Behavior of circular RC columns with two layers of spirals

Sun, Lijun; Wu, Dongyan; Zhao, Junliang; Yang, Fang; Li, Wei

doi:10.1007/s12205-016-0928-0

Cited by 10 publications

(7 citation statements)

References 14 publications

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“…The effects of the inner stirrups and outer stirrups on core concrete are different. To simplify the calculation, according to area weighting of core concrete confined with single‐layer stirrups and two‐layer stirrups, the average effective confinement stress is adopted:

\begin{matrix} lefttrue \\ f_{l, eff}^{'} = \frac{A_{italicout} f_{l, eff}^{'} + A_{italicin} (f_{l, out}^{'} + f_{l, in}^{'})}{A_{cc}} \\ = f_{l, out}^{'} + \frac{A_{in}}{A_{cc}} f_{l, in}^{'} = f_{l, out}^{'} + α f_{l, in}^{'}, \end{matrix}

where

f_{l, italicout}^{'}

and

f_{l, italicin}^{'}

are the effective confinement pressures due to the outer and the inner stirrups, respectively; A out and A in are the areas of the singly confined and doubly confined concrete, respectively; A cc = A out + A in is the area of the concrete core; and α = A in / A cc is the ratio of A in and A cc .…”

Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

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Seismic performance of reinforced concrete columns confined with two layers of stirrups

Sun

Zhao

et al. 2018

Structural Design Tall Build

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Summary This paper presents an experimental study on seismic behavior of reinforced concrete columns confined with 2 layers of stirrups. Six specimens, namely, 3 square‐section columns and 3 circular‐section columns, were manufactured using 2 layers of high‐strength stirrups. They were tested under cyclic lateral loading. The main parameters under investigation were the cross‐section type and stirrup spacing. The seismic behavior of the test specimens was analyzed in terms of various factors: load–displacement relationship, strength and stiffness degradation, ductility, and dissipated energy. The test results indicate that in general, all tested specimens exhibited very ductile behavior and dissipated energy. They presented a flexural failure mode, and the strength and stiffness degradation of the postelastic stage was not obvious. The results also indicate that a DCS square‐section column exhibited lower lateral displacement capacity than that of a companion DCC circular‐section column with the same stirrup spacing. Furthermore, on the basis of principles of equilibrium and compatibility of strains as well as ACI code, we developed equations to estimate the seismic bending moment capacity, accounting for the confinement effect of 2 layers of high‐strength stirrups. The calculated solutions were then compared with the test results, and the relationships were observed with reasonable accuracy for engineering applications.

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\begin{matrix} lefttrue \\ f_{l, eff}^{'} = \frac{A_{italicout} f_{l, eff}^{'} + A_{italicin} (f_{l, out}^{'} + f_{l, in}^{'})}{A_{cc}} \\ = f_{l, out}^{'} + \frac{A_{in}}{A_{cc}} f_{l, in}^{'} = f_{l, out}^{'} + α f_{l, in}^{'}, \end{matrix}

where

f_{l, italicout}^{'}

and

f_{l, italicin}^{'}

Section: Analysis Of Experimental Resultsmentioning

confidence: 99%

“…The effects of the inner stirrups and outer stirrups on core concrete are different. To simplify the calculation, according to area weighting of core concrete confined with single-layer stirrups and two-layer stirrups, the average effective confinement stress is adopted [12][13][14] :…”

Section: Confinement Effect Of Stirrupsmentioning

confidence: 99%

Seismic performance of reinforced concrete columns confined with two layers of stirrups

Sun

Zhao

et al. 2018

Structural Design Tall Build

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“…Chen et al [12] and Sun et al [13] discussed the compressive behavior of reinforced concrete columns confined by multispiral hoops, which showed the strength and ductility of the column can be greatly enhanced due to better confinement. Inspired by this approach, we design a new type of column, namely, stirrup confinement rectangular CFT stub column (CCFT), to overcome the shortage of conventional CFT stub columns and steel-reinforced concrete columns.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Axially Loaded Stirrup Confinement Rectangular Concrete‐Filled Steel Tubular Stub Columns

Liu

Wang

Ding

et al. 2019

Advances in Civil Engineering

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is article presents the experimental and finite element (FE) analyses of two conventional rectangular concrete-filled steel tubular (CFT) stub columns, two stiffened rectangular concrete-filled steel tubular (SCFT) stub columns, and two stirrup confinement rectangular concrete-filled steel tubular (CCFT) stub columns concentrically loaded in compression to failure. e influences of the ductility and ultimate bearing strength of these stub columns with stiffening ribs or spiral stirrup confinement were discussed. Abaqus was used to establish a 3D FE model and analyze the properties of CFT stub columns subjected to axial compression. e effect of the concrete core and rectangular steel tube under loop stirrup confinement was discussed. Analytical results showed that spiral stirrup confinement can availably retard the local bucking of the rectangular steel pipe, and the effect of the spiral stirrup confinement was stronger than that of stiffeners. e DI values of SCFT and CCFT were 21.9% and 31.9% larger than those of CFT, respectively. e ultimate capacity values of SCFTand CCFT were 10.2% and 18% larger than those of CFT, respectively. e ductility and ultimate bearing strength of the specimens improved effectively under spiral stirrup confinement, and the ductility of the CCFT columns was preferable to that of the SCFT columns.

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“…In the recent past a rapid constructional development along with a phenomenal rise in the construction of earth quake resistant structures have come up. The reinforced concrete columns confined with two layers of lateral hoops or ties have also been new concepts inferred from recent studies that would enhance the ductility and strength of columns in [2] and [3].…”

Section: Introductionmentioning

confidence: 99%

“…Although a few very fine researchers on assessment of doubly confined concrete columns exists. None of them has applied Non Destructive methods of testing e.g., researches in [3], [22], [23], [24] and [25]. Further the authors' current research provides an opportunity studying the impact upon largest number of samples so far.…”

Section: Introductionmentioning

confidence: 99%

Reliability of Non-Destructive Testing Methods in the Assessment of the Strength of Concrete Columns Reinforced with Two Layers of Transverse Confining Stirrups: Empirical Evidence

Kumar¹,

Zaidi²,

Jain³

et al. 2019

IJRTE

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Wide spread literature is available on the approach to assess the strength of Reinforced Concrete structures. However no attention has been made so far to study the similar potential when the RC columns are reinforced with double layer of transverse confining stirrups. An obvious reason could be that studies in double layered stirrups options are quite at their infancy. The authors took the advantage of their involvement in studying the axial compression behaviour in terms of strength and ductility of concrete columns reinforced with double layered transverse confining stirrups, applied the two non-destructive measures, viz., Rebound Hammer Test Method (RHTM) and Ultrasonic Pulse Velocity Test Technique (UPVTT), and destructive testing measure, viz., Compression Testing Method (CTM) on the specimens that they have developed in this study. The results have been subjected to regression techniques to build relevant equations for predictability. The present study attempts to explain the detailed procedures adopted within the frame work of the informed knowledge and had attempted to derive meaningful implications for the use of practitioners and academic fraternity. The findings of this paper drew attention to the superior impact of a combined non-destructive testing approach whereby RHTM and UPVTT have been merged in a fashion to yield better assessment of RC columns with double layers of transverse confining stirrups. The combined influence of RHTM and UPVTT clearly explain, greater characteristic compressive strength as one moves from a specimen with a Normal Strength Concrete (NSC) to a specimen with High Strength Concrete (HSC).

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Behavior of circular RC columns with two layers of spirals

Cited by 10 publications

References 14 publications

Seismic performance of reinforced concrete columns confined with two layers of stirrups

Seismic performance of reinforced concrete columns confined with two layers of stirrups

Behavior of Axially Loaded Stirrup Confinement Rectangular Concrete‐Filled Steel Tubular Stub Columns

Reliability of Non-Destructive Testing Methods in the Assessment of the Strength of Concrete Columns Reinforced with Two Layers of Transverse Confining Stirrups: Empirical Evidence

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