Stress Transfer between Steel Tubular Column and Infill Concrete at A Connection of H-Beams to Concrete Filled Tubular Columns with Diagonal Braces

在2003年，我们进行了一个推出试验的钢管混凝土短柱和填充混凝土之间的粘结强度和机械剪切连接器的效果，由于通过横隔梁梁连接。2004年，为了保证钢管混凝土柱、H形梁和斜撑的实际粘结强度和机械抗剪连接件在框架中的作用，对钢管混凝土柱、H形梁和斜撑组成的框架模型进行了试验研究，取得了以下结论：（1）通过钢管混凝土柱的刺柱试验，对钢管混凝土柱粘结强度的传统认识进行了追溯。也就是说，粘结强度受管截面形状（圆形或矩形空心截面）的影响很大，而受混凝土强度的影响不大。（2）横隔梁的抗剪连接效果可以用横隔梁与填充混凝土之间的承载力或填充混凝土与横隔梁之间的承载力的降低来预测。 ...更多信息 管或隔膜板的剪切屈服强度，甚至具有大的安全裕度。实际上，承载强度在强度预测中占主导地位。在这种情况下，应考虑混凝土的围压效应，使围压效应引入较大的安全裕度。(3)In对于外加劲肋连接的框架模型，应力通过粘结作用从钢管传递到混凝土。在框架模型中观察到的粘结强度几乎类似于从钢管混凝土短柱推出试验中获得的粘结强度，其中只有混凝土截面在顶部受到压缩载荷，只有钢管部分在底部被支撑。在另一个试验中，混凝土和钢管都在顶部承受压缩荷载，这将大大低估从框架模型中获得的强度。(4)In对于采用贯通式横隔板连接的框架模型，可以预期机械剪力连接件效应会将应力从钢管传递到混凝土。尽管所有的框架模型都设计了带有用于混凝土浇筑的非常大的孔的隔板，但是柱脚处的暴露混凝土部分被其自身的轴向压应力压碎，该轴向压应力必须从钢管转移。因此，一般而言，贯通式横隔板连接的机械剪力连接效应可以足够大，以满足实际应用。少

In 2003,we performed a push-out test of concrete-filled tubular stub columns to investigate the bond strength between tubular columns and infill concrete and the mechanical shear connector effect due to the cut-through diaphragm for beam-to-column connections. In 2004,frame models composed of a concrete-filled tubular column, H-shape beam and diagonal brace are tested to ensure the realistic bond strength and the effect of mechanical shear connectors in building frames.From the tests, the following conclusive remarks were introduced :(1)The conventional knowledge about the bond strength of concrete-filled tubes were traced by the stab column test. That is the bond strength is affected by tubular section shapes (circular or rectangular hollow section) strongly, but not so much by the concrete strength.(2)The effect of mechanical shear connector caused by the cut-through diaphragm can be predicted by the lower strength either the bearing strength between infill concrete and diaphragm in … More a tube or the shear yield strength of a diaphragm plate even with a large safety margin. In fact, the bearing strength dominated the strength prediction. In such a case, the concrete confining effect should be considered, so that the large safety margin is introduced by the confining effect.(3)In case of frame models with outside diaphragm stiffened connections, the stress transfers from a steel tube to concrete by the bond action. The bond strength observed in the frame models is almost similar to the one obtained from push-out test of concrete-filled tubular stub columns, where only concrete section is subjected to compressive load at the top and only steel tubular potion is supported at the bottom. The bond strength from another test where both of concrete and steel tube are subjected to compressive load at the top will give too much underestimation for the strength obtained from the frame model.(4)In case of frame models with cut-through diaphragm connections, the mechanical shear connector effect can be expected for stress transfer from steel tube to concrete. Even though all of the frame models were designed to have the diaphragm with very large hole for concrete casting, the exposed concrete portion at the column base crushed by the it own axial compressive stress which must be transferred from the steel tube. Therefore, in general, the mechanical shear connecting effect by cut-through diaphragm connections may be large enough for the practical use. Less