This paper describes a collaborative project between the US, Ireland, and Northern Ireland (UK) to investigate advanced manufacturing cutting techniques for the creation of a new class of intermeshed steel connections that rely on neither welding nor bolting. To date, advanced manufacturing equipment has only been used to accelerate traditional processes for cutting sheet metal or other conventional fabrication activities. Such approaches have not capitalized on the equipment's full potential. This project lays the groundwork to transform the steel building construction industry by investigating the underlying science and engineering precepts for intermeshed connections created from precise, volumetric cutting. The proposed system enhances the integration between design, fabrication, installation and maintenance through building information modeling platforms to implement advanced connections. Fully automated, precise, volumetric cutting of open steel sections introduces intellectual challenges regarding the load-transfer mechanisms and failure modes for intermeshed connections. The research activity addresses knowledge gaps concerning the load resistance and design of steel systems with intermeshed connections. Physical tests, finite element simulation and multi-scale modeling are being used to investigate the mechanics of intermeshed connections including stress and strain concentrations, fracture potential and failure modes, and to optimize connection geometry.

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In recent years, advanced manufacturing techniques, such as high-definition plasma, water jet, and laser cutting, have opened up an opportunity to create a new class of steel connections that rely on intermeshed (i.e. interlocked) components. The main advantage of this type of connection is that they do not require either welding or bolting, which allows faster construction. Although the interest in intermeshed connections has increased in recent years, the mechanical behavior of these connections has not been fully understood. This paper presents a numerical study on the ultimate load capacity failure modes of intermeshed connections under mixed-mode loading. The experimental behavior of the connection components is also investigated through a series of tests. The study considers a recently developed intermeshed connection for beams and columns. The numerical simulations were performed by using a commercially available 3D finite element software package. By considering different types of mixed mode loading, interaction diagrams of axial, shear, and moment capacities of the intermeshed connection were obtained. The results 2 indicated that there exists an intricate interaction among axial, shear, and moment capacities, which arises from the intermeshed configuration of the flanges and web. For each interaction diagram, the corresponding failure mechanism was analyzed. The simulated interaction between axial, shear, and moment capacities were further compared with the provision of the current design codes. While the intermeshed connection studied here showed promise for gravity loading, further study is needed to ensure alignment of the flanges so as to avoid axial and/or flexural failures.

Digital manufacturing has transformed many industries but has had only a limited impact in the construction sector. To capitalize on advanced manufacturing techniques, this paper introduces a radically new connection approach for gravity structural steel frames. The proposed intermeshed steel connection (ISC) exploits robotic abilities to cut structural steel member ends precisely to accelerate deployment and offer better disassembly options over existing approaches. Forces are transferred through common bearing surfaces at multiple contact points, and connections can be secured by small locking pieces. This paper introduces the geometry, manufacturing, and initial analysis and test results of the connection. The paper demonstrates the ability of the connection to (1) be manufactured within current industrial tolerances, (2) be erected and disassembled, and (3) perform at expected design levels.

This paper presents the work carried out on a collaborative tripartite project between the USA, Republic of Ireland and Northern Ireland to create and investigate the design, development and testing of a new class of intermeshed steel connections (ISCs) that do not rely on field welding and minimise bolting, thus targeting the facilitation of fast disassembly of steel structures and material reuse. This research took advantage of fully automated, precise, advanced manufacturing cutting technologies (e.g. laser, waterjet and high-definition plasma cutting) to achieve a connection method in steel that previously was only possible in materials such as timber, with the potential to revolutionise the steel construction industry. The paper outlines the ongoing research work by the collaborative team, focusing on the design, fabrication, finite-element analysis (FEA) and scaled experimental testing of side ISCs for the flanges of open sections, which included the use of state-of-the-art digital image correlation technology for non-contact measurements. A simplified connection design procedure is presented based on yielding of the side plates. This design procedure is refined based on the results of experimental testing and FEA of the local axial behaviour of the flange connection, addressing stress concentrations in the flange, fabrication tolerances and material overstrength.