足尺钢框架结构真实火灾下耐火性能试验研究OA北大核心CSTPCD

To analyze the fire resistance of the whole steel frame structure under real fire,a two-story,two-span full-size steel frame structure with a plane size of 6 mx6 m and height of 3 m was designed,and three real fire tests were carried out.The experimental phenomena,actual temperature field and mechanical response of house fire,warehouse fire and unprotected fire were studied.The results show that the temperature rise curve of steel frame structure under real fire conditions demonstrates big difference from the standard fire curve.The temperature of the fire room presents uneven distribution along the vertical direction and tends to be the same along the horizontal direction.Fire protection causes the surface temperature of the members to lag behind the fire site temperature.The peak of the surface temperature and its decreasing rate are both smaller than those without fire protection.The increase of fire load density and the lack of fire protection will increase the axial temperature difference of steel beam,but do not affect the temperature gradient along the section direction of steel beam and column and the axial direction of steel column.Steel beams and concrete slabs have higher temperature than steel columns.For the design of steel frame structure,full consideration of fire protection is necessary and appropriate consideration of the beneficial effect of walls on fire resistance is recommended.