Branch Plate-to-Circular Hollow Structural SectionConnections. I: Experimental Investigation and Finite-Element Modeling

Abstract

Although branch plate-to-circular hollow section (CHS) connections under branch axial load are simple to fabricate and cost-effective, they generally experience significant deformation at relatively low loads resulting in an imposed deformation limit. To increase the connection capacity, various stiffening methods such as use of ring stiffeners, grout filling, and “through plate” connections have been proposed. To determine the effectiveness of previously unstudied plate-to-CHS through plate connections, an experimental investigation consisting of 12 connections was undertaken. Additionally, the behavior of nonorthogonal or skewed connections and the effect of load sense were examined. The experimental study determined that through plate-to-CHS connection behavior can be obtained by algebraically combining the behavior of a T-type branch plate-to-CHS connection in tension with another in compression. Moreover, the through plate connection increased the capacity by more than three times that of a branch plate connection loaded in compression. Finite-element (FE) models were constructed to replicate, and be compared with, the experimental connections to validate the use of FE modeling for a subsequent parametric study with the aim of expanding the scope of the experimental results database.