|Formwork Making - Course: Timberwork techniques. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 14 p.)|
Before placing the concrete, the formwork is to be cleaned and checked again for proper execution.
After cleaning, the cleaning holes of wall and column formworks are to be tightly closed since the maximum pressure of the concrete mix is occurring at the foot of the formwork where the cleaning holes are situated. For this purpose, the sheeting pieces of the cleaning holes are always to be put against the thrust-board and against formwork bearers. If necessary, additional formwork bearers are to be mounted. Immediately before concreting, the formwork is to be thoroughly wetted with water because thereby less water will be extracted from the concrete mix and later stripping will be facilitated. When placing the concrete, it is to be made sure that no changes take place with the formwork.
Stripping of the formwork must not be started unless the site engineer in charge has given the respective express instructions. Too early removal of the formwork parts may cause heavy damage to the structure and/or injury of persons.
Stripping is to be done very carefully. Neither the concrete nor the formwork timbers must be damaged. Emergency columns are the last to be removed. When stripping, greatest attention is to be attached to the structural direction of forces of the formwork. All nails are to be removed from the stripped formwork timbers, and the stripped timbers are to be cleaned and overly stacked. The strict observance of labour safety regulations is of special importance for stripping work because of the danger of falling-down formwork parts.