Effective use of steel

The mechanical significance of making steel from iron ore is that it gives it tensile strength. If iron ore is simply piled up to form a shape, it can withstand compression to a certain extent, but will collapse when tension is applied. Historically, when only stone and brick, which are weak in tension, could be used, walls were built by piling them up, and arches and domes were used for large spaces. However, larger-scale structures and structures with tension cannot be realized without using structural materials that can withstand tension. Furthermore, in an earthquake-prone country like Japan, the use of steel, which has high tension resistance, is essential to ensure earthquake resistance.

Such value-added steel materials form the backbone of structures and are used for decades or more. In addition, they are recycled when they are no longer needed. In other words, they are not simply consumed and lost. If you keep this in mind, the appropriate price of steel materials for construction costs is a relationship between the cost of steel manufacturing and the wisdom of the users.

Steel prices are currently soaring. The current price level of steel per unit weight is on par with that of mineral water, so it cannot be said to be high in general. However, in the act of construction, the mission is to build high-quality buildings quickly and cheaply. It is necessary to reaffirm the significance of steel and make even better use of it. So, what should we do specifically to make better use of it?

The first thing to consider is to reduce the amount of steel used. Reinforced concrete construction can be considered as a structure that does not use steel, or uses as little steel as possible. However, it is questionable whether steel construction and reinforced concrete construction are directly interchangeable. A rational building must be created by comprehensively considering the various performance requirements for a building, the spatial composition, and the relationship between facade and exterior. Even with a steel structure, there is room to further utilize the characteristics of reinforced concrete construction in the underground structure and foundations, and ingenuity in this area would be effective.

Second, we need to make full use of the properties of steel. Until about 20 years ago, steel used in construction was of general or shipbuilding standards. Of course, the requests of the construction industry were likely reflected when deciding on the standards, but they did not reflect all of the unique demands of construction. Since then, a variety of standard steel materials for construction have been produced to reflect the needs of construction. These standards are an addition to general standards, so the resulting steel is valuable. We want to make full use of the properties of steel. On the other hand, for parts of a structure that do not require special standards, general steel materials can be used. By using steel materials that meet the required quality in the right places, unnecessary standards will be eliminated, which will also lead to an improvement in supply and demand.

As steel prices rise, longer delivery times are also becoming an issue. Building owners and designers are making various efforts to prevent construction periods from becoming too long, such as by reviewing order timing and construction plans. We hope that suppliers will also make further efforts to use valuable steel materials to enhance social capital.