Improving Flexural Moment Capacity of Concrete Beam by Changing the Reinforcement Configuration (original) (raw)
Related papers
IAEME, 2019
Various methods were developed to increase the flexural capacity of reinforced concrete beams. One of method possibility method is by using truss system reinforcement. Therefore, this study aims to analyze the effect of spacing of steel truss system on the behavior of reinforced concrete beam in flexure and crack pattern, and to obtain the theoretical equation to calculate the moment capacity of concrete beams reinforced by steel truss system. This study was conducted experimentally. The number of specimens was twelve, which consist of three control beams (BN) with the vertical stirrups, and nine beams reinforced by steel truss system (BTR). The dimension of all specimens was 150 mm x 2500 mm x 3300 mm. The spacing of steel truss system varied into 0.25d in BTR25, 0.5d in BTR50 and 0.75d in BTR75. The d is the effective depth of the beam. The results of this study showed that the spacing variation of steel truss system can enhance the ultimate capacity of the concrete beams. Compared to BN, the ultimate capacity of BTR25, BTR50 and BTR75 was 10.72%, 7.83% and 4.82%, respectively. In addition, the stiffness of the beam can be also increased due to the effect of steel truss system. Compared to BN, the increment of stiffness in BTR25, BTR50 and BTR75 was 10.23%, 7.47%, and 4.60%, respectively. The steel truss system also affected the number and the propagation of crack pattern, where the number of cracks was higher in BN than in BTR. The diagonal tension crack was also not observed in BTR. Finally, the empirical equation to estimate the moment capacity of the concrete
Global Journal of Arts Education, 2019
The design of the buildings to the earthquakes is a very critical issue. Some of existing reinforced concrete buildings does not have sufficient performance in terms of earthquake. These buildings must be demolished or strengthened. Strengthening design is not a simple engineering account but requires deep knowledge of composite material behaviour. In this study, the structural advantages and disadvantages of various strengthening types of reinforced concrete beams are investigated. In the analyses, the reinforced concrete jacketing increased the bending and shear strength of the existing beam but the difficulty of this application was found to make it difficult for such designers to be preferred in beams. Also, the addition of new reinforced concrete section to be added to the lower zone of the beam has also contributed to the bending capacity by increasing the useful height of the beam.
Effect of Mode of Continuity of Tension Reinforcement Bars on Flexural Strength of R.C. Beam
Construction Science
The research investigation was carried out to determine the effect of different modes of continuity of tension reinforcement bars on the flexural strength of reinforced concrete beams. Nine (9) full size beams (2150 mm × 250 mm × 180 mm) were cast with 2 numbers of 16 mm diameter high yield bars in tension and 10 mm diameter high yield stirrups at 100 mm centres at the shear spans. Three (3) beams each were cast with full length bars (reference), lap-spliced bars and butt-welded reinforcement bars in tension. Twenty-seven (27) 150 mm cubes were also cast to monitor concrete strength. The beams and cubes were cured for twenty-eight (28) days and tested in flexure under four points bending system and in compression respectively. The test results showed that full length bars, lap-spliced and butt-welded bars had an average moment capacity of 25.54 kN•m, 19.16 kN•m and 10.64 kN•m respectively. Lap-spliced beam gave a higher moment of resistance compared to the beams with butt welded steel reinforcing bars. The average midspan deflection of butt welded reinforcement was smaller than that of in the beam with lap spliced type of continuity. It was concluded that continuity using lap spliced bars in tension is more effective and efficient than butt welded continuity. 58.34 %, 25.00 % of the moment capacity of beams with full length reinforcement was lost by using butt weld, without a coupler, and lap spliced bars, respectively.
Strengthening of reinforced concrete beam: An experimental investigation
ISET INTERNATIONAL CONFERENCE ON APPLIED SCIENCE & ENGINEERING (CASE 2021)
A detailed survey was made on the different cement proportions and concrete grades used for the structural elements. The various strengthening methods studies in concrete were done by researchers in different part of the world. Strengthening increase the ultimate load carrying capacity this approach is relatively simple to implement and result in reduction in retrofitting cost compared to other for a structure or a bridge with identical beam diameters, there are practical and dependable techniques. The primary goal of these experiments is to learn more about the behaviour of RCC beams that have been strengthened using RC plates. All material testing were carried out in the laboratory in accordance with the Indian Standard regulations. Fine aggregate, coarse aggregate, and cement were subjected to basic tests to determine their suitability for concrete production. The concrete mix was created according to IS 10262:1982 for M20 concrete grade.
Flexural Capacity of Concrete Beams Reinforced with High-Strength Steel Bars Under Monotonic Loading
International journal of GEOMATE : geotechnique, construction materials and environment, 2021
This paper presents the flexural capacity of reinforced concrete beams designed with highstrength steel bars. Reinforced concrete beams with steel bars fy = 550 MPa are designed to have flexural strength like beams with steel bar fy 420 MPa. According to ACI 318M-19, the high-strength steel bars (fy = 550 MPa) are allowed to use as the reinforcing steel, which previously unpermitted. This study was conducted to represent the possibility of using high-strength steel bars as reinforcement. There are five sample beams that design with various diameters (13 and 19 mm) and strength (fy 420 and 550 MPa) of longitudinal reinforcement. These beams were placed on two simple supported and undergo monotonic loads at two points-load. It is reviewed the flexural capacity of beams with high-strength steel bars involve load capacity, moment, and beam deflection. Also, the behavior of beams when receiving loads in terms of the relationship between load and deflection. Based on the research, beams with a high-strength steel bar can accept higher loads than normal beams by a difference of about 16-18%. While at the same deflection condition, which is 100 mm, beams with high strength reinforcement can achieve a higher load of around 18 percent. Beam with high-strength steel bars showed flexural behavior that was not much different from the normal-strength steel bars because it did not show brittle collapse. It proves that high-strength steel bars can be used on reinforced concrete structural elements if it satisfies the requirements specified in the code.
Procedia Engineering, 2014
That the failure of large beam column specimens occurs in the joint rather than in the adjoining members or the beam proves that the joint shear strength of the current methods are inadequate. Moreover, the addition of transverse shear reinforcement in the joint up to a certain limit will increase the shear strength and otherwise it would result in a decrease, if this limit is exceeded. So to increase the shear strength to a greater value, other means are required. With the simplifying assembling and the ductile performance of steel, it is proposed that the use of King-cross steel profile implants at beam-column-joints as a shear reinforcement could be expected to replace the transversal reinforcement and enhance the joint shear strength, ductility and stiffness of the structure.
Flexural Strength Design of Concrete Beams
This paper presents a methodology for the flexural strength design of concrete beams reinforced with high-strength reinforcing steel that conforms to the requirements of ASTM A1035-07. The design method is based on simple analysis techniques that satisfy fundamental principles of equilibrium and compatibility. Strain limits for tension-controlled sections and compression-controlled sections are proposed that are consistent with the approach of the current and past ACI 318 Codes. The proposed method is compared with experimental results previously reported by others. The application of the proposed method is demonstrated by a numerical design example.
Composites Part B: Engineering, 2014
Reinforced Concrete (RC) beam is a paramount structural member for sustaining loads. As result, finding an appropriate strengthening technique is necessary not only for maintaining the safety of the structures but also for achieving the life span requirements. This paper provided an analytical inspection for experimental work of RC beams strengthened with Self-compacting concrete (SCC) and galvanized steel welded wire mesh (SWM) as reinforcement in flexural. As for practical work, the test program included eighteen small-scale beams. All beams were subjected to monotonically loading rate until failure on three control beams, on four monolithic casted control beams and eleven strengthened beams. The strengthened beams were categorized into two groups A and B based on test variables, namely, the SWM properties and the bonding technique. Based on achieved test results, this strengthening technique improved the flexural capacity of strengthened beams significantly. Simplified structural design for predicting the flexural strength and deflection was introduced in this paper at yielding and at the ultimate stages. The comparison was conducted between tested experimental results and the theoretical analysis results. This analysis was performed based on the basis of flexural theory and also reasonable consistent between experiment test results and calculated values was gained at the ultimate and yield stage as well as the derived formulas can be used in real-world strengthening applications.
Strength and flexural behaviour of reinforced concrete beams using deflected structural steel reinforcement and the conventional steel reinforcement are conducted in this study. The reinforcement quantity of both categories was approximately equalised. Mild steel flats with minimum thickness and corresponding width are deflected to possible extent in a parabolic shape and semi-circular shape are fabricated and used as deflected structural steel reinforcement in one part, whereas the fabrication of ribbed tar steel circular bars as conventional reinforcement on the another part of the experiment for comparison in the concrete beams. All the beams had same dimensions and same proportions of designed mix concrete, were tested under two point loading system. As the result of experiments, it is found that the inverted catenary flats and their ties, transfers the load through arch action of steel from loading points towards the supports before reaching the bottom fibre at the centre of the beam as intended earlier. Thereby the load carrying capacity and the ductility ratio has being increased in deflected structural steel reinforced beams when compared with ribbed tar steel reinforced concrete beams, it is also observed that the failure mode (collapse pattern)is safer.