The introduction of Post Tensioned slabs by Somers Engineering and the Dywidag Systems International, Germany into East & Central African market is changing the way the structures are built with greater flexibility.
This provides a system of strengthening concrete by tensioning the steel members and putting the concrete in compression. In traditional reinforced concrete the steel reinforcement remains inactive until the formwork is removed. In post tensioned concrete high tensile steel tendons are placed and stressed making the reinforcing steel active.
Somers Post-Tensioned Slabs
Post-tensioned slabs contain many valuable properties that help architects, engineers and contractors overcome the design restrictions of traditional reinforced concrete – such as curved edges and irregular column grids – to construct increasingly imaginative and innovative structures.
Somers offers post-tensioned slab systems for elevated slabs or slabs on grade. Somers Systems utilize DSI’s post tensioning systems for which their bonded strand post-tensioning 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.
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 cement based 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 localized region of the slab only.
Monostrand Unbonded System
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.
Somers Post-Tensioning in Civil Structures
Post-Tensioning Systems are used in civil structures across the globe, including bridges, reservoirs, silos, Nuclear, LNG Tanks; Cryogenic, and oil platforms.
In the design of bridges, Somers post-tensioning allows the creation of longer, more slender spans with fewer supports, thereby facilitating the design of more elegant structures. Post-tensioned concrete can also minimize problems of cracking, to improve structural durability and longevity.
Somers scope of work on civil structures includes Consulting, Design & Shop drawing engineering, Manufacturing and Supply, site supervision, inspection and maintenance.