Prestressing
Products / Prestressing / Post Tensioning

Prestressing-Post Tensioning

Ismal Prestressing System is based on Gifford Udall System and is used extensively by all major construction companies in India. The post-tensioning products, such as anchorage, sheathing, multipull & single pull hydraulic jacks & pumps, grout pumps & agitators are manufactured at the factory of Usha Ismal Division at Ranchi.
Post Tensioning Post Tensioning Products Prestressing System
Anchorage

Anchorage

Ismal anchorage is manufactured (in compliance with BS 4447:1973 and FIP recommendations:1993) to suit cables having 4,7,12, 19, 27 & 31 numbers of 12.7 mm strands and also cables up to 19 nos. of 15.2 mm strands. Anchorage to suit cables of any intermediate number of strand can also be manufactured on request.
The anchorage comprise the following
a) One cast iron tube unit, which guides the strands into the duct.
b) One forged steel bearing plate having taper holes for seating of wedges.
c) Necessary number of hardened wedges for locking of strands after stressing. :
Anchorage
While standard anchorage are for use as live end, dead end anchorage (for ends buried in concrete) and anchorage coupling (used in continuous spans) are also available.
Sheathing

Sheathing

Drossbatch type sheathing with internal diameter 42 mm to 110 mm are manufactured with bright metal or galvanized cold rolled cold annealed steel strips. The thickness of the strips conform to the requirement specified in IRC 18-2000 and MOST guidelines.
Multipull Jack

Multipull Jack

Ismal multipull hydraulic jacks are manufactured for stressing cables with considerable ease of operation. The special feature of these jacks is hydraulic lock off, which effects proper seating of the wedges inside the taper holes of the bearing plates with pre-determined force.

Various models of jacks as listed below are manufactured to suit most of the requirements:
a) model no. 1000 MG - capacity 1000 KN
b) model no. 1800 MG - capacity 1800 KN
c) model no. 4000 MG - capacity 4000 KN
d) model no. 5000 M - capacity 5000 KN
Multipull Jack
All the above jacks are of middle grip type and have stroke of about 200 to 210 mm. Length of strand required for gripping in these jacks is 500 to 750 mm.
Single Pulling Jacks

Single Pulling Jacks

Single Pulling Jacks
Ismal J20 jacks are manufactured with 220 KN and 300 KN capacity and 200 mm or 400 mm stroke. These are suitable for 12.7 mm as well as 15.2 or 15.7 mm strands.
Hydraulic Power Operated Pumps

Hydraulic Power Operated Pumps

For use with multipull hydraulic jacks, two models of hydraulic power operated pumps are manufactured as under:
a) with 3 hp, 440 V motor, three plunger rotary co-axial pump, 450 kg/sq cm operating pressure and 2.25 ltr/min delivery rate.
b) With 7.5 hp, 440 V motor, five plunger rotary co-axial pump, 450 kg/sq cm operating pressure and 9.5 ltr/min delivery rate.

These pumps are fitted with relief valve and two direction control valves, one for stressing and another for lock off. Pressure gauges are provided for reading pressures during stressing as well as during lock off.
Hydraulic Power Operated Pumps
Hydraulic pumps having single direction control valves and one pressure gauge are also manufactured for use with single pulling J20 jacks.
Grout Pump and Agitator

Grout Pump and Agitator

Positive displacement screw type rotary grout pumps with 1000 ltr/hr delivery , 3hp, 440 volt power are manufactured for use in almost all grouting application of bonded tendons.

Power operated grout agitators of different sizes are also manufactured for use with the grout pumps.
 
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