scholarly journals Floors number influence on the instability parameter of reinforced concrete frame-braced buildings

2019 ◽  
Vol 12 (5) ◽  
pp. 1034-1057
Author(s):  
R. J. ELLWANGER
Keyword(s):  
Reinforced Concrete ◽  
Analytical Study ◽  
Shear Stiffness ◽  
Physical Nonlinearity ◽  
Reinforced Concrete Frame ◽  
Lateral Deflection ◽  
Order Analysis ◽  
Concrete Frame ◽  
Instability Parameter ◽  
Method Accuracy

Abstract This work aims to investigate the floors number influence on the instability parameter limit α1 of reinforced concrete frame-braced buildings; it succeeds another work in this field of knowledge, in which the same question was investigated for wall- and core-braced buildings. Initially, it is showed how the ABNT NBR 6118:2014 (Brazilian code for concrete structures design) defines when a second order analysis is needed. Topics concerning to physical nonlinearity consideration and to the lateral deflection components of frames are also presented. It follows an analytical study that led to the derivation of a method for determining the limit α1 as a function of the floors number and the relation between bending and shear stiffness. Finally, some examples are presented and their results are used for checking the method accuracy.

scholarly journals Shear model with shear-flexure interaction for non-linear analysis of reinforced concrete frame element

2018 ◽  
Vol 192 ◽  
pp. 02003
Author(s):  
Worathep Sae-Long ◽  
Suchart Limkatanyu
Keyword(s):  
Reinforced Concrete ◽  
Interaction Effect ◽  
Plastic Hinge ◽  
Shear Stiffness ◽  
Reinforced Concrete Frame ◽  
Shear Model ◽  
Concrete Frame ◽  
Frame Element ◽  
Proposed Model ◽  
Frame System

This paper presents the shear constitutive model for the reinforced concrete (R/C) frame structures analysis under monotonic and cyclic loading. The proposed model is adopted and modified from Mergos and Koppos model [1] that accounts the shear stiffness degradation effect by the shear-flexure interaction in the plastic hinge region. Firstly, the proposed shear model starts from the primary curve without the damages due to the shear-flexure interaction effect. Then, the shear-flexure interaction effect is taken into consideration at the locations of plastic hinges and this effect leads to the degradation of the shear strength and shear stiffness on the undamaged primary curve that is replaced with the damaged primary curve. To determine the sectional shear stiffness with the shear-flexure interaction, an alternative way of the iterative procedure is proposed here. Finally, a numerical example is used to verify the characteristics and behavior of the R/C frame system and confirm accuracy and computational efficiency of the proposed model among the experimental data.

scholarly journals Floors number influence on the instability parameter of reinforced concrete wall- or core-braced buildings

2013 ◽  
Vol 6 (5) ◽  
pp. 783-796 ◽  
Author(s):  
R. J. Ellwanger
Keyword(s):  
Reinforced Concrete ◽  
Analytical Study ◽  
Concrete Structures ◽  
Concrete Wall ◽  
Concrete Walls ◽  
Order Analysis ◽  
Reinforced Concrete Walls ◽  
Continuous Models ◽  
Reinforced Concrete Wall ◽  
Instability Parameter

This work aims to investigate the floors number influence on the instability parameter limit α1 of buildings braced by reinforced concrete walls and/or cores. Initially, it is showed how the Beck and König discrete and continuous models are utilized in order to define when a second order analysis is needed. The treatment given to this subject by the Brazilian code for concrete structures design (NBR 6118) is also presented. It follows a detailed analytical study that led to the derivation of equations for the limit α1 as functions of the floors number; a series of examples is presented to check their accuracy. Results are analyzed, showing the precision degree achieved and topics for continuity of research in this field are indicated.

Stiffness of Reinforced Concrete Frame Joint

2015 ◽  
Vol 769 ◽  
pp. 107-111
Author(s):  
Ivana Veghova
Keyword(s):  
Reinforced Concrete ◽  
Shear Stiffness ◽  
Tension Test ◽  
Seismic Load ◽  
Shear Stresses ◽  
Reinforced Concrete Frame ◽  
Maximum Tension ◽  
Concrete Frame ◽  
Simple Tension ◽  
Tension Strength

In the design of multi-storey frame structures, there is a question of a proper evaluation of the stiffness of reinforced concrete frame joints. This problem is very important especially in the case of structures subjected to seismic load, where the forces act repeatedly. Concrete is able to carry the compression stresses and partially the shear stresses. The tension stresses can reach only low level. The maximum tension stresses (tension strength) obtained from simple tension test of the concrete are not the same as the maximum tension stresses in the reinforced concrete. The shear stiffness is the matter of the width of the concrete cracks. To improve the knowledge in this field, the experimental verification of the reinforced concrete frame joint had been arranged.

scholarly journals Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System

2020 ◽  
Vol 12 (24) ◽  
pp. 10360
Author(s):  
Hyun-Do Yun ◽  
Sun-Woong Kim ◽  
Wan-Shin Park ◽  
Sun-Woo Kim
Keyword(s):  
Reinforced Concrete ◽  
Shear Behavior ◽  
Seismic Retrofitting ◽  
Reinforced Concrete Frame ◽  
Main Research ◽  
Torsion Spring ◽  
Concrete Frame ◽  
Energy Dissipation Capacity ◽  
Research Questions ◽  
Torsion Springs

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.

Deformation Characteristics of Reinforced Concrete Beam-Column Joint Cores under Earthquake Loading

2003 ◽  
Vol 6 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Sayed A. Attaalla ◽  
Mehran Agbabian
Keyword(s):  
Reinforced Concrete ◽  
Shear Deformation ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Frame ◽  
Bond Failure ◽  
Strain Compatibility ◽  
Concrete Frame ◽  
Column Joint ◽  
Reinforced Concrete Frame Structures

The characteristics of the shear deformation inside the beam-column joint core of reinforced concrete frame structures subjected to seismic loading are discussed in this paper. The paper presents the formulation of an analytical model based on experimental observations. The model is intended to predict the expansions of beam-column joint core in the horizontal and vertical directions. The model describes the strain compatibility inside the joint in an average sense. Its predictions are verified utilizing experimental measurements obtained from tests conducted on beam-column connections. The model is found to adequately predict the components of shear deformation in the joint core and satisfactorily estimates the average strains in the joint hoops up to bond failure. The model may be considered as a simple, yet, important step towards analytical understanding of the sophisticated shear mechanism inside the joint and may be implemented in a controlled-deformation design technique of the joint.

Resistance of Reinforced Concrete Frames with Masonry Infill Walls to In-Plane Vertical Loading

2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Progressive Collapse ◽  
Lateral Loading ◽  
Masonry Walls ◽  
Reinforced Concrete Frame ◽  
Masonry Infill ◽  
Concrete Frame ◽  
Vertical Loading ◽  
Infill Masonry

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.

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