Next Article in Journal
Next Article in Special Issue
Previous Article in Journal
Previous Article in Special Issue
Polymers 2014, 6(2), 443-463; doi:10.3390/polym6020443
Article

CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder

1,* , 2
, 1
 and 1
Received: 29 November 2013; Accepted: 28 January 2014 / Published: 11 February 2014
(This article belongs to the Special Issue Selected Papers from "SMAR 2013")
View Full-Text   |   Download PDF [1906 KB, updated 12 February 2014; original version uploaded 11 February 2014]   |   Browse Figures
Abstract: Empa’s research efforts in the 1990s provided evidence that a considerable increase of the fatigue strength of welded aluminum beams can be achieved by externally bonding pultruded carbon fiber reinforced polymer (CFRP) laminates using rubber-toughened epoxies over the fatigue-weak welding zone on their tensile flange. The reinforcing effect obtained is determined by the stiffness of the unidirectional CFRP laminate which has twice the elastic modulus of aluminum. One can therefore easily follow that an unstressed CFRP laminate reinforcement of welded beams made of steel will not lead to a substantial increase in fatigue strength of the steel structure. This consideration led to the idea of prestressing an external reinforcement of the welded zone. The present investigation describes experimental studies to identify the adhesive system suitable for achieving high creep and fatigue strength of the prestressed CFRP patch. Experimental results (Wöhler-fields) of shear-lap-specimens and welded steel beams reinforced with prestressed CFRP laminates are presented. The paper concludes by presenting a field application, the reinforcement of a steel pendulum by adhesively bonded prestressed CFRP laminates to the tensile flanges of the welded box girder. Inspections carried out periodically on this structure revealed neither prestress losses nor crack initiation after nine years of service.
Keywords: carbon fiber reinforced polymer; epoxy; bonding; strengthening; prestress; welded steel; fatigue; reinforcement; mean stress effect carbon fiber reinforced polymer; epoxy; bonding; strengthening; prestress; welded steel; fatigue; reinforcement; mean stress effect
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Export to BibTeX |
EndNote


MDPI and ACS Style

Koller, R.E.; Stoecklin, I.; Valet, S.; Terrasi, G.P. CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder. Polymers 2014, 6, 443-463.

AMA Style

Koller RE, Stoecklin I, Valet S, Terrasi GP. CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder. Polymers. 2014; 6(2):443-463.

Chicago/Turabian Style

Koller, Roland E.; Stoecklin, Iwan; Valet, Sebastian; Terrasi, Giovanni P. 2014. "CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder." Polymers 6, no. 2: 443-463.


Polymers EISSN 2073-4360 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert