Experimental study on the seismic behavior of precast concrete column with grouted corrugated sleeves and debonded longitudinal reinforcements

2019 ◽  
Vol 22 (15) ◽  
pp. 3277-3289 ◽  
Author(s):  
Jun Chen ◽  
Chenhui Zhao ◽  
Faxing Ding ◽  
Ping Xiang
Keyword(s):  
Axial Load ◽  
Seismic Behavior ◽  
Precast Concrete ◽  
Concrete Columns ◽  
Damage Spreading ◽  
Loading Tests ◽  
Column Foundation ◽  
Low Cyclic Loading ◽  
Cyclic Loading Tests ◽  
Seismic Behaviors

The seismic performance and the influence of debonded longitudinal reinforcements at the footing on the precast concrete columns connected with the embedded grouted corrugated sleeve were investigated experimentally in this research. Low cyclic loading tests were carried out on eight bending columns and four shear columns, considering the designed parameters of the partial debonding of the longitudinal reinforcements above the column–foundation interface, the axial load index, and the strength of the stirrups. Experimental results indicate that the partial debonding of the longitudinal reinforcements heavily influenced the damage spreading of the bending columns, but does not affect the damages of the shear columns. Compared to the columns without debonded longitudinal reinforcements, the seismic behaviors in terms of the ductility and energy dissipation can be improved clearly by the partial debonding of the longitudinal reinforcements for bending columns, but there was no clear improvement for shear columns. In addition, with the decrease of the axial load index or the increase of the strength of the stirrups, the seismic behaviors of the precast columns with the partial debonding of the longitudinal reinforcements are improved largely.

scholarly journals Low-Cyclic Loading Tests of Self-Centering Variable Friction (SCVF) Brace

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingguang He ◽  
Yanxia Bai ◽  
Weike Wu ◽  
Yongfeng Du
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Variable Friction ◽  
Loading Tests ◽  
Low Cyclic Loading ◽  
Energy Dissipation System ◽  
Cyclic Loading Tests ◽  
Dissipation System

A novel assembled self-centering variable friction (SCVF) brace is proposed which is composed of an energy dissipation system, a self-centering system, and a set of force transmission devices. The hysteretic characteristics and energy dissipation of the SCVF brace with various parameters from low-cyclic loading tests are presented. A finite element model was constructed and tested under simulated examination for comparative analysis. The results indicate that the brace shows an atypical flag-type hysteresis curve. The SCVF brace showed its stable self-centering ability and dissipation energy capacity within the permitted axial deformation under different spring and friction plates. A larger deflection of the friction plate will make the variable friction of this SCVF brace more obvious. A higher friction coefficient will make the energy dissipation capacity of the SCVF brace stronger, but the actual friction coefficient will be lower than the design value after repeated cycles. The results of the fatigue tests showed that the energy dissipation system formed by the ceramic fiber friction blocks and the friction steel plates in the SCVF brace has a certain stability. The finite element simulation results are essentially consistent with the obtained test results, which is conducive to the use of finite element software for calculation and structural analysis in actual engineering design.

SEISMIC ENHANCEMENT OF REINFORCED-CONCRETE COLUMNS BY REBAR-RESTRAINING COLLARS

2012 ◽  
Vol 06 (03) ◽  
pp. 1250015 ◽  
Author(s):  
ANAT RUANGRASSAMEE ◽  
ARCHAWIN SAWAROJ
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Concrete Columns ◽  
Bridge Columns ◽  
Concrete Bridge ◽  
Reinforcing Bars ◽  
Plastic Hinges ◽  
Reinforced Concrete Bridge ◽  
Loading Tests ◽  
Cyclic Loading Tests

When reinforced-concrete columns are subjected to lateral cyclic loading, columns usually suffer failures at plastic hinges. If the buckling of longitudinal reinforcements at plastic hinges can be prevented or delayed, columns are expected to carry gravity loads at a higher ductility level. In this study, the rebar-restraining collar (RRC) was developed to improve the post-buckling behavior of longitudinal reinforcements. The behavior was investigated under monotonic loading tests of reinforcing bars with the RRCs and the cyclic loading tests of two reinforced-concrete bridge columns with and without RRCs. From the monotonic loading test, it was found that the RRCs significantly improved the post-yielding behavior of longitudinal reinforcing bars. The ductility and energy dissipation of longitudinal reinforcing bars with RRCs was significantly higher than that of the bare bar. Then, cyclic loading tests of two reinforced-concrete bridge columns were conducted. The cross section of columns was 0.4 m × 0.4 m, and the effective height was 2.15 m. The ratio of longitudinal reinforcing bars was 0.0123, and the volumetric ratio of transverse reinforcement was 0.00424. The column with RRCs did not have buckling of longitudinal reinforcements and had the ductility enhancement of about 17%, comparing to the column without RRCs. One evident benefit of using the RRCs is to control damage at plastic hinges of columns. Hence, the repair cost of columns after an earthquake can be reduced.

Experimental Research on Seismic Behaviors of T-Shaped Concrete-Filled Steel Tubular Frame Joints

2011 ◽  
Vol 368-373 ◽  
pp. 38-41 ◽  
Author(s):  
Cheng Xiang Xu ◽  
Zan Jun Wu ◽  
Lei Zeng
Keyword(s):  
Energy Dissipation ◽  
Axial Compression ◽  
Design Principle ◽  
Hysteretic Behavior ◽  
Loading Tests ◽  
Energy Dissipation Capacity ◽  
Concrete Joints ◽  
Cyclic Loading Tests ◽  
Seismic Behaviors ◽  
Better Than

To understand mechanical characteristics and seismic behaviors of T-shaped concrete-filled steel tubular (CFST) joints, cyclic loading tests were carried out on four 1/2-scale exterior joints of top floor. The study includes joints’ mechanical character, failure mode, hysteretic behavior, ductility, energy dissipation and stiffness degradation under different height of beam and different axial compression ratios. The results indicate that frame joints satisfy the design principle of stronger joints and weaker components. The hysteretic loops are plump, ductility and energy dissipation capacity is better than that of ordinary reinforced concrete joints. Axial compression ratios can influence seismic behaviors of frame joints to some degree.

Seismic Behavior of Concrete Columns Confined by CFRP and GFRP Jackets

2013 ◽  
Vol 405-408 ◽  
pp. 657-663
Author(s):  
Yu Mei Teng ◽  
Ye Tian ◽  
James Liu
Keyword(s):  
Tensile Strength ◽  
Seismic Performance ◽  
Axial Load ◽  
Seismic Behavior ◽  
Large Scale ◽  
Concrete Columns ◽  
Cyclic Displacement ◽  
Transverse Steel ◽  
The Moment ◽  
Constant Axial Load

This paper presents experimental results of a series of large-scale reinforced concrete circular and square columns tested under lateral cyclic displacement excursions while simultaneously subjected to constant axial load. All the specimens contained only minimal transverse steel and were then retrofitted with CFRP or GFRP jackets except control specimens. The measured hysteretic loops of the moment vs. curvature and shear vs. deflection relationships are reported for each specimen. It was observed that both CFRP and GFRP wrapping could provide effective confinement and significantly improve the seismic performance of columns. The effectiveness of FRP in enhancing column ductility relates more closely to its tensile strength than stiffness, thus the application of GFRP confinement to concrete columns is promoted due to obtainability and economical concern.

An experimental study of the axial compression performance of two-part precast concrete columns

2021 ◽  
pp. 136943322110159
Author(s):  
Bo Wu ◽  
Zhikai Wei
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Axial Load ◽  
Precast Concrete ◽  
Concrete Columns ◽  
Longitudinal Reinforcement ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Compression Performance ◽  
Waste Concrete

Recycled lump concrete (RLC) made with demolished concrete lumps (DCLs) and fresh concrete (FC) provides a solution for effective waste concrete recycling. To promote the development of precast RLC structures, this study tested a new type of connection for precast concrete columns: connecting the upper and the lower halves of columns with bent longitudinal reinforcements and structural adhesive. In this work the behavior of precast RLC columns with the new connection was studied under axial compression. The axial compressive strength of nine two-part columns was tested. The effects of the degree of bending in the longitudinal reinforcement, the replacement ratio of DCLs and the stirrup spacing were investigated. Tests showed that: (1) the failure mode of precast concrete columns is different from that of cast-in-place columns; (2) when the strength of the waste concrete is close to that of the fresh material, there is no significant difference in the axial compression performance of either precast or cast-in-place columns; (3) the bent longitudinal reinforcement causes the axial load bearing capacity of precast concrete columns to be 4.2%–12.3% lower than that of a similar cast-in-place column; (4) reducing the stirrup spacing has little effect on a precast column’s axial load bearing capacity and ductility; (5) when using Chinese and American codes to predict the axial load bearing capacity of the column, the predicted value should be multiplied by a reduction factor.

Pendulum impact loading tests of precast concrete columns with various column base connections

2022 ◽  
Vol 252 ◽  
pp. 113736
Author(s):  
Yun Zhou ◽  
Jianbo Yang ◽  
Xianming Luo ◽  
Hyeon-Jong Hwang ◽  
Hui Chen ◽  
...  
Keyword(s):  
Impact Loading ◽  
Precast Concrete ◽  
Concrete Columns ◽  
Loading Tests ◽  
Base Connections ◽  
Column Base ◽  
Pendulum Impact
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