Numerical Study on Behavior of Teduced – Beam Connections to T-Shaped Columns in Moment Resisting Frames
Subject Areas : Analysis of Structure and Earthquake
amin fallahi motlagh
1
(
)
ahmad maleki
2
(
استادیار واحد مراغه
)
Keywords: energy absorption, cyclic load, non-elastic strain, shear force, resistance drop,
Abstract :
Extensive studies carried out following the Northridge earthquake showed that several factors contributed to this failure. The high stress concentration in the welds and the attachment vulnerability to high ductility requirements were identified as two main causes of this rupture. A logical way to solve this problem is to reduce the need for a weld in the welded areas and to lower the concentration level of stress. Several corrective methods have been proposed for the construction after the Northridge earthquake as well as the retrofitting of existing reinforced steel structures. One of these methods is the configuration of the shotgun. In this research, after verifying the modeling results using Abacus software, 9 models of modeling of the beam with the dropped wing to the cross column were modeled in three groups. The results of this study are as follows: Reducing the length of the graft has the greatest effect of shear force on non-elastic performance. The shorter graft shear submission mechanism is better than the flexural bending mechanism of the long joints, and the main reason is that in shear joints, the shear forces are constant throughout the bond, so non-elastic strains will be uniformly distributed throughout the graft. Also in the specimen with a 0.6b interval, which has the weakest function, the initial failure (third cycle) of the resistance drop has begun. So that the amount of energy absorption is lower than other samples. The non-cross-sectional sample with energy absorption of 9272 kN / m is 0.75b and 0.6b, respectively, with 11.5% and 66.6% respectively, with energy absorption and greater depreciation than other samples. In the specimen with a bone geometry in the elementary cycles (third cycle), the resistance drop has begun. So that the amount of energy absorption is lower than other samples. The sample with a circular cross section with an energy absorption of 8875 kN / m is 18.6% and 1. 54%, respectively, with a geometric bone and oval geometry, with energy absorption and greater depreciation than other specimens.
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