Strengthening and prestressing of bridge decks with ribbed iron-based shape memory alloy bars


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Date

2021-08-15

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Given the increasing age of our built environment, including concrete structures, stakeholders in the construction industry require innovative and effective strengthening methods. In several studies and onsite applications, iron-based shape memory alloy (Fe-SMA) reinforcements have proven to be competitive alternatives to well-established materials. The objective of this investigation was to study the effectiveness of two different prestressed strengthening methods for concrete members in flexure using recently available ribbed Fe-SMA (“memory-steel”) bars. Reinforced concrete slabs similar to the cantilever extension of box-girder cross-sections were strengthened using only cementitious anchorages and subjected to quasi-static loading. The first strengthening method comprised the removal of the concrete cover and the installation of memory-steel bars with an additional mortar layer. The second strengthening method comprised the cutting of grooves in the concrete cover, followed by the installation of memory-steel bars with mortar (near-surface-mounted). The prestress was obtained via resistive heating of the memory-steel bars. The strengthened specimens exhibited highly improved cracking, yielding, and maintained ductility until ultimate concrete compression failure. Observations utilizing a digital image correlation system indicated a damage-free prestressing process and no premature failure of the strengthening reinforcement. Different analytical approaches were used to estimate the prestress.

Publication status

published

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Book title

Volume

241

Pages / Article No.

112467

Publisher

Elsevier

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Subject

Memory-steel; Near-surface-mounted; Cover replacement; Concrete structures; Slab; Crack monitoring; Digital image correlation

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