scholarly journals Retrofitting of shear strength self-compacting reinforced concrete deep beams with FRP

2018 ◽  
Vol 162 ◽  
pp. 04016
Author(s):  
Nabeel Al-Bayati ◽  
Bassman Muhammad ◽  
Sarah Sadkhan
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Load Capacity ◽  
Experimental Program ◽  
Deep Beams ◽  
Ultimate Load Capacity ◽  
Failure Loads ◽  
Effective Depth ◽  
Midspan Deflection

Experimental program were carried out to investigate the behavior of self-compacting reinforced concrete deep beams retrofitting with carbon fiber reinforced polymer (CFRP). Six simply supported deep beams were tested under symmetrically two point loads, three beams were tested up to failure without strengthening as a control beams with different shear span to effective depth ratio (a/d) while the other two beams were loaded up to 60% from the ultimate load of control beams for each a/d ratio and then retrofitted by the same configuration of CFRP to study the effect of a/d ratio on the properties of deep beams retrofitted. a/d for tested beams were (0.8, 1, 1.2). Study was focused on determining failure loads, cracking loads, failure modes, load midspan deflection. All the beams had the same compressive strength, overall dimensions and flexural and shear reinforcement. It was concluded that using this retrofitted method is very efficient and a gain in the ultimate load capacity of the deep beams was obtained also the results showed that when a/d ratio increase from 0.8 to 1.2, the ultimate load was decrease by 25% and midspan deflection was increased approximately at all load stages for control and retrofitted beams.

scholarly journals Enhancing the Behavior of One-Way Reinforced Concrete Slabs by Using Laced Reinforcement

2019 ◽  
Vol 5 (3) ◽  
pp. 718
Author(s):  
Ali Faiq Hallawi ◽  
Ali Hussein Ali Al-Ahmed
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Load Capacity ◽  
Experimental Program ◽  
Concrete Slabs ◽  
Ultimate Load Capacity ◽  
Steel Ratio ◽  
Reinforced Concrete Slabs ◽  
Line Loads ◽  
Monotonic Load

This paper studies experimentally the behavior of laced reinforced concrete one-way slabs under monotonic load. The experimental program included testing three simply supported one-way slabs of dimensions (1500 mm length, 600 mm width, and thickness 130mm. One of these slabs was the control specimen which was designed without lacing reinforcement steel and the other two specimens designed were with two variable lacing reinforcement ratio (0.27% and 0.52%). All specimens were cast with normal of 22 MPa compressive strength. Specimens were tested under two equal line loads applied at the third parts of the slab (monotonic load) gradually applying up to failure. The specimens showed an enhanced in ultimate load capacity up to 40% as a result of increasing the lacing steel ratio to 0.52 %. Also, decreasing in deflection at service and at ultimate load levels by 42% and %57 respectively. In addition, the results showed that specimen with lacing reinforcement are more ductility than specimen without lacing reinforcement so using of lacing steel reinforcement leads to significant improvements in ductility index which reached to about 49% with increasing the lacing steel ratio to (0.52%).

scholarly journals The Assessment of Using CFRP to Enhance the Behavior of High Strength Reinforced Concrete Corbels

2021 ◽  
Vol 28 (1) ◽  
pp. 71-83
Author(s):  
Mazin Abdulrahman ◽  
Shakir Salih ◽  
Rusul Abduljabbar
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Load Capacity ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Ultimate Load Capacity ◽  
Load Carrying ◽  
Externally Bonded ◽  
Effective Depth

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively Using CFRP .

Performance of Reinforced Concrete Beams with Multiple Openings

2020 ◽  
Vol 857 ◽  
pp. 162-168
Author(s):  
Haidar Abdul Wahid Khalaf ◽  
Amer Farouk Izzet
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Ultimate Load Capacity ◽  
Concentrated Load ◽  
Simply Supported ◽  
Group I

The present investigation focuses on the response of simply supported reinforced concrete rectangular-section beams with multiple openings of different sizes, numbers, and geometrical configurations. The advantages of the reinforcement concrete beams with multiple opening are mainly, practical benefit including decreasing the floor heights due to passage of the utilities through the beam rather than the passage beneath it, and constructional benefit that includes the reduction of the self-weight of structure resulting due to the reduction of the dead load that achieves economic design. To optimize beam self-weight with its ultimate resistance capacity, ten reinforced concrete beams having a length, width, and depth of 2700, 100, and 400 mm, respectively were fabricated and tested as simply supported beams under one incremental concentrated load at mid-span until failure. The design parameters were the configuration and size of openings. Three main groups categorized experimental beams comprise the same area of openings and steel reinforcement details but differ in configurations. Three different shapes of openings were considered, mainly, rectangular, parallelogram, and circular. The experimental results indicate that, the beams with circular openings more efficient than the other configurations in ultimate load capacity and beams stiffness whereas, the beams with parallelogram openings were better than the beams with rectangular openings. Commonly, it was observed that the reduction in ultimate load capacity, for beams of group I, II, and III compared to the reference solid beam ranged between (75 to 93%), (65 to 93%), and (70 to 79%) respectively.

scholarly journals Shear strength enhancement of lightweight aggregate reinforced concrete deep beams by using CFRP strips

2018 ◽  
Vol 162 ◽  
pp. 04011 ◽  
Author(s):  
Ahlam Mohammad ◽  
Kaiss Sarsam ◽  
Nabeel Al-Bayati
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Shear Cracks ◽  
Deep Beams ◽  
Control Beam ◽  
Shear Span ◽  
Number Of Layers

In this research, results of an experimental investigation on the shear strengthening of lightweight aggregate reinforced concrete deep beams are presented. A total of eight lightweight aggregate deep beams were cast and tested in the experimental work to study the effect of externally bonded CFRP strips in improving their structural behavior, one of them was unstrengthened to serve as a control beam while the remaining seven beams were strengthened in different orientation, spacing and number of layers of CFRP. The locally available natural porcelanite rocks are used to seek the possibility of producing structural lightweight aggregate concrete. The beams were designed to satisfy the requirements of ACI 318M- 14 building code. Results show that the CFRP strips have increased the load carrying capacity for the strengthened deep beams up to 50 % when comparedto the unstrenghtened control one. The diagonal compression strut crack of unstrenghtened control beam is changed to several diagonal cracks in the mid-depth within the shear span of the strengthened beams and exhibited more ductile failure modes. The results also indicate that bonded CFRP system in the shear span was seen to delay the formation of diagonal shear cracks and provided positive restraint to the subsequent growth of cracks. Increasing the amount of CFRP (by increasing the number of layers from one to two layers) results in increase in the ultimate load by about 15%. However, the increase in the spacing between the strips (from 100 to 150mm) led to a decrease in the ultimate load by about 13%.

scholarly journals Experimental analysis of eccentrically loaded reinforced concrete columns with an added jacket of self-compacting concrete

2019 ◽  
Vol 12 (2) ◽  
pp. 329-336
Author(s):  
J. P. VIRGENS ◽  
R. B. GOMES ◽  
L. M. TRAUTWEIN ◽  
G. N. GUIMARÃES ◽  
A. P. R. VAZ
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Ultimate Load ◽  
Load Capacity ◽  
Concrete Columns ◽  
Reinforce Concrete ◽  
Self Compacting Concrete ◽  
Ultimate Load Capacity ◽  
Reinforced Concrete Columns ◽  
Concrete Layer

Abstract This paper presents the experimental study of eccentrically loaded reinforced concrete columns with an added 35 mm self-compacting concrete jacket attached to the column’s most compressed face using wedge bolts. Nine columns with a 2000 mm height were tested under compression and one-way bending until failure. Columns were denominated as original column (PO) with a cross section of 120 mm x 250 mm; reference column (PR) with a cross section of 155 mm x 250 mm, and seven columns with an initial cross section of 120 mm x 250 mm and later reinforced by the addition of 35 mm self-compacting concrete layer and various configurations of wedge bolts. Except for the original column PO, the columns were submitted to a 42.5 mm load eccentricity due to the added concrete layer at the compressed face. Although failure of the wedge bolts did not occur, it was not possible to prevent detachment of the added layer. The results indicate that it is possible to structurally rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average ultimate load capacity gains of 271% compared to original column’s ultimate load.

scholarly journals STRUCTURAL CAPACITY OF NSM STEEL BARS STRENGTHENED DEEP BEAMS UNDER COMBINED LOADS OF REPEATED AND ELEVATED TEMPERATURE

2021 ◽  
Vol 25 (6) ◽  
pp. 91-102
Author(s):  
Aula H. Faeq ◽  
◽  
Ali H. Aziz ◽  
Keyword(s):  
Elevated Temperature ◽  
Ultimate Load ◽  
Load Capacity ◽  
Shear Capacity ◽  
Deep Beams ◽  
Ultimate Load Capacity ◽  
Near Surface ◽  
Combined Loads ◽  
Structural Capacity ◽  
Steel Bars

The current experimental investigation is devoted to study the structural capacity of near-surface mounted steel bars strengthened deep beams. Six reinforced SCC deep beam specimens with a dimension of 1400mm x175mm x350mm were tested under Combined Loads of Repeated and Elevated Temperature. The adopted variable includes the type of loading, degree of elevated temperature, and presence or absence of the strengthening by NSM-steel bars. The experimental results show that the ultimate load of B2-R-T20 decreased by about 33% when the applied load changed from monotonic to repeated; also, when the degree of burning increased to (200oC) and (350oC), the ultimate load decreased by 44% and 65% , respectively. The presence of the strengthened NSM-steel bars leads to increase the lateral strength of the tested beams and arrested the diagonal cracks to be widening as a result, the ultimate load capacity increases by (193%-197%) for the samples exposed to elevated temperature, in comparison with reference beams. The adopted strengthened technique proved to be adequate to restore and increase the shear capacity of the tested beams.

scholarly journals Behavior of The RC Slab-Beam System Using Self Compacting Concrete

2018 ◽  
Vol 7 (4.20) ◽  
pp. 507
Author(s):  
Nameer A. Alwash ◽  
Fatimah H. Naser Al-Mamoori
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
Experimental Program ◽  
Slab Thickness ◽  
Self Compacting Concrete ◽  
Ultimate Load Capacity ◽  
Conventional Concrete ◽  
Reinforced Concrete Slabs ◽  
Rc Slab ◽  
Ultimate Load Carrying Capacity

The present study includes an experimental investigation of the behavior of square reinforced concrete slabs. These slabs are with and without edge beams under uniformly distributed load with corner supports using two types of self compacting concrete (SCC), the first type of SCC incorporated limestone filler and the other was without filler, the results obtained are compared with those obtained from conventional concrete (CC).The experimental program consists of testing nine square slab samples. Three of these slab samples are flat in shape with panel dimensions of 1050×1050×50 mm depth. The others three slab samples are of the same outer dimensions with surrounding edge beams of depth to slab thickness equal 100/50 and 100 mm width. The last three slab samples are similar to the former slab-beam systems but with increasing the depth of edge beams by 50%.In general, for a specified flat plate panel, the ultimate load carrying capacity can be increased, if the panel is restricted by four surrounding beams. The slab-beam samples with surrounding beams of depth to slab thickness equal to 3 showed greater ultimate load capacity by about 79.37%, 52% and 97.82% when compared with the corresponding flat slabs samples produced using CC, SCC with and without filler, respectively.  

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