Laing O’Rourke are building a 40 storey residential tower in Elephant and Castle entirely out of precast concrete units.
Upon completion of the structure, precast cladding panels will make up the envelope of the building. These precast units can weigh up to 10t with cladding panels up to 7.8t and are lifted in to position via the three tower cranes on site.
Due to the weight of these components there were concerns raised around the consequences of a lifting accessory failing whilst 40 storeys up in the air, especially given the confined nature of the site and arterial roads and heavy footfall around the project.
As such a decision was made by the project team to develop and trial ‘secondary lifters’ fitted to the precast units.
The precast loads were slung as normal via a primary master link attached to the crane and chains to positive attachments fitted to the precast units and panels as normal.
A secondary chain, rated for the full unit weight, was then attached directly to the hook with a lever hoist used to ensure the secondary chain (again fixed by a positive attachment) is taught but not taking much load.
This secondary lifter is fitted is the centre point of gravity and is capable of taking the full load of the precast unit plus a factor of safety on top.
- Mitigates risk of falling objects in the event of a primary lifting failure
- Provides increased confidence in lifting operations for both the lifting team and others working on site as well as those beyond the site boundary.
- Easily fitted and adapted to different precast unit shape or size.