Welded circular hollow section joints subjected to cyclic loads are prone to crack propagation contributing to failure at the welded toe due to
the fragile stiffness of the chord joint at its radial direction. The tubular chord connection equipped with a brace can be reinforced by a doubler plate to
increase the chord stiffness and avoid such failure. In this research experimental and analytical investigations were carried out to justify the efficiency of
doubler plate in strengthening CHS T-joints against cyclic loads. An experimental study was performed on four full-scale specimens, two with doubler
plate, and the others without the reinforced plate. The joint capacity of hysteretic curve plotting was extracted from the experimental results. A finite
element analysis study was conducted using the ABAQUS software package and results were in favorable agreement with the experimental findings.
The effect of chord stiffness α on the joint capacity required the extension of a numerical study with an additional Finite Element Model (FEM). The
current research justified the improvement of joint positive capacity by 40%, and enhancement of negative capacities by 70%. The relation between
capacity and α is expressed by an empirical equation Enhancement in energy dissipation was confirmed with the existence of doubler reinforced plate