Trade Journals for the Concrete Industry

Adhesion forces, occurring when normal precast concrete components produced in series are lifted from their formwork, increase stress on transport anchors significantly. Precise knowledge of these additional forces is indispensable for the purpose of dimensioning transport anchors safely, in order both to exclude any danger to the personnel involved in the manufacturing process and to avoid damage to the precast components during transport. This paper will present experimental investigations into the measurement of adhesion forces with formwork. The investigations include groups of similarly shaped precast components, such as wall panels, purlins and floor slabs. The effects of influences from environmental factors, the sequence in which several precast components are lifted from a common formwork stripping table, as well as supporting measures such as formwork vibration, will be quantified. The measured data obtained will be compared critically with the referral values recommended up to the present date. A statistical concept based on experimental data will be introduced with a view to deriving referral values for the adhesion force of formwork.