Comparison of steel and concrete structures
Steel structures are commonly referred to as building systems in which the vertical and horizontal elements that make up the frames are made of metal. Now with this simple definition, we go to the stages of construction of steel structures as follows:
- Construction of foundations and foundations
- Construction of steel columns
- Installation of metal beams
- Roof systems
- Fastening system
- Joinery
Concrete is inextricably linked to twentieth-century architecture. What few people know: “The ancient Romans built their structures from artificial stone, the composition of which was very similar to modern concrete .”The Romans first used lime and then volcanic rock in their mortar, thus discovering the first hydraulic binders.” We still owe admirable architectural treasures like the Pantheon in Rome. With a 43-meter-diameter domed roof made of “Roman concrete”, it still stands after 2,000 years.
The use of steel and concrete structures is still common and none of them could be superior to the other. Metal structures are often used in very tall buildings or towers because it is difficult and very time consuming to build concrete structures for such structures. On the other hand, concrete structures are more common in the construction of tunnels , bridges and smaller buildings.
Steel and concrete structures can be evaluated from different aspects:
Steel and concrete structures can be evaluated from different aspects:
1- Earthquake
There is usually a misconception that the structure of a steel structure is more resistant to earthquakes, or vice versa. he does. In fact, the important factor is the correct design of the structure. Of course, it should be noted that concrete structures systems suffer more force in earthquakes due to the increase in the weight of the structure.
2- Longevity
There is a fact that concrete structures have a design life, which means that a concrete structure is designed for a certain life, even if it is 50 or 60 years old. Concrete experiences fluctuations over time, which ultimately has a negative effect on the performance of the structure during an earthquake. But in steel structures, there is no problem of decreasing resistance with increasing life, and this is an advantage for steel structures
3- The value of abortion
Usually, in the common constructions in the country, less attention is paid to the issue of structural demolition, which means that at the time of structural demolition, metal buildings have a much higher demolition value and lower demolition costs. This can also be an advantage for the steel frame.
4- Steel fire resistance
Steel has a low fire resistance, so it loses its resistance when heated, while the concrete structure is much more fire resistant. Of course, it should be noted that by making arrangements in the metal structure, which are sometimes costly, its fire resistance can be increased. Therefore, higher fire resistance of concrete structures is considered as an advantage
5- Ease of implementation
The important thing in choosing a metal or concrete load-bearing structural system is the facilities for constructing the structure at the time of construction. Therefore, it must be accepted that the implementation of concrete structures requires less expertise, skills, supervision and control than steel structures, and given the current situation in our country, this is an advantage for concrete structures.
6- Execution time
Due to the simultaneous execution of the floors, metal structures have a faster progress rate than concrete structures. Also, if the steel frame is made in the factory, the execution time will be further reduced. But in the concrete structure, due to the implementation of each floor after the basement and also the observance of the initial setting time of concrete, the speed of progress is much slower. Also, high speed in the execution of metal structures reduces overhead costs and project operation time, which compensates for some of the more expensive construction costs.
7- Architecture
Metal columns, especially in high-rise buildings on the lower floors, have smaller dimensions and this is an advantage due to the location of the parking lot on the lower floors. Also, in conventional buildings, steel structures have less limitations in design than concrete structures. Such as the distance between columns and openings. Hence, the steel frame allows for special structures
