A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Fatigue Behavior of Large-Scale Reinforced Concrete Beams Strengthened in Flexure with Fiber-Reinforced Polymer Laminates
AbstractThe aim of the present research is the experimental investigation of the response of carbon-fiber-reinforced polymer (CFRP) strengthened reinforced concrete (RC) beams of large scale under fatigue loading. Reinforced concrete beams were cast for this purpose, both with rectangular and T cross-sections, with web dimensions of 200×500 mm and 3,050 mm in length. Beams were strengthened in flexure with externally bonded CFRP laminate [externally bonded reinforcement (EBR)] or with CFRP laminates bonded into slits on the concrete cover surface [near-surface-mounted (NSM)]. Transverse CFRP sheets were placed on the shear spans of the beams to avoid fragile shear failure. All specimens were tested under fatigue loading, with load-unload cycles of 2 Hz frequency. Two different amplitudes of cycles were investigated. The different fatigue life and modes of failures are discussed. Beams subjected to the low loading range, simulating the service loads of a bridge beam, could sustain more than 2 million cycles. Beams subjected to the high loading range, according to the maximum limit of industry standards, presented fatigue failure of the reinforcing steel in cycles less than 1.5×106. The ratio of the axial rigidity of the tensile steel bar ks to the axial rigidity of fiber-reinforced polymer (FRP) strengthening kf plays a significant role in extending the fatigue life of steel and thus of RC FRP strengthened beams. The lower the ks/kf ratio, the higher the fatigue life of the retrofitted member. NSM strengthening may maintain a full bond with the concrete substrate even after the fatigue fracture of steel bars. Therefore, it may provide residual capacity to the retrofitted member to survive detrimental collapse.
Fatigue Behavior of Large-Scale Reinforced Concrete Beams Strengthened in Flexure with Fiber-Reinforced Polymer Laminates
AbstractThe aim of the present research is the experimental investigation of the response of carbon-fiber-reinforced polymer (CFRP) strengthened reinforced concrete (RC) beams of large scale under fatigue loading. Reinforced concrete beams were cast for this purpose, both with rectangular and T cross-sections, with web dimensions of 200×500 mm and 3,050 mm in length. Beams were strengthened in flexure with externally bonded CFRP laminate [externally bonded reinforcement (EBR)] or with CFRP laminates bonded into slits on the concrete cover surface [near-surface-mounted (NSM)]. Transverse CFRP sheets were placed on the shear spans of the beams to avoid fragile shear failure. All specimens were tested under fatigue loading, with load-unload cycles of 2 Hz frequency. Two different amplitudes of cycles were investigated. The different fatigue life and modes of failures are discussed. Beams subjected to the low loading range, simulating the service loads of a bridge beam, could sustain more than 2 million cycles. Beams subjected to the high loading range, according to the maximum limit of industry standards, presented fatigue failure of the reinforcing steel in cycles less than 1.5×106. The ratio of the axial rigidity of the tensile steel bar ks to the axial rigidity of fiber-reinforced polymer (FRP) strengthening kf plays a significant role in extending the fatigue life of steel and thus of RC FRP strengthened beams. The lower the ks/kf ratio, the higher the fatigue life of the retrofitted member. NSM strengthening may maintain a full bond with the concrete substrate even after the fatigue fracture of steel bars. Therefore, it may provide residual capacity to the retrofitted member to survive detrimental collapse.
Fatigue Behavior of Large-Scale Reinforced Concrete Beams Strengthened in Flexure with Fiber-Reinforced Polymer Laminates
2016
Article (Journal)
English
| British Library Online Contents | 2016
| British Library Online Contents | 2004