Adding Fatigue Life to Cover Plate Ends

A parametric analysis was performed of simple-span and two-span continuous bridge girders with cover plates. The cover plates were either end-bolted or end-welded and ground, with available data suggesting a fatigue resistance corresponding to Category B and C, respectively. All results were compared with conventionally welded cover plates, with ends designed to Category E. End-bolted cover plates need not be extended beyond the theoretical cut-off point because fatigue does not control the design for any loading case. Stress ranges are lower than the fatigue limit, and girders up to 5 percent lighter. When the end weld is ground to a 1:3 taper, fatigue governs the cover plate length for over 2 million cycles, but not for 500,000 cycles. Girders weigh up to 3.7 percent less. The saving in the cost of cover plate material is equal to or greater than the added cost of end-bolting or end-grinding.