Retrofit effects for composite beam: - Study on seismic retrofit of beam-to-column connection using supplemental H-section haunches Part 2

Cyclic loading tests were conducted to investigate the seismic retrofit effects for steel beams with floor slab. Strain concentration in the lower flanges due to the presence of concrete slab was significantly reduced by attaching haunches to either upper and lower or lower beam flanges in comparison with un-retrofitted specimen, and plastic deformation capacity was improved. However, when the haunch was applied to only lower beam flanges, strains in the upper flanges tended to increase subjected to negative bending. FE analyses were conducted to verify the effect of retrofit, when attaching haunch to only lower beam flange. Numerical results indicate possibility of avoidance of extensive damage to the upper flanges by enhancing force transfer efficiency of lower haunch.