INFLUENCE OF INITIAL IMPERFECTION ON ULTIMATE STRENGTH OF T-SECTION STEEL COMPRESSION MEMBERS

Abstract

The slenderness ratio is one of the most important factors for the steel compression members
and the initial displacement and residual stress are most widely used in practical fields while considering initial
imperfection factors as they show significant influence in the decreasing of the ultimate strength. Present work
emphasizes on the capacity analysis of T-section steel compression member with the initial imperfection to
predict the ultimate strength of T-section members as there were some difficulties in fully understanding and
introducing initial imperfection into 3D FE models. To fulfill the goal, finite element models with different
slenderness ratios are considered to assess the good accuracy in numerical results and ultimate strength
formulae of T-section steel compression members are established for both beam and shell element models.
Comparison between numerical results of current work and some design strength such as JSBH 2012,
AASHTO 2010, etc., were performed to confirm the agreement between current work and existing design
strength. Moreover, the influence of initial displacement and residual stress on beam and shell element models
was investigated. The parametric study of relative loads Vs relative displacement due to initial imperfection
regarding slenderness ratio was also presented. According to the numerical analyses results, initial
displacement affects more in beam element models and residual stresses affect more in shell element models.
For the models considering both initial imperfection factors, effects in shell elements models are more
dominant. The ultimate stresses get form present study’s formula show slightly higher values than the design
strength of existing codes.