Development of Steel-Concrete Hybrid Structures

1.通过对钢筋混凝土T形刚架结构的试验和分析研究，明确了以下几点：(1)在T形刚架中，钢筋混凝土构件承载的拉力通过纵向钢筋从钢筋混凝土构件延伸并锚固到钢构件连接部位的混凝土上传递给钢构件，并通过构件的直接接触传递压力。在这种连接方法中，传递的压缩力由连接部分形成的压杆承担，拉力主要由钢构件腹板承担。(2)如果连接部分的钢构件截面与相邻部分相同，则保证足够的安全性，有时可以在一定程度上减小受压翼缘、腹板和加劲肋的厚度。(3)如果连接部分合理布置栓钉剪力连接件，可以减少钢构件的应力集中，分配从RC单元传递的力。(4)用有限元分析方法可以准确地分析这种混合结构的力学行为。2.钢桥墩直接埋入混凝土基础的锚固试验结果表明，如果(1)埋入长度大于桥墩侧向尺寸的1.5倍以上，(2)采用保证混凝土与钢材之间充分粘结的方法，(3)将基础适当地加固到转换后的墙体上，这种方法的承载性能与采用锚固框架的方法是相同的。这种锚固方法可以应用于各种结构。

1.The followings were made clear through experimental and analytical studies on T-shaped rigid frame structures where steel element was connected to reinforecd concrete clement.(1) In the T-shaped rigid frame, it is practical that tensile force carried by RC clement is transferred to steel element through longitudinal reinforcements which are extended from the RC element and anchored to concrete placed in conncetion part of the steel element and compressive force through direct contact of the elements. In this connection method, transferred compressive force is carried by compression strut that is formed in the connection part and teusile force is carried mainly by the web of the steel element.(2) Sufficient safety is guaranteed if the section of steel element at the connection part is same as the adjacent part, and in some cases, thickness of compression flange, web and stiffener can be reduced to some extent.(3) If stud shear connectors are arranged properly in the connection part, stress concentration in steel element can be reduced, distributing the forces transferred from the RC element.(4) The mechanical behaviors of the mixed structures of this kind can be analyzed accurately with FFM,where non-linear constitutive equations with smeared crack model are assumed for concrete.2.From the results of experiments on an anchoring method where steel pier is embedded directly to concrete footing without using anchor frame, it was proved that such method shows the same load carrying performances as the method where anchor frame is used, if (1) the embedded length is greater than 1.5 times of the lateral dimension of the pier, (2) methods to secure sufficient bond between concrete and steel are adopted, (3) the footing is reinforced properly to the transferred forecs etc. are satisfied. The anchoring method of this kind can be applied to various structures.