Static strength of doubler plate reinforced CHS X-joints loaded by in-plane bending

In offshore platforms, doubler plates are used to facilitate field installation of auxiliary structural components to the main structure. Recent research on the static strength of axially loaded doubler plate reinforced Circular Hollow Section (CHS) T- and X-joints showed that appropriately proportioned plates can significantly improve the joint strength. This paper extends the numerical study to doubler plate reinforced CHS X-joints subjected to in-plane bending through systematic variation of the main geometric parameters. The load transferring mechanisms and failure modes of such joints, with different doubler plate size and thickness, are investigated and compared to corresponding un-reinforced joints. Within the range of geometric parameters investigated, the doubler plate is observed to provide strength enhancement up to 240% for the corresponding un-reinforced joint. Strength equations are established using the computed results for assessment of the static strength of doubler plate reinforced X-Joints, and. design recommendations are provided for this joint type. (C) 2004 Elsevier Ltd. All rights reserved.