Analysis of Local Stress and Vertical Deflection of Down Chord of Inverted Triangle Cargo Boom of Tower Crane

Abstract

Based on the inverted triangle cargo boom of ST80238 tower crane as the research object, the author took its local down chord as calculation model. ANSYS software is applied to impose the constraints and loads on the model, and the stress and deflection are analyzed. The results show that the top flange of the down chord and the web will be influenced by the axial force of the oblique truss, and larger local stress in the joint position and the surrounding of the oblique truss and the down chord are produced, as well as the largest local stress will be produced in the centre of the connective position, and reducing gradually to the surrounding. In the condition of the box section center line of the down chord is constant, moreover the size of the down flange and the web is increased, and the local stress and vertical deflection nearby the joint of the oblique truss and the down chord will be reduced. Though the research, the local instability of down chord of ST80238 tower crane can be prevented,and a direct reference and basis for box beam of down chord can be provided.