1. The tensile, compressive and shear strength of steel is relatively high, and the structural section of steel structure members is small and the dead weight is light. In general, the dead weight of high-rise reinforced concrete buildings is about 1.5-2.0t /m2, and the steel structure of high-rise buildings is mostly below 1 T/m2, and even some office buildings are only 0.5-0.6t /m2. The light weight of the structure can reduce the cost of transportation and lifting, and the load of the foundation can reduce the cost of the foundation, especially in the poor geological conditions of the region, its characteristics are more prominent.
2. Steel structure has good ductility and good seismic performance, especially in high intensity earthquake area, the use of steel structure is more favorable, the ductility of reinforced concrete structure is guaranteed that the stress of the structure is not too high, and the ductility of steel structure is to make some members into plastic.
In high intensity earthquake area, there are fortification requirements of high-rise buildings, if the weight of half, equivalent to reducing seismic fortification degree. Take Beijing 8° seismic crack prevention degree as an example, medium-height buildings using steel structure structure weight reduced by 1/3, earthquake effect can be reduced by 30-40%, the load per unit area on the foundation can also be reduced by more than 25%.
3. The area occupied by the structure (or called the structure plane density) is small, which actually increases the usable area. Steel structure building steel structure occupies only 28% of the same type of reinforced concrete building area. The use of steel structure can increase the use area of 4%-8%, which is actually to increase the use value of the building, increase economic benefits. For example, Changfugong Center in Beijing (26-story pure steel frame system) adopts steel structure, and the section of steel column is only 450*450mm, while the number of floors and column network of similar reinforced concrete structure, the section of column is about 900*900mm. If according to the increase in the use area of 4% calculation, for a building of 50,000 square meters, equal to the increase of about 200 square meters of use area, its value is quite considerable.
