Realization of a Construction Method Using Both Steel and Wooden Formwork to Accommodate the Manufacture of Precast Concrete Members with Special Shapes
By G. Horiuchi, F. Kobayashi, E. Asaba and M. Matsubara
Concrete Journal, Vol.64, No.8, Aug. 2026
- Synopsis
- To address labor shortages in the construction industry, wider use of precast concrete construction methods is needed. However, for special-shaped PC members with only a limited number of formwork reuses, steel formwork costs account for a large share of manufacturing costs, and this has become an issue that often leads to the adoption of PC construction being deferred. This report describes the Rakuwaku Formwork Method, a formwork technology that combines reusable steel bed formwork with inexpensive wooden side formwork. By increasing the rigidity of the wooden side formwork to eliminate separators and using a magnetic fixing method in combination, the method enables manufacturing by PC workers alone. The product dimensional accuracy satisfied the JASS10 standards, and formwork costs were reduced by 60% compared with the conventional method. Magnet performance tests confirmed the load-bearing capacity under shear and combined (tension and shear) forces, and application to a project confirmed the practical applicability of the method. Use of this method helps reduce on-site construction labor hours.
- Keywords:
- Precast concrete, Magnet, Formwork, Productivity improvement, Special shape, Plywood in-plane flexural performance
