Statistical System:

The lifting equipment shall allow a statically determinate load distribution to all present lifting inserts and lifting insert systems. Figures below give examples of statically indeterminate systems where only two lifting inserts carry the load. The load distribution is not clearly defined in these applications. Therefore, statically indeterminate systems shall be avoided.

To ensure a statically determinate system and that all lifting inserts carry their required part of the load in case of applications with more than two lifting inserts transport aids such as sliding or rolling couplings or balancing beams shall be used. In below figure, more transportation aids for slabs and wall elements are illustrated.

In case of inclined lifting slings the lifting inserts are loaded by combined tension and shear loads. The inclination β according to figure above (on previous page) governs the level of combined tension and shear loads to be taken into account in the design. In the special case of three lifting inserts located in a slab located and situated in a star pattern with the same distance to the centre of gravity with equal inclinations of 120° it is ensured that all three lifting inserts experience the same load.

Element Self-Weight:

The weight FG of precast elements shall be determined as given by equation below

- FG = V · ρG where,
- FG Weight of the precast element, in kN
- V Volume of the precast element, in m3
- ρG Density of the concrete, in kN/m3

Adhesion and Form Friction:

Adhesion and form friction are assumed to act simultaneously during the lifting of the precast element from the formwork.
The actions for demoulding situations shall be determined from equation below

- Fadh = qadh · Af where,
- Fadh Action due to adhesion and form friction, in kN
- qadh Basic value of combined adhesion and form friction as per table below, in kN/m2
- Af Contact area between concrete and formwork, in m2