Effect of the varation of hollow core diameter in rectangula plain concrete beams

2009 ◽  
Vol 12 (1) ◽  
Author(s):  
OU Orie ◽  
OM Alile
Keyword(s):  
Concrete Beams ◽  
Plain Concrete ◽  
Hollow Core ◽  
Core Diameter

scholarly journals Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang
Keyword(s):  
Structural Parameters ◽  
Transmission Band ◽  
Confinement Loss ◽  
Hollow Core ◽  
Core Size ◽  
Core Diameter ◽  
Mid Infrared ◽  
The Core ◽  
Tubular Type ◽  
Beam Delivery

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.

Determination of Creep Behavior of Concrete Beams Made with Rice Husk Ash

2021 ◽  
Vol 15 (1) ◽  
pp. 339-346
Author(s):  
Winfred Mutungi ◽  
Raphael N. Mutuku ◽  
Timothy Nyomboi
Keyword(s):  
Prediction Model ◽  
Rice Husk ◽  
Creep Behavior ◽  
Rice Husk Ash ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Reinforced Concrete Beams ◽  
Partial Replacement ◽  
Design Strength ◽  
Concrete Production

Background: Creep in concrete is a long-term deformation under sustained loading. It is influenced by many factors, including constituent materials, environmental conditions, among others. Whenever there is an alteration in the convectional concrete preparation process, the creep characteristics need to be realistically assessed. In the present construction, rice husk ash has been used for partial replacement of cement in concrete production. This is because its properties of both tensile and compressive strength in concrete have been tested and found comparable with plain concrete. However, durability characteristics such as creep, which take place in the long run, have not been realistically assessed. Therefore, it is important to study the creep of rice husk ash concrete, which will further help in the development of a creep prediction model for such concrete for use by design engineers. Objectives: Rice husk ash was used as supplementary cementitious material in concrete, and the creep behavior was studied with the aim of producing a creep prediction model for this concrete. Methods: The cement was replaced with 10% of rice husk ash in concrete with a design strength of 30MPA. Reinforced concrete beams were cast and loaded for flexural creep 35 days after casting. The loading level was 25% of the beam’s strength at the time of loading. The creep observation was done for 60 days. The rice husk used was obtained locally from Mwea irrigation scheme in Kenya. The experiments were carried out in our school laboratory at Jomo Kenyatta university of Agriculture and Technology. Results: The creep strain data of rice husk ash concrete beams was obtained with the highest value of 620 micro strain for 60 days. The results were used to develop a creep prediction model for this concrete. Conclusion: A creep prediction model for rice husk ash concrete has been developed, which can be adopted by engineers for class 30 of concrete containing rice husk ash at a 10% replacement level.

Energy Balance in Instrumented Impact Tests on Plain Concrete Beams

1989 ◽  
pp. 26-36 ◽  
Author(s):  
N. P. Banthia ◽  
Sidney Mindess ◽  
Arnon Bentur
Keyword(s):  
Energy Balance ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Impact Tests

Inducing recovery stress of NiTiNb SMA wires using heat of hydration for confining concrete

2011 ◽  
Vol 22 (17) ◽  
pp. 1949-1957 ◽  
Author(s):  
Eunsoo Choi ◽  
Baik-Soon Cho ◽  
Joonam Park ◽  
Kyoungsoo Park
Keyword(s):  
Residual Stress ◽  
Shape Memory ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Heat Of Hydration ◽  
Reinforced Concrete Beams ◽  
Recovery Stress ◽  
Concrete Cylinders ◽  
Temperature Window ◽  
Compressive Tests

This study suggests the utilization of heat of hydration of concrete to activate the shape memory effect (SME) of shape memory alloy (SMA) wires embedded in concrete and produce recovery and residual stress on the wires. This method is more convenient than the previous electronic resistance heating. For the purpose, this study prepares NiTiNb SMA wires that show appropriate temperature window for the use of heat of hydration. Axial compressive tests of concrete cylinders confined by the NiTiNb SMA wire jackets are used to prove that the utilization of heat of hydration is valid to generate recovery and residual stress in the SMA wires. The confined cylinders show increased peak strengths and much larger failure strains than those of the plain concrete. The general behavior of the SMA wire-confined specimens in this study is similar to that of specimens heated by electronic heating jacket. Also, this study explains two examples for the utilization of heat of hydration for the SME in reinforced concrete beams and columns.

Flexural Tests of Fiber-Reinforced-Concrete Beams Reinforced with FRP Rebars

2012 ◽  
Vol 166-169 ◽  
pp. 1797-1800
Author(s):  
Hong Chang Qu ◽  
Hong Yuan Li ◽  
Xuan Zhang
Keyword(s):  
Concrete Beams ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Performance ◽  
Flexural Tests ◽  
Hybrid Reinforcement ◽  
Brittle Mode

This paper investigates the flexural performance of FRP/FRC hybrid reinforcement system as well as FRP/plain concrete beams. Test results showed that the crack widths of FRP/FRC beams were smaller than those of FRP/plain concrete beams at the different corresponding load. With the increase of load, the crack spacing slightly decreased. The plain concrete beams failed in a more brittle mode than the FRC beams. Once they reached their ultimate moments, the load dropped fleetly. Compared to the companion beam, the addition of fibers improved the flexural behavior.

Size-independent fracture energy in plain concrete beams using tri-linear model

2011 ◽  
Vol 25 (7) ◽  
pp. 3051-3058 ◽  
Author(s):  
S. Muralidhara ◽  
B.K. Raghu Prasad ◽  
B.L. Karihaloo ◽  
R.K. Singh
Keyword(s):  
Fracture Energy ◽  
Linear Model ◽  
Concrete Beams ◽  
Plain Concrete

Prediction of Fatigue Life of Plain Concrete Beams from Fracture Tests

1994 ◽  
Vol 22 (3) ◽  
pp. 183 ◽  
Author(s):  
DR Petersen ◽  
DV Ramsamooj
Keyword(s):  
Fatigue Life ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Fracture Tests

Dynamic fracture of notched plain concrete beams: 3D finite element study

2015 ◽  
Vol 77 ◽  
pp. 176-188 ◽  
Author(s):  
Natalija Bede ◽  
Joško Ožbolt ◽  
Akanshu Sharma ◽  
Bariş İrhan
Keyword(s):  
Finite Element ◽  
Dynamic Fracture ◽  
Concrete Beams ◽  
Plain Concrete ◽  
3D Finite Element ◽  
Finite Element Study ◽  
Element Study
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