Technical, economic, and environmental feasibility of ribbed slabs with reusable metal formwork and truss reinforcement
Technical, economic, and environmental feasibility of ribbed slabs with reusable metal formwork and truss reinforcement
DOI:
https://doi.org/10.51473/rcmos.v1i1.2026.2242Keywords:
Ribbed slabs, Reusable formwork, Structural performanceAbstract
The conventional trussed slab system in Brazil is based on the combination of precast joists and disposable infill elements, such as expanded polystyrene (EPS) or ceramic blocks. This configuration presents logistical limitations, high waste generation, and cold joints between the joist and the cast-in-place concrete topping. This study analyzes a technical proposal in which a self-supporting metal truss replaces the concrete joist and eliminates the infill using reusable metal formwork. The main objective is to evaluate the technical, economic, and environmental feasibility of the solution applied to H12 slabs. The methodology included analytical modeling in accordance with NBR 6118, stress and deformation calculations, full-scale prototyping, and cost analysis. Additionally, a simplified Life Cycle Assessment (LCA) (ISO 14040) was performed, focusing on embodied carbon and cradle-to-grave scope. Technical results indicate that the formwork (galvanized sheet #18, thickness 1.2 mm) withstands a maximum stress of 87.5 MPa, below the allowable limit of 112 MPa, with a safety factor of 3.2. The recorded deformation was 1.41 mm, considered adequate for temporary elements. Economically, the system outperforms EPS between the 12th and 15th reuse cycles and ceramics between cycles 19 and 22, with a payback period of 3.5 months. The LCA revealed net avoided emissions of 5,800 kg CO₂e per 1,000 m². It is concluded that the solution optimizes monolithicity, reduces environmental impact, and is financially viable, consolidating the principles of the circular economy.
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Copyright (c) 2026 Pablo Santos Mota, Shirley Amaral Dias Santos, Jessé Regino de Oliveira Mendes, Jefferson Lira Santos (Autor)
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