scholarly journals Analisis Kapasitas Lentur Balok Beton Tulang Berongga Akibat Perbedaan Kuat Tarik Tulangan

2021 ◽  
Vol 21 (3) ◽  
pp. 681-689
Author(s):  
Syahrul Sariman ◽  
Rita Irmawaty
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
The Difference ◽  
The Moment

Penelitian ini bertujuan menetapkan karakteristik lentur balok beton tulang berongga akibat perbedaan kuat tarik tulangan.  Dalam penelitian ini  digunakan balok beton bertulang dengan mutu beton f’c=27Mpa dan dimensi  150x350mm, Panjang 3300mm dengan tulangan pokok 3D16mm  dengan kuat leleh fy=475 Mpa (type WS) dan fy=324MPa (type RM). Setiap balok dengan type tulangan yang berbeda  terdiri dari   3 balok yang dibedakan menurut panjang rongganya dan diberi notasi  BR3A,  BR3B dan BR3C.  dengan tinggi rongga tetap : 180mm. Hasil penelitian menunjukkan bahwa  variasi rongga  tidak mempengaruhi kapasitas setiap balok  dalam memikul momen. Perbedaan kapasitas momen lentur disebabkan oleh perbedaan kuat tarik baja tulangan. This study aims to determine the flexural characteristics of hollow reinforced concrete beams due to differences in the tensile strength of reinforcement. In this study used reinforced concrete beams  f'c=26.85 MPa and dimensions 150x350mm, length 3300mm.  Bar reinforcement of  3D16mm with fy=475Mpa  (WStype) and fy=324MPa (RMtype). Each beam with a different type of reinforcement consists  of  3  beams that are distinguished by the length of the hollow which is  namely BR3A, BR3B and  BR3C.  with a fixed hollow  height (180mm). The results showed that hollows variations did not affect the carrying capacity of the moment. Different of  capacity  bending moment is caused by the difference in the tensile strength of the reinforcement

Evaluation of ductility and allowable moment redistribution in reinforced concrete structures

2000 ◽  
Vol 27 (6) ◽  
pp. 1286-1299 ◽  
Author(s):  
Adnan Shakir ◽  
David M Rogowsky
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Bond Slip ◽  
Plastic Rotation ◽  
Moment Redistribution ◽  
Rotation Capacity ◽  
The Moment ◽  
Plastic Rotation Capacity

Designers can use moment redistribution to reduce the design bending moment envelope. Code provisions for moment redistribution are not entirely rational. They neglect the effects of important parameters on permissible moment redistribution and can be very conservative. To establish a realistic limit on permissible moment redistribution, one needs a rational model for predicting the plastic rotation capacity of critical sections (plastic hinges). This paper presents a model for computing the plastic rotation capacity, θp, and permissible moment redistribution, β, in reinforced concrete beams. Important parameters, affecting θp and β, are identified and incorporated in the model. The model is validated against experimental results and shows good agreement. A comparison of the moment redistribution limits is made between the model and CSA A23.3-94. Although the code provides a reasonable estimate of β for unfavourable combinations of parameters, the code can be very conservative when conditions are favourable for moment redistribution. Deeper beams with closely spaced stirrups allow significantly more moment redistribution than that predicted by the code.Key words: moment redistribution, ductility, plastic rotation capacity, bond-slip, shear cracking, reinforced concrete beams, c/d, ultimate concrete strain.

Analysis on Deformation of Pre-Splitting Steel Reinforced Concrete Beams Strengthened by Prestressed CFRP

2011 ◽  
Vol 243-249 ◽  
pp. 929-933
Author(s):  
Na Ha ◽  
Lian Guang Wang ◽  
Shen Yuan Fu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Steel Reinforced Concrete ◽  
Cfrp Sheets ◽  
Deformation Curves ◽  
Prestressed Cfrp Sheets ◽  
Theoretical Results

In order to improve the bearing capacity of SRC which is related with deformation and stiffiness, SRC beams should be strengthened by CFRP. Based on the experiment of six pre-splitting steel reinforced concrete beams strengthened with (Prestressed) CFRP sheets, the deformation of beams are discussed. Load-deformation curves are obtained by the experiment. Considering the influence of intial bending moment on SRC beams, the calculated deformation formulas of SRC beams strengthened by (Prestressed) CFRP are deduced. The results showed that the load-deformation curves of normal and strengthened beams respectively showed three and two linear characteristics. The theoretical results which calculated by the formulas of deformation are well agreement with the experimental results.

scholarly journals Experimental Investigation of Shear Strength for Steel Fibre Reinforced Concrete Beams

2021 ◽  
Vol 15 (1) ◽  
pp. 81-92
Author(s):  
Constantinos B. Demakos ◽  
Constantinos C. Repapis ◽  
Dimitros P. Drivas
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Steel Fibre ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete

Aims: The aim of this paper is to investigate the influence of the volume fraction of fibres, the depth of the beam and the shear span-to-depth ratio on the shear strength of steel fibre reinforced concrete beams. Background: Concrete is a material widely used in structures, as it has high compressive strength and stiffness with low cost manufacturing. However, it presents low tensile strength and ductility. Therefore, through years various materials have been embedded inside it to improve its properties, one of which is steel fibres. Steel fibre reinforced concrete presents improved flexural, tensile, shear and torsional strength and post-cracking ductility. Objective: A better understanding of the shear performance of SFRC could lead to improved behaviour and higher safety of structures subject to high shear forces. Therefore, the influence of steel fibres on shear strength of reinforced concrete beams without transverse reinforcement is experimentally investigated. Methods: Eighteen concrete beams were constructed for this purpose and tested under monotonic four-point bending, six of which were made of plain concrete and twelve of SFRC. Two different aspect ratios of beams, steel fibres volume fractions and shear span-to-depth ratios were selected. Results: During the experimental tests, the ultimate loading, deformation at the mid-span, propagation of cracks and failure mode were detected. From the tests, it was shown that SFRC beams with high volume fractions of fibres exhibited an increased shear capacity. Conclusion: The addition of steel fibres resulted in a slight increase of the compressive strength and a significant increase in the tensile strength of concrete and shear resistance capacity of the beam. Moreover, these beams exhibit a more ductile behaviour. Empirical relations predicting the shear strength capacity of fibre reinforced concrete beams were revised and applied successfully to verify the experimental results obtained in this study.

scholarly journals Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads

2022 ◽  
Author(s):  
Paolo Foraboschi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Reinforced Concrete Structure ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Load Carrying

Renovation, restoration, remodeling, refurbishment, and retrofitting of build-ings often imply modifying the behavior of the structural system. Modification sometimes includes applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. For a reinforced concrete structure, the new condition causes a beam to bear a concentrated load with the crack pattern that was produced by the distributed loads that acted in the past. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum around the midspan. But around the midspan, the cracks are vertical or quasi-vertical, and no inclined bar is present. So, the actual shear capacity around the midspan not only is low, but also can be substantially lower than the new demand. In order to bring the beam capacity up to the demand, fiber-reinforced-polymer composites can be used. This paper presents a design method to increase the concentrated load-carrying capacity of reinforced concrete beams whose load distribution has to be changed from distributed to concentrated, and an analytical model to pre-dict the concentrated load-carrying capacity of a beam in the strengthened state.

Guidelines for flexural design of FRP reinforced concrete beams

2020 ◽  
pp. 002199832097373
Author(s):  
Fares Jnaid
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Large Diameter ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Concrete Compressive Strength ◽  
Load Carrying ◽  
Multiple Variables

This paper investigates the effects of different parameters on the live load carrying capacity of concrete beams reinforced with FRP bars. The author performed a parametric study utilizing an innovative numerical approach to inspect the effects of multiple variables such as reinforcement ratio, concrete compressive strength, span to depth ratio, FRP type, and bar diameter on load carrying capacity of FRP reinforced concrete beams. This study concluded that unless the span to height ratio is smaller than 8, tension-controlled sections are impractical as they do not meet code requirements for serviceability. In addition, it is recommended to use higher reinforcement ratios when using larger span to depth ratios and/or when using CFRP reinforcing bars. Moreover, larger number of bars with small diameter is more practical than fewer large diameter bars. Furthermore, this research suggests that increasing the concrete compressive strength is associated with a significant increase in the ultimate flexural capacity of FRP reinforced beams.

scholarly journals The influence of simultaneous action of the aggressive environment and loading on strength of RC beams

2018 ◽  
Vol 183 ◽  
pp. 02002 ◽  
Author(s):  
Jacek Selejdak ◽  
Roman Khmil ◽  
Zinoviy Blikharskyy
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Simultaneous Action ◽  
Load Carrying Capacity ◽  
Aggressive Environment ◽  
Load Carrying ◽  
Acid Environment ◽  
Simultaneous Influence

The article is devoted to an experimental research of the strength of reinforced concrete beams, and its dependence on a simultaneous influence of a corrosion environment and a loading factor. The tests have been carried out upon reinforced concrete specimens of 2100×200×100 mm size, with a regular reinforcement. The beams are of a span equaling to 1,9m with different reinforcing ratio of beams. The acid environment, namely 10 % H2SO4, was taken as a model of an aggressive environment. Reinforced concrete beams have been tested with and without the co-action of the aggressive environment and loading factor. Beams, which underwent a simultaneous action of the corrosive environment and loading, were loaded to a level 0.7 of its load-carrying capacity. The load-carrying capacity in aggressive environment in all the beams of all the series was achieved in 46-60 days. The influence of the simultaneous action of the aggressive environment and loading on the strength of reinforced-concrete beams has been described in the following work. It is necessary to note that the design code of Ukraine does not allow determining load carrying capacity of the beams affected by corrosion with simultaneous influence of loading with adequate accuracy. The analysis of experimental data has been done and the main directions of the design code’s correction have been formulated.

THE REINFORCED CONCRETE BEAM DEFLECTION AND CRACKING BEHAVIOR WITH ADDITIONAL FIBER STEEL

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Faisal Ananda ◽  
Agoes Soehardjono ◽  
Achfas Zacoeb ◽  
Gunawan Saroji
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Beam Deflection ◽  
Cracking Behavior ◽  
Classic Theory

The classic theory mentions that the assessment of deflection and crack width should be taken to minimize those two behaviors. This research itself has the objective to examine whether the additional fiber steel and increased reinforcement ratio has any significant impact on the deflection and existing crack width. This test used the reinforced concrete beams with a size of 15 cm x 25 cm x 180 cm which placed on a simple pedestal. The test was done gradually in every 108 kg until the reinforced yield reached. The fiber increased from 0%, 1.57%, 3.14% and 4.71% while the performance rebar ratio increased from 2 # 10, 2 # 12, and 2 # 14. The result shows that additional 4.71% of maximum fiber decrease compressive strength and rupture modulus while the tensile strength increased. The additional fiber reached a maximum in 4.71% and the additional diameter of 10 mm, 12 mm, and 14 mm increased the deflections and crack width.

Responses of Plain and Steel Fiber-Reinforced Concrete Beams to Temperature and Mechanical Loads: Experimental Study

2000 ◽  
Vol 1740 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Ali Alavizadeh-Farhang ◽  
Johan Silfwerbrand
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Load Carrying

To study the structural responses of plain and steel fiber-reinforced concrete pavements under combined mechanical and thermal loads, two test series have been conducted with plain and steel fiber-reinforced concrete beams. The magnitude and duration of the differences in the induced stresses caused by traffic load and a positive nonlinear temperature gradient (the top surface was warmer than the bottom surface during the day) may lead to some relaxation of thermal stresses and subsequently increase the load-carrying capacity. Considering the loss of support contact in the interior part of the concrete pavement, the experimental study of combined loading with restrained concrete beams may provide some insight and an indication of whether the superposition of stresses is a proper approach. The beams were subjected to solely thermal, solely mechanical, and combined thermal and mechanical loads while the rotation of the beam at supports was prevented. The results of tests conducted with both plain and steel fiber-reinforced beams showed that the superposition of stresses under combined loading before cracking gave a satisfactory estimation of the load-carrying capacities. The results also showed that the effect of relaxation of stresses due to short-term thermal loads was not noticeable in the load-carrying capacity achieved in tests with combined thermal and mechanical loads. On the contrary, a tendency for reduction of the load-carrying capacity was observed at higher thermal gradients. In addition, the overall structural responses of steel fiber-reinforced concrete beams under mechanical load and a nonlinear temperature gradient combined were similar to the responses of plain concrete beams up to the cracking stage. However, the release of thermal stresses due to cracking and the considerable residual load-carrying capacity after cracking were the most important observations for steel fiber-reinforced concrete beams.

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