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

91the stress is generally oriented in the direction of rolling, so cracks will usually not bepresent to initiate a fracture in this direction. However, if stresses do occur perpendicularto the longitudinal direction then extreme caution should be used.The fracture surfaces of the charpy impact specimens were also examined. Forthe longitudinal specimens (LS and LU), the fractured surfaces were typical cleavagetype. The transverse specimens had a fracture surface unique to wrought iron which hadan appearance of a slipping or sliding of the grains of the wrought iron again each other.Figure 4.21and Figure 4.22 illustrate these two different types of fracture surfaces.Very few charpy impact data on historic wrought iron were located during theliterature search completed in this study. Green et al. (1999) reported charpy impactstrength data for temperatures ranging 68 o F to 208 o F, which were much higher than thetemperatures used in the testing that was completed in this study. The average charpyimpact strength at room temperature (68 o F) for the data reported by Greeen et al. (1999)was 9.7 ft lbs, which is lower than the average found during testing (16.7 for the LSSpecimens). Other charpy impact strength data and requirements for wrought iron thatwere found during the literature search were based on wrought iron that was producedusing a modern Aston process, which creates a different microstructure and, therefore,should not be compared to the historic wrought iron being evaluated in this study.4.7 Typical Eyebar Connection Testing ResultsBoth finite element analysis and experimental testing were undertaken to evaluatethe end connections of the eyebars from the Bell Ford Bridge. The procedures that wereused for both the analytical and experimental approaches were described in Chapter 3. Inboth methods the stress patterns that arose in the eyebars upon loading were determined.