Fatigue Strength of Composite Beams With a Reduced Number of Shear Connectors in Highway Bridges

摘要

The report is an investigation comparing the fatigue strength of shear connectors in composite beams of 8 WF 17 (ASTM A36 steel) with 1/2 inch diameter, 2 inches long headed shear connectors; in a 3 inches thick, 30 inches wide concrete slab of 3000 psi cylinder strength. There were three series of beams, with four identical beams in each series designed for two concentrated loads applied 9 feet from each end support of a 20 foot span. Series A and B beams were designed for a repetition of 500,000 cycles at a rate of 100 cycles per minute on the basis of an S-N curve for fatigue data on 1/2 in. stud shear connectors obtained by other investigators. The difference between series A and B is that the series A beams have a stress factor of safety of 1.4 whereas series B have only 1.0 factor of safety. Series C beams were designed in accordance with the AASHO specifications of the 1961 edition. Three beams of each series were tested under cyclic loading and the fourth beam was tested statically to determine and compare ultimate load capacity of these beams. (Author)