Contact Thermal Resistance Of Concrete Steel Research At High Temperatures

Concrete-filled steel tube structure, developed in recent decades, is a new kind structure between steel structure and reinforced concrete structure. It has been widely used in all kinds of buildings for it is characteristic of good bearing capacity, ductility, easy construction and economy. It has achieved good economic benefit and architectural effect. Under the background of concrete-filled steel tube structure, with thermal contact resistance at high temperatures as the entry point, this paper conducts the thorough research which can provide applicable analysis models and methods for damage assessment, structure design and safety evaluation of concrete-filled steel tube structure in fire.Now international and domestic academics have had a lot of experience and achievements in the research of temperature field of concrete-filled steel tube. But most ignore the influence of contact thermal resistance between steel tubes and concrete. Considering the contact thermal resistance is necessary because of its great influence on the temperature field.This paper, based on the material testing machine of INSTRON8874, does research on the contact thermal resistance of concrete-filled steel tube at high temperatures. The research is under different interface pressure. The contact thermal resistance can be calculated by the temperature measured in experiment. Practical thermal resistance values in engineering can be obtained by analysis of test results. The test shows that the interface pressure has great effect on thermal resistance.This paper, based on the test, uses the Finite Element Method of Lines to solve the problem of temperature field with the contact thermal resistance. The temperature field is simulated by leading in the element of the contact thermal resistance. The example shows the effectiveness of the method. And a new numeric calculation method is provided for these problems.