Result Validation Analysis of Steel Testing Machines
Structural failures occur due to a number of reasons. These may include under design, poor workmanship, substandard materials, misleading laboratory tests and lots more. Reinforcing steel bar is an important construction material, hence its properties must be accurately known before being utilized in construction. Understanding this property involves carrying out mechanical tests prior to design and during construction to ascertain correlation using steel testing machine which is usually not readily available due to the location of project. This study was conducted to determine the reliability of reinforcing steel testing machines. Reconnaissance survey was conducted to identify laboratories where yield and ultimate tensile strengths tests can be carried out. Six laboratories were identified within Ibadan and environs. However, only four were functional at the time of the study. Three steel samples were tested for yield and tensile strengths, using a steel testing machine, at each of the four laboratories (LM, LO, LP and LS). The yield and tensile strength results obtained from the laboratories were compared with the manufacturer’s specification using a reliability analysis programme. Structured questionnaire was administered to the operators in each laboratory to consider their impact on the test results. The average value of manufacturers’ tensile strength and yield strength are 673.7 N/mm2 and 559.7 N/mm2 respectively. The tensile strength obtained from the four laboratories LM, LO, LP and LS are given as 579.4, 652.7, 646.0 and 649.9 N/mm2 respectively while their yield strengths respectively are 453.3, 597.0, 550.7 and 564.7 N/mm2. Minimum tensile to yield strength ratio is 1.08 for BS 4449: 2005 and 1.15 for ASTM A615. Tensile to yield strength ratio from the four laboratories are 1.28, 1.09, 1.17 and 1.15 for LM, LO, LP and LS respectively. The tensile to yield strength ratio shows that the result obtained from all the laboratories meet the code requirements used for the test. The result of the reliability test shows varying level of reliability between the manufacturers’ specification and the result obtained from the laboratories. Three of the laboratories; LO, LS and LP have high value of reliability with the manufacturer i.e. 0.798, 0.866 and 0.712 respectively. The fourth laboratory, LM has a reliability value of 0.100. Steel test should be carried out in a laboratory using the same code in which the structural design was carried out. More emphasis should be laid on the importance of code provisions.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.2021585Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 258
 ASTM A37-07a, Standard Test Methods and Definitions for Mechanical Testing of Steel Product: America Society of Testing Materials
 A615/A615M-14. Standard Specification for Deformed and Plain Carbon-steel Bars for Concrete Reinforcement. America Society of Testing Materials
 Akinpelu, J.A. 2002. The need for code of conduct, building regulations and by-laws for the industry in Nigeria. The Professional Builder, Nigeria Institute of Building, 2(1): 11 – 14.
 Fredericks, M. and Ambrose, J. 1989. Building Engineering and Systems Design, Van Nostrand Reinhold, New York 2(3)
 Jansen, R., Wiertz, L., Meyer, E., and Noldus, L. 2003. Reliability analysis of observational data: Problems, solutions, and software implementation. Behaviour Research Methods, Instruments and Computers, 35(3), 391-399.
 Oyenuga V.O. 2001. Simplified Reinforced Concrete Design. Second Edition, Asros Ltd, Surulere, Lagos.
 Oyewande, B. 1992. A Research for Quantity in the Construction Industry’s Building Magazine, June/July Ed., Lagos.
 Satyendra 2014. Reinforcement Bars and its Important Characteristics. Posted on July 5, 2014 in Ispat Digest.
 Yao W., Jiang, Wei S., Fei W, and Cai T. 2017. Correlation between the Compressive, Tensile Strength of Old Concrete under Marine Environment and Prediction of Long-Term Strength. Advances in Materials Science and Engineering Vol 2017(2017) Article ID 8251842, 12 pages.
 Bhandari V.B. 2001. Introduction to Machine Design. Tata McGraw-Hill Publishing Company Limited, New Delhi.
 BS 4449:2005. Steel for the reinforcement of concrete