1 Name:Post-tensioned concrete slabs
2 Application: bridge,building
3 Matreial:ASTM5140
4Certification: ISO9001:2008
LQM Post-tensioned concrete slabs in buildings have many advantages
1. LQM bonded flat slab anchors use No. 15.24mm seven-wire prestressing strands or No. 12.7mm seven-wire prestressing strand and the maximum characteristic tensile strength of 2000 MPa.
2. Longer Spans
Longer spans can be used reducing the number of columns. This results in larger,
column free floor areas which greatly increase the flexibility of use for the structure and
can result in higher rental returns.
3. Overall Structural Cost
The total cost of materials, labour and formwork required to construct a floor is reduced
for spans greater than 7 metres, thereby providing superior economy.
4. Reduced Floor to Floor Height
For the same imposed load, thinner slabs can be used. The reduced section depths
allow minimum building height with resultant savings in facade costs. Alternatively, for
taller buildings it can allow more floors to be constructed within the original building
envelope.
5. Deflection Free Slabs
Undesirable deflections under service loads can be virtually eliminated.
6. Waterproof Slabs
Post-tensioned slabs can be designed to be crack free and therefore waterproof slabs
are possible. Achievement of this objective depends upon careful design, detailing and
construction. The choice of concrete mix and curing methods along with quality
workmanship also play a key role.
7. Early Formwork Stripping
The earlier stripping of formwork and reduced backpropping requirements enable faster
construction cycles and quick re-use of formwork. This increase in speed of
construction is explained further in the next section on economics.
8. Materials Handling
The reduced material quantities in concrete and reinforcement greatly benefit on-site
cranage requirements. The strength of post-tensioning strand is approximately 4 times
that of conventional reinforcement . Therefore the total weight of reinforcing material is
greatly reduced.
9. Column and Footing Design
The reduced floor dead loads may be utilised in more economical design of the
reinforced concrete columns and footings. In multi-storey buildings, reduced column
sizes may increase the floor net lettable area.
