scholarly journals Assessment and Optimization of a Clean and Healthier Fusion Welding Procedure for Rebar in Building Structures

2020 ◽  
Vol 10 (20) ◽  
pp. 7045
Author(s):  
Javier Ferreiro-Cabello ◽  
Esteban Fraile-Garcia ◽  
Pedro María Lara-Santillán ◽  
Montserrat Mendoza-Villena
Keyword(s):  
Electrical Resistance ◽  
Thickness Measurement ◽  
Fusion Welding ◽  
Building Structures ◽  
Reinforcing Bars ◽  
Viable Option ◽  
Cycle Times ◽  
Reinforcing Bar ◽  
Welding Procedure ◽  
Welding Cycle

The welding procedure for reinforcing bars used in reinforced concrete takes place at fixed industrial installations. The welders must ensure that the reinforcing bar positions are maintained throughout all stages leading up to concreting. Fusion welding offers an alternative procedure that entails fewer risks for the workers’ health. In this study, we aimed to determine the minimum parameters for the intensity, pressure, and time necessary to ensure the level of performance required by this assembly welding. A total of 2160 joints were manufactured, comprising the different thicknesses. For each thickness measurement, 45 different combinations of parameters were applied. The joints were evaluated based on the resulting dimensions and on the failure force necessary to break the joint. For different thicknesses, the breaking loads were over 7350 N. In addition, the welding cycle times did not exceed three seconds. Based on the results obtained in this study, we concluded that assembling rebar (manufacturing reinforcing bars) by electrical resistance welding is a viable option. This method is fast, safe, and clean, and reduces the risks to the workers’ health.

scholarly journals Study on the Bending and Joint Performances of Reinforced Concrete Beams Using High-Strength Rebars

2021 ◽  
Vol 13 (6) ◽  
pp. 3482
Author(s):  
Seoungho Cho ◽  
Myungkwan Lim ◽  
Changhee Lee
Keyword(s):  
Yield Strength ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
High Yield ◽  
Performance Tests ◽  
Reinforcing Bars ◽  
Joint Performance ◽  
Lap Splice ◽  
Reinforcing Bar ◽  
Nominal Strength

High-strength reinforcing bars have high yield strengths. It is possible to reduce the number of reinforcing bars placed in a building. Accordingly, as the amount of reinforcement decreases, the spacing of reinforcing bars increases, workability improves, and the construction period shortens. To evaluate the structural performance of high-strength reinforcing bars and the joint performance of high-strength threaded reinforcing bars, flexural performance tests were performed in this study on 12 beam members with the compressive strength of concrete, the yield strength of the tensile reinforcing bars, and the tensile reinforcing bar ratio as variables. The yield strengths of the tensile reinforcement and joint methods were used as variables, and joint performance tests were performed for six beam members. Based on this study, the foundation for using high-strength reinforcing bars with a design standard yield strength equal to 600 MPa was established. Accordingly, mechanical joints of high-strength threaded reinforcing bars (600 and 670 MPa) can be used. All six specimens were destroyed under more than the expected nominal strength. Lap splice caused brittle fractures because it was not reinforced in stirrup. Increases of 21% to 47% in the loads of specimens using a coupler and a lock nut were observed. Shape yield represents destruction—a section must ensure sufficient ductility after yielding. Therefore, a coupler and lock nut are effective.

scholarly journals Development of a structure of norms for steel products based on a principle of advanced standardization

2019 ◽  
Vol 17 (1) ◽  
pp. 86-93
Author(s):  
Sergey V. Snimshchikov ◽  
Marina A. Polyakova ◽  
Aleksandr S. Limarev ◽  
Veniamin A. Kharitonov
Keyword(s):  
Product Quality ◽  
International Norms ◽  
International Standards ◽  
National Standards ◽  
Reinforcing Bars ◽  
Reinforcing Bar ◽  
Analysis And Synthesis ◽  
Standard Structure ◽  
National Practice ◽  
Quality Indexes

Problem Statement (Relevance): It is shown in the paper that at present one of the important problems in standardization is to harmonize requirements in standards with international norms. It is caused by the necessity to increase the product competitiveness in the external market conditions. At the same time, national practice in standardization, a variety of valid standards on the same product as well as the existing structure of standards do not make it possible to fully harmonize product quality indexes which are normalized in national standards with the relevant indexes of the best world similar standards. Objectives: Development of a new concept for a standard structure which allows combining requirements of both valid national standards and international norms. Methods Applied: When developing a new concept for the standard structure, the authors used universal methods of scientific cognition: analysis and synthesis, deduction, analogy, extrapolation, abstraction. Originality: Novelty of the proposed approach is based on the development of a new procedure for creating standards taking into consideration the existing practice in the product quality indexes setting, the level of similar world quality indexes, and economical factors. Findings: The paper presents the application of the developed concept for a standard structure by the example of an interstate standard for reinforcing bars. It was shown that a basic difference in the standard structure is that the standard had two sections. The first section contains norms valid in revoked national standards. The second section includes the requirements which were harmonized with the international standards. This makes it possible for a manufacturer to choose independently such kind of a technological process for reinforcing bar production which fully corresponds with the existing process facilities. Practical Relevance: The proposed concept for arrangement of the standard structure makes it possible to take into consideration the existing national experience in the area of setting norms for product quality indexes which are to the maximum extent harmonized with the level of similar world properties.

Study on Evaluation Method of Corroded Reinforcing Steel

2010 ◽  
Vol 26-28 ◽  
pp. 1184-1189 ◽  
Author(s):  
Ying Zi Zhang ◽  
Ying Fang Fan ◽  
Hong Nan Li ◽  
Xue Nan Wu
Keyword(s):  
Weight Loss ◽  
Energy Loss ◽  
Cross Section ◽  
Strain Energy ◽  
Evaluation Method ◽  
Reinforcing Bars ◽  
Reinforcing Bar ◽  
Important Index ◽  
Steel Bars ◽  
Strain Energy Loss

Corrosion ratio is an important index to study the mechanical deteriorates of the steel bars, which has a significant effect to evaluate the residual bearing capacity of reinforced concrete structures. To investigate the mechanical properties of the corroded steel bars, Strain energy loss as corrosion ratio is firstly proposed. Tensile test are conducted on ribbed and plain steels, which are corroded by acceleration corrosion method. Comparing with the weight loss and cross-section loss to describe the effect of corrosion of reinforcing bar, the strain energy loss of reinforcing bars is calculated by Simpson quadrature. Results from this paper and other researchers’ test suggest that the strain energy loss may be a better parameter than weight loss or section loss which to assess the corroded steel bars.

Research on Effects of Inhibitors on Anti-Corrosion Performance of Reinforced Bar in the Concrete

2011 ◽  
Vol 239-242 ◽  
pp. 1195-1198 ◽  
Author(s):  
Liu Bin Song ◽  
Dao Wu Yang ◽  
Zhong Liang Xiao ◽  
Feng Zhang
Keyword(s):  
Open Circuit Potential ◽  
Electrode Array ◽  
Open Circuit ◽  
Reinforcing Bars ◽  
Corrosion Performance ◽  
Cement Concrete ◽  
Corrosive Media ◽  
Reinforcing Bar ◽  
Wire Beam Electrode ◽  
The Impact

The corrosion behavior of reinforcing bars in concrete was studied by simulating the 4×4 wire-beam electrode array. Different inhibitors were added to reinforced concrete. By measuring the open-circuit potential of an iron wire, the impact of different inhibitors on the corrosion of rebar in the concretes was studied after immersion in NaCl solution. The result showed that best protection was achieved by adding NaNO2 and aniline as inhibitors jointly to the concrete, as this combination maintained the open-circuit potential within the passivation range at all times, so ensuring the integrity of the passive membrane. By addition of this combination of the inhibitors, the compactibility of the cement concrete structure can be increased, thereby protecting the reinforcing bar against the external corrosive media.

scholarly journals Experimental Study on Bond Behavior between Plain Reinforcing Bars and Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guohua Xing ◽  
Cheng Zhou ◽  
Tao Wu ◽  
Boquan Liu
Keyword(s):  
Aluminium Alloy ◽  
Structural Characteristics ◽  
Bond Stress ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Bond Behavior ◽  
Reinforcing Bar ◽  
Test Parameters ◽  
Steel Bars ◽  
Plain Bars

To evaluate the bond behavior between the reinforcing bar and surrounding concrete, a total of six-group pullout specimens with plain steel bars and two-group specimens with deformed steel bars, serving as a reference, are experimentally investigated and presented in this study. The main test parameters of this investigation include embedment length, surface type of reinforcing bars, and bar diameter. In particular, the bond mechanism of plain steel reinforcing bars against the surrounding concrete was analyzed by comparing with six-group pullout specimens with aluminium alloy bars. The results indicated that the bond stress experienced by plain bars is quite lower than that of the deformed bars given equal structural characteristics and details. Averagely, plain bars appeared to develop only 18.3% of the bond stress of deformed bars. Differing from the bond strength of plain steel bars, which is based primarily on chemical adhesion and friction force, the bond stress of aluminium alloy bars is mainly experienced by chemical adhesion and about 0.21~0.56 MPa, which is just one-tenth of that of plain steel bars. Based on the test results, a bond-slip model at the interface between concrete and plain bars is put forward.

scholarly journals THE RISK-ORIENTED APPROACH TO THE DEVELOPMENT OF CONTROL METHOD

2018 ◽  
Vol 9 (2) ◽  
pp. 155-166
Author(s):  
P. S. Serenkov ◽  
V. L. Hurevich ◽  
M. R. Movlamov ◽  
A. S. Yetumya
Keyword(s):  
Flame Retardant ◽  
Coating Thickness ◽  
Process Model ◽  
High Efficiency ◽  
Control Method ◽  
Control Point ◽  
Thickness Measurement ◽  
Building Structures ◽  
Flame Resistance ◽  
Model Control

The necessity for scientific and methodical study of methods for monitoring the characteristics of flameresistance of building structures has the highest priority in the field of fire safety. The aim of this work was to provide the required degree of reliability of the results of quality control of flame-resistant coatings of building structures and high efficiency of decisions due to the risk-based approach to the development of control methods.Substantiated risk-based approach to the development of methods of control, involving the consideration on the basis of process model, control flame-resistance of building object in all possible potential problems that can cause the risk of incorrect decision-making. A model of the risks arising from the control of the flameretardant coating thickness has been developed. Two major risk groups have been identified. The first group is related to the uncertainty of coating thickness measurement at a single control point. The second group of risks is related to the unrepresentativeness of selective control over the entire surface of the construction object as a whole Potential risk sources have been identified for each group. For the entire range of sources of particular risks the results of studies of the mechanisms of their manifestation, the estimated degree of influence on the accuracy of the control of compliance of flame-retardant coating thickness requirements. The analysis is carried out on the basis of both theoretical and experimental statistical studies on a number of construction projects.According to the results of the analysis of all particular risks of control unreliability, rational ways of their minimization in the form of technical or organizational and technical measures, which are refl in the developed project of the control method, are proposed. Project control method was built on the basis of a agreed scheme of control of the thickness of the fl coating of building structures sequentially the three parties. Formulated and solved the task of the metrological control of the thickness of the flame-retardant coating as indirect measurement methods non-destructive thickness measurements. Theoretical and applied aspects of the process of flame-retardant coating thickness control of building structures under conditions of high risk of making incorrect decisions on the results of control are considered.

Effect of edge distance on shear friction capacity of steel plates anchored with reinforcing bars in comparison with headed bolts

2019 ◽  
Vol 46 (8) ◽  
pp. 742-758
Author(s):  
Tarek S. Sabra ◽  
Hatem Hassan Ibrahim
Keyword(s):  
Steel Plate ◽  
Shear Capacity ◽  
Steel Plates ◽  
Experimental Program ◽  
Reinforcing Bars ◽  
Reinforcing Bar ◽  
Edge Distance ◽  
Shear Friction ◽  
Design Values ◽  
Friction Capacity

The shear friction capacity calculated using clauses 11.6.4 to 11.6.10 in ACI 318-14 or clauses 11.5.1 to 11.5.6 in CSA-A23.3-14 do not take into consideration the effect of edge distance on the shear friction capacity. The main objectives of this research are to study the effect of edge distance on the shear friction capacity by means of a specifically designed experimental program, to determine the minimum edge distance to develop the shear friction capacity, and to derive an expression for reduction of shear friction capacity for edge distances less than the minimum edge distance. The study involved testing eight specimens. In four specimens, a steel plate was anchored using welded reinforcing steel bars, and in the other four specimens the steel plate was anchored using headed concrete anchors (bolts) (HCA). The steel plates were tested under shear load at edge distances of 75, 150, 225, and 300 mm (3.0, 6.0, 9.0, and 12.0 in), for the two types of anchorage. The results were compared to design values according to ACI 318-14 and CAN/CSA-A23.3-14 standards. An equation is derived to compute the minimum edge distance after which the full shear friction capacity is developed. Another equation is derived to compute the proposed shear capacity for reinforcing bar anchors for edge distances less than the minimum edge distance.

scholarly journals Experimental Study Regarding the Influence of Welding Parameters on the Mechanical Behaviorof High Density Polyethylene Pipes

2021 ◽  
Vol 57 (4) ◽  
pp. 209-215
Author(s):  
Ibrahim Ramadan ◽  
Maria Tanase
Keyword(s):  
Experimental Study ◽  
High Density Polyethylene ◽  
Experimental Tests ◽  
High Density ◽  
Fusion Welding ◽  
Welding Parameters ◽  
Visual Examination ◽  
Polyethylene Pipes ◽  
Pressure Tests ◽  
Welding Procedure

The experimental study conducted for this article was made using the butt fusion welding procedure for high density polyethylene (HDPE) pipes. PE100 (SDR 17, PN 10) water pipes were used, as for the experimental study parts of around 200 to 300 mm were welded, using different welding parameters. The influence of the welding parameters on the pipes resistance was analyzed, through visual examination and experimental tests such as tensile, bending and pressure tests.

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