Strain Rate Effects on a Ductile Moment Resisting Frame with RBS Connection Subjected to Seismic Ground Motions

A procedure has been developed to generate stress-strain curves for mixed-mode hardening plasticity model using test data by other researchers conducted at different strain rates for two grades of steel. The strain rate dependent material properties for these materials are used in different combinations on beams and columns of moment resisting frame (MRF) with RBS to conduct non-linear dynamic analyses subjected to earthquake records at different seismic hazard levels in ABAQUS. The maximum bending moment at different locations of MRF and maximum base shear are found to increase significantly while only a slight decrease in mean predicted inter-storey drift is observed when strain rate dependent material properties are used in analyses. It is observed that MRF with RBS connections can experience a maximum strain rate up to 0.30 per second. The strain hardening factor at RBS center is found to be greater than prescribed value in design specifications.