Strengthening of one-way reinforced concrete slabs using near surface mounted bars

Abstract

In this work, an experimental study on the performance of continuous one-way RC slabs strengthened by near surface mounted (NSM) bars under static loads is presented. Seven slab specimens were cast, with 2400mm total length, 500mm width and 100mm thickness. The first specimen slab had no strengthening and considered as a control and the other six specimens were strengthened with either different embedded lengths of near-surface mounted bars; or using different bars spacing, adopting a different material type of bars, or adding steel plates as end-anchors to prevent unexpected premature failure that may occur by debonding of steel bars. Tests were done under two-point loads that centered at each span of 1100mm length. Results were discussed in terms of ultimate loads, crack width, cracking, failure mode and load-deflection curves. The results of experimental tests showed enhancement on the ultimate load when using near-surface mounted steel bars ranged between (156.25%) and (225%). Steel bars may give a more efficient contribution than CFRP bars when it is used in the strengthening of the negative moment region of continuous one-way slabs due to its high ductility. In addition, adopting end-anchors considerably restricted the crack width in the negative moment zone.