Retrofitting of defected reinforced-concrete cantilever slabs using different techniques

Abstract

This paper presents the experimental findings for different strengthening techniques applied on defected reinforced-concrete cantilever slabs to restore lost flexural capacities owing to insufficient bond length of the main tensile steel. The restoration technique was based on compensation of the main tensile steel by near-surface mounted steel bars, externally bonded steel plates or externally bonded carbon fibre-reinforced polymer sheets. In addition, new hybrid techniques are presented, which merge the traditional techniques with a 20 mm thick ultra-high-performance strain-hardening cementitious composites (UHP-SHCC) layer. It was found that the strengthening technique based on the embedded steel bars on the UHP-SHCC overlay enabled the strengthened slab to restore its lost capacity and outperformed it by about 5% compared to that of the properly detailed slab. Nevertheless, this restoration was at the expense of the exhibited ductility. Conversely, the strengthening technique based on the application of externally bonded steel plates on a transition layer of the UHP-SHCC material enabled the strengthened slab to restore the lost capacity by about 96% as well as to outperform its ductility by more than 29% compared to those of the properly detailed slab.

Structural evaluation of RC overhang cantilever slab strengthened with FRP near‐surface mounted (NSM) composites for bridge applications

“…In the latter case, NSM composites installation can be done quickly and efficiently on the top surface of a member without the need for scaffolding. [15][16][17][18] In the past few years, this technique has been used for strengthening masonry walls 19,20 and timber structural members. 21,22 Numerous studies were published on the use of this technique for strengthening RC beams and slabs.…”

“…Another popular application is in situations where negative flexural upgrade of members such as slabs, bridge decks, and beams is required. In the latter case, NSM composites installation can be done quickly and efficiently on the top surface of a member without the need for scaffolding 15–18 . In the past few years, this technique has been used for strengthening masonry walls 19,20 and timber structural members 21,22 .…”

Behavior of RC Beams with Circular Openings reinforced with Strain-Hardening Cementitious Composites (SHCC)

“…In recent years, numerous studies have examined the structural performance of SHCC-RC composite components. They figured out how to combine SHCC with a variety of elements to enhance their strength and ductility [19][20][21][22][23][24][25][26][27]. The structural application of SHCC pre-cast forms is still a major issue, despite the fact that several studies have been undertaken on SHCC materials and members.…”