GEL is the pioneer of the post-tensioned slab system in Thailand since 1968. There are several million square meters such as parking building, condominium, commercial building, department store and other buildings which have structural height ranges from 1 up to 60 storeys. Post-tensioned slab can be designed the modern building with few columns at intervals and no beam between column, enabling an increase in number of floors and also making the construction become faster and more efficient.
1. Concrete: Compressive strength of concrete cylinder should not be less than 240 ksc at stressing process and not less than 320 ksc at age of 28 days.
2. PC Strand : Seven-Wire Stress-Relieved Uncoated Strand Grade 270k with the diameter of 12.7 mm (1/2 inch), according to ASTM A-416 and TIS 420-2540
3. Bonded Tendon: The tendon must be strong to withstand vibration during pouring and vibrating concrete. Grouting process will be done by Portland cement type I.
4. Anchorage must be more than 95% of compressive strength and able to hold wire effectively throughout the life structure.
Step 1: Erect formwork for post-tension slab.
Step 2: Place bottom reinforcing steel bar.
Step 3: Lay tendon with PC strand.
Step 4: Set up the anchorage.
Step 5: Place top reinforcing steel bar.
Step 6: Pour concrete
Step 7: Stress PC strand
Step 8: Fill anchor socket after stressing
Step 9: Grout tendon with cement paste