A Study of Historical Test Data for Better Informed Assessment of Wrought Iron Structures

Abstract

Wrought iron was the dominant structural framing material from 1850 to 1890. With similar properties to early mild steel, wrought iron is more variable, creating uncertainty in the assessment of existing structures for which sampling and testing opportunities are limited. This article considers the factors that determine how historical test data may be used to better inform the assessment of wrought iron in structures. Strength values for wrought iron lie between wide limits. Sources of variability include test methods used, the grade or quality of wrought iron, and the type of structural element tested or from which samples have been taken. Yield point became of great importance when the use of elastic stress analysis for beam design became commonplace, and, by 1879, Watertown Arsenal in the United States was publishing stress–strain data. Ten years later, testing wrought iron was a routine part of the education of engineers at universities.