粗纤维增强钢筋混凝土截面的时效分析

将粗合成纤维用于隧道管片衬砌可以提高其强度,但在持续弯曲荷载作用下构件会随时间发生蠕变和出现裂缝。随着对混凝土裂缝应对能力的提升,粗合成纤维作为一种可用的替代品,凭借优良的经济性和耐久性等优势,在隧道管片制作中将得到越来越广泛的应用。文章基于时效特性分析了在持续弯矩和轴向应力作用下,粗纤维增强钢筋混凝土横截面的蠕变和收缩效应,并通过算例进行了验证。研究结果表明:混凝土中的纤维对于提高构件横截面的抗弯强度作用有限,但是纤维减少了构件在服役期间的蠕变,并且当纤维与普通钢筋共同作用时,能显著减少最大裂缝的宽度值。

Time-dependent Analysis on Cross Section of Macro-fiber Reinforced Concrete

The use of synthetic macro-fibers for the lining of tunnel segments contributes to increasing strength,but creep and cracking of components may occur over time under continuous bending load.With the improvement of ability to deal with cracks,synthetic macro-fiber will be more and more widely applied in the fabrication of tunnel segments by virtue of its superior economical efficiency and durability.Based on the time-dependent characteris tics,this paper analyzes and verifies the creep and shrinkage effects of cross section of macro-fiber reinforced con crete under continuous bending moment and axial stress by numerical examples.The results show that fiber in con crete has limited effect on increasing flexural strength of cross section,but it reduces the creep of component during service and significantly decreases the maximum crack width under interaction of fibers and ordinary rebars.