Numerical evaluation of structural stay-in-place formwork in textile reinforced cement composite for concrete shells

This article presents the structural evaluation of textile reinforced cement composite elements as formwork and reinforcement for concrete shells. Different shell geometries of 10 m span and a height between 2.5 and 5m are examined. On one hand, the minimum thickness of the composite element functioning as formwork for these shells is determined when supported with a different number of supports and for different concrete sections. On the other hand, the minimum thickness of the composite functioning as reinforcement is calculated to withstand the occurring maximum bending moment. For shells with a 10 to 15 mm concrete section, a minimum composite formwork of 5-6mm is needed to carry the load of the cast concrete, while the minimum composite reinforcement needed to withstand the maximum occurring bending moment equals 2-3mm. Conclusively, this preliminary numerical study demonstrates the structural potential of textile reinforced cement composite stay-in-place formwork for concrete shells and indicates the dominance of the casting stage over the final stage. More specifically, local buckling of the formwork is the determining factor and should drive future work towards this issue.