Robustness of light steel frames and modular construction

Abstract

The robustness or structural integrity of light steel framing and modular constructions is important because these are relatively new structural forms, in which the components have different forms of inter-connectivity in comparison with primary steel frames. There is an increased need to understand the sensitivity of these forms of construction to so-called accidental actions, including terrorist threats. Various forms of construction using light steel and modular technologies are identified and their implications for robustness are reviewed. A series of stressed skin tests on modular constructions is presented. These show that modules are able to span as deep beams with one longitudinal support removed with minimal displacements, indicating that the torsional stiffness of the ‘box’ provides a high level of robustness. Removal of a corner support again demonstrates the role that torsional action of the box plays in redistributing loads away from damaged sections of a structure. For light steel framing, multiple inter-connections provide robustness by tying action and alternative load paths in the event of one or more elements being severely damaged. For modular construction, a scenario-based approach is required in which modules are selectively removed and the horizontal and vertical forces in the connections between the modules can be calculated explicitly.

Robustness of Prefabricated Prefinished Volumetric Construction (PPVC) High-rise Building

“…Complete modules made of multiple units complete with internal finishes, fixtures and fittings are manufactured in factories, and are then transported to site for installation in a Lego-like manner. Aside from enhancing construction productivity, PPVC also delivers significant advantages in on-site safety, quality control and sustainability [7].…”

“…A research done by [7] studied the robustness of modular construction by adopting a scenariobased approach in which modules are selectively removed. His work indicates that typical modules possess sufficient shear capacity to cantilever damaged sections of the building.…”

“…His work indicates that typical modules possess sufficient shear capacity to cantilever damaged sections of the building. It was concluded that the alternate load path method was the most appropriate means by which modular construction can comply with the regulations for robustness [7]. However, tests carried out by Lawson et al [7] did not consider the geometric nonlinearity and overall response of a building under progressive collapse.…”

“…It was concluded that the alternate load path method was the most appropriate means by which modular construction can comply with the regulations for robustness [7]. However, tests carried out by Lawson et al [7] did not consider the geometric nonlinearity and overall response of a building under progressive collapse. This calls for further research to be done on the robustness of modular construction.…”

Modular design for high-rise buildings

“…This is the scenario presented in Approved document A of the Building Regulations (HMSO, 2006), which leads to minimum tying force requirements. A recent paper (Lawson et al, 2008) reviews the robustness requirements for modular construction based on a 'localisation of damage' route. Modules or loadbearing elements are removed individually to assess the ability of the rest of the assembly to support the applied loads at the accidental limit state.…”