The FailureAssessment Diagram (FAD) is an accepted approach in assessing the structural safety and integrity of any cracked tubular joint. In order to extend its application to a more complex geometry of any cracked Circular Hollow Section (CHS) tubular T-joint, there are three major challenges needed to be overcome; firstly there is a need to validate the existing FAD curves based on a fixed crack size for the prediction of instability crack growth, secondly it is important to check the accuracy of the available 3D stress intensity factor solutions and the crack driving force Jep or CTOD, and thirdly it is necessary to estimate the fully plastic collapse load Pc solutions for the cracked CHS joints of interest. This paper focus on the plastic collapse load Pc and the CTOD for a cracked CHS T-joint subjected to brace end axial loads, and both Pc and CTOD are estimated using the experimental test and non-linear Finite Element (FE) method.