Methods for shear strengthening of thick concrete slabs

Authors: Fiset, MathieuBastien, Josée; Mitchell, Denis
Abstract: This paper presents different strengthening techniques to improve the shear capacity of existing thick concrete slab structures that were constructed without shear reinforcement. Reinforcing bars are installed into vertical drilled holes and anchored with epoxy adhesive to increase the shear capacity. Experiments on retrofitted beams, representing slab strips, showed that all of the strengthening techniques investigated resulted in increased shear capacities. The shear failure mechanisms of the strengthened beams showed that, as expected, current evaluation methods for elements with conventional, well-anchored stirrups can lead to an overestimation of the shear capacities. The efficiency of the strengthening techniques is strongly influenced by the performance of the end anchorage of the drilled-in bars. The effectiveness of the epoxy-bonded bars is a function of their embedded length and they can, in some cases, debond before they reach their yield strength. By using the maximum bar spacing required by the Canadian design code for bridges or the AASHTO-LRFD design specifications, bonded shear-reinforcing bars may debond and offer poor performance. A maximum transverse reinforcement spacing criterion is therefore suggested for the added bonded bars.
Document Type: Article de recherche
Issue Date: 31 October 2016
Open Access Date: 3 October 2017
Document version: AM
This document was published in: Journal of Performance of Constructed Facilities, Vol. 31 (3) (2017)
American Society of Civil Engineers
Alternative version: 10.1061/(ASCE)CF.1943-5509.0000960
Collection:Articles publiés dans des revues avec comité de lecture

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