无粘结部分预应力混凝土梁极限抗弯强度的试验研究

Study on the Ultimate Flexural Strength of Unbonded Partially Prestressed Concrete Beams

本文试验研究了37根配有不同预应力筋与非预应力筋、不同跨高比的无粘结部分预应力混凝土梁的极限抗弯强度。试验表明,梁的力学配筋指标 q_0是影响梁的极限强度、刚度和裂缝开展的重要参数,非预应力筋的配置大大改善了无粘结部分预应力梁的裂缝分布,跨高比对梁的强度基本没有影响。在试验研究与理论分析的基础上,结合有关文献,提出计算无粘结预应力筋极限应力和梁的极限强度的方法.还用两根6米跨曲线配筋的无粘结预应力混凝土 T 形梁进行了试验验证。

Unbonded partially Prestressed concrete beams,thirty-seven in number,with various amounts of prestressed and non-prestressed rein- forcement and different span—height ratios have been studied.It is shown that the crack pattern of unbonded partially prestressed concrete beams could be improved by the additional non—prestressed reinforcement.Reinforcement index of a beam has influence on the crack growth,rigidity and ultimate strength,while the span-height ratio has no influence on the ultimate strength of a beam.Based on experimental results and theoritical analysis,the formulas for evaluating the ultimate stress in unbonded tendons and ultimate strength of beams have been pro- posed.Tests of T-beams are also presented.