Non-Standard Structural Connections in Streetscape Elements: Engineering Challenges, Design Solutions and Sustainability Implications

This article presents a qualitative engineering assessment of non-standard structural connections used in streetscape elements, including shelters, canopies, pergolas, recreational facilities, and other small-span structures. The analysed structures are made of steel, aluminium alloys, timber, and hybrid material systems. The need for individually designed connections arises primarily from specific functional and loading conditions, small member cross-sections, the use of hollow sections, restricted installation access, demanding architectural requirements, constraints associated with bending, hot-dip galvanising, and transportation, as well as the risk of galvanic corrosion. The research methodology comprises the identification of key design constraints, the analysis of selected case studies, and a comparative assessment of connection solutions in terms of structural performance, durability, constructability, maintainability, adaptability, demountability, and circularity. The solutions discussed include concealed connections within hollow sections, small-diameter and stainless-steel fasteners, locally reinforced joints, modular field splices, and electrically isolated interfaces between dissimilar metals. The findings indicate that appropriately designed non-standard connections can support durability, selective component replacement, upgrading, relocation, non-destructive disassembly, and the reuse of structural components. However, these benefits do not arise automatically from the customised nature of a connection, as additional material use, fabrication complexity, limited fastener accessibility, and degradation-sensitive interfaces may increase whole-life impacts. Structural connections should therefore be assessed as integral components influencing the performance of a structure throughout its service life rather than solely as local load-transfer details.