大型火力发电厂钢筋混凝土框架异型边节点抗震性能及设计方法研究

针对火力发电厂主厂房中存在高梁变截面柱构成的异型边节点,进行4个异型边节点静力试验及含有空间异型边节点整体结构的拟动力试验,分析了直交梁、上下柱变截面、节点区箍筋等对该类节点破坏模式的影响。研究结果表明该类节点初裂荷载、极限荷载较常规节点显著降低,通裂阶段与极限阶段非常接近,易发生小核心剪切破坏和直交梁以下区域剪切破坏等两种破坏模式。采用约束机理对小核芯剪切破坏进行分析并提出承载力计算方法;对于直交梁以下区域剪切破坏应采用限制大梁底部纵向钢筋的方法予以避免。

Study on seismic behavior and design method of large-scale thermal power plant RC frame with abnormal exterior joints

The main building of large-scale thermal power plant usually contains the abnormal exterior joints consisting of deep beam and column with abruptly changed sections. Based on the pseudo-static experiments of four 1/5-scale specimens and their failure characteristics in the structural test, the factors affecting shear failure modes of abnormal joints, such as the longitudinal orthogonal beam, the abruptly changed sections of upper and lower columns, the stirrup ratio of joints etc., are analyzed. The experimental result showed that the crack load and ultimate load of abnormal joints obviously decrease in comparison to the normal joints, the penetrating crack load are very close to the ultimate load, two typical failure modes may occur, i.e. the small core shear failure and the joint area under longitudinal orthogonal beam shear failure. The method of using the constraint mechanism to express the small core shear failure and the formula for calculating shear-bearing capacity of abnormal joints are given. The steel ratio on the bottom of the large beam ought to be limited to ensure the safety of the joint area under longitudinal orthogonal beam.