Exterior walls are increasingly manufactured as precast concrete units with integrated polystyrene thermal insulation. The advantages com- pared to the in-situ concrete method, such as meeting high quality demands thanks to prefabrication in the precast component factory or the elimination of work steps on the building site, enable an economical building process. In the semi-precast construction system, the con- crete shells are precast in the factory, transported to the building site and then concreted to achieve their final cross-section. This saves the time and cost-intensive shuttering process and simultaneously reduces transport weight. The fresh concrete pressure arising during con- creting of the semi-precast elements must be absorbed with adequate safety by connectors that link the concrete shells. The shuttering pres- sure must be assumed in accordance with DIN 18218 “Fresh concrete pressure on vertical shuttering“ [1]. However, the influence of inter- nal thermal insulation in element walls upon shuttering pressure has not been taken into account until now. Depending upon cross-section geometry and the type of thermal insulation, the shuttering pressure is overestimated, which leads to an uneconomical calculation result during construction.
