STRUCTURAL CAPACITY OF NSM STEEL BARS STRENGTHENED DEEP BEAMS UNDER COMBINED LOADS OF REPEATED AND ELEVATED TEMPERATURE

Abstract

The current experimental investigation is devoted to study the structural capacity of near-surface mounted steel bars strengthened deep beams. Six reinforced SCC deep beam specimens with a dimension of 1400mm x175mm x350mm were tested under Combined Loads of Repeated and Elevated Temperature. The adopted variable includes the type of loading, degree of elevated temperature, and presence or absence of the strengthening by NSM-steel bars. The experimental results show that the ultimate load of B2-R-T20 decreased by about 33% when the applied load changed from monotonic to repeated; also, when the degree of burning increased to (200oC) and (350oC), the ultimate load decreased by 44% and 65% , respectively. The presence of the strengthened NSM-steel bars leads to increase the lateral strength of the tested beams and arrested the diagonal cracks to be widening as a result, the ultimate load capacity increases by (193%-197%) for the samples exposed to elevated temperature, in comparison with reference beams. The adopted strengthened technique proved to be adequate to restore and increase the shear capacity of the tested beams.

Keywords

• deep beam
• self-compacting concrete
• nsm
• elevated temperature
• repeated load