10.11: Fire design of rectangular hollow section joints

Abstract

The component method is a design approach for the characterization of the mechanical properties of structural joints and it is referred to in Eurocode 3 Part 1-8. Eurocode design rules for open sections are already based on the component method. The design rules for joints between tubular hollow sections are still based on simple theoretical mechanical models validated against experimental test results. However, there are research activities in progress to extend the application of the component method also to hollow section joints in the next revision of Eurocode. The fire design of steel joints is carried out in accordance with Eurocode 3 Part 2. Eurocode gives only a guidance on how the temperature of the joint components can be assessed based on the local values of thermal resistance of the joint's fire protection. The method is not sufficient for the component method and Tampere University of Technology is currently carrying out experimental fire research to better understand the temperature distributions in the vicinity of the joint. The aim of the research is to develop experimental methods to determine steel temperatures at the actual joint component, spring, locations and to transfer this information into the joint design approach based on the component method. This paper introduces an experimental research demonstrating the actual temperature distributions within the joint area and highlights the differences between the failure modes and the design criteria at normal temperature design and fire design of a joint.

Effect of radiation inside square hollow section under moderate non-symmetric fire

“…To validate the numerical model of the steel tubular beam, the finite element results of the heat distribution analysis were compared with the experimental results that Bączkiewicz et al provided. 18 The experiments that Bączkiewicz et al 18 conducted were concentrated on tubular joints, but it was observed that temperatures far from the brace/chord connection follow the heat distribution for beam elements. Appendix Figure 4 demonstrates a strong correlation between experimental and numerical results, which means that the model provides a fairly solid prediction of steel tubular beam's thermal behaviour of.…”

“…Meanwhile, Balarupan et al 17 tested also SHS columns under axial loading but subjected to uniform temperatures up to 700°C to study a steel member's global buckling behaviour. A preliminary study on the thermal response of an SHS joint has been described in Bączkiewicz et al 18 The research investigated three KT-joints subjected to standard fire exposure. The research showed that the temperature distribution within a joint is not uniform and that it highly depends on the location of the measured point.…”

“…Therefore, the goal of the paper is to evaluate if the radiation inside the steel tube should be taken into account considering the thermal distribution under the moderate non-symmetric fire conditions. This study was restricted to moderate non-symmetric cases because it was shown 18 that the temperature differences near welded tubular joints can be considered moderate. The further scope of this research was to study the behaviour of these joints in fire.…”

Influence of Internal Pressure on Hollow Section Steel Members in Fire

“…As the material properties change, the interaction of joint and member behaviour at elevated temperatures is a complicated process. The mechanical behaviour of tubular joints, such as T-joints and K-joints of CHS, RHS, and SHS, has been extensively studied in recent years [9][10][11][12][13][14][15][16]. However, there are only a few works that study trusses regarding the interaction of several members and joints.…”