Web crippling design of optimised cold-formed channel beams

Mcintosh, Alex (2023) Web crippling design of optimised cold-formed channel beams. Doctoral thesis, Northumbria University.

Text (Doctoral thesis) mcintosh.alex_phd(15002875).pdf - Submitted Version Restricted to Repository staff only until 25 May 2025. Download (7MB) | Request a copy

Abstract

The UK Housing problem has reached a critical point, as evident by the fact that 70,000 families were being forced to live in emergency housing in 2017 alone. The current construction model is failing to deliver efficiently and on time, which may ultimately lead to a large-scale economic crisis. However, since 2010 there has been an increase in productivity as the economy recovered from the 2008 market crash, this has coincided with the acceptance of cold-formed steel (CFS), which has been extensively used within the construction industry as an alternative to traditional construction methods. The attractiveness of the material can be attributed to its ease of mass production and prefabrication as well as its minimal design and installation procedures, allowing for an increase in productivity within the UK construction industry. Therefore, CFS has become increasingly important in conventional and emerging modular building constructions.

Conversely, aluminium and stainless-steel are more recent emerging markets within the industry, seeing a rise in demand due to their distinctive advantages when compared to CFS. For stainless-steel this arises from its superior corrosion resistance, aesthetic qualities and the longer-term value over the total life cycle. In contrast, aluminium provides advantages when considering its lightweight nature and increased tensile strength at low temperatures. These structural and resistive properties license both materials to become competitive and provide advanced engineering solutions, apace with greater compatibility with today’s fast track construction techniques.

Evolving developments in the construction industry have sought to employ cold-formed (CF) carbon steel, CF aluminium and CF stainless-steel as flexural members and in some occurrences as primary load-carrying members, with applications including floor, wall and roof systems. Though this does generate structural design concerns, as flexural thin-walled members are highly predisposed to various types of buckling instabilities when subjected to concentrated loads, due to their large width-to-thickness ratios. Web crippling is one of the major vulnerabilities when exposed to concentrated and concentrated transverse reactions. Thin-walled members should be designed to resist these reaction forces; though these design provisions can be complex, with numerous parameters having a direct influence on the web crippling strength. These parameters include the yield strength, thickness, cross-sectional dimensions, internal radius and the modulus of elasticity.

Actions (login required)

View Item

Downloads