带铝肋先张预应力复材筋混凝土梁的长期刚度

长期黏结性能退化会导致复材筋与混凝土之间的不可控滑移问题，附加铝肋是提高黏结性能的有效方式。为研究铝肋对抑制预应力复材筋混凝土梁长期刚度退化的作用，设计制作了6个试件，依次开展了短期和长期加载试验。通过对比梁端部无铝肋的试件，综合研究了铝肋对长期挠度、复材筋滑移和裂缝发展的影响规律。结果表明:附加铝肋能够显著抑制构件长期挠度的发展，使预应力复材筋混凝土梁保持良好的长期性能;设置了短铝肋(SA)和长铝肋(LA)的试件，相较于无铝肋试件，最大滑移分别减少了81.3%和86.7%，筋材滑移得到有效抑制;无铝肋试件近固定端裂缝宽度增加了323.53%，远大于有铝肋试件，附加铝肋对剪跨区混凝土裂缝发展的抑制效果明显。

关键词: 先张法预应力; 复材筋; 铝合金附加肋; 长期刚度

Degradation of long-term bonding performance will cause uncontrollable slippage between FRP bars and concrete. The additional Al-ribs are effective ways to improve bonding performance. In order to study the effect of Al- ribs on restraining the long-term stiffness degradation of prestressed concrete beams reinforced with FRP bars, 6 specimens were designed and fabricated, and short-term and long-term loading tests were carried out in sequence. By comparing the specimens without Al-ribs at the beam ends, the influence of Al-ribs on long-term deflection, slippage of FRP bars and development of crack width was comprehensively studied. The results showed that the additional Al-ribs could significantly inhibit the development of long-term deflection of the members, so that the prestressed concrete beams reinforced with FRP bars maintained good long-term performance. The maximum slippage of the specimens with short Al-ribs(SA) and long Al-ribs(LA) was reduced by 81.3% and 86.7%, respectively, and the slippage of the ribs was significantly suppressed, The crack width near the fixed end of the specimens without Al-ribs was increased by 323.53%, which was much larger than that of the specimens with Al-ribs. The additional Al-ribs had a significant effect on restraining the development of concrete cracks in the shear span area．

Key words : pre-tensioned prestress; FRP bar; additional Al-rib; long-term stiffness