无粘结预应力板-柱结构抗连续倒塌模式研究

Study on Mode of Unbonded Prestressed Slab-Column Structures against Progressive Collapse

目的研究无粘结预应力混凝土板-柱结构的抗连续倒塌模式,为钢筋混凝土板柱结构防连续倒塌设计提供参考.方法采用有限元软件ABAQUS对一栋8层的无粘结预应力板-柱结构进行连续倒塌分析,探讨在柱失效工况和板-柱节点失效工况下板、柱以及板-柱节点的应力状况.结果两种失效工况下都以普通钢筋和预应力筋被拉断,板受拉薄膜力失效而宣告破坏;不同失效工况的板面破坏呈现模式存在差异,柱失效体现为屈服线破坏,节点失效体现为冲切裂缝破坏.结论在节点失效工况的初期,从增长速度上来说,无粘结预应力板柱结构普通钢筋和预应力筋应力增长速度较快,在连续倒塌前增长速度较慢;而柱失效工况则与之相反,在柱失效后的初始阶段,失效柱所在跨内其他节点处普通钢筋和预应力筋的应力增长速度较慢,随着连续倒塌极限状态的临近,增长速度逐渐加快.

In order to study the mode of unbonded prestressed concrete slab-column structures against progressive collapse and provides reference for the design of unbonded prestressed concrete slab-column structures against progressive collapse,progressive collapse analysis of an 8-layer unbonded prestressed slab-column structure is studied using ABAQUS;The stress state of slab,column and slab-column joints under column failure condition and slab-column joint failure condition are discussed.Under both failure conditions,it is declared to be damaged due to ordinary reinforcing bars and prestressed tendons are pulled off,and the failure of the slab tension film force;There are differences in the failure modes of the slab surface under different failure conditions.Under the column failure condition,the failure mode of the slab surface presents yield line failure,and under the joint failure condition,the failure mode of punching crack appears on the slab surface.In the initial stage of joint failure,the stress speed of ordinary reinforcing bars and prestressed tendons of unbonded prestressed slab-column structure is faster,and it is slow before continuous collapse.In contrast to the failure condition of the column,the stress growth rate of ordinary reinforcing bars and prestressed tendons is slow in the initial stage after the failure of the column at other nodes in the span where the failure column is located,and it is faster near the ultimate state of continuous collapse.