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 .

scholarly journals Effect of Hollowing Ratio on the Behavior of Hollow Self-Compacting Reinforced Concrete Slender Column Under Eccentric Loading

2018 ◽  
Vol 7 (4.20) ◽  
pp. 390 ◽  
Author(s):  
Ihsan A. S. Al- Shaarbaf ◽  
Mohammed J. H. Al-zubaidi ◽  
Emad A. A. Al- Zaidy
Keyword(s):  
Reinforced Concrete ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Small Eccentricity ◽  
Compression Load ◽  
Load Carrying ◽  
Different Diameters ◽  
Slender Columns ◽  
Slender Column

In this research the behavior of reinforced concrete slender columns with longitudinal hole under axial compression load and uniaxial bending is investigated. The paper includes testing of ten slender columns with dimensions (150 150 1300 mm). The investigation deals with the effect of using different diameters of  column hole on the values of the load carrying capacity and cracking loads, mid-height lateral deflection and longitudinal shortening of the columns. Five diameters for the column holes were considered (0, 25.4, 38.1, 50.8,  and 76.2)mm. Test results have showed that when the holes were located at the center of the column cross-section and the column was loaded with high load eccentricity, the effect of hollowing ratio on load capacity is insignificant. For hollowing ratios used in this study (0%, 2.3% ,5.1%, 9% and 20.3%), the ultimate load is decreased by (0%, 0.28%, 1.03%, 3.28% and 6.48%) respectively. The effect of hollowing ratio on columns  loaded with small eccentricity of 50mm (e/h=.33)  is greater than the effect of hollow ratio of columns with 150 mm eccentricity(e/h=1.0) which reduces the load capacity  for the columns by (0.00%, 0.66%, 2.65%, 4.97% and 11.26%) for hollowing ratios (0%, 2.3%, 5.1%, 9% and 20.3%) respectively.  

scholarly journals Rebars for Durable Concrete Construction: Points to Ponder

2021 ◽  
Author(s):  
Anil K. Kar
Keyword(s):  
Reinforced Concrete ◽  
Carbon Steel ◽  
Carrying Capacity ◽  
High Strength Steel ◽  
Global Climate ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Glass Fiber Reinforced ◽  
Load Carrying ◽  
Total Failure

Reinforced concrete is the number one medium of construction. It is important to have good quality concrete and reinforcing bar (rebar). It is equally important to have competent bond between rebar and concrete. About six decades ago ribbed rebars of high strength steel started replacing plain round bars of mild steel, the use of which had made reinforced concrete constructions durable. It was overlooked that ribbed rebars of carbon steel would be highly susceptible to corrosion at accelerated rates. That would not only make reinforced concrete constructions reach states of distress early, that could also destroy or reduce bond between ribbed rebars and concrete. The continued use of ribbed rebars of high strength carbon steel demonstrates a widespread lack of understanding of the phenomenon of bond between rebars and concrete. This lack of understanding of bond has led to the introduction of epoxy coated ribbed rebars, ribbed stainless steel bars and glass fiber reinforced and granite reinforced polymer rebars, all of which permit reinforced concrete carry static loads because of engagement between such rebars and concrete. But the load-carrying capacity of reinforced concrete elements is impaired, and such elements become vulnerable to local or even total failure during vibratory loads. The use of PSWC-BAR, characterized by its plain surface and wave-type configuration, permits the use of medium strength and high strength steel. In the absence of ribs, the rate of corrosion is greatly reduced. The use of PSWC-BARs, at no added effort or cost, in lieu of conventional ribbed bars, leads to enhancement of effective bond or engagement between such rebars and concrete, thereby leading to increased load-carrying capacity, several-fold higher life span, ductility and energy-absorbing capacity, and great reduction in life cycle cost and adverse impact of construction on the environment and the global climate. In keeping with a lack of understanding of bond between rebars and concrete, there is arbitrariness in the selection of the required level of percent elongation and ductility of rebars.

scholarly journals BEHAVIOUR OF REINFORCED CONCRETE BEAMS WITHOUT STIRRUPS SUBJECTED TO STEEL REINFORCEMENT CORROSION

2016 ◽  
Vol 22 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Rizwan AZAM ◽  
Ahmed K. EL-SAYED ◽  
Khaled SOUDKI
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Longitudinal Reinforcement ◽  
Rc Beams ◽  
Test Results ◽  
Structural Behaviour ◽  
Three Point Bending ◽  
Load Carrying ◽  
Crack Widths

The effect of corrosion on the structural behaviour of reinforced concrete (RC) beams without stirrups was experimentally investigated. A total of seven medium-scale RC beams without stirrups were constructed. The beams measured 150 mm wide, 250 mm deep and 1700 mm long. The test variables included: three different longitudinal reinforcement ratios (0.91%, 1.21%, and 1.82%) and two different corrosion levels (3% and 10%). Four beams were subjected to artificial corrosion whereas three beams acted as control un-corroded. Following the corrosion phase, all beams were tested to failure in three point bending. Corrosion crack widths and cracking patterns were recorded at different stages of corrosion. The effect of different longitudinal reinforcement ratios on the rate of corrosion was observed. Test results revealed that the beams with higher reinforcement ratios experienced slower corrosion rate compared to beams with lower reinforcement ratios. All control beams failed in shear whereas corroded beams failed in bond. There was a significant reduction in the load carrying capacity of the corroded beams without stirrups compared to the control beams.

Vertical load-carrying behavior and design models for micropiles considering foundation configuration conditions

2017 ◽  
Vol 54 (2) ◽  
pp. 234-247 ◽  
Author(s):  
Doohyun Kyung ◽  
Daehong Kim ◽  
Garam Kim ◽  
Junhwan Lee
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
Initial Increase ◽  
Vertical Load ◽  
Test Results ◽  
Ultimate Load Capacity ◽  
Case Examples ◽  
Installation Angle ◽  
Load Carrying ◽  
Load Tests

In the present study, the vertical load-carrying behavior of micropile foundations with various configuration conditions was investigated based on results from model load tests. Considered configuration conditions included micropile inclination angle, spacing of micropiles, and types of micropile foundations. The ultimate load capacity of micropiles varied with installation angle, showing an initial increase and peak followed by a gradual decrease with further increase in installation angle. The ultimate load capacity of micropiled rafts was affected by both installation angle and micropile spacing. The load-carrying mechanism of micropiles for the inclined condition was proposed based on the decomposed axial and lateral load and resistance components. Using the proposed load-carrying mechanism and test results obtained in this study, the load capacity ratio for an inclined micropile was proposed. The group effect and interaction effect factors for group micropiles and micropiled rafts were proposed, respectively, all of which can be used to estimate the load-carrying capacity of micropile foundations. Field load tests were conducted and it was seen that estimated results using the proposed method were in good agreement with measured results. Additional comparison with case examples from the literature also confirmed the validity of the proposed method.

scholarly journals Effect of Number of Wire Mesh Layers and Depth Ratio on Ultimate Shear Force for Monopanel Beam Specimens

2017 ◽  
Vol 26 (1) ◽  
pp. 407-413
Author(s):  
Faris J. Al-Talqany
Keyword(s):  
Shear Force ◽  
Load Capacity ◽  
Local Buckling ◽  
Wire Mesh ◽  
Load Carrying Capacity ◽  
Ultimate Load Capacity ◽  
Steel Bar ◽  
Load Carrying ◽  
Steel Bars ◽  
Different Depths

A monopanel is the system building witch consists of two thin ferrocement block as a faces and  between them a bushy layer of low strength, density and cost as a core made from lightweight material for example from polystyrene foam as using in this investigation  or any material as an insulation . The simple structural idealization of a monopanel system is that the core provides transverse trusses between the faces that prevent flexural ,shear force and compression. Transverse trusses made of steel bars having a diameter of 3.2 mm, which make available as tie reinforcement to prevent the thin ferrocement skins from local buckling, have been used in the present work. These transfer system consist of two longitudinal bars connected by inclined steel bar forming trusses shape making an angle equals to 60o with the longitudinal bars. The main object of this research is to present an experimental investigation on the behavior and load carrying capacity of monopanel beams. The experimental work includes testing six groups of  monopanel beams, and has been investigated the effect of a different depths of monopanel beams and number of layer of wire mesh of skin faces (one or two layers )  on the behavior and the ultimate load capacity. Also comparison of these results with the ACI code 318M-08 formulations have been made.

Study on Ultimate Strength Analysis Method for SWATH Ships

2009 ◽  
Author(s):  
Bin Liu ◽  
Weiguo Wu
Keyword(s):  
Ultimate Strength ◽  
Structural Model ◽  
Strength Analysis ◽  
Test Model ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Analysis Method ◽  
Element Analysis ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

Nowadays, numerical calculation and structural model test are mainly applied in the ultimate strength analysis of ship structure. This paper presents the results of an ultimate strength test to determine the ultimate load-carrying capacity of an ocean-survey SWATH ship. A comparison between nonlinear FEA (finite element analysis) for test model and test results is presented. The FE-models of real ship and model ship as well as their relations are studied.

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.

Steel and Steel-Concrete Composite Columns of HEA-Cross-Sections with Member Imperfections, Subjected to Buckling Compression

2013 ◽  
Vol 743 ◽  
pp. 164-169
Author(s):  
Marcela Karmazínová
Keyword(s):  
Cross Sections ◽  
Initial Imperfection ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Composite Columns ◽  
Geometrical Imperfection ◽  
Load Carrying ◽  
Buckling Resistance ◽  
Normal Strength

The paper deals with the problems of the load-carrying capacity of steel and steel-concrete composite members composed of high-strength materials, subjected to compression. The attention is mainly paid to the buckling resistance in the connection with member imperfections, which are usually covered by the equivalent initial geometrical imperfection expressed as the maximal initial member curving in the mid-length of the buckled member subjected to compression. The paper is oriented to the analytical solution of the initial eccentricity based on the conception of the buckling strength and to the possibilities how to verify the initial imperfection experimentally. The analysis of this problem is shown on the examples of steel and steel-concrete composite columns represented by open HEA cross-section and by the same cross-sections partially encased by normal-strength and high-strength concrete. Using test results of the specimens subjected to compression the comparison of actual values of initial imperfections with the corresponding theoretical values is presented here.

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