Bond strength of concrete plugs embedded in tubular steel piles under cyclic loading

2006 ◽  
Vol 33 (2) ◽  
pp. 111-125 ◽  
Author(s):  
Abolghasem Nezamian ◽  
Riadh Al-Mahaidi ◽  
Paul Grundy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Bond Strength ◽  
Steel Tube ◽  
Test Results ◽  
Pull Out ◽  
Steel Piles ◽  
Loading Tests ◽  
Cyclic Loading Tests ◽  
Push Out

Investigation of the load transfer of concrete plugs to tubular steel piles subjected to tension and compression and cyclic loading has been conducted at Monash University over the past 3 years. The work presented in this paper reports on the results of the combination of pull-out, push-out, and cyclic loading tests carried out on 15 steel tube specimens filled partially with reinforced concrete with variable lengths of embedment. The pull-out force was applied through steel reinforcing bars embedded in the concrete plug, and push-out forces were applied through a thick top circular plate on the top of the concrete plug. Test results included the cyclic loading, ultimate pull-out and push-out forces, slip of concrete plugs, and longitudinal and hoop strains along the piles for some specimens. The tests clearly showed that average bond strength significantly exceeds expectations and is higher than the results of previous investigations using plugs without reinforcement. The test results also indicated that cyclic loading tests reduced the bond strength due to the accumulation of damage to the plug–pile interface. The push-out and pull-out tests conducted under symmetric cyclic loading demonstrated that slip between the concrete plug and the steel tube increased with repeated loading, and the rate of slip growth increased with an increase in the peak load.Key words: tubular steel pile, reinforced concrete plug, bond, cyclic loading.

Experimental Study on Reinforced Concrete Framework that Reinforced by Steel Tube Concrete Wing Wall

2014 ◽  
Vol 1079-1080 ◽  
pp. 22-27
Author(s):  
Shao Wu Zhang ◽  
Geng Biao Zhang ◽  
Ying Chuan Chen
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Skeleton Curve ◽  
Ductility Factor ◽  
Loading Tests ◽  
Low Cyclic Loading ◽  
Cyclic Loading Tests

In order to verify the feasibility of a new overallseismic reinforcement method of the framework. Firstly，carried low cyclic loading tests on reinforcedconcrete framework, then reinforced the framework with a new method, and repeatthe low cyclic loading tests , finally, compared and analyzed the data from twotests. Compared with the original framework, the shape of the hysteresis curveis more full and the skeleton curve of the parallel period is longer andthe ductility factor increased by 35% and the bearing capacity increased by 40%.The results show that reinforcement framework has better energy dissipationcapacity, ductility and transgender capacity.

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.

scholarly journals Bond Strengths of Geopolymer and Cement Concretes

2010 ◽  
Vol 69 ◽  
pp. 143-151 ◽  
Author(s):  
Prabir Sarker
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Geopolymer Concrete ◽  
Reinforcing Steel ◽  
Test Results ◽  
Reinforcing Bars ◽  
Pull Out ◽  
Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

Cyclic loading tests of thin-walled square steel tube beam-column joint with different joint details

Structures ◽  
2020 ◽  
Vol 25 ◽  
pp. 386-397
Author(s):  
Jinliang Bian ◽  
Wanlin Cao ◽  
Zongmin Zhang ◽  
Qiyun Qiao
Keyword(s):  
Cyclic Loading ◽  
Steel Tube ◽  
Column Joint ◽  
Loading Tests ◽  
Thin Walled ◽  
Cyclic Loading Tests ◽  
Square Steel Tube

A Study on the Bond Strength between Rebar and Concrete after Electrochemical Realkalisation Treatment for Carbonated Concrete

2010 ◽  
Vol 133-134 ◽  
pp. 1185-1189
Author(s):  
Wen Jun Qu ◽  
Kun Wang ◽  
Yan Xiong
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Sodium Silicate ◽  
Current Density ◽  
Test Results ◽  
X Ray Diffraction ◽  
Chemical Action ◽  
X Ray ◽  
Pull Out ◽  
Physical And Chemical

During the electrochemical realkalisation treatment for carbonated concrete, the bond strength between rebar and concrete was changed duo to the physical and chemical action. The pull-out test was used to study the effect of current density on the bond strength between rebar and concrete. The realkalisated products of the concrete were studied using X-ray diffraction (XRD). Test results show that after electrochemical realkalisation treatment (ERT), the bond strength of reinforced concrete increases; The current density has the significant effect on the bond strength; The amount of sodium silicate of the concrete is changed after ERT, Due to the increment of the sodium silicate that can increase the bond strength between the concrete and the rebar, it makes for the increase of the bond strength.

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