Plastic hinge relocation in moment-resisting frames using CFRP retrofit

2015 ◽  
Author(s):  
Pang Jen Lim
Keyword(s):  
Plastic Hinge ◽  
Moment Resisting Frames ◽  
Moment Resisting

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 Assessment of plastic hinge in RC structures with and without shear walls applying pushover analysis

2020 ◽  
Vol 1 (1) ◽  
pp. 11-18
Author(s):  
Jean Pierre Lukongo Ngenge ◽  
Abdallah M. S. Wafi
Keyword(s):  
Plastic Hinge ◽  
Pushover Analysis ◽  
Computer Software ◽  
Shear Walls ◽  
Span Length ◽  
Base Shear ◽  
Rc Structures ◽  
High Rise ◽  
Moment Resisting Frames ◽  
Moment Resisting

This paper gives a brief presentation about different types of analysis, plastic hinge, moment-resisting frames (MRFs) and shear walls (SWs) in reinforced concrete (RC) Structures. ETABS computer software is employed to model and analyse the structures applying the pushover. The performances of the modelled structures are also evaluated considering different parameters such as the number of stories, spans length, shear walls, reinforcement yield strength and characteristic strength of concrete. The study includes two cases, which are moment-resisting frames with and without shear walls (i.e. MRFs and MRF-SWs, respectively). Each case covers low-, mid- and high-rise buildings. In this regard, a comparative study has been performed for the results obtained from all models. It was observed that the stiffness of MRFs compared to MRF-SWs was less and also the stiffness of low-rise frames was higher than that of mid-rise and high-rise frames. Technically this means that a low-rise building is stiffer than a mid-rise building and a mid-rise building is stiffer than a high-rise building. Additionally, when the span length increases, the stiffness of the building decreases. Therefore, it can be concluded that the span length is inversely proportional to the stiffness. Finally, all stiffness values were calculated taking into consideration the displacement and base shear at the first hinge formation on the pushover curve of each model.

scholarly journals Plastic hinge assessment of RC moment-resisting frames

2020 ◽  
Vol 1 (3) ◽  
pp. 37-41
Author(s):  
Mahmoud Alhassan ◽  
Mohamad Abdelrahim
Keyword(s):  
Plastic Hinge ◽  
Pushover Analysis ◽  
Computer Software ◽  
Elastic Stiffness ◽  
Frame Structure ◽  
Nonlinear Static Analysis ◽  
Rc Structures ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Fundamental Reason

This paper gives a short introduction about various kinds of analysis, plastic hinges, moment-resisting frames (MRFs) in RC Structures. It likewise gives computer software ETABS displaying and an investigation of structures concerning Pushover Analysis. The fundamental reason for this examination is to apply a push to all models, analyse and get a reasonable thought regarding their behaviour. The behaviour of these structures likewise was evaluated considering various variables such as the changes in the number of floors, spans length, reinforcements' yield strength and characteristic strength of concrete. This investigation incorporates the moment-resisting frames (MRFs) having 4, 7, and 10 storeys and a relative report for all models' outcomes. Pushover analysis is a nonlinear static analysis used to determine the relationship between strength and displacement in order to evaluate the performance of the RC frame structure. It was found that the plastic hinge may be assessed using parameters such as span lengths and the number of storeys. When the number of storeys increases, the elastic stiffness value decreases and when the span length increases the elastic stiffness also decreases. The collapse of members happens only when there is a formation of 3 hinge mechanisms. Plastic hinge colours have been given, and each colour has its significance to permit a good design.

scholarly journals A Review on the Plastic Hinge Characteristics of Beam-Column Joints in RC Moment Resisting Frames

2021 ◽  
Author(s):  
Surya SS ◽  
R Sajeeb
Keyword(s):  
Plastic Hinge ◽  
High Strength ◽  
Joint Interface ◽  
Careful Study ◽  
Plastic Hinges ◽  
Moment Resisting Frames ◽  
Extreme Loads ◽  
Moment Resisting ◽  
Column Joint ◽  
Joint Behavior

The behavior of beam-column joints plays a crucial role in the performance of Reinforced Concrete (RC) moment-resisting frames in earthquake-prone areas. In beam-column joints with high strength concrete and shear reinforcement in joints, the plastic hinge is formed at the beam-column joint interface, which is an undesirable failure mode. Predicting the behavior of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquake plays an important role in assessing maximum stable deformation capacities of framed concrete structures. The present paper reviews the plastic hinge characteristics of beam-column joints of RC moment-resisting frames. A careful study and understanding of joint behavior are essential to arrive at a proper judgment of the design of joints. Various types of joints and the influence of bond strength characteristics, forces acting on joints, reinforcement detailing, and the concept and formation of plastic hinges in the joints are thoroughly reviewed.

scholarly journals Ductility demand for uni-directional and reversing plastic hinges in ductile moment resisting frames

1999 ◽  
Vol 32 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Richard Fenwick ◽  
Raad Dely ◽  
Barry Davidson
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Simple Relationship ◽  
Plastic Hinges ◽  
Ductility Demand ◽  
Displacement Ductility ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Negative Moment ◽  
Unidirectional Plastic

In a major earthquake the beams in moment resisting frames may develop either reversing or unidirectional plastic hinges. The form of plastic hinge depends upon the ratio of the moments induced by the gravity loading to those induced by the seismic actions. Where this ratio is low the plastic hinges form at the ends of the beams and the sign of the inelastic rotation changes with the direction of sway. These are reversing plastic hinges, and the magnitude of the rotation that they sustained is closely related to the inter-storey displacement. However, when the moment ratio exceeds a certain critical value, unidirectional plastic hinges may form. In this case negative moment plastic hinges develop at the column faces and the positive moment plastic hinges form in the beam spans. As the earthquake progresses the positive and negative inelastic rotations accumulate in their respective zones so that peak values are always sustained at the end of the earthquake. With this type of plastic hinge no simple relationship exists between inter-storey drift and inelastic rotation. Several series of time history analyses have been made to assess the relative magnitudes of inelastic rotation that are imposed on the two forms of plastic hinge. It is found that with design level earthquakes typically the unidirectional plastic hinge is required to sustain 21/ 2 to 4 times the rotation imposed on reversing plastic hinges, with the curvature ductilities ranging up to 140. These values are appreciably in excess of the values measured in tests using standard details. This indicates that in structures where unidirectional plastic hinges may form, the design displacement ductility and or the allowable inter-storey drift should be reduced below the maximum values currently permitted in the New Zealand codes. The problems associated with the formation of unidirectional plastic hinges can be avoided by adding positive moment flexural reinforcement in the mid regions of the beams. By this means the potential positive moment plastic hinges can be restricted to the beam ends.

scholarly journals Some possible revisions to the seismic provisions of the New Zealand concrete design code for moment resisting frames

1992 ◽  
Vol 25 (1) ◽  
pp. 37-43
Author(s):  
P. C. Cheung ◽  
T. Paulay ◽  
R. Park
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Plastic Hinge ◽  
Design Code ◽  
Concrete Frames ◽  
Rational Models ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Column Joint ◽  
Experimental And Theoretical Studies

Possible revisions to the seismic design provisions of the New Zealand concrete design code NZS 3101: 1982 for ductile reinforced concrete moment resisting frames are discussed. Topics include shear reinforcement for beam-column joint cores, anchorage of longitudinal reinforcement passing through beam-column joint cores, and transverse reinforcement in columns for confinement in potential plastic hinge regions of columns. The recommendations are based on recent experimental and theoretical studies of the simulated seismic response of beam-column joints and columns in ductile reinforced concrete frames. Rational models for the evaluation of behaviour are presented.

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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