Design of circular steel flange plates subjected to tension loads – yield line approach

Abstract

The use of circular steel flange plates with circular bolts pattern connections is common in tubular structures used in different applications such as transmission and communication structures. Several published literatures include methods for the design of these connections under tension loads. These methods are not widely used in the industry as they are either complex or yielding results that are not always consistent with published test data. Therefore, there is still a need for a simplified, yet accurate, method for designing these connections when subjected to tension loads.This paper presents a numerical study performed on circular flanged connections subjected to concentric axial tension loads. The analysis part of the study is conducted using the Finite Element (FE) package ADINA considering one common geometrical flange plate configuration, ring configuration, while considering contact surface separation. The results obtained from the FE analyses are compared with published experimental data from which it is concluded that the FE model can predict the behaviour of these connections with a high degree of accuracy.Parametric investigation is then conducted to numerically expand the experimental data to gain more insight into the behaviour of these flange plate connections and to use this data later in this work to validate the proposed design method. The varying parameters considered in the numerical investigation include base plate thickness; number of bolts; bolt circle diameter and plate diameter.A simple design approach based on yield line theory is then introduced and a comparison between yield loads predicted using the proposed model and the finite element results is presented. The yield loads resulting from proposed design method show good agreement with the finite element results with 10% maximum difference.