Lifting System with Sockets
When using lifting inserts, precast elements must be provided with a minimum surface reinforcement (cf. table 1) and concrete must have a minimum strength of 15 MPa at first time of lifting.
Existing static-structural reinforcement may be taken into account. The user is personally responsible for further transmission of load into the unit.
Table 1: Minimum reinforcement
acier HA / FeE500
This minimum reinforcement can be replaced by comparable stirrups with longitudinal reinforcement. Diagonal tension requires additional reinforcement (table 3).
For transmission of load into the concrete, a reinforcement stirrup of FeE500 is inserted through the cross hole of the lifting socket.
Contact of reinforcement and insert has to be ensured in suitable manner (binding wire, but no welding).
Lifting sockets must be used in units with minimum dimensions according to table 2.
Table 2: Minimum axis distance, edge distance, minimum thickness of unit
|Reference||Minimum axis distance|
|Minimum edge distance|
|Minimum thickness of unit|
In case of lateral and diagonal tension, minimum reinforcement (table 1) must be strengthened by additional reinforcement (table 3 and 4).
Additional reinforcement must have pressure contact with the insert. Diagonal tension reinforcement is arranged in the opposite direction of that of tensile force.
Table 3: Additional reinforcement on diagonal tension (necessary if β ≥ 12,5°)
|L||Ø Bending diameter|
Table 4: Additional reinforcement on lateral tension (necessary if γ ≥ 7°)
|L||H||Ø Bending diameter|
Tilt-up of slabs can lead to simultaneous diagonal and lateral tensions. Those cases request only lateral reinforcement and also cover diagonal tension.
Repeated tilt-down or tilt-up of the unit during installation requires a taking into account of lateral reinforcement.