方钢管混凝土柱梁下栓上焊节点受力性能研究

为研究带外环板的方钢管混凝土柱H形钢梁下栓上焊节点的受力性能,以梁上翼缘连接方式和梁截面尺寸为试验参数,设计制作了3个节点构件,并对其进行拟静力试验。引入了数字散斑相关方法(DSCM)测量系统,对节点核心区应变进行非接触式高精度测量。结果表明,受焊缝质量的影响,构件主要破坏位置都在焊缝附近,其中下栓上焊节点和全螺栓节点分别发生在梁上翼缘与外环板连接的焊缝处和下内隔板与柱连接的焊缝处;下栓上焊节点相对于全螺栓节点核心区变形更小,更符合“强柱弱梁”准则,并推断梁柱之间荷载传递主要通过外环板,但全螺栓节点由于螺栓滑移以及焊接缺陷少,延性要显著好于下栓上焊节点;梁截面尺寸和节点连接方式对构件核心区受力性能和应变分布有较大影响,其中核心区主应变及剪应变云图均呈45°斜向发展。

Mechanical behavior of the bottom flange bolted and top flange welded joints between concrete-filled steel tubular columns and steel beam

In order to study the mechanical behavior of the bottom flange bolted and top flange welded joints with vertical stiffener between concrete-filled steel tubular columns and H-shaped steel beams, three joint members were designed and manufactured, and their pseudo-static tests were carried out with the connection mode of upper flange and the cross-section size of the beam as test parameters. At the same time, DSCM (digital speckle correlation method) measurement system was introduced to measure the strain in the core area of the node with non-contact high precision. The results show that the main damage locations of the components are near the weld due to the quality of the weld seam. The damage of the bottom flange bolted and top flange welded joints occurs at the weld joints of the upper flange and the outer ring plate of the beam, while the damage of the full bolt joints occurs at the weld joint between the inner diaphragm and the column. The core area deformation of the bottom flange bolted and top flange welded joints is smaller than that of the full bolt joint, suggesting that it is more in line with the criterion of "strong column and weak beam". It can be concluded that the load transfer between beam and column is mainly through the outer ring plate, but the ductility of full-bolted joints is significantly better than that of the bottom flange bolted and top flange welded joints due to the slippage of bolts and fewer welding defects. Moreover, beam cross-section size and joint connection mode have a greater impact on the stress performance and strain distribution in the core area, and the principal strain and shear strain nephogram in the core area develop obliquely at 45 degrees.