systems for which their bonded strand post-tensiioning systems are in accordance with European Technical Approval
ETA-06/0022 and their unbonded monostrand post-tensioning systems are in accordance with ETA-03/0036.
Bonded and Unbonded Options
Amsteele Systems offers both bonded and unbonded post-tensioning options.
Monostrand Unbonded Systems
The DSI unbonded single strand tendon system is quick to install. Tendons can be easily deflected to avoid openings and to cope with irregular slab shapes. The system has reduced friction losses, increased eccentricity and requires no grouting. Anchors remain active throughout the life of the system.
Multi-strand Bonded Flat Slab Systems
DSI bonded systems incorporate groups of 2, 3, 4, 5 or 6 strands contained within a flat duct and anchored at the live end by a DSI anchorage and through bonding to the concrete at the dead ends. Strands are individually stressed and after stressing the ducts are filled with a cementbased grout to fully bond the strands to the concrete through the duct wall and all along the length of the tendon. Bonded systems do not rely on the anchors after grouting and any damage to a tendon, or structural modification requirements, impacts on the localised region of the slab only.
Elevated Slabs and Concrete Pavements
Pre-stressing of concrete produces more efficient and stronger floor slab designs.
Post-tensioned elevated slabs offer solutions and benefits to some of the common restrictions faced by developers, architects, engineers and contractors. These include:
- Increased spans and therefore larger column-free areas, as well as a reduction in the number of columns
- Alternatively, or concurrently, slab thicknesses may be reduced, providing greater floor to ceiling volumes or increasing the number of floors that may be incorporated within a building envelope, increasing rentable floor area
- Thinner floors also contribute to reduced facade-to-floor area costs
- Thinner slabs mean between 20 to 30% less concrete as well as minimal, and less complicated, conventional reinforcing. Both result in less crane hook times and less steel fixing and concrete pouring times
- Reduced cracking for improved durability and lower maintenance costs. The deflections can be controlled by varying the amount of post-tensioning to balance any portion of the applied loads
- Thinner slabs or reduced column numbers result in reduced foundation requirements, resulting in material, cost and program savings
- Reduced decking stripping times and back propping increases turnaround of slab support material and increases accessibility to lower floors; reducing building costs and construction program
- Reduced concrete and steel usage contributes significantly towards a Green Building Status
Some of the applications for post-tensioned elevated slabs include:
- Parking garages
- Office blocks
- Apartment buildings
- Shopping centers
- Airport terminals
- Sports stadia
- Water structure roofs
Post-tensioning of concrete pavements, for both internal and external use, has provided many developers, architects, engineers and contractors across the globe with a cost-effective solution for more than 40 years.
Benefits of post-tensioned concrete pavements include:
- Large, joint-free slab areas
- Reduced long-term maintenance due to the reduction of joints
- Reduced, or eliminated, corner curling
- Reduced construction costs
- Reduced subgrade preparation
- High effectiveness on poor ground conditions
- Accelerated construction
- Increased load capacity
- Reduced permeability
Amsteele Systems, in association with a specialist flooring contractor, offers a complete package to it’s clients. We provide for detailed design and, on receipt of the completed subgrade, we supply, fix, place and finish off all materials and activities until full and final slab completion. This includes slab grinding to ultra-high tolerances where required.
Some of the more common applications of post-tensioned concrete pavements include:
- Distribution facilities (Internal and external pavements)
- Warehouses (Internal and external pavements)
- Factories (Internal and external pavements)
- Bulk storage facilities (Internal and external pavements)
- Container storage and handling facilities
- Aircraft hangers
- Airport apron slabs and runways
- Indoor and outdoor sports courts
- Freezer stores
- Raft slabs
- Floor slabs for water retaining structures
Amsteele Systems provides a full design service.
To obtain maximum benefits from Amsteele’s post-tensioned slabs, it is recommended that the system is incorporated into the building structure in the early design stages.
Our design teams have the experience and expertise, gained by working on projects throughout Southern Africa, to provide prompt and effective design solutions. We utilise state of the art design software, which is continuously updated to reflect the latest international codes of practice.
Amsteele specialists are available to help structural engineers determine the best option from an early design stage, through extensive value engineering in order to meet specific requirements for each project.
Amsteele can provide schemes with sufficient information for tender purposes and then, when required, develop the detailed design and produce shop drawings for construction.