Experimental research and finite element analysis on square flange joint used in steel poles under bending moments.

This paper reports an experimental study about the mechanical properties of square rigid flange used in steel transmission poles. Static tests were carried out on six specimens of square flange in two groups, and finite element models were employed to simulate the test loading procedure. It is indicated that good agreement exists between FEA results and experimental results. According to the current standards, the square flange and ribs can be safely designed with the method of circular flange design, but it is unreliable to use the method for bolts under combined tension and bending stresses. Actually, overstress of bolts is caused by the asymmetrical distribution of flange stiffness. In this paper, it is recommended to use the comer cut flange and ribs placed along the upper and lower sides to reduce the non-uniformly distributed stress. Finally, the axis of bolts in second row is suggested to be the rotation axis under the bending load, and the maximum stress of bolts is close to the experimental results, which is 20% larger than the value according to the current standards. [ABSTRACT FROM AUTHOR]