Evaluation of Influence of Hole Making Upon the Performance of Structural Steel Plates and Connections

15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. Project title: Performance and Effects of Punched Holes and Cold Bending on Steel Bridge Fabrication 16. Abstract A large experimental study was undertaken to determine the effect of hole making upon the strength, ductility, and fatigue performance of structural steel plates and connections. The variables included steel strength, plate thickness, hole size, punch to die clearance, galvanizing, temperature, and edge distance. Approximately 300 tension and fatigue tests were performed. The study agreed with the results of previous research that plates with punched holes have lower strength and ductility than ones with drilled holes. The fatigue performance of plates with punched holes was also less than ones with drilled holes. Galvanizing further reduced the fatigue strength of plates with punched holes. The effect upon hole making upon the fatigue strength and to some extent the tensile strength reduced when fully pretensioned bolts were used. Empty holes had a lower fatigue strength then holes used in a bolted connection. The practice of increasing the hole diameter by 1/16 in. when calculating the net section of a tension member did not account for the reduction in strength when the hole was punched. It is recommended that this increase in hole be eliminated and the tension strength of members with punched holes be taken as 90% of normal design values. Due to the low ductility of plates and connection with punched holes, punched holes should only be used in secondary members that do not need the ductility required in main members. The appendix of the report gives the recommended specifications.