scholarly journals Effect of Configuration and Yield Strength of Transverse Reinforcement on Lateral Confinement of RC Columns

2021 ◽  
Vol 11 (15) ◽  
pp. 6696
Author(s):  
Min-Jun Kim ◽  
Bum-Sik Lee ◽  
Dong-Hwan Kim ◽  
Sang-Pil Han ◽  
Kil-Hee Kim
Keyword(s):  
Yield Strength ◽  
Cross Sections ◽  
Plastic Hinge ◽  
Transverse Reinforcement ◽  
Seismic Loads ◽  
Rc Columns ◽  
Lateral Confinement ◽  
Flexural Failure ◽  
Hinge Zone ◽  
Ductile Behavior

In general, the lateral confinement capacity of RC columns is influenced by the strength and configuration of transverse reinforcement. In this study, performed antisymmetric flexural moment experiments that simulated seismic loads, with the configuration and yield strength of the transverse reinforcement of RC square columns as main variables. The eight specimens were square cross-sections measuring 250 × 250 mm, and the lateral confinement effect in relation to main variables was examined by inducing flexural failure in the plastic hinge zone under a shear span-to-depth ratio (a/D) of 3.0. Transverse reinforcements comprised a square and octagonal S-series and tie-based H-series. The yield strengths of the transverse reinforcements were 453 MPa and 1053 MPa, respectively. Compared to the H-series, the S-series, whose configuration of transverse reinforcement is closer to a circular form, exhibited more prominent ductile behavior after flexural yield with increasing yield strength of transverse reinforcement, which indicates greater lateral confinement.

Transverse reinforcement for confinement at plastic hinge of circular composite hollow RC columns

2016 ◽  
Vol 17 (3) ◽  
pp. 387-406
Author(s):  
Deok Hee Won ◽  
Taek Hee Han ◽  
Seungjun Kim ◽  
Woo-Sun Park ◽  
Young Jong Kang
Keyword(s):  
Plastic Hinge ◽  
Transverse Reinforcement ◽  
Rc Columns

scholarly journals Experimental Research on Reinforced Concrete Columns Strengthened with Steel Jacket and Concrete Infill

2021 ◽  
Vol 11 (9) ◽  
pp. 4043
Author(s):  
Aleksandar Landović ◽  
Miroslav Bešević
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Experimental Research ◽  
Failure Modes ◽  
Steel Tube ◽  
Rc Columns ◽  
Rc Column ◽  
Steel Jacket ◽  
Ductile Behavior

Experimental research on axially compressed columns made from reinforced concrete (RC) and RC columns strengthened with a steel jacket and additional fill concrete is presented in this paper. A premade squared cross-section RC column was placed inside a steel tube, and then the space between the column and the tube was filled with additional concrete. A total of fourteen stub axially compressed columns, including nine strengthened specimens and five plain reinforced concrete specimens, were experimentally tested. The main parameter that was varied in the experiment was the compressive strength of the filler concrete. Three different concrete compression strength classes were used. Test results showed that all three cross-section parts (the core column, the fill, and the steel jacket) worked together in the force-carrying process through all load levels, even if only the basic RC column was loaded. The strengthened columns exhibited pronounced ductile behavior compared to the plain RC columns. The influence of the test parameters on the axial compressive strength was investigated. In addition, the specimen failure modes, strain development, and load vs. deformation relations were registered. The applicability of three different design codes to predict the axial bearing capacity of the strengthened columns was also investigated.

Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns

2013 ◽  
Vol 671-674 ◽  
pp. 1319-1323
Author(s):  
Zi Xue Lei ◽  
Yu Hang Han ◽  
San Sheng Dong ◽  
Jun Qing Guo
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Pushover Analysis ◽  
Seismic Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Rc Column ◽  
Rc Frames ◽  
Load Carrying

A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.

Strengthening of RC columns with inadequate transverse reinforcement

2004 ◽  
pp. 211-218 ◽  
Author(s):  
O Peker ◽  
A Ilki ◽  
N Kumbasar ◽  
V Koc ◽  
E Karamuk
Keyword(s):  
Transverse Reinforcement ◽  
Rc Columns

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

2019 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bars congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables are transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns are compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility only can be obtained with lower amount of transverse reinforcement when high-strength transverse reinforcements are used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement can improve bearing capacity and post-peak deformability of concrete columns. Besides, three different equivalent rectangular stress block (ERSB) parameters in predicting bearing capacity of columns with high-strength steel were discussed based on test and simulated results. It is concluded that the Code of GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas bearing capacities computed using Codes of ACI 318-14 and CSA A23.3-04 agree well with test results.

scholarly journals Inelastic behavior of reinforced concrete cantilever beam with embedded steel truss in flexural plastic hinge under cyclic loading

2019 ◽  
Vol 258 ◽  
pp. 04007
Author(s):  
Fatmawati Amir ◽  
Iman Satyarno ◽  
Djoko Sulistyo
Keyword(s):  
Cyclic Loading ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Hysteretic Behavior ◽  
Inelastic Behavior ◽  
Plastic Hinges ◽  
Laboratory Test Results ◽  
Steel Truss ◽  
Shear Failures ◽  
Ductile Behavior

Structures are expected to have ductile behavior under major earthquakes. One requirement to achieve this ductile behavior is when the structures have no shear failures in their elements. This paper discusses a new method by using the embedded steel truss in the flexural plastic hinges of beam to avoid shear failure. As already known that the shear strength provided by the concrete will be decreased when the ductility of flexural plastic hinges develop in a member. Therefore, a conservative procedure by ignoring the role of concrete in flexural plastic hinges in resisting the shear demand is adopted by some codes. This will increase the demand for shear reinforcement provided by the stirrup or transverse reinforcement in the plastic hinge; yet it still does not ensure that the shear failure does not come to happen. From the laboratory test results under cyclic loading in this study, it can be noted that the beam with embedded steel truss in the plastic hinge has better hysteretic behavior than the one without the embedded steel truss. The evaluation of test result is also shown the strength of the beam with the embedded steel truss in the plastic hinge is not reduced with an increase in the amplitude of the drift of 1.4 to 3.5. Besides, the strength of the beam without embedded steel truss in the plastic hinge is reduced with an increase in the amplitude of the drift after reaching 2.5.

scholarly journals Premature destruction of two-span RC beams exposed to high temperature caused by a redistribution of shear forces

2016 ◽  
Vol 23 (4) ◽  
pp. 431-439 ◽  
Author(s):  
Robert KOWALSKI ◽  
Michał GŁOWACKI ◽  
Marian ABRAMOWICZ
Keyword(s):  
High Temperature ◽  
Cross Sections ◽  
Bending Moment ◽  
Middle Part ◽  
Transverse Reinforcement ◽  
Shear Load ◽  
Bending Moments ◽  
Rc Beams ◽  
Shear Forces ◽  
Load Bearing Capacity

When multi-span RC elements are exposed to fire one usually observes a yielding of span cross-sections while a safety reserve of support cross-sections is still significant. Due to this phenomenon a redistribution of bending moments occurs and the values of sagging moment in span cross-sections decrease while the values of hogging moment in support cross-sections increase. This paper shows the results of tests conducted on two-span RC beams in a situation when only one span has been exposed to high temperature from the bottom. The beams were 12×16 cm in their cross-section. The length of the span was 165 cm. The load has been applied by two forces put on each span. The beams were made of C25/30 concrete with siliceous aggregate. As a result of significant stiffness decrease of the heated span, redistribution of shear forces and bending moment occurs. Due to this redistribution the tested beams were prematurely damaged due to exhaust of the shear load bearing capacity in the middle part of the beam span where there was no transverse reinforcement.

scholarly journals Assessment of Standards and Codes Dedicated to CFRP Confinement of RC Columns

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2390 ◽  
Author(s):  
Stefan Kaeseberg ◽  
Dennis Messerer ◽  
Klaus Holschemacher
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Rupture Strength ◽  
Axial Strain ◽  
Design Guidelines ◽  
International Standards ◽  
National Standards ◽  
Rc Columns ◽  
New Findings ◽  
Cfrp Confinement

Reinforced concrete (RC) columns are often placed under confinement to increase their strength and ductility. Carbon fiber reinforced polymer (CFRP) materials have recently been recognized as favorable confinement systems. At present, a number of national standards and codes dedicated to the design of concrete components strengthened with CFRP in general and CFRP confinement in particular are available. These sets of rules provide design equations for confined reinforced concrete columns with circular and rectangular cross sections. Most of the standards and codes exhibit significant differences, including the used predictive models, limitations, observed effects and covered loading conditions. In this paper, five international standards and design guidelines are introduced and discussed. The purpose is to present a constructive and critical assessment of the state-of-the-art design methodologies available for CFRP confined RC columns and to discuss effects not previously considered properly. Therefore, some recent research efforts and findings from the Leipzig University of Applied Sciences are also introduced. The obtained data is used for a comparative study of the guideline predictive equations. Furthermore, it is shown that some new findings concerning the rupture strength and the maximum strength plus accompanying axial strain of a CFRP confined column are suitable to improve the current guidelines.

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2139 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bar congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables were the transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns were compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility could only be obtained with a lower amount of transverse reinforcement when high-strength transverse reinforcements were used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement improved the bearing capacity and post-peak deformability of the concrete columns. Furthermore, three different equivalent rectangular stress block (ERSB) parameters for predicting the bearing capacity of columns with high-strength steel are discussed based on test and simulated results. It is concluded that the China Code GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas the bearing capacities computed using the America Code ACI 318-14 and Canada Code CSA A23.3-04 agree well with the test results.

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