预应力CFRP筋混凝土T梁受力性能试验研究

本文对配置部分粘结和完全粘结预应力CFRP筋的部分预应力混凝土T梁进行了受力性能试验研究。根据试验结果对预应力CFRP筋混凝土T梁的受力过程、破坏模式、部分粘结筋应力增量以及裂缝分布等进行了较为详细的研究,对基于能量耗散的观点引入的延性指标进行了探讨,提出承载力计算公式,并对预应力CFRP筋混凝土梁的破坏模式、开裂弯矩、极限弯矩以及部分粘结筋的应力进行了预测。试验研究结果表明:部分粘结预应力CFRP筋混凝土梁与完全粘结预应力CFRP筋混凝土梁相比,前者具有更好的变形能力和延性性能而两者的极限承载能力相差较小;为避免CFRP配筋结构由于CFRP筋拉断而发生灾难性的破坏,CFRP配筋梁期望发生混凝土压碎破坏;采用本文方法计算得到预应力CFRP筋混凝土梁的破坏模式、开裂弯矩、极限弯矩以及CFRP筋的极限应力与试验结果吻合较好,计算结果具有较高的精度。

Experimental study on behavior of concrete T beam prestressed with CFRP tendons

Based on the tested values of T-beams prestressed with CFRP tendons, the detailed studies on the flexural behavior, failure modes, stress increment in partially bonded tendon as well as the crack distribution are conducted. The ductility index based on an energy concept is discussed and the corresponding formulas for predicting failure modes, crack moment, ultimate moment of beams and the stress in partially bonded tendon are proposed. It is shown from the tested values that partially bonded, partially prestressed concrete beams have better deformation capability and ductility than those of fully bonded, partially prestressed concrete beams, while their difference in ultimate capacity is quite small. For concrete structure prestressed by CFRP tendons, it is expected the failure mode to be concrete crushing instead of the catastrophic ruin due to fracture of CFRP tendons. The predicted values of the failure mode, the crack moment, ultimate moment of beams and the ultimate stress in CFRP tendon are in good agreement with the experimental results. It verifies that the computed values are very precise.