界面状态对矩形钢管混凝土构件抗弯性能的影响
Influence of Interface State of Rectangular Concrete-filled Steel Tube on Flexural Performance of Component

考虑钢-混凝土界面完全粘结和自由滑移2种极限状态，研究矩形钢管混凝土构件受弯过程的截面中和轴平移规律，并基于平截面假定，分别给出2种界面状态下构件抗弯承载力、抗弯刚度的理论计算方法。同时，针对钢管与核心混凝土界面平均粘结强度，分析抗弯构件在界面脱粘时的有效受压区高度。研究结果表明：矩形钢管混凝土的界面脱粘导致核心混凝土的抗弯承载力过早失效，构件的整体抗弯刚度和承载力降低；高宽比越大，钢管混凝土梁的整体钢管与混凝土之间的界面状态性能对构件抗弯承载力的影响越明显；实际中核心混凝土在未达到极限受压强度前与钢管发生脱粘，为充分利用核心混凝土的材料强度，应对矩形钢管混凝土的界面粘结进行构造加强。
The authors studied fully-bond and free-slip of steel and concrete which were the two kinds of ultimate state, discussed the neutral axis translation rules of rectangular concrete-filled steel tube component under bending process, and based on the plane cross-section assumption, the two kinds of calculation method about interface state under flexural bearing capacity were given. At the same time, average bond strength between steel tube and core concrete interface to analyze effective compressive zone height of the flexural member was introduced. The results show that the interface debond leads to premature failure of the core concrete flexural bearing capacity and decrease of overall flexural rigidity and bearing capacity of components. The greater aspect ratio is, the greater influences of the performance interface between steel tube and core concrete on the performance of the bearing capacity of bending members are. In fact, it makes full use of material strength of the core concrete by enhancing the bond strength between steel and concrete to reach the ultimate compressive strength before the steel-concrete interface debond