scholarly journals The Effect of Changing Stirrup Spacing and Hook Angle on RC Cantilever Beams with Industrial Iron Chips Waste

2021 ◽  
Author(s):  
MUHAMMET ZEKİ ÖZYURT ◽  
Ömer Fatih Sancak
Keyword(s):  
Reinforced Concrete ◽  
The Other ◽  
Experimental Setup ◽  
Cantilever Beams ◽  
Loading Process ◽  
End Point ◽  
Side Load ◽  
Load Displacement ◽  
Strength And Ductility

Abstract In this study, the usability of industrial iron chips waste was investigated in order to provide recycling in the production of reinforced concrete cantilever beams with different stirrup spacing and hook angle. In the concrete produced for cantilever beams, aggregates not larger than 4 mm in diameter were reduced by 20% and replaced with iron chips waste. Cantilever beams are manufactured with stirrup spaces of 50, 100 and 150 mm. The hook angles of the stirrups are differentiated to be 90 and 135 degrees. The experimental setup was prepared in such a way that one side of the samples was fixed, and the other side was free. The loading process was done from the end point of the released side. Load-Displacement curves of cantilever beams were obtained. In the research, it was observed that although 20% iron chips added cantilever beams experienced a decrease in their strength compared to the reference beams, they increased their ductility values at all three different stirrup spaces. As the stirrup spacing widened, the ductility values decreased. However, the effect of iron chips additive on ductility has increased. Samples with stirrup hook angle of 135 degrees increased both strength and ductility values compared to samples with 90 degrees.

Adding an expansive agent to increase the toughness of steel fibre reinforced concrete

2019 ◽  
Vol 26 (4) ◽  
pp. 197-208
Author(s):  
Leo Gu Li ◽  
Albert Kwok Hung Kwan
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
The Other ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Compressive Properties ◽  
Shrinkage Cracking ◽  
Steel Fibre Reinforced Concrete ◽  
Expansive Agent ◽  
Concrete Matrix

Previous research studies have indicated that using fibres to improve crack resistance and applying expansive agent (EA) to compensate shrinkage are both effective methods to mitigate shrinkage cracking of concrete, and the additions of both fibres and EA can enhance the other performance attributes of concrete. In this study, an EA was added to fibre reinforced concrete (FRC) to produce concrete mixes with various water/binder (W/B) ratios, steel fibre (SF) contents and EA contents for testing of their workability and compressive properties. The test results showed that adding EA would slightly increase the superplasticiser (SP) demand and decrease the compressive strength, Young’s modulus and Poisson’s ratio, but significantly improve the toughness and specific toughness of the steel FRC produced. Such improvement in toughness may be attributed to the pre-stress of the concrete matrix and the confinement effect of the SFs due to the expansion of the concrete and the restraint of the SFs against such expansion.

scholarly journals Influence of Ceramic Particles Character on Resulted Properties of Zinc-Hydroxyapatite/Monetite Composites

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 499
Author(s):  
Klára Hosová ◽  
Jan Pinc ◽  
Andrea Školáková ◽  
Vilém Bartůněk ◽  
Petr Veřtát ◽  
...  
Keyword(s):  
Significant Influence ◽  
Degradation Rate ◽  
Point Of View ◽  
The Other ◽  
Ceramic Particles ◽  
Biological Aspects ◽  
Strength And Ductility

Zinc and its alloys seem to be promising candidates for biodegradable applications. Those materials are often modified by other elements or compounds in order to enhance their properties. The combination of zinc and apatites is challenging for several reasons. However, the advantages connected with the biological aspects suggest the need for further research into such materials. In this study, three zinc-based composites with 4 and 8 wt. % of nanohydroxyapatite or nanomonetite (Zn-4MO, Zn-4HA, Zn-8HA) were prepared by sintering and subsequent extrusion. Materials prepared in this way were characterized from the microstructural, mechanical and corrosion point of view. The obtained results showed a significant influence of particle character (amount and morphology) on the strength and ductility of the prepared materials. In case of Zn-4MO, the presence of monetite significantly increased the ductility compared with the other materials. In addition, the increment of the degradation rate caused by the presence of monetite was observed as well. All obtained results pointed out to significant advantages of monetite for the preparation of Zn-apatite composites compared with hydroxyapatite.

scholarly journals Finite element analysis of reinforced concrete deep beam with large opening

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elsayed Ismail ◽  
Mohamed S. Issa ◽  
Khaled Elbadry
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
The Other ◽  
Deep Beam ◽  
Web Openings ◽  
Design Load ◽  
Large Opening

Abstract Background A series of nonlinear finite element (FE) analyses was performed to evaluate the different design approaches available in the literature for design of reinforced concrete deep beam with large opening. Three finite element models were developed and analyzed using the computer software ATENA. The three FE models of the deep beams were made for details based on three different design approaches: (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978), (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006), and Strut and Tie method (STM) as per ACI 318-14 (ACI318 Committee, Building Code Requirements for Structural Concrete (ACI318-14), 2014). Results from the FE analyses were compared with the three approaches to evaluate the effect of different reinforcement details on the structural behavior of transfer deep beam with large opening. Results The service load deflection is the same for the three models. The stiffnesses of the designs of (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and STM reduce at a load higher than the ultimate design load while the (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) reduces stiffness at a load close to the ultimate design load. The deep beam designed according to (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) model starts cracking at load higher than the beam designed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) method. The deep beam detailed according to (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) and (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) failed due to extensive shear cracks. The specimen detailed according to STM restores its capacity after initial failure. The three models satisfy the deflection limit. Conclusion It is found that the three design approaches give sufficient ultimate load capacity. The amount of reinforcement given by both (Mansur, M. A., Design of reinforced concrete beams with web openings, 2006) and (Kong, F.K. and Sharp, G.R., Magazine of Concrete Res_30:89-95, 1978) is the same. The reinforcement used by the STM method is higher than the other two methods. Additional reinforcement is needed to limit the crack widths. (Mansur, M. A., Design of reinforced concrete beams with web openings, (2006)) method gives lesser steel reinforcement requirement and higher failure load compared to the other two methods.

scholarly journals Experimental analysis of reinforced concrete columns strengthened with self-compacting concrete and connectors

2012 ◽  
Vol 5 (3) ◽  
pp. 305-315
Author(s):  
P. P. Nascimento ◽  
R. B. Gomes ◽  
L. L. J. Borges ◽  
D. L. David
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Experimental Analysis ◽  
Thick Layer ◽  
Concrete Columns ◽  
The Other ◽  
Experimental Phase ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Steel Bars

There are many problems involving cases of destruction of buildings and other structures. The columns can deteriorate for several reasons such as the evolution and changing habits of the loads. The experimental phase of this work was based on a test involving nine reinforced concrete columns under combined bending and axial compression, at an initial eccentricity of 60 mm. Two columns were used as reference, one having the original dimensions of the column and the other, monolithic, had been cast along the thickness of the strengthened piece. The remaining columns received a 35 mm thick layer of self-compacting concrete on their compressed face. For the preparation of the interface between the two materials, this surface was scarified and furrowed and connectors were inserted onto the columns' shear reinforcement in various positions and amounts.As connectors, 5 mm diameter steel bars were used (the same as for stirrups), bent in the shape of a "C" with 25 mm coatings. >As a conclusion, not only the quantity, but mainly, the location of the connectors used in the link between substrate and reinforcement is crucial to increase strength and to change failure mode.

scholarly journals RETROFITTING AND DACTILITY OF REINFORCED CONCRETE BEAMS USING AN EXTERNAL REINFORCEMENT METHOD

2019 ◽  
Vol 3 (2) ◽  
pp. 135
Author(s):  
Novita Ike Triyuliani ◽  
Sri Murni Dewi ◽  
Lilya Susanti
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Concrete Block ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Building Structures ◽  
Average Increase ◽  
External Reinforcement ◽  
Strength And Ductility

The innovations strengthening building structures are important topics. Failure in structures such as beams and columns due to time, re-functions of a building, even initial design errors that are weak or lack the safety factor of a building structure. External reinforced concrete beams are one of the beams currently being developed. It is a concrete block with reinforcement of steel reinforcement on the outer (external) of the beam. This study aims to determine the index of increasing beam strength and ductility after retrofitting external steel reinforcement, which has the dimension of beams 15 x 15 x 100 cm, repeating 12 pcs, with external reinforcement each 6 pcs 2Ø6 and 3Ø6. The results from this study are an increasing the index of beam flexural strength after retrofit with external steel reinforcement. Meanwhile, beams after retrofit with 2Ø6 external steel have an average increase index of 1.25 and 1.21 while for external steel 3Ø6 are 1.29 and 1.60 respectively. The ductility depends on the value of ultimate load and maximum deflection that occurs, where the ductility value for the comparison of each specimen experiences a reduction in the average ductility value with 2Ø6 external steel which is 37.74% and 70.95% while with 3Ø6 external steel is 61,65% and 60.62%. Berbagai inovasi upaya peningkatan kekuatan struktur bangunan telah menjadi bahasan yang penting. Kegagalan pada struktur seperti balok dan kolom karena umur, alih fungsi suatu bangunan, bahkan kesalahan desain awal yang lemah atau kurang memenuhi faktor keamanan suatu struktur bangunan. Balok beton bertulangan eksternal adalah salah satu balok yang sedang dikembangkan pada saat ini, yaitu balok beton dengan perkuatan tulangan baja di sisi terluar (eksternal). Penelitian ini bertujuan untuk mengetahui indeks peningkatan kekuatan balok dan daktilitas setelah dilakukan perbaikan menggunakan tulangan baja eksternal, dengan dimensi balok 15 × 15 × 100 cm berulang 12 buah, penambahan tulangan baja eksternal masingmasing 6 buah 2Ø6 dan 3Ø6. Hasil yang didapat dari penelitian ini adalah indeks peningkatan kekuatan lentur balok setelah dilakukan perbaikan menggunakan tulangan baja eksternal. Dimana balok setelah dilakukan perbaikan dengan baja eksternal 2Ø6 memiliki indeks peningkatan rata-rata 1,25 dan 1,21 sedangkan untuk baja eksternal 3Ø6 masing-masing 1,29 dan 1,60. Daktilitas tergantung dari nilai beban ultimit dan lendutan maksimum yang terjadi, dimana nilai daktilitas untuk perbandingan tiap benda uji mengalami reduksi nilai daktilitas rata-rata dengan baja eksternal 2Ø6 yaitu sebesar 37,74% dan 70,95% sedangkan dengan baja eksternal 3Ø6 sebesar 61,65% dan 60,62%.

scholarly journals DUCTILITY RESPONSE OF HYBRID FIBRE REINFORCED CONCRETE BEAMS

2018 ◽  
pp. 174-179 ◽  
Author(s):  
Eswari Natarajan
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Fibre Volume ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Hybrid Fibre ◽  
Service Load ◽  
Strength And Ductility

Abstract: The effect of fibre content on the Strength and ductility behaviour of hybrid fibre reinforced concrete (HFRC) beams having different fibre volume fractions was investigated. The parameters of this investigation included service load, ultimate load, service load deflection, ultimate load deflection, crack width, deflection ductility and energy ductility. The fibre volume fraction (Vf) ranged from 0.0 to 2.0 percent. Steel and polyolefin fibres were combined in different proportions and their impact on the above parameters was studied. The ductile response of hybrid fibre reinforced concrete beams was compared with that of control beam. The test results show that addition of 2.0 percent by volume of hybrid fibres improve the strength and ductility appreciably. Empirical expressions for predicting the strength and ductility of hybrid fibre reinforced concrete (HFRC) are proposed based on regression analysis. A close agreement has been obtained between the predicted and experimental results.

The First Reinforced Concrete Structures in Urban Renewal in an Italian Provincial City

2010 ◽  
Vol 133-134 ◽  
pp. 187-192
Author(s):  
Maria Paola Gatti ◽  
Giorgio Cacciaguerra
Keyword(s):  
Twentieth Century ◽  
Reinforced Concrete ◽  
Urban Renewal ◽  
Research Group ◽  
The Other ◽  
Reinforced Concrete Structures ◽  
Provincial City ◽  
Depth Study ◽  
The University ◽  
The City

For reinforced concrete, we may consider two histories: one focuses on the influence reinforced concrete has exerted on the process of renewal of the architecture of twentieth century; the other pertains to the manners in which the development of this material effectively came about in various geographic areas. The research group at the University of Trento analysed the complex of military constructions produced in the city, and, specifically, it undertook in-depth study of the manner in which the use of reinforced concrete spread to civilian architecture.

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