Halfen - Cast-in hoop lifting system

Introduction

Cast-in wire rope lifting hoops are the most economic way of providing a crane hook attachment in precast units. However, they require relatively large edge distances. Consideration must also be given to the exposure of steel rope hoops after panel assembly. Once finally in position, protruding hoops can be cut off, if required, but consideration must still be given to the provision of corrosion protection to the cut ends to avoid rust staining.

The flexibility of steel rope makes it the safest method for forming a cast-in hoop. Lifting loops formed from reinforcement bars are liable to fatigue, particularly if bent during angled lifts.

Provided that hoops are installed in reinforced concrete and to the minimum dimensions in the table, no anchorage reinforcement is generally required. However, for acute angled lifts, additional lateral reinforcement may be required.

Description

Cast-in lifting hoops are manufactured from bright or galvanised mild steel rope. They have a swaged connecting ferrule and a tag that clearly identifies the SWL of the hoop. The tag is designed not to slide down the hoop during casting and should therefore remain visible.

Cast-in hoops are suitable for use through a single cycle from production to final installation but are not suitable for multi-use applications.

Selection

To select the correct size for any lift, carry out the calculation on pages 6 and 7. It is essential to take into account the angle of lift, the crane factor and any adhesion to the formwork.

Installation

Hoops should be installed in the direction of the expected load, with the ferrule directly opposite the direction of pull. They should be suspended from supports attached to the formwork so that 2/3 of the hoop will be cast-in and 1/3 remains exposed.

Carefully fasten the hoop to the cage to avoid movement during concreting. It fixed through the shuttering, the wire should be carefully sealed to the shuttering.