Experimental Study on Constant-Amplitude Fatigue Performance of Weld Toe in Steel Tube of Welded Hollow Spherical Joints in Grid Structures

Abstract EN

The grid structure with welded hollow spherical joints (WHSJs) is widely used in industrial buildings with suspended cranes.

Cyclic loadings generated by the suspended cranes could result in the fatigue failure of WHSJs.

However, a corresponding fatigue design method has not been established.

This paper presents an experimental study on the fatigue performance of the weld toe in the steel tube of WHSJs under axial force.

Stress distribution on the joint’s surface was obtained by the static load test.

By using the MTS fatigue testing machine, a constant-amplitude fatigue test was performed on the full-scale joint specimens.

Twenty effective test data were obtained and fitted to a fatigue S-N curve by the least squares method.

The corresponding fatigue design method for allowable stress amplitude was established.

The mechanism of fatigue failure at the joint was investigated through microscopic analysis using scanning electron microscopy.

The results of this paper can be potentially used as a basis for revising specifications and to promote the practical application of grid structures with WHSJs.