Japanese construction company Obayashi Corporation has begun to reuse steel and concrete structural components from demolished buildings in new construction projects. This innovative method was employed in the construction of a laboratory building in the company's Technical Research Institute in Kiyose City, Tokyo. In the new building, 57% of the steel and 33% of the concrete structural materials are reused from dismantled structures. This practice is expected to reduce carbon dioxide emissions from structural material production by 65.8 tons, a 49% reduction compared to the 135.1 tons of CO2 that would be emitted if all new materials were procured.

While the reuse of wood in new construction from demolished wooden buildings is common, the reuse of steel and concrete from demolished structures typically involves melting or crushing them for recycling into new building materials. The direct reuse of such materials in new building structures is unprecedented in Japan.

In this project, all types of steel components, such as columns, beams, and braces, from the dismantled experimental building were removed and processed by a steel fabrication company to fit the new building. Similarly, concrete structural components, including foundations, foundation beams, small beams, and floors, were cut to match the new building's layout. These were then processed and connected to new materials at the construction site to form the structure of the new building.

This method allows for flexibility in terms of location and span changes, thereby maximizing the effective use of structural materials. The use of reused materials also results in lower CO2 emissions during production compared to recycled materials. (2024/06/28)