文档介绍：摘要
钢筋混凝土结构的抗裂性、耐久性和跨越能力差,为解决这一问题,预应力结构应运而生,得到了广泛的应用,目前,在较大跨经的结构中运用预应力几乎仍是唯一的选择。有没有增强结构抗裂、耐久性能和跨越能力的其他选择呢,答案是肯定的。
本文基于断裂力学的基本原理分析了传统钢筋混凝土结构的破坏过程,提出了一种复合钢筋混凝土新结构的设计构想。新结构能够延缓结构中裂纹的出现,并能有效阻止裂纹的发展,具有比普通钢筋混凝土结构更加优良的抗裂性和更高的极限承载力。
理论分析及实验室的实验证实:新结构不但有较高的开裂荷载,而且裂纹出现后,发展缓慢;极限承载能力显著提高;新结构抗弯刚度明显增大;新结构具有良好的变形性能和延性。
复合钢筋混凝土新结构和普通钢筋混凝土结构相比,各方面的性能均有显著的提高,是一种更加优良的新结构。新结构的思想不仅可以用来设计、新建结构,也可用于加固旧结构。新结构与普通钢筋混凝土结构相比,在结构跨径相同的情况下,新结构的截面高度可以减小,使结构轻型化;在结构截面相同的情况下,新结构的跨径可以增加,使结构的跨越能力增大。
本文提出的复合钢筋混凝土新结构是一种新的结构设计思路,是在预应力之外的另一种实现结构轻型化、大跨化的新方法。
关键词:断裂力学,钢筋混凝土结构,复合钢筋混凝土新结构
ABSTRACT
Due to the low anti-crack performance and poor durability and spanning ability of the reinforced concrete (RC) structures, pre-stressed concrete (PC) structures have been widely used. At present, the PC structure is almost the only choice in long spans. Could the situation be changed? The answer is positive.
In the paper the failure process of traditional RC structure is detailedly analyzed based on the principles of fracture mechanics, then a posite reinforced concrete (CRC)structure is proposed. The new structure can delay the emergence of cracks and hold back the propagation of the cracks effectively, so the new CRC structure has better properties than the traditional RC structure.
Theoretical analysis and the experimental results show that the new structure has a higher cracking-point load; a much higher ultimate carrying capacity because the growing cracks are held back, and a more excellent ductility.
Owing to the property promotion, the new CRC structure can not only be beneficially applied in designing new buildings and bridges, but also in strengthening old RC structure. Compared with the traditional RC structure, the new structure can span a bigger length with the same section, or weight much less with the same span length.
The new posite structure put forward in the paper makes a new design concept about structure and a new method (compare with the PC structure) to construct a lighter-weight and