Evaluation and Repair of Wrought Iron and - Purdue e-Pubs ...

20significant variation in the percent elongations of the wrought iron tested. Figure 2.12 isa plot showing the percent elongations found from this testing.All of the data collected from the historic sources previously described wascomplied together and compared. Figure 2.13 shows a plot of the tensile stress valuesfound for every type of wrought iron. This plot shows that majority of the tensilestrength values collected fall into a one-standard-deviation range, with the exception ofthe data collected from Sweden. The average ultimate tensile stress for the entire set ofdata collected was 54,000 psi with a standard deviation was 9,000 psi which is 16.71% ofthe average.The wrought iron bar data was also collected and compared to get a betterestimate of the strength of the material that would be typically used for bridgeapplications. The average of all the wrought iron bar tensile strengths was 53,300 psiwith a standard deviation of 5,800 psi, which was 11% of the average tensile strength.The standard deviation of just the bars was smaller than the standard deviation for all ofthe material, which indicates that separating the ultimate tensile stress values by producttype (angle iron, bar, plate, etc) is more accurate. Figure 2.14 shows a plot of the bartensile strengths. In this plot, majority of the tensile strength values fall between plus andminus one standard deviation from the mean.A comparison of the percent elongation data was also completed. It is importantto note that all this data consists of testing samples with different lengths used tocalculate the percent elongation which could increase the variability of the data. In thiscomparison, all the data collected for percent elongation of wrought iron was from barmaterial. Figure 2.15 is a plot showing this data. In this plot it can be seen that there is awide variation in the data. The average for this data was 23.2% with a standard deviationof 7.6%, which was 33% of the mean. This shows that the percent elongation data variesconsiderably.