When the temperature of the steel structure changes from zero to 150 ℃, the fire resistance of the steel structure decreases greatly, but the test shows that the fire resistance grade of the steel structure decreases from zero to 600 ℃. When the steel structure is wrapped or covered with bricks, when the thickness of the fireproof coating of the fireproof coating is 15mm, the fire resistance limit of the steel member can reach 1.5h.
1. Single storey: buildings with only one floor on the ground are single storey buildings, including industrial plants (with a single storey height of more than 6-8m), civil buildings (2.2-3m), agricultural plant greenhouses (more than 2.2m), etc.
2. Multi storey: refers to a 4-6 storey building.
3. High rise: refers to buildings with more than 10 floors and a total height of less than 100m.
4. Super high rise: refers to buildings with more than 40 floors and more than 100 meters.
5. High rise and super high rise mainly adopt steel-concrete structure, such as cross column, box column and other structural forms.