High-Strength Steel Bars in Earthquake-Resistant Reinforced Concrete T-Shaped Walls

2021 ◽  
Vol 118 (1) ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 56-69
Author(s):  
Retno Anggraini ◽  
Tavio Tavio ◽  
Gusti Putu Raka ◽  
Agustiar Agustiar

High-strength steel bars have different characteristics from normal-strength steel bars. Thus, the use of high-strength steel bars still needs to be investigated further before it can be used confidently in concrete structures. In the design, a reinforced concrete beam should also have enough ductility besides its loading capacity. One of the indicators identifies that a structure has sufficient ductility is its ability to maintain the load steadily due to progressive deformation. This paper presents the test results of three reinforced concrete beams designed with concrete strength (fc) of 30 MPa. Two different yield strengths (fy) of longitudinal and transverse reinforcements were used, namely, 420 and 550 MPa. The cross-sectional dimensions of the beams were 200  300 mm with a total span of 2000 mm and a rigid stub at the midspan. The beams were simply supported by double rollers at their tops and bottoms. These special supports were located at both ends of the beams. The load applied at the midspan of the beam through the rigid stub with the displacement control. The loading pattern protocol by the drift was set from 0 to 5.5 percent. Based on the test results, it can be seen that the beams with high-strength steel bars could achieve a higher load capacity than the beams with normal-strength steel bars. On the other hand, the beams with high-strength steel bars produced lower deflection than the beams with normal-strength steel bars. Furthermore, it can be concluded that all the beams could withstand the minimum required of 3.5 percent. None of the beams indicated brittle failures. All of the beams could survived until the end of the cycles at a drift of 5.5 percent. This condition indicates that the reinforced concrete beams with higher-strength reinforcement (fy of 550 MPa) could also maintain their load capacities under large deformation beyond the first yielding of the longitudinal steel bars.


2019 ◽  
Vol 116 (6) ◽  
Author(s):  
Changhyuk Kim ◽  
Seungeun Kim ◽  
Kil-Hee Kim ◽  
DongIk Shin ◽  
Muhammad Haroon ◽  
...  

2012 ◽  
Vol 446-449 ◽  
pp. 435-444
Author(s):  
Jian Min Zhou ◽  
Shuo Chen ◽  
Xiao Feng Wang ◽  
Yong Zhao ◽  
Yun Tan

Several batches of reinforced concrete (RC) and prestressed reinforced concrete (PRC) beams with 500MPa steel bars were tested in Tongji University, recently. The results indicated that the development of flexural stiffness after concrete cracking was influenced mainly by three parameters including initial elastic flexural stiffness, longitudinal reinforcement ratio and load level. Based on our 20 years' systematic research on crack and stiffness, a simpler unified formula is suggested after theoretical analyses for predicting short term flexural stiffness of concrete beams using high strength steel bars. Comparison with calculations from different codes at home and abroad exhibits that the suggested formula is precise and practical for both RC and PRC beams.


2013 ◽  
Vol 838-841 ◽  
pp. 605-610
Author(s):  
Xiao Xiao ◽  
Zhao Hui Li ◽  
Sheng Bo Liu ◽  
Qiong Fang Wu

This paper mainly focuses on the affect factors of ductility of reinforced concrete pier with the high-strength longitudinal reinforcement and stirrups. By finite element software ANSYS, changed the amount of longitudinal reinforcement and high-strength stirrups in the piers, the ductility performance of concrete piers was studied. The results show that under certain conditions, the ductility coefficient of concrete piers with high-strength reinforcement can increase with the amount of stirrups. In addition, high-strength longitudinal reinforcement can improve the ductility performance of the concrete piers, but it should be controlled in a reasonable range. If there are too much high-strength longitudinal reinforcement in the concrete piers, the ductility performance will be lower, and structural seismic performance will also be affected.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.


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