scholarly journals Seismic Performance of Full-Scale Reinforced Concrete Frames Retrofitted with Bolted Concrete-Filled Steel Tubes

2021 ◽  
Vol 11 (16) ◽  
pp. 7382
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Dae-Sung Hwang ◽  
Young Hak Lee

The effective retrofit strategy of non-seismic designed structures is required to improve the strength and ductility. Jacketing is the most typical method which can enhance seismic resistance capacity, but there are many disadvantages due to its enlarged jacket section. This study developed a non-welded concrete-filled steel tube system (NoWS) which was installed using bolts in the form of tube-type steel-encased beams and columns; the NoWS could increase the capacity of seismic resistance strength and the ductility of members. One reinforced concrete (RC) frame specimen with non-seismic details and one NoWS were manufactured, and cyclic loading tests were conducted until critical failure was observed in the column after reaching maximum load. As experimental results, the specimen retrofitted with NoWS had excellent seismic performance, showing resistance to lateral load, effective stiffnesses, and energy dissipation capacity approximately 2–3 times greater than the results of an RC frame specimen.

2020 ◽  
Vol 10 (20) ◽  
pp. 7061 ◽  
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Young Hak Lee

Buildings constructed with non-seismic details are at risk of damage and collapse when an earthquake occurs due to a lack of strength, stiffness, and ductility. For reinforced concrete (RC) moment-resisting frames, seismic retrofitting methods that can enhance strength or ductility should be applied. However, such strategies have many disadvantages related to constructability, serviceability, securing integrity, and cost. In this paper, a welded concrete-filled steel tube (WCFST) system was examined in order to resolve the problems of the existing seismic retrofitting methods for RC moment-resisting frames. To evaluate the seismic performance of the proposed system, two specimens, one with non-seismic details and another reinforced with a WCFST seismic system, were manufactured for the cyclic loading tests. As a result of the experiments, the specimen retrofitted with the WCFST system showed maximum load, effective stiffness, and energy dissipation capacity values approximately 3, 2, and 2.5 times greater, respectively, than those obtained from the existing reinforced concrete frame specimen. The experimental results indicate that the proposed WCFST system is expected to be effective at improving the seismic performance by enhancing both the strength of the existing reinforced concrete frame structures and the dissipation of the seismic energy.


2012 ◽  
Vol 256-259 ◽  
pp. 2063-2066
Author(s):  
Hui Ma ◽  
Jian Yang Xue ◽  
Xi Cheng Zhang ◽  
Zong Ping Chen

In order to evaluate whether concrete with recycled coarse aggregate can be applied for steel reinforced concrete (SRC) under the earthquake, low cyclic loading tests of SRC with different recycled coarse aggregate (RCA) replacement percentage were carried out in this paper. Based on the tests of three SRRC column specimens, the failure modes, the hysteresis curves, the skeleton curves, the ductility, and the stiffness degradation of SRRC columns are investigated. The influence of variation in the RCA replacement percentage on the SRRC column is analyzed in detail. Test results show that the seismic performance of SRRC column is reduced to an allowable extent with the increasing magnitude of the RCA replacement percentage. The SRRC column still has a good seismic performance and the recycled coarse aggregate can be applied for steel reinforced concrete through the proper design.


2006 ◽  
Vol 33 (2) ◽  
pp. 111-125 ◽  
Author(s):  
Abolghasem Nezamian ◽  
Riadh Al-Mahaidi ◽  
Paul Grundy

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.


2014 ◽  
Vol 1079-1080 ◽  
pp. 22-27
Author(s):  
Shao Wu Zhang ◽  
Geng Biao Zhang ◽  
Ying Chuan Chen

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.


2010 ◽  
Vol 163-167 ◽  
pp. 2267-2273 ◽  
Author(s):  
Hong Ying Dong ◽  
Wan Lin Cao ◽  
Jian Wei Zhang

Two 1/6 scale core walls, including one RC core wall with steel tube-reinforced concrete columns and concealed steel trusses and one conventional RC core wall, were tested under eccentric horizontal cyclic loading. The load-capacity, ductility, hysteresis characteristics, stiffness, stiffness deterioration process, energy dissipation and damage characteristics of the two specimens were compared and discussed in this paper. It shows that the seismic performance of the RC core walls under combined action could be improved by setting the concealed steel trusses in the walls and using the steel tube-reinforced concrete columns as the boundary elements.


2016 ◽  
Vol 142 (11) ◽  
pp. 04016096 ◽  
Author(s):  
Henry V. Burton ◽  
Gregory G. Deierlein ◽  
David Mar ◽  
Khalid M. Mosalam ◽  
Janise Rodgers ◽  
...  

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