钢筋混凝土结构立柱钢筋爆破失稳机理对比研究  

A Comparative Study on Mechanism of Blasting Instability of Reinforced Concrete Columns

作　　者：蒙云琪 MENG Yun-qi(China Railway Fourth Survey and Design Institute Group Co.,Ltd.,Wuhan 430063,China)

机构地区：[1]中铁四院集团岩土工程有限责任公司,武汉430063

出　　处：《爆破》2020年第2期20-25,共6页Blasting

摘　　要：钢筋混凝土结构爆破倒塌的前提是其立柱钢筋失去支撑能力,这是爆破设计的关键内容。传统爆破设计采用压杆失稳机理判断钢筋失稳,压杆失稳机理是建立在钢筋直轴受力刚度不足失稳的基础上的,由于假设条件过于理想,具有较大的局限性,特别是一些上部结构自重较轻,立柱钢筋直径较密较粗的情况下,压杆失稳机理往往不能适用。研究一个更符合实际的钢筋失稳机理,对于钢筋混凝土结构立柱的爆破设计尤为重要。对压杆失稳机理和弯曲钢筋受力进行了材料力学理论剖析,提出了用弯筋压屈机理作为爆破立柱钢筋破坏的理论,并将其与传统的压杆失稳机理进行比较。弯筋压屈机理强调的是钢筋的弯曲变形量对极限承载力的影响,认为钢筋是最大应力超过极限强度而破坏,而非刚度不够失稳。弯筋压屈机理是更为贴近工程实际的钢筋混凝土结构爆破倒塌理论。The premise of blasting collapse of reinforced concrete structure is the loss of supporting capacity of the blasting column steel bar,which is the key content of blasting design.The instability mechanism of the compression bar is used in the traditional blasting design to judge the instability of the reinforcement.The instability mechanism of the compression bar is established on the basis of the insufficient rigidity of the reinforcement in the straight axis.Due to too ideal assumption conditions,there are great limitations,especially when the weight of the upper structure is relatively light and the diameter of the vertical column reinforcement is relatively thick,the instability mechanism of the compression bar is often not applicable.It is very important for the blasting design of reinforced concrete columns to develop a more practical mechanism of steel instability.Based on the instability mechanism analysis of the compression bar and the stress of the bending bar with material mechanics theory,the theory of using the bending bar as the failure of the reinforcement of the blasting column is put forward,which is compared with the traditional instability mechanism of the compression bar.The bending mechanism emphasizes the influence of the bending deformation on the ultimate bearing capacity of the steel bar,if the maximum stress of the steel bar exceeds the ultimate strength,the steel bar will be destroyed,rather than the instability due to insufficient rigidity.The bending mechanism is closer to the blasting collapse theory of reinforced concrete structure.

关 键 词：压杆失稳 柔度 弯曲钢筋 压弯构件 极限强度 

分 类 号：TU746.5[建筑科学—建筑技术科学]