Rotational Stiffness of Rectangular Hollow Sections Composite Joints

Abstract

Joints in steel rectangular hollow sections filled with concrete present the added difficulty of involving the deformability of the connected faces in bending. This implies that, unless a good estimate of the moment-rotation curve can be obtained, complex and expensive detailing is required to ensure a fairly rigid response of the joint. A first step to achieve the objective of predicting the behavior of such a joint corresponds to an assessment of the initial stiffness of the joint. Starting with a brief review of the current state-of-the-art in the behavior of joints in hollow sections, this paper presents and discusses an analytical model based on an equivalent strip of the loaded face. A simple solution based on this model that has been calibrated with numerical simulations is also derived. The main parameters considered are the thickness of the loaded face and the dimensions of the loading area. Comparisons with some available numerical and experimental results are quite encouraging.