بررسی زمان بقای قاب سه بعدی با اتصال نبشی در حرارت

The effect of fire on the structural steel frames has been frequently studied in the recent years due to its special importance. Because steel is sensitive to the temperature and reinforcing of steel frames against fire is highly expensive it is needed that behavior of steel frames in high temperature for reduction of undesired effect of temperature increase to be studied exactly. Now, for achieving to this goal and with regard to the expensive costs laboratory test and their limitations in analyzing at various parameters in each test, employing of finite element method as a strong tool for modeling of steel frames has depicted its value under temperature conditions. With respect to the above mentioned remarks, this paper aimed is to study the effect of fire on steel structures considering the softening behavior of connections and decreasing of strength. Then by using ANSYS software the duration of structure against ignition analyzed and the tested frame is a single span with three dimension and finally different conditions on frame has been compared, which this condition include the effect of connection type, studying the effect of longitudinal expansion, the effect of temperature loading type and beam length as well as fire type. After providing computer data, this result has been compared with results of other researchers.