Stiffness of FRP pultruded tubes under repeated axial impacts

Guades, Ernesto J. and Aravinthan, Thiru and Islam, Md. Mainul and Manalo, Allan C. (2012) Stiffness of FRP pultruded tubes under repeated axial impacts. In: 3rd Asia-Pacific Conference on FRP in Structures (APFIS 2012), 2-4 Feb 2012, Sapporo, Japan.

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Fibre composites in deep foundation industry have been recognized to replace conventional materials such as concrete, steel and timber in harsh marine environment. The emergence of hollow fibre reinforced polymer (FRP) composite tubes as a structural component provided the industry to consider this material as a potential composite pile type as they can carry design load. However, issue such as driving performance of this material warrants investigation as they are considered the lowest performer among composite piles. The thin-walled section generally ruptures under high driving stresses, thus its stiffness for post-impact performance is in question. This paper experimentally investigated the effects of impact energy and number of impacts on the axial stiffness of hollow FRP composite tubes. Six incident energy variants were considered, and two specimens for a given impact energy were subjected to a maximum of 130 repeated impacts using a drop-weight impact tester. The impact response and the contact stiffness were evaluated in terms of damage
progression and the evolution of peak force for both collapsed and non-collapsed tubes. Results point out that no significant difference exists in the behaviour of the tubes for which no collapse occurs with test duration. On the contrary, the location of the initiation of collapse influenced the shape of the load and number of impact curves for collapsed tubes. The value of the stiffness after the initiation of collapse remains the same regardless of the magnitude of the applied energy. Furthermore on the collapsed tubes, it was observed that impact energy does not significantly reduce the stiffness of tubes during initial impacts, however, their effects were apparent as the number of impacts increases.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: Copyright resides with the authors' and/or their employing or funding institutions. Other than brief abstracts, no part of this publication may be produced in any form without the consent of the authors.
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 26 Apr 2013 08:15
Last Modified: 03 Dec 2014 05:14
Uncontrolled Keywords: composite piles; FRP pultruded tubes; repeated impacts; collapsed tubes; drop-weight test
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090501 Civil Geotechnical Engineering
09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
09 Engineering > 0905 Civil Engineering > 090506 Structural Engineering
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering

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