Jacking & Launching
We provide systems and services for the lifting of heavy structures utilising either;
- Flat jacks
- Cylinder jacks
Incremental Launching Method (ILM)
Amsteele Systems provides a full service to the contractor or client:
- Complete temporary works design
- Manufacture, supply and installation of the launching nose
- Launching jacks and equipment,
- Assistance with monitoring, alarm and emergency stop systems and mechanisms.
- Supply of temporary launch bearings and Teflon pads
- Supply, installation and stressing of the primary pre-stressing
- Launching of the bridge segments.
- Supply, installation and stressing of the secondary pre-stressing
- Supply of permanent bridge bearings.
- Lifting of the bridge and replacing temporary launching bearings with permanent bearings.
The Incremental Launch Method of bridge construction is suitable for box girder sections where the bridge is straight or has constant horizontal or vertical curvature. The method eliminates temporary supports and is therefore, most applicable where these are impossible because of the nature of the crossing or the support height required. The construction sequence commences behind one abutment where a highly mechanised casting yard is set up. After the first segment is cast, a launching nose is attached and the segment is launched out of the cast bed and into the first span. Typically, the launch nose is about 60% of the length of the span.
The segments are launched using hydraulic jacks to either pull the segment via a “stick” or utilising a lift-and-push system. The next segment is then cast, stressed onto the first segment, and the process repeated until the entire bridge is in position. Secondary pre-stressing is then installed and temporary bearings are replaced with permanent ones.
Structural Sliding or Transverse Launch
Amsteele Systems are also contracted to slide heavy structures into position. This typically occurs when a structure cannot be built in its final position because of the disruption to existing traffic. The structure is therefore, built in close proximity and moved into place in a short period of time, causing minimal disruption to road, rail or similar users.
Structures can be pushed, but are more frequently pulled into position using high strength bars and hydraulic jacks. The structure slides on Teflon pads resting on 100% flat and level beams or similar supports.