Advanced modelling of joints between hollow and open sections

Abstract

This dissertation intends to increase the knowledge on the structural behaviour of welded joints between hollow and open sections under static loading. On the most common design rules for steel joints, such as EC 3-1-8, there are two kind of design philosophies. One for joints with open sections and another for joints with hollow sections. As far as the open sections are concerned, it’s possible to apply the component method which allows the designer to consider the joint as a set of individual components and acquire a large knowledge on the strength, stiffness and deformation capacity of each component. Thus, performing its later assembly, it’s possible to obtain the behaviour of the joint as a whole. However, for hollow sections it’s only possible to access the knowledge on the resistant capacity of the joint based on empirical formulas. Considering this limitations, arises the interest to obtain more information on the performance of joints with hollow sections respecting to its resistance, stiffness and deformation capacity. In this study, an analytical, experimental and numerical analysis on the behavior of welded T joints between hollow and open sections was made, with the open section acting as the chord and the hollow section acting as the brace. These joints were studied under compression or bending. Soon after, the referred joints were compared with T-joints between two open sections. For these joints it’s possible to achieve their behaviour according to the component method, so, the aim of this comparison was to verify if it’s appropriate to apply the component method for similar T-joints with hollow sections. Thereby, bringing together all the information achieved, it’s intended to define the basis for a simpler and intuitive method for the design of steel joints independently of the structural elements used. In this particular case, the study is carried out in such a way that the hollow sections could be used in civil engineering with more reliability, accuracy and frequency.