University of Massachusetts Amherst
Adaptive Use Bridge Project
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Lower Bridge in Bondsville Tension Test Methods
View the results of these tension tests here
The tension coupons used in testing were cut from pieces of wrought iron bridge members. Two curved beam hangers from the Lower Bridge in Bondsville were used to create 8 tension coupons. Figure 1 features a photograph of these beam hangers before being cut into tension coupons.
Figure 1. Bondsville beam hangers before being cut into tension coupons.
Tension testing was performed in accordance to ASTM E8-04. The wrought iron material was machined into round coupons with a gauge diameter of 0.5 inches. The dimensions of the tension coupons can be seen in Figure 2. The coupons were held in the tension machine by custom made shoulder grips. Figure 3 features a photograph of the tension grips.
Figure 2. Tension coupon dimensions.
Figure 3. Custom made shoulder grips used to hold the tension coupons during testing.
While testing, the specimens were subject to 0.005 inches of strain per minute until 15 ksi of stress was reached.
During this time, an extensometer was used to accurately measure strain.
After 15 ksi of stress was reached, the extensometer was removed and the strain rate was increased to 0.05 inches per minute.
The testing machine's cross head displacements were used to record strain measurements after the extensometer was removed.
Testing continued until the specimen failed.
Figure 4. Uncorrected and corrected stress strain diagrams.
The tension test results provide valuable information on the material at hand. The modulus of elasticity, yield strength, tensile strength and percent elongation at failure can all be obtained from tension testing. These material properties are used when planning reconstruction of historic bridges.
This material is based upon work supported by the National Science Foundation under
Grant No. DUE-0736972 and Award 0552548.
Any opinions, findings, and conclusions or recommendations expressed in this material are those
of the author(s) and do not necessarily reflect the views of the National Science Foundation.