Design of Composite Steel Beams for Bridges

Current AASHTO bridge specifications require that composite beams have sufficient shear studs to fully yield the steel beam cross section in tension. The large number of studs required is independent of the loading on the bridge. It is recommended that partial composite design as used in building specifications be permitted. It is shown that 85% of the full composite strength can be achieved with 40% fewer studs.

The minimum stud spacing requirements in AASHTO were compared with the requirements in other design specifications. Additional research was recommended to evaluate the possibility of relaxing the current minimum requirement. It was shown that the current AASHTO fatigue requirements for stud design are conservative compared to the most recent research but no change is recommended.