Research on the Short-Time Deflection of Concrete Beams Reinforced with 500MPa Steel Bars

2012 ◽  
Vol 166-169 ◽  
pp. 1592-1597
Author(s):  
Zhi Hua Li ◽  
Xiao Zu Su

Fourteen concrete beams reinforced with 500MPa longitudinal steel bars were tested under two-point symmetrical concentrated static loading to investigate their deflection characteristics. And the formula for short-time stiffness specified in the code for design of concrete (GB50010-2010)were evaluated using the experimental results and available test data of 74concrete beams reinforced with 500MPa longitudinal steel bars. The results show that the deflection behavior of beams with 500MPa longitudinal steel bars is essentially similar to that of beams reinforced with conventional steel reinforcements. It is also shown that the formula for short-time stiffness under service loads specified in GB50010-2010 is applicable for flexural members reinforced with 500MPa longitudinal steel bars. Comparisons of the test results with the calculated values for the short-time deflection according to GB50010-2010 show that the code method can be used to estimate the short-time deflection for beams reinforced with 500MPa longitudinal steel bars, but that the method is somewhat less accurate for beams with light reinforcement ratio and low-strength concrete.

2013 ◽  
Vol 790 ◽  
pp. 120-124
Author(s):  
Zhi Hua Li ◽  
Xiao Zu Su

Fourting concrete beams reinforced with 500MPa longitudinal steel bars, of which 6 with skin reinforcement and 8 without skin reinforcement, were tested under two-point symmetrical concentrated static loading to investigate their crack patterns. Crack distributions in constant moment region of beams are compared. The propagation of side cracks along the beam depth is obtained. The results of this study indicate that the concrete cover of longitudinal tensile steel bars and the spacing of skin reinforcement has significant effect on crack distributions; substantial crack control in beams can be achieved if the spacing of skin reinforcement is limited to certain critical values. The curve of d-w(d is the distance between observation points of side cracks and tension face of beams, w refers to crack width at observation points) is approximately characterized by a zig-zag shape and concave-left near longitudinal tensile steel bars.


2018 ◽  
Vol 13 (3) ◽  
pp. 141-150 ◽  
Author(s):  
Cene Krasniqi ◽  
Naser Kabashi ◽  
Enes Krasniqi ◽  
Vlorian Kaqi

Author(s):  
Leopold Mbereyaho ◽  
Francois Twayigize ◽  
Laury Givens Musabe Ishimwe ◽  
Sandrine Mutumwinka

With the development of infrastructures in Rwanda, the roads construction has been one of busiest area, and as the country counts thousands hills the design and construction of drainage systems required a great attention. Most of road drainage channels are covered with concrete plates that are reinforced with ordinary steel bars, while others are not covered due to the high cost of reinforced concrete plates. As the majority of these  plates are only subjected to light pedestrian loads, they should be reinforced accordingly. This study was intended to check the potentials of sisal fibres from Agave Sisalana’ cactus plant which has shown good results in flexural members, as plates reinforcements. At first the quality of ordinary concrete components was checked. Then some of sisal fibres were prepared, manufactured into ropes of 10 mm diameter and then used as replacements of main steel bars in concrete plates before their tensile capacity was checked. Other pieces of sisal fibres of 5 cm length were mixed in concrete mass with different percentages of 0.5%, 1% and 1.5% of concrete volume. Test results showed that the compressive, tensile and flexural strengths for concrete with 1% of sisal fibres were more adequate for M30 concrete and therefore able of sustaining the real loads applied to the  drainage concrete cover plates. As the performance of natural sisal fibres depends on fibres treatment methods, length, and type of required concrete, further studies on the use of sisal fibres should consider those factors. Keywords: Agave sisalana, drainage channel, Reinforced Concrete, Sisal Fibres, Sisal ropes.


2014 ◽  
Vol 584-586 ◽  
pp. 889-893
Author(s):  
Jing Wen Su ◽  
Hai Tao Li ◽  
Li Xin Liu ◽  
A.J. Deeks ◽  
Fan Wu ◽  
...  

This paper presents development length comparison between Chinese and Australian codes study on HRB500 steel bars in concrete. After introducing the existing code provisions about the anchorage length and experimental investigation of tensile HRB500 steel bars, the calculation approaches in different codes are compared with the test data. Additionally, the development length of tensile HRB500 reinforcement bars in AS3600-2001, Proposed Revision of AS3600, GB50010-2010 and the calculation equation proposed from test results are compared with each other in beams and slabs. It is proved that AS3600-2001 is inconsistent with other standards and the tests results and needs to be revised, while the Proposed Revision of AS3600 provided a good agreement with the test data and brings the code into line with other international codes, particularly Eurocode 2. Moreover, the Proposed Revision of AS3600 is a significant improvement on the method in AS3600-2001. The anchorage length formula in GB50010-2010 can still be used for designing HRB500 steel bar.


2011 ◽  
Vol 183-185 ◽  
pp. 1979-1983
Author(s):  
Jiang Yong Cai ◽  
Xi Bo Zhou ◽  
Xiong Jia ◽  
Yan Tao He

The application and development of FRP bars for reinforce concrete structures necessitates the need for either adopt the current code method or exploiting a new design one to account for the properties of FRP materials. The method for predicting deflection of concrete beams with FRP bars in ACI440 is based on the method for that with steel bars in ACI318. Similarly, a modified method based on GB50010 is proposed in this paper to estimate deflection of concrete beams with FRP bars. Furthermore, the new method, together with ACI318, ACI440 and GB50010 ones, are verified by nine test beams in three existing experiment and show a good agreement with the experimental data. Simultaneously, the new method is also proved to be of the most precise and accurate one and indicates the potential of the method to estimate deflection in Chinese code system.


2012 ◽  
Vol 446-449 ◽  
pp. 3160-3164 ◽  
Author(s):  
Hong Yu Zhou ◽  
Zhen Bao Li ◽  
Er Wei Guo ◽  
Li Fei Liu

Analysis and calculation methods of reinforced concrete structure at present are based on test results of small-size component. This paper carried out test research on size effect of flexural capacity of RC cantilever beams. Sectional height of the biggest experimental specimen is 1000 mm. Obtaining detailed test data during different loading stage, such as carrying capacity, deflection, steel and concrete strain etc. Through observing test phenomenon and analyzing test data, verifying the safety to calculation formulas for ultimate bearing capacity of flexural members. Strength and ductility reserves show a growing trend with specimen size increasing.


2013 ◽  
Vol 368-370 ◽  
pp. 1668-1673
Author(s):  
Zhi Hua Li ◽  
Xiao Zu Su

Fourteen concrete beams reinforced with 500MPa longitudinal steel bars, of which 6 with skin reinforcement and 8 without skin reinforcement, were tested under two-point symmetrical concentrated static loading to investigate their flexural behavior. The results indicate that the flexural behavior and deflection mode of test beams with skin reinforcement are basically consistent with those of test beams without skin reinforcement. The use of skin reinforcement can significantly reduce average crack spacing and short-time maximum crack width. And the use of skin reinforcement can also slightly increase the short-time stiffness. Under the serviceability limit state, mid-span deflections are in good agreement with the calculated values according to formula in GB50010-2010. However most of calculated average crack spacing and short-time maximum crack width are larger than measured values. According to the test results, the normal formula of crack width should be revised.


2014 ◽  
Vol 919-921 ◽  
pp. 1396-1399
Author(s):  
Bin Lei ◽  
Hui Wu ◽  
Yu Song Yan ◽  
Chun Hua Rao

The comparison between the experimental results of bending rigidity of recycled concrete collected from the bending test carried out by domestic and overseas researchers and the calculated results by formulas from available codes is done. The results show that formulations of from available codes are not suitable for recycled concrete beams. Then, based on the factors that influence the bending rigidity of recycled concrete beams, the formulation of bending rigidity for recycled concrete beams is proposed by theory. The experimental results by this the formulation and the test results is very close, the mean value and variation coefficient of the ratio of experimental value and calculated value for recycled concrete beams is respectively 1.01 and 0.16.Keywords: recycled concrete beams;bending rigidity; deflection; formulation


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.


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