高层及超高层钢筋混凝土结构的徐变影响分析

Analysis of creep effect on tall and super tall R.C. buildings

在长期重力载荷作用下,高层及超高层钢筋混凝土建筑结构竖向构件压应力水平差异较大,而不均衡分布时,混凝土的徐变效应可能导致建筑产生较大的侧移倾斜变形,影响建筑的长期使用,甚至导致结构安全隐患.采用简单合理的徐变分析模式和能量原理,针对竖向构件压应力水平差异较大而不均衡分布的典型单跨单层框架结构,通过计算分析,揭示混凝土徐变效应引起此类结构侧移倾斜的根本原因.通过简化高层框架结构算例,提出调整竖向构件配筋率、截面面积和混凝土强度等级等有效减小侧移倾斜的措施.

There may exist large difference and asymmetrical distribution of the compressive stress level in the vertical members in some tall and super tall R. C. buildings. Under long-term gravity loads, concrete creep effect can cause large sideway and inclined deformations. As a result, not only would the long-term service of the buildings be influenced, but also hidden structural security trouble would be induced. Combined with a set of simple and reasonable creep mode and energy principle, a typical frame structure example is analyzed and the essential causes of the structural sideway and incline due to creep are found. Some technical measures, including adjusting columns reinforcement ratios, section sizes, concrete grades are presented and proved to reduce the structural sideway and incline effectively, by a tall frame structure example