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Structural evaluation of a novel box beam system of Pultruded Fibre Reinforced Polymer shapes
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Evernden, Mark (2006) Structural evaluation of a novel box beam system of Pultruded Fibre Reinforced Polymer shapes. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b2096408~S1
Abstract
Presented in this thesis is an evaluation of a novel box beam system of Pul-
truded Fibre Reinforced Polymer (PFRP) shapes. The flat-pack modular beam
system consists of separate PFRP flange and web shapes joined together with
a new method of mechanical fastening. It is based on the first generation Star-
tlink building system, conceived by UK engineers in 1999. The Startlink building
system is introduced, and classified within the scope of Modern Methods of Con-
struction (MMC), and its merits are discussed. In the context of MMC a critical
review by the author finds that, although the proposed 1999 generation Startlink
system offers design flexibility, it will probably have a limited market potential.
The novel use of the steel MlO Unistrut connection method as a means of
fastening distinct PFRP shapes in a building system is characterised. Individ-
ual connector design parameters for joint stiffness and resistance are identified
and determined, under pure shear loading. The results of a series of physical
tests show no significant loss of stiffness or strength with long term environmen-
tal exposure. Values of key mechanical properties for design calculations are
recommended.
A 400 x 200 x 2848 mm prototype PFRP box beam assembly is fabricated from
two flange and two web panel-type shapes, cut from existing off-the-shelf PFRP
shapes. This is 60 mm deeper than the largest single PFRP shape that could
be used as a beam. The assembly is joined at the web-flange junction with M10
Unistrut connectors set at various spacing's, in the range 50 to 400 mm. These
connectors carry the longitudinal shear that is generated between the joined
shapes when the modular assembly is in flexure, Theoretical deflections, cal-
culated using a modified form of a partial-interaction analysis model developed
for composite concrete and steel structures, are predicted for the assembly ac-
counting for the finite shear stiffness of the web-flange connection. A series of
16 four-point bending load tests on the beam assembly, across two load arrange-
ments, show that its performance is linked to the designated spacing of the M10
Unistrut connections. The flexural rigidity and degree of interaction present in
the assembly are determined from analysis of vertical deflections and longitudi-
nal strains, as the beam is deformed. The influence of secondary effects, due to
the poor tolerances achieved in the hand fabrication of the beam's assembly, are
found to greatly affect the ability of the deflection analysis to give the required
measured deflections. Comparison of the effective joint shear rigidities obtained
from theory and testing indicates a higher individual connection stiffness in the
prototype beam than previously determined by way of the individual Unistrut
connector characterisation.
It is found through the combined analytical and physical testing research that
the M10 Unistrut connection method can only provide the necessary joint shear
stiffness and resistance to the 400 mm deep beam if the connector spacing, along
the four joints, is ≤ 50 mm. The total number of connectors this represents in the
beam is likely to make this modular construction approach too expensive for it to
be commercially viable. Although the M10 connector could be used to fabricate
beams of lesser depths, since the number of connectors will then be reduced, these
beams would find it difficult to compete with the available off-the-shelf PFRP
beam shapes, of up to 300 mm deep. There is however scope to use the Unistrut
method of connection to provide longitudinal shear resistance in building systems
where, for example, a floor panel is to be stiffened by a channel shaped beam and
the overall depth is ≤ 300 mm.
The research work contained in this thesis has contributed to a radical change
in the PFRP product offerings now proposed in the 2006 generation Startlink
building system.
Item Type: | Thesis (PhD) |
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Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
Library of Congress Subject Headings (LCSH): | Polymer engineering |
Official Date: | 2006 |
Institution: | University of Warwick |
Theses Department: | School of Engineering |
Thesis Type: | PhD |
Publication Status: | Unpublished |
Supervisor(s)/Advisor: | Mottram, Toby |
Extent: | xvi, 206 leaves : illustrations |
Language: | eng |
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