STUDY ON DESIGN METHOD FOR IRREGULAR JOINTS BETWEEN STEEL BOX COLUMNS AND BEAMS

Quasi-static tests have been carried out on six irregular joints between steel box columns and beams, which are with an abrupt change of cross-sections and commonly used in large-scale plants. Failure mechanism and mechanical behaviors of the irregular joint in steel structures have been studied. A mechanics model is established based on the plastic hinge theory, and the design method for the irregular joint has been put forward. Both test and calculation results indicate that the formula for moment resisting capacity of a regular joint can be employed to calculate the moment resisting capacity of the end of the beam. Only the shear capacity of a small core area needs to be checked if the strength of the panel zone has been ensured. The study can be referred for the design of the irregular joint.