Steel structure calculation table

             In order to ensure the bearing capacity of load-bearing structure and prevent brittle failure under certain conditions, appropriate steel grade and material properties should be selected according to the importance of structure, load characteristics, structural form, stress state, connection method, steel thickness and working environment. 

             Q235 steel, Q345 steel, Q390 steel and Q420 steel should be used as the steel for load-bearing structure, and their quality should conform to the current national standards GB / T 700 carbon structural steel and GB / T 1591 low alloy high strength structural steel.When other grades of steel are used, they shall meet the requirements of relevant standards.For Q235 steel, killed steel or semi killed steel should be selected.The steel of load-bearing structure shall have the qualification assurance of tensile strength, elongation, yield strength, sulfur and phosphorus content, and the qualification assurance of carbon content for welded structure.

             The steel of welded load-bearing structure and important non welded load-bearing structure should also have the qualification guarantee of cold bending test.For the steel of welded structure that needs to be checked for fatigue, it shall have the qualification guarantee of normal temperature impact toughness.When the working temperature of the structure is equal to or lower than 0 ℃ but higher than – 20 ℃, Q235 steel and Q345 steel shall have the qualification assurance of 0 ℃ C impact toughness; Q390 steel and Q420 steel shall have the qualification assurance of – 20 ℃ impact toughness.When the working temperature of the structure is equal to or lower than – 20 ℃, Q235 steel and Q345 steel should be qualified with – 20 ℃ impact toughness; Q390 steel and Q420 steel should be qualified with – 40 ℃ impact toughness assurance.For the non welded structure steel which needs to check the fatigue, it should also have the qualified guarantee of normal temperature impact toughness. When the working temperature of the structure is equal to or lower than – 20 ℃, the qualified guarantee of 0 ℃ impact toughness should be provided for Q235 steel and Q345 steel, and – 20 ℃ impact toughness guarantee should be provided for Q390 steel and Q420 steel.When Z-direction steel is used for welding load-bearing structure to prevent lamellar tearing of steel, the material shall comply with the current national standard GB / T 5313.