Four different types of full-scale slotted end plate (SEP) connection joints are tested to determine their failure modes and damage mechanisms under ultimate loading. Researches on mechanical behaviors of I-type, T-type, U-type and Groove SEP connection joints bearing compression are studied, which also analyze their force-displacement behaviors and developing processes of deformation and strain. The results show that the bearing capacities of I, grooved, T and U types SEP connections are increased gradually, which indicate the SEP’s type has great influence on the ultimate strength of joints. The instability of SEP is the main factor to cause the loss of bearing capacity of the connection, which is shown through the development of strain, that SEP enters into plastic stage and the other regions still are elastic.
