钢筋混凝土框架爆破拆除时后承重柱的应力分布

钢筋混凝土框架结构定向爆破拆除的力学过程,是一个复杂的结构动力学过程.后承重柱的应力分布,影响着整个框架倒塌定向的准确与施工安全.以某钢筋混凝土框架结构为建模实体,建立了有限元分析模型,并对其倒塌过程进行了定性分析.获得的后承重柱应力分布规律表明:后承重柱的应力值随爆破缺口的高度呈线性递增;梁的存在能有效地"拦截"后承重柱的应力;爆破缺口与梁间的距离越大,后承重柱的应力变化率也越大;含筋率的提高能有效地降低后承重的应力值,同样的含筋率有相同的应力降低幅度;应力突变与梁的状态和后承重柱的钢筋局部加密相关,其突变幅度随爆破缺口的高度的增加而增大,突变点的位置不受爆破缺口高度的影响,只受在倒塌过程发挥力学作用的梁的位置及其下方钢筋加密区长度的影响;后承重柱发生高位断裂的位置是在距爆破缺口最近的梁的下方钢筋加密区与非加密区的联接处附近,断裂口的形状呈"V"字形.

The Stress Distribution of the Back Bearing Pillar in Blasting Demolishing Reinforced Concrete Frame Structures

It is a complicated dynamics process when reinforced concrete fame structures are demolished by controlling blasting. The stress distribution of back bearing pillar have an influence upon directional collapsing and engineering safety. In this paper, a finite element model of collapsing is built for qualitative analysis according to the rules of the reinforced concrete frame structure. The laws of the stress distribution of the back beating pillar are obtained that the stress increases with increasing the height of the blasting breach and the distance between the blasting breach and the beam, reduces with increasing the rate of reinforcing bar in the reinforced concrete, and a same reducing rate of the stress is caused by the same rate of reinforcing bar in the reinforced concrete. The beam has a great influence upon the stress distribution g but the height of blasting breach has no influence. The site of the beam and the thick section of reinforcing bar have an influence upon the situations of inflection point of stress, the higherposition rupturing situation of the back bearing pillar is near connects of thick reinforcing hat and thin reinforcing bar, the shape of the rupturing breach is V.