摘要
本文根据断裂力学理论和虚拟裂缝模型,结合钢筋与混凝土的粘结模型,详细分析配筋方式对堆石坝面板表面裂缝扩展的作用,对工程中普遍采用的面板中部单层配筋方式提出质疑,认为只有将配筋设置在面板上部,才能很好地控制面板表面裂缝的扩展,充分发挥材料各自的力学特征。首先从混凝土结构学的角度,对以上观点进行论证,并以三点弯曲切口梁为例,详细分析无配筋、单层配筋和双层配筋这三种情况下,极限荷载与裂缝扩展长度的关系。通过对比认为,配筋能有效抑制裂缝的扩展,而在配筋率相同的情况下,将单层配筋置于面板上部比双层配筋更能控制裂缝的扩展,论证了将配筋置于堆石坝面板中部这一做法的不合理性,从而使得面板配筋设计更加科学合理。
Based on the fracture mechanics and fictitious crack model, and the application of model of bond between concrete and steel bar, the influence of steel bar on concrete crack extension is elaborately analyzed, the common design of locating steel bar in middle of concrete plane to deduce crack extension is doubted. It is pointed out that crack extension can be more effectively demolished by locating steel bar in upper part of concrete plane than in middle, so that the mechanical characteristic of each material is fully used. This viewpoint is firstly demonstrated based on the theory of concrete structure. With the example of three-point bending notched beam, the relationship between critical load and crack extension is deliberately analyzed under three conditions of no steel bar, single layer of steel bar and double layers of steel bar. By comparison of the computing results, steel bar in concrete plane can suppress the crack extension in concrete. If the area ratio of steel bar to concrete plane intersection is kept the same, the crack extension will be more obviously suppressed by single layer of steel in upper part than by double layer. The doubts on the common design of single layer of steel bar locating in the middle of the concrete slab is demonstrated and above analysis will make the design of steel bar near to the surface of the slab more reasonable.
出处
《水力发电学报》
EI
CSCD
北大核心
2005年第5期45-48,共4页
Journal of Hydroelectric Engineering
基金
国家电力公司科学技术项目(SP11-2002-03-52)
关键词
水工结构
裂缝扩展
理论分析
断裂韧度
极限荷载
hydraulic structure
crack extension
theoretical analysis
fracture toughness
critical load
