Strengthening of aluminium and stainless steel structural tubular sections using
adhesive bonded fibre-reinforced polymer (FRP) subjected to web crippling has been
investigated. Aluminium and stainless steel tubular sections may experience web
crippling failure due to local concentrated loads or reactions. The web crippling
strength can be enhanced by strengthening the webs of the sections in localized
regions. The current international specifications of aluminium and stainless steel
structures do not provide web crippling design rules for strengthening of tubular
sections. Therefore, there is a need to develop safe and reliable web crippling design
rules for FRP strengthened aluminium and stainless steel structures.
An extensive test program was performed on FRP strengthening of aluminium and
cold-formed stainless steel tubular sections subjected to web crippling. The test
specimens consisted of 6061-T6 heat-treated aluminium alloy, ferritic stainless steel
type EN 1.4003 and lean duplex type EN 1.4162 square and rectangular hollow
sections. A total of 254 web crippling tests was conducted in this study. The tests
were performed on eighteen different sizes of tubular sections which covered a wide
range of web slenderness (flat portion of web depth-to-thickness) ratio from 6.2 to
62.2.
The web crippling tests were conducted under the four loading conditions according
to the American Specification and Australian/New Zealand Standard for cold-formed
steel structures, namely End-Two-Flange, Interior-Two-Flange, End-One-Flange and
Interior-One-Flange loading conditions. The investigation was mainly focused on the
effects of different adhesive, FRP, surface treatment, widths of FRP plate and web
slenderness of tubular sections for strengthening against web crippling. Six different
adhesives, six different FRPs, two different surface treatments, three different widths
of FRP plate were considered. It was found that the web crippling capacity of
aluminium tubular sections are significantly increased due to FRP strengthening,
especially for those sections with large value of web slenderness. The web crippling
strength can be increased up to nearly 3 times using the appropriate adhesive and
FRP for aluminium tubular sections, whereas the web crippling strength can be
increased up to 51% and 76% for ferritic and lean duplex stainless steel tubular
sections, respectively.
The finite element models for FRP strengthened aluminium and stainless steel
tubular structural members subjected to web crippling were developed and calibrated
against the experimental results. The debonding between FRP plate and aluminium
or stainless steel tubes was carefully modelled using cohesive element. It is shown
that the calibrated model closely predicted the web crippling strengths and failure
modes of the tested specimens. An extensive parametric study included 212 web
crippling specimens was carried out using the verified finite element models to
examine the behaviour of strengthened aluminium and stainless steel tubular sections
subjected to web crippling.
Design equations are proposed to predict the web crippling strengths of FRP
strengthened aluminium and stainless steel tubular sections based on the
experimental and numerical results. The web crippling strengths obtained from the
tests and numerical analysis were compared with the design strengths calculated
using the proposed equations. The reliability of the proposed design rules was
evaluated using reliability analysis. / published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174466 |
| Date | January 2012 |
| Creators | Islam, S. M. Zahurul. |
| Contributors | Young, B |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47752865 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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