Retrotting I-beam to double-I built-up columnconnections using through plates and T-stiffeners

Double-i built-up sections have been used extensively in iran, according toprevious versions of iranian building codes. despite recent developments in steel momentconnections, based on studies for i-beam to h-shaped column connections, there arefew documents available for i-beam to double-i built-up column connections. recentstudies have revealed that connections with double-i built-up columns exhibit dierentbehavior compared to connections with h-shaped columns. due to excessive out-of-planedeformations of the cover plate in non-retrotted moment connections, they have semi-rigidbehavior. the objective of this study is to build on previous studies and to investigate straindistribution patterns and load transfer mechanisms in the retrotted i-beam to double-ibuilt-up column connections using plates and t-stieners. in this paper, both horizontaland vertical elements of the t-stieners were modied and studied. analytical modelswere designed and analyzed under cyclic and monotonic loadings. three dierent indiceswere computed in the connection region in order to assess the local failure potential and themoment-rotation hysteretic curves were employed to evaluate the seismic performance of theconnections. with the proposed congurations, strain is uniformly distributed within thecritical elements. moreover, excessive deformation of the column cover plate is eliminated