Rehabilitation of one-way slabs using pre-stressed concrete prisms
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Date
2017
Authors
Gerami
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Abstract
During service life structural elements in bridges are exposed to wear and tear from vehicular loads, overloading and exposure to harsh environmental conditions that slowly deteriorate the structure. Typically, deficiencies in concrete structures are revealed as excessive deflection, cracking and spalling of concrete and corrosion of steel reinforcement. Rehabilitation of bridges is a complex process that includes many considerations. The techniques for rehabilitation of reinforced concrete structural members and bridge decks are very similar. The most practical techniques are concrete jacketing, steel plate bonding, FRP bonding, external post-tensioning and the use of near surface mounted (NSM) reinforcement. In this study, prestressed concrete prisms (PCPs) were utilized as an NSM reinforcement. The PCPs were cast with high strength concrete and had cross-sectional area of 50 x 50 and/or 35 x 35 mm. They were concentrically prestressed by 9 mm diameter seven-wire strands. Six one-way slabs with dimensions of 3000 mm in length, 600 mm width and depth of 200 mm were cast, then cracked and subsequently rehabilitated with PCPs. Deflected profiles and crack widths of the slabs before and after rehabilitation were compared in this research. Utilization of PCPs for rehabilitation diminished the magnitude of deflection and crack width at service load. Slabs strengthened by prisms with higher prestressing level and larger cross section demonstrated slightly smaller deflection and narrower crack widths in comparison with those reinforced with prisms of smaller cross section and prestressing level.
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Keywords
prestressed concrete prisms, high strength concrete, near surface mounted, strengthening, rehabilitation, bridge