The steel used for steel structure has high strength and high elastic modulus. Compared with concrete and wood, the ratio of density to yield strength is relatively low.
Therefore, under the same stress conditions, the component section of steel structure is small, the self weight is light,
it is convenient for transportation and installation, and it is suitable for structures with large span, high height and heavy load.
It is suitable for bearing impact and dynamic loads and has good seismic performance. The internal structure of steel is uniform, close to isotropic homogeneous body.
Steel structural members are easy to manufacture in the factory and assemble on the site.
Steel structure is one of the most industrialized structures.
Because the welded structure can be completely sealed, it can be made into high-pressure vessels with good air tightness and water tightness, large oil pools, pressure pipelines, etc.
When the temperature is below 150 ℃, the change of steel properties is very small.
Therefore, the steel structure is suitable for thermal workshop, but when the structural surface is radiated by heat at about 150 ℃, it should be protected by heat insulation board.
When the temperature is 300 ℃ – 400 ℃ The strength and elastic modulus of steel decreased significantly.
When the temperature was about 600 ℃, the strength of steel tended to zero.
In buildings with special fire protection needs, the steel structure must be protected with refractory materials to improve the fire resistance rating.
Especially in the environment of wet and corrosive medium, it is easy to rust.
General steel structures shall be derusted, galvanized or coated, and shall be maintained regularly.
For offshore platform structures in seawater, special measures such as “zinc block anode protection” shall be adopted to prevent corrosion.
The demolition of steel structure buildings will hardly produce construction waste, and the steel can be recycled.
Before installation, the construction unit shall check the product certificate, design documents and pre assembly records of components, and recheck and record the dimensions of components.
When the deformation and defect of steel structure exceed the allowable deviation, it shall be handled.
A certain camber shall be preset for the assembled roof truss.
After the steel structure is hoisted in place, the component positioning axis, elevation and control points required by the design shall be measured, marked and the quality of the hoisting butt joint shall be inspected before welding.
Install the temporary support and steel wave cable to make the steel roof truss safe and stable during construction.
During the installation of steel structure, the construction unit shall submit the elevation, dimension, welding, coating, etc. of each member after hoisting to the supervisor for acceptance.