When we decide to move members (rebars cage, precast, etc) sometimes we need to hitch it up and then lift it up. First of all, we need to concern about the stability of the member being picked. Then we’ll consider what lifting equipment requirement shall be met. We should ensure that all lifting equipments are:
- sufficiently strong, stable and suitable for the proposed use. Similarly, the load and anything attached (e.i. timber pallets, lifting points) must be suitable;
- positioned or installed to prevent the risk of injury, eg from the equipment or the load falling or striking people;
- visibly marked with any appropriate information to be taken into account for its safe use, eg safe working loads. Accessories, eg slings, clamps etc, should be similarly marked.
One of the common equipment for lifting is SPREADER BEAM.
Spreader beam takes part in lifting activity in many various way and design. It will be suited with its function in time we will use it. The spreader beam should be able to support itself. The spreader beam must be centered about the center of gravity of the picked member to avoid rotation of the spreader beam and shifting weight on the bridle hitches. As we can understand from the name itself, the spreader beam is expected to spread the load (became smaller than when it as pointed load) while lifting activity is undertaken.
Four basic of spreader beam types are as follows:
1. Spreader beam with two leg
This type of spreader beam is suitable for long member with thin shape body. Two points of lifting lugs should be prepared to lift the member in its stability point of lift.
2. Spreader beam with four leg
When the member width is wide enough, this type of spreader beam more fit to be used.
3. Adjustable spreader beam
When we will lift many type of members with different lifting point position, the adjustable spreader beam is the correct choice.
4. Fixed spreader beam
Vise verse with the adjustable one.
the end fitting for spreader beam can be seen as follow:
Below is the flowchart of designing process of spreader beam :
The process above should be ensured met the following items:
(1) SF = 3 to 5 depending on risk tolerance, environment and application;
(2) “Registered proffesional engineer” to designed & sign a specific lifting fixture;
(3) Documentation of load calculations mentioned;
(4) Rated capacity (working load limit) stamped on fixture;
####### Wrote in Ciwandan ######