Experimental Study on Flexural Bearing Capacity of Reinforced Ceramsite Concrete Beam

2011 ◽  
Vol 366 ◽  
pp. 253-257
Author(s):  
Wei Jun Yang ◽  
Zheng Bo Pi ◽  
Zhen Lin Mo
Keyword(s):  
Bearing Capacity ◽  
Concrete Beam ◽  
Failure Modes ◽  
Concrete Beams ◽  
Cement Mortar ◽  
Reinforced Concrete Beams ◽  
Ordinary Concrete ◽  
Steel Bar ◽  
Steel Bars ◽  
Flexural Bearing Capacity

In order to investigate the flexural bearing capacity of reinforced ceramic concrete beams, static loading experiments were carried out. 10 ceramic reinforced concrete beams and 2 non-reinforced ceramic concrete with different steel ratios, cover thicknesses and bar diameters were fabricated. The gauges of concrete was arraged on the surfaces of section in mid-span and and steel gauges was arraged on the surfaces of steel bars. The loading device was consisted of a 200kN hydraulic jack, a distributive girder and reaction frame while the dial indicators was arraged in supports and mid-span. The strain of concrete and steel bar in different loading along with the crack,yield and utimate of load were recorded .It found that the stress-strain law, crack extension regularity , failure modes of specimens was similar to the ordinary concrete beams and the current procedures formulas about flexural bearing capacity is reliability. It also found that both ceramic aggregate and cement mortar were crushed for the perfectly bonding of the interface and the strength of aggregate was to be fully utilized.

scholarly journals Study on the Flexural Performance of Hybrid-Reinforced Concrete Beams with a New Cathodic Protection System Subjected to Corrosion

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 234 ◽  
Author(s):  
Yingwu Zhou ◽  
Yaowei Zheng ◽  
Lili Sui ◽  
Biao Hu ◽  
Xiaoxu Huang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Steel Corrosion ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Steel Bar

Steel corrosion is considered as the main factor for the insufficient durability of concrete structures, especially in the marine environment. In this paper, to further inhibit steel corrosion in a high chloride environment and take advantage of the dual-functional carbon fiber reinforced polymer (CFRP), the impressed current cathodic protection (ICCP) technique was applied to the hybrid-reinforced concrete beam with internally embedded CFRP bars and steel fiber reinforced polymer composite bar (SFCB) as the anode material while the steel bar was compelled to the cathode. The effect of the new ICCP system on the flexural performance of the hybrid-reinforced concrete beam subjected to corrosion was verified experimentally. First, the electricity-accelerated precorrosion test was performed for the steel bar in the hybrid-reinforced beams with a target corrosion ratio of 5%. Then, the dry–wet cycles corrosion was conducted and the ICCP system was activated simultaneously for the hybrid-reinforced concrete beam for 180 days. Finally, the three-point bending experiment was carried out for the hybrid-reinforced concrete beams. The steel bars were taken out from the concrete to quantitatively measure the corrosion ratio after flexural tests. Results showed that the further corrosion of steel bars could be inhibited effectively by the ICCP treatment with the CFRP bar and the SFCB as the anode. Additionally, the ICCP system showed an obvious effect on the flexural behavior of the hybrid-reinforced concrete beams: The crack load and ultimate load, as well as the stiffness, were enhanced notably compared with the beam without ICCP treatment. Compared with the SFCB anode, the ICCP system with the CFRP bar as the anode material was more effective for the hybrid-reinforced concrete beam to prevent the steel corrosion.

Composite action in masonry walls under vertical in-plane loading: experimental results compared with predictions

2015 ◽  
Vol 42 (7) ◽  
pp. 449-462
Author(s):  
A.T. Vermeltfoort ◽  
D.R.W. Martens
Keyword(s):  
Bearing Capacity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Compressive Force ◽  
Reinforced Concrete Beams ◽  
Elastic Behavior ◽  
Masonry Walls ◽  
Load Bearing Capacity ◽  
Cracking Behavior ◽  
Load Bearing

The results of five experimental test series on masonry walls supported by reinforced concrete beams or slabs are reported and compared to theoretical predictions of the load bearing capacity. The experiments were performed on deep masonry beams built with respectively calcium silicate and clay brick. Investigated parameters were: position of the supports, concrete beam-masonry interface, concrete beam stiffness, type of loading, and height of masonry wall and concrete beam. Based on literature, the method proposed by Davies and Ahmed as well as the method according to Eurocode 6 were used to estimate the load bearing capacity of the tested masonry walls supported by concrete beams. The method of Davies and Ahmed allows for the determination of the stresses and stress resultants in the masonry. The analysis shows that near the support an inclined compressive force acts at the bed joint, which means that a shear-compression stress state exists in the bed joint. Strength evaluation has been carried out using the Mann-Müller criterion that is adopted in Eurocode 6. Based on the test results, it may be concluded that both methods yield conservative values of the load bearing capacity, as could be expected. Before cracking a linear elastic behavior was observed, while after cracking a strut-and-tie model may be applied. To develop more accurate design models, it is recommended to investigate the post-cracking behavior in more detail.

scholarly journals Experimental Study of Replacement the Tension Reinforcing Bars in Concrete Beams by Steel Pipes

2018 ◽  
Vol 7 (4.20) ◽  
pp. 229
Author(s):  
Labeeb Saadoon Al-Yassri ◽  
Alaa Mahdi Al-Khekany ◽  
Hajer Satea Abbas
Keyword(s):  
Reinforced Concrete ◽  
Construction Projects ◽  
Concrete Beams ◽  
Small Diameter ◽  
Reinforced Concrete Beams ◽  
Steel Pipe ◽  
Steel Pipes ◽  
Steel Bar ◽  
Steel Bars ◽  
The Difference

Structures designed with reinforced concrete beams are used extensively in construction projects because of their functional and economic features. In this research, tested concrete beams were cast and reinforced with small diameter steel pipes and /or steel bars as flexural reinforcement to study the effect of this configuration of reinforcement on the structural behavior of reinforced concrete beams. The idea of this research involves performing and testing of four reinforced concrete beams reinforced by small diameter steel pipes with different percentages of replacement with traditional steel bars (0%, 33%, 66% and 100%). The experimental results showed that using of steel pipes reduces the flexural capacity by (2.7, 18.3, 37.5%) if compared with traditional steel bar according to the replacement percentages of (33%, 66%, and 100%) respectively. Moreover, the stiffness of beams reinforced with steel pipes (fully or partially) decreased as a result of the difference in the mechanical properties between steel bar and the steel pipe and also, the bond strength reduction between the smooth steel pipe and surrounded concrete.  

scholarly journals Flexural performance of reinforced concrete beams made with locally sourced fly ash

2021 ◽  
Vol 15 (2) ◽  
pp. 38-50
Author(s):  
Nguyen Van Chinh
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Portland Cement ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Flexural Performance ◽  
Steel Bars ◽  
Cracking Pattern

The paper investigates the flexural performance of reinforced concrete beams in which fly ash from Vinh Tan power station was used to replace original Portland cement in the proportions of 0%, 10%, 20% and 40% by weight. Twelve reinforced concrete beams with the dimensions of 100×150 mm in cross section and 1000 mm in length were cast and cured in water. These beams were flexurally tested under 4 points bending at 28 days, 56 days and 90 days. Load deflection curves, first cracking load, yielding of steel bars, ultimate load, and cracking pattern of the reinforced concrete beams are used to investigate the performance of the control and fly ash beams at 28 days, 56 days and 90 days. The results show that locally sourced fly ash does not affect the load and deflection curves. Fly ash reduced slightly the flexural strength of reinforced concrete beams at 90 days when 40% of fly ash was used to replaced Portland cement. Keywords: fly ash; reinforced concrete beam; flexural performance; load; deflection.

scholarly journals EXPERIMENTAL LOAD-DRIFT RELATIONS OF CONCRETE BEAM REINFORCED AND CONFINED WITH HIGH-STRENGTH STEEL BARS UNDER REVERSED CYCLIC LOADING

2021 ◽  
Vol 11 (4) ◽  
pp. 56-69
Author(s):  
Retno Anggraini ◽  
Tavio Tavio ◽  
Gusti Putu Raka ◽  
Agustiar Agustiar
Keyword(s):  
Reinforced Concrete ◽  
High Strength Steel ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Steel Bars ◽  
Normal Strength

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.

Study on Damaged Reinforced Concrete Beams Strengthened with Basalt Fiber Polymer Sheets

2012 ◽  
Vol 446-449 ◽  
pp. 2941-2944 ◽  
Author(s):  
Hua Nan He ◽  
Wei Dong
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reference Beam ◽  
Basalt Fiber ◽  
Reinforced Concrete Beams ◽  
Steel Bar ◽  
Polymer Sheets ◽  
Fiber Sheet ◽  
Strengthening Technique

In practical concrete structures, once reinforced concrete beams serve in case of over cracking or are even damaged due to sudden overloading, it is necessary to repair or strengthened the damaged members for purpose of restoring the structural capacities and keeping the structures working well. At present FRP strengthening technique is one of the most accepted methods available in civil engineering. This paper particularly presents a new FRP material，basal fiber, which is applied to strengthen flexural behaviors of reinforced concrete beams suffering from different amplitudes of cracking damage. Herein, total 4 reinforced concrete beams were tested including one reference beam and three beams strengthened with basalt fiber polymer sheets. The three strengthened beams were preloaded to an expected load and then strengthen by basalt fibers under loading. The test parameters are involved in different pre-loads and layers of basalt fiber sheets. During test some flexural behaviors were obtained in terms of variation of strain in concrete, steel bar and basalt fiber sheet, flexural deflection, collapse loads and the failure modes as well as cracking properties of R.C beams strengthened with basalt fiber sheets. The results of test indicated that flexural behaviors of the beams strengthened under loading with basalt fiber polymer could be improved in different degree with varied initial flexural moment and numbers of basalt fiber.

Finite Element Analysis of Reinforced Concrete Beam Stress Performance at Ultra-Low Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 514-518
Author(s):  
Shuang Liu ◽  
Chao Lv
Keyword(s):  
Reinforced Concrete ◽  
Low Temperature ◽  
Concrete Beam ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Software Environment ◽  
Element Analysis ◽  
Component Test

To study the reinforced concrete beam stress performance under ultra-low temperature, Monotonic static load tests of 6 reinforced concrete beams were conducted at a temperature range from -180 oC to -40°C by using home-made jig and fixture for low temperature. The failure modes and the mechanical properties of the reinforced concrete beams under low temperature were investigated. The test results showed that both the bearing capacity and the stiffness of the beams increased with the decrease of the temperature. Based on the material constitutive and mechanism at ultra-low temperature, the numerical simulations are implemented and component test is expanded by using DIANA software environment.

scholarly journals Influence of Corrosion and Fatigue on the Bending Performances of Damaged Concrete Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shiqin He ◽  
Zeyang Cao ◽  
Jiajun Ma ◽  
Shuai Zeng ◽  
Pengfei Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Load Test ◽  
Reinforced Concrete Beams ◽  
Sustained Load ◽  
Chloride Salt ◽  
Fatigue Lifetime ◽  
Steel Bars

The durability of in-service reinforced concrete bridges will be greatly reduced under the action of corrosion and the repeated load such as vehicles. In this paper, six reinforced concrete beams were cast and subjected to sustained load test for one year, and then, the alternating test of corrosion and fatigue load were carried out with the damaged concrete beams. The long-term deflection, fatigue lifetime, failure modes, and crack growth were investigated under different corrosion and fatigue working conditions. The fracture section of steel bars was scanned by electron microscopy at the end of fatigue test. The results indicate that the deflection of the beams will continue to increase under a long-term load. The chloride salt in the beam has little influence on the deflection performance, but will shorten the fatigue lifetime due to the corrosion of the steel bars. Moreover, the corrosion environment can accelerate the rusting of the beam bar and reduce the fatigue lifetime, the accumulation of deflection damage and crack damage, and other fatigue characteristics. The crack initiation-propagation-fracture stage of steel bars occurs in the process of fatigue.

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