Cyclic Testing of Steel Moment Connections Rehabilitated With RBS or Welded Haunch.
Cyclic Testing of Steel Moment Connections Rehabilitated
With RBS or Welded Haunch.
Uang, C. M.; Yu, Q. S.; Noel, S.; Gross, J. L.
Journal of Structural Engineering, Vol. 126, No. 1,
57-68, January 2000.
steels; reduced beam section; welded haunch; steel
moment connection; cyclic testing; concretes; concrete
The effectiveness of using the reduced beam section
(RBS) and welded haunch for seismic rehabilitation of
pre-Northridge steel moment connections was investigated
through cyclic testing of six full-scale specimens-three
of them incorporated lightweight concrete slabs. Test
results showed that, unless the low-toughness E70T-4
groove weld was replaced by notch-tough weld metal,
introducing RBS to the beam bottom flange alone could
not prevent brittle fracture in the groove weld of the
top flange. The presence of a concrete slab or removing
steel backing only improved the cyclic performance
slightly. Although two RBS specimens with weld
replacement performed well, a new type of ductile
fracture along the "k" line of the beam was observed.
With E70T-4 groove welds in place, however, the welded
haunch specimens performed better than the RBS
specimens. No brittle fracture occurred when the slab
was present. The composite slab only increased the beam
positive flexural strength by about 10%.