Experimental and numerical study on compressive behavior of welded hollow spherical joints with external stiffeners

Abstract

Welded hollow spherical joints are one of the most popular joints used in reticulated shell structures. Welded hollow spherical joints in service may need to be strengthened due to age-related damage or unexpected overloading. Adding external stiffeners to the welded hollow spherical joint is an effective way to strengthen it. In this paper, experimental and numerical studies are performed to investigate the enhanced behavior of welded hollow spherical joint with external stiffeners. Axial compression tests of five specimens are performed with a particular focus on the effects of the number, height, and thickness of the external stiffeners on the load-bearing capacity of the joint. A 3D finite element model is developed and calibrated against the experimental results. Parametric studies on a number of design variables are conducted using the calibrated finite element model. The results show that the external stiffeners significantly enhanced the compressive capacity of the joint, and the compressive capacity of the joint is increasing with the number, height, and thickness of the external stiffeners increasing. It is also found that the diameter of the hollow sphere has little impact on the enhanced behavior of the welded hollow spherical joint with external stiffeners. Practical formulas for axial load-bearing capacity and initial axial stiffness of the welded hollow sphere joint with external stiffeners are developed, based on the results of parametric studies.