Steel Strong-Back for Building Envelope—Design for Manufacture

Abstract

Manufacturing aspects are playing an increasingly important role in the design and development of building systems. This paper describes the design, development, and testing of a cold-formed steel strong-back system for curtain walling. The principal criteria in the design were ease of manufacture and flexibility in application. By careful design of key components of the system, assembly was by semiskilled operatives instead of conventional structural steel fabricators. The components of the truss are manufactured from pregalvanized roll-formed structural sections. The components are assembled using cap head socket screws at node points. The strong backs are then manufactured by the cladding contractor, providing greater control in tendering, detailing, and costs. A series of component tests and full-scale structural tests under both vertical and lateral loading was undertaken and used to develop a practical structural design method. Subsequent modifications to the system are also described.