◽  
Gregory A. MacRae ◽  
George Charles Clifton
Keyword(s):  
Energy Dissipation ◽  
Coefficient Of Friction ◽  
Large Displacements ◽  
Effective Coefficient ◽  
Sliding Surface ◽  
Moment Frame ◽  
Braced Frame ◽  
Static Testing ◽  
Moment Resisting ◽  
The Moment

This paper describes quasi-static testing of Asymmetrical Friction Connection (AFC) and Symmetrical Friction Connections (SFC) in steel braces. It is shown that stable energy dissipation mechanisms have been achieved in braces using Bisalloy 500 shims on the sliding surface. When incorporated into a moment frame, the braces and the moment resisting frames underwent large displacements without significant frame yielding. The effective coefficient of friction is shown to be dependent on prying.

Assessing the Collapse Probability of Base-Isolated Buildings considering Pounding to Moat Walls using the FEMA P695 Methodology

2015 ◽  
Vol 31 (4) ◽  
pp. 2069-2086 ◽  
Author(s):  
Armin Masroor ◽  
Gilberto Mosqueda
Keyword(s):  
Seismic Hazard ◽  
Ground Motions ◽  
Moment Frame ◽  
Isolation System ◽  
Braced Frame ◽  
Frame Model ◽  
Impact Forces ◽  
Collapse Probability ◽  
The Moment ◽  
The Impact

The collapse probability of two three story base-isolated buildings considering pounding to moat walls is examined using the methodology in FEMA P695. The superstructure models consist of a steel intermediate moment frame and a steel ordinary braced frame designed for the same seismic hazard. The behavior of these buildings under various ground motions is first examined, and it is found that the more rigid braced frame results in larger displacements demands on the isolation system, increasing the potential for impact. The collapse studies examine the effect of moat wall gap distance on the probability of collapse for these structures. These studies show that the flexibility and ductility of the moment frame model allow the superstructure to better absorb the impact forces. The braced frame superstructure tends to impact at lower shaking intensities and degrades in strength more rapidly due to the limited ductility that increases the risk of collapse.

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

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.

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>

scholarly journals Evaluation of behavior and performance of the braced/ unbraced four story of steel frame with semi rigid connection

2019 ◽  
Vol 270 ◽  
pp. 01002
Author(s):  
Daniel Rumbi Teruna
Keyword(s):  
Stiffness Parameter ◽  
Braced Frame ◽  
Analysis And Design ◽  
Moment Resisting Frame ◽  
Story Drift ◽  
Moment Resisting ◽  
Inelastic Behaviour ◽  
Rigid Connection ◽  
And Performance ◽  
The Moment

Structural analysis and design with taken into account the flexibility of the beam to the column connections of steel frameworks takes on importance of the growing development and utilization of new commercial software. However, for design purposes, the beam to the column connection are usually considered to be either pinned or fully rigid, and drastically simplifies the analysis and design procedures. In this paper, a four story of unbraced and concentric braced steel moment resisting frame having different connection stiffness is analysed using linear and nonlinear static procedure. In the finite element modelling, the semi rigid connection is modelled by rotational spring having linear moment and rotation relationship. To account the inelastic behaviour of beam and column members, concentrated plastic hinges based on FEMA 356 are applied for both ends of the member. It was found that, the response quantity of the unbraced frame are influenced by the flexibility connection. However, for the braced frame the effect of the initial connection stiffness parameter on the response quantity can be neglected due to present of the braces. Furthermore, the higher the initial connection stiffness parameter, the smallest the story drift index. Moreover, the present of the braces at the moment resisting frame (braced frame) reduce the sensitivity of the connection stiffness on the behaviour and the performance frame under consideration.

scholarly journals Improving resilience of moment frames using steel pipe dampers

2018 ◽  
Vol 195 ◽  
pp. 02014
Author(s):  
Junaedi Utomo ◽  
Antonius
Keyword(s):  
Numerical Study ◽  
Steel Pipe ◽  
Frame Structures ◽  
Earthquake Risk ◽  
Moment Frames ◽  
Moment Frame ◽  
Story Drift ◽  
Moment Resisting ◽  
Lateral Displacements ◽  
The Moment

Earthquake resiliency of moment resisting frames, either new or existing ones, are important for maintaining community functionality. Improving earthquake resiliency needs a strong initiative in reducing earthquake risk. Steel pipe dampers can be used to increase earthquake resiliency. Steel pipe dampers, when installed at strategic locations in the moment frame structures, dissipate most of the earthquake energy in structures through inelastic deformation so that other components of the structure are protected. Steel pipe dampers control vibration in moment frame structures and are a disposable component in structures so that the damaged dampers can be replaced easily. Steel pipe dampers are cheap and require low workmanship, therefore the recovery time after disasters is short and the cost of recovery is low. Utilizing steel pipe dampers in passive energy dissipation systems help maintain community functionality during and after disasters. Lateral displacements were quantified and used as performance indicators. Significant drift and inter story drift reduction were achieved during a numerical study. All structural components, except the steel pipe dampers, remain elastic, indicating the effectiveness of the dampers in reducing the losses due to earthquakes.

scholarly journals An elastoplastic finite element study of cylindrical plane-strain contact for steel/steel and Inconel 617/Incoloy 800H undergoing unidirectional sliding

2019 ◽  
Vol 234 (1) ◽  
pp. 126-133
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Coefficient Of Friction ◽  
Tangential Force ◽  
Leading Edge ◽  
Effective Coefficient ◽  
Incoloy 800H ◽  
Inconel 617 ◽  
Von Mises ◽  
Sliding Distance

The current work employs a two-dimensional plane strain finite element analysis to investigate the unidirectional sliding contact between a deformable half-cylinder and a deformable flat block. The unidirectional sliding is governed by a displacement-controlled action where the materials of the two contacting bodies are first set to identical steels at 20 ℃ and then to Inconel 617 and Incoloy 800H at 800 ℃. First, a normal interference (indentation) is applied, which is followed by unidirectional sliding. The von Mises stress distribution, plastic strain distribution, junction growth, normal force, tangential force, effective coefficient of friction, and scars on the surface of the block are obtained during the sliding motion. The leading edge of the contacting area and the bulk material under the leading edge experience large von Mises stresses. The large plastic strain is found on the surface of the block, and forms a “pocket” shape under the surface. The junction growth is also investigated, showing the direction of the growth is in the same direction of the tangential force that the weaker material experiences. The forces and the effective coefficient of friction are found to stabilize after a certain sliding distance, and the effective coefficient of friction converges to the coefficient of friction used in the model. Pileup is found on the surface of the block after a sufficient unidirectional sliding distance.

Structural Behaviour of Blind Bolted Connection to Concrete-Filled Steel Tubular Columns

2010 ◽  
Vol 163-167 ◽  
pp. 591-595
Author(s):  
Jing Feng Wang ◽  
Xin Yi Chen ◽  
Lin Hai Han
Keyword(s):  
Analysis Model ◽  
Bolted Connections ◽  
Structural Behaviour ◽  
Tubular Columns ◽  
End Plate ◽  
Moment Resisting ◽  
Strength And Stiffness ◽  
Plate Connections ◽  
The Moment ◽  
Plate Connection

This paper studies structural behaviour of the blind bolted connections to concrete-filled steel tubular columns by a serial of experimental programs, which conducted involving eight sub-assemblages of cruciform beam-to-column joints subjected to monotonic loading and cyclic loading. The moment-rotation hysteretic relationships and failure models of the end plate connections have been measured and analyzed. A simplified analysis model for the blind bolted connections is proposed based on the component method. It is concluded that the blind bolted end plate connection has reasonable strength and stiffness, whilst the rotation capacity of the connection satisfies the ductility requirements for earthquake-resistance in most aseismic regions. This typed joint has excellent seismic performance, so it can be used in the moment-resisting composite frame.

Interpretation of significant ground-response and structure strong motions recorded during the 1994 Northridge earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S231-S246 ◽  
Author(s):  
A. F. Shakal ◽  
M. J. Huang ◽  
R. B. Darragh
Keyword(s):  
Flexible Structures ◽  
Northridge Earthquake ◽  
Moment Frame ◽  
Ground Response ◽  
Short Period ◽  
Frame Buildings ◽  
Story Drift ◽  
San Fernando ◽  
San Fernando Valley ◽  
The Moment

Abstract Some of the largest accelerations and velocities ever recorded at ground-response and structural sites occurred during the Northridge earthquake. These motions are greater than most existing attenuation models would have predicted. Although the motions are large, the correspondence between measured acceleration and damage requires further study, since some sites with high acceleration experienced only moderate damage. Also, some peak vertical accelerations were larger than the horizontal, but in general, they are smaller and fit the pattern observed in previous earthquakes. Strong-motion records processed to date show significant differences in acceleration and velocity waveforms and amplitudes across the San Fernando Valley. Analysis of processed data from several buildings in the San Fernando Valley indicates that short-period buildings such as shear-wall buildings experienced large forces and relatively low inter-story drift during the Northridge earthquake. However, long-period (1 to 5 sec) steel or concrete moment-frame buildings experienced large inter-story drift. For this earthquake, accelerations did not always amplify from base to roof for flexible structures like the moment-frame buildings, but the displacements were always larger at the roof. The drifts at many of the moment-frame buildings were larger than the drift limit for working stress design in the building code. The records from a base-isolated building indicate that high-frequency motion was reduced significantly by the isolators. The isolators deformed about 3.5 cm, which is much less than the design displacement. The records from a parking structure show important features of the seismic response of this class of structure.

scholarly journals COMPARATIVE STUDY OF THE BEHAVIOUR OF BUILDING STRUCTURE OF HOTEL DAFAM LOTUS JEMBER BY USING MOMENT RESISTING FRAME AND ECCENTRICALLY BRACED FRAME

2018 ◽  
Vol 2 (01) ◽  
pp. 13
Author(s):  
Reza Kurniawan ◽  
Dwi Nurtanto ◽  
Gati Annisa Hayu
Keyword(s):  
Axial Force ◽  
Shear Force ◽  
Steel Structure ◽  
System Structure ◽  
Braced Frame ◽  
Eccentrically Braced Frame ◽  
Moment Resisting Frame ◽  
Concentrically Braced Frame ◽  
Moment Resisting ◽  
Short Link

Eccentrically Braced Frame (EBF) is one of several types of braces that can be used in steel building. EBF has a good stiffness and ductility to withstand earthquake load. In EBF itself there are 3 types of links, namely: Long Link, Intermediate Link, and Short Link. Meanwhile, MRF of Moment resisting Frame is a structural system where the beams and columns are connected rigidly. MRF has a good ductility in accepting load even it has no lateral braces installed. In this research the Dafam Lotus Jember hotel consisting of 10 floors with total height of 33,6 m is modeled as a MRF system structure and steel structure equipped with EBF short link. The objective of this research is to compare the effectiveness of EBF and MRF in terms of displacement, axial force, shear force, and moment occurring in buildings. The modeling results show that EBF with short link has smaller displacement value compared to MRF. The difference between the two is 86,99%. In terms of axial force, shear force, and moment, EBF has smaller values than MRF. The differences are 79,76%, 53,91%, and 10,48% respectively. These results indicate that EBF has better capacity compared to MRF. Indonesia merupakan negara yang memiliki tingkat intensitas kegempaan yang tinggi. Ini menjadikan Indonesia tidak terhindarkan dari dampak negatif yang akan ditimbulkan oleh gempa bumi, yaitu menyebabkan kerusakan insfrastruktur fisik. Peraturan gempa SNI 03-1726-2012 membahas mengenai bresing sebagai salah satu alternatif yang dapat digunakan untuk menangani masalah gempa. Eccentrically Braced Frame (EBF) adalah salah satu jenis bresing yang memiliki kekakuan dan daktilitas yang baik jika dibandingkan dengan Concentrically Braced Frame (CBF) yang hanya memiliki kekakuan yang baik. Selain itu terdapat pula Moment Resisting Frame (MRF) yaitu salah satu sistem struktur yang memiliki sifat daktail. Melihat permasalahan yang ada, maka pembahasan ini bertujuan untuk membandingkan efektivitas dari EBF menggunakan short link dengan MRF apabila diaplikasikan pada bangunan Hotel Dafam Lotus Jember 10 lantai yang memiliki tinggi 33,6 m. Adapun efektivitas yang dibadingkan disini adalah nilai story displacement dan gaya dalam (momen, gaya geser, dan gaya aksial) yang terjadi. Hasil analisa dengan bantuan program analisa struktur menunjukkan bahwa EBF menggunakan short link memiliki nilai yang lebih kecil dibandingkan dengan MRF dalam menerima beban yang bekerja. Dari segi story displacement, selisih prosentasenya adalah 86,99% sedangkan untuk gaya dalam yang meliputi momen, gaya geser, dan gaya aksial, selisihnya secara berturut-urut adalah 79,76%, 53,91% dan 10,48%. Hal ini menunjukkan bahwa EBF menggunakan short link lebih efektif jika dibandingkan dengan MRF.

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