CFRP sheet strengthening with fiber anchors has been recently proven to be an effective technique for seismic upgrades. However, the use of multiple layers of thick CFRP sheets may pose limitations in seismic strengthening due to the limited ductility and energy dissipation characteristics of this solution. A recent patent suggests the use of a small steel plate as a ductility fuse by sandwiching it in between two layers of FRP at the critical plastic hinge region. This study applies the proposed technique in cyclic testing of RC beams to allow for more ductile seismic response. Six full-scale rectangular reinforced concrete beams are cyclically tested under four-point bending. Two beams were tested as control specimens. The remaining four beams are strengthened with two identical thick CFRP sheets top and bottom. These sheets are anchored with fiber anchors along the shear spans as well as to secure the sheets in the constant moment region from buckling under compression. Two of the four beams had ductility steel fuses on top and bottom covering the constant moment region in between the two thick CFRP sheets and secured with two fiber anchors. Furthermore, these two beams are further strengthened in shear by side sheet bonding with through anchors to delay shear failure. This work compared the flexural strengthened beams without the steel fuse to the ones with steel fuse to highlight the benefit of this solution. Comparisons are performed experimentally for low and high concrete strength with low and moderate internal steel ratios.

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Cyclic Response of RC Beams Strengthened and Anchored Using CFRP with and Without Steel Fuse

  • Salman A. Alshamrani,
  • Hayder A. Rasheed,
  • Ali H. Alqarni

摘要

CFRP sheet strengthening with fiber anchors has been recently proven to be an effective technique for seismic upgrades. However, the use of multiple layers of thick CFRP sheets may pose limitations in seismic strengthening due to the limited ductility and energy dissipation characteristics of this solution. A recent patent suggests the use of a small steel plate as a ductility fuse by sandwiching it in between two layers of FRP at the critical plastic hinge region. This study applies the proposed technique in cyclic testing of RC beams to allow for more ductile seismic response. Six full-scale rectangular reinforced concrete beams are cyclically tested under four-point bending. Two beams were tested as control specimens. The remaining four beams are strengthened with two identical thick CFRP sheets top and bottom. These sheets are anchored with fiber anchors along the shear spans as well as to secure the sheets in the constant moment region from buckling under compression. Two of the four beams had ductility steel fuses on top and bottom covering the constant moment region in between the two thick CFRP sheets and secured with two fiber anchors. Furthermore, these two beams are further strengthened in shear by side sheet bonding with through anchors to delay shear failure. This work compared the flexural strengthened beams without the steel fuse to the ones with steel fuse to highlight the benefit of this solution. Comparisons are performed experimentally for low and high concrete strength with low and moderate internal steel ratios.