LRPC Strands

About this product

Fine Quality LRPC Strands DP Wires have made a name for themselves by providing their every single client exactly what they expected even if it is something as simple as a steel wire or something as complex as a premium quality LRPC strand. It is important for us that you are aware of the fact that DP Wires stands among the India’s top 3rd largest manufacturers of LRPC Strands which find their application in different construction works. But it is yet to be answered what is LRPC strand and how exactly is it useful at a construction site. So, without any further ado, let’s get to the useful part. About Our LRPC Strands It is really hard to distinguish between two different quality of LRPC strands and that is why it is important that you trust a brand which will not compromise with the quality of these strands. Our HT Strands are made of high quality steel which is subjected to a lot of tests and trials which are done under the expert supervision of our adroit professionals. Apart from that, the price of our strands are way better than that of our competitors as we only charge for the quality you are promised and the efforts that go into bringing that quality out. Our LRPC steel strands adhere to all the standard guidelines issued by the respective authorities which certainly favors our claim of being a reliable brand. What is LRPC Strand? LRPC strand Or HT Strands is short for Low Relaxation Pre-Stressed Concrete Steel Strands which are used in pre-stressing of concrete for different kind of construction works. They are used in concrete slabs which are usually fitted in the roofs of commercial and domestic establishments, bridges, tunnels and aqueducts. These strands are essential in the construction of a commercial establishment because of the strength and robustness they bring to the entire structure. It is because of their strong build that many commercial and domestic buildings are able to withstand the wrath of different types of natural calamities. How does an LRPC Strand Works? An LRPC Strand releases the stress on a structure by taking that stress upon itself. This helps the structure get a stronger base and a better build which in turn assures the safety and longevity. Therefore, it is important to use LRPC strands as not only do they bring strength to the entire structure, they also make sure that the building is going to last a lifetime. Supply, Packing, Storage and Handling The strands manufactured by us are supplied in reel less coils of 3MT and packed carefully in the following ways – wrapped in VPI paper or LD polythene film or one side LD laminated bituminized jute and strapping of coils in 6 ways. These methods make it easier for user to pull out strands at their own comfort. About storage, they should be stacked in a covered warehouse where ventilation is not a problem. Handling of LRPC strands coil shouldn’t be done with electric arcs or gas cutters, instead abrasive disc cutters should be used.

Loss of prestress in concrete structure This occurs naturally over a period of time due to certain factors such as elastic shortening / shrinkage / creep in concrete, relaxation of steel is the single largest source of loss of prestress. Relaxation Loss Relaxation loss is the loss of stress with time, in a stressed tendon maintained at a constant length. It is measured as the maximum loss at 1000 hours, as a percentage of the stress applied (normally 70%), at a specified temperature (Normally 20°C) Application Our products are used for construction of major bridges, silos, buildings, dams, atomic reactors buildings, stadium, airport hanger, precast segment etc. Making of Low Relaxation LRPC Strands. The low relaxation properties of steel strands are achieved by a process called 'Stabilising'. In this thermo mechanical process, also known as hot stretch process, the PC strand is stretched to a predetermined value to creep, thereby reducing 'Relaxation loss'. We have been able to achieve a high degree of process standardization leading to better control on the manufacturing process. Coupled with world class technology, our products enjoy a very good reputation among the users. ADVANTAGES OF LOW RELAXATION LRPC STEEL STRANDS-A SUPERIOR PRODUCT The world over, low relaxation Pre-stressed concrete strands have almost completely replaced the normal relaxation strands due to numerous advantages over normal relaxation strands such as: 1. Saving in concrete due to reduced size of structural member. 2. Lower relaxation losses which are 2.5% max. after 1000 hours. 3. 'Hot Strech' process which is used for manufacturing LRPC, a. Eliminates failure of the strand at the size under normal conditions. b. Gives a nearly straight strand, thereby eliminating the extra post-straightening treatment. 4. Upto 10% reduction in pre stressing steel is possible. 5. Higher yield point. 6. Higher proof stress (0.2% elongation). 7. Better performance at ambient and elevated temperature. 8. Saving in the number of anchorages, ducts, sheaths, wedges and labour. This leads to overall reductions in cost. 9. Higher fatigue and corrosion resistance. 10. Lower weight per unit length of the strand. 11. Uniform stress - strain relation. ADVANTAGES OF POST-TENSIONED FLAT SLABS IN BUILDING: The main advantages of post - tensioned floors over conventional reinforced concrete in-situ floors, may be summarized as follows: 1. Increased clear spans. 2. Thinner slabs. 3. Lighter structures. 4. Faster speed of work. 5. Reduced cracking and deflection. 6. Increased headroom 7. Better water - tightness. 8. The reduced slab weight leads to smaller column and saving in the foundation work. 9. Large spans are possible which permit a more flexible arrangement of partition walls. 10. There are also some situations where the height of the building is limited, in which the reduced storey height has allowed additional storey to be constructed within the building envelope. 11. As the slab is virtually crack-free and the deflection due to live load is very small, the quality is improved and the durability of the structure is increased. 12. By arranging the tendons is supports strip, crossing the idealized punching shear cylinder, the punching shear conditions are considerably improved. 13. The reinforcement quantity is considerably reduced. 14. The formwork can be removed at an earlier concrete age because the deflections due to creep and shrinkage are significantly less important. These advantages normally result in significant saving in overall cost of the project. Introducing for the first time in India Galvanized LRPC Strands : Apart from bright LRPC strands for some application, particularly in the case of extreme corrosive environment. D.P. Wires LRPC strands provides the additional protection required & can manufacture Bonded & Unbonded strands as per customers' requirements. PE Coated Strands Grease filled - Bonded & Unbounded LRPC strand for post Tensioning : This speciality LRPC strand may be bright or galvanized depending upon the environment is coated with a corrosion resistant / water repellent - high temperature grease / wax to fill the interstices between the wires followed by a co-extrusion of an UV stabilized polymer layer with thickness (Min. 0.5mm, max as per customer's requirement). D.P. Wires Galvanized unbounded LRPC strands has an excellent durability & provides perfect protection against corrosion through tricomplimentary nested barrier formed by (A) galvanization followed by (B) anti-corrosive. Water repellent - grease / wax coating in the intrinsic (C) UV Stabilized polymer sheath. This particular arrangement also enables monitoring of strands, by replacing a post-tensioned strand at regular interval. Specification of PE coated Bonded & Unbounded strand. As per ASTM A-416-2006. Grade-1860/ IS-14268/1995 Class II Sheathing material: Polyethylene or Polypropylene. Minimum Density: 0.941/cm³, Minimum thickness: 0.75mm to 1.25mm. Grease coating: 30 to 35 gms per meter. Supply and Packing The strands are supplied in cheese coils of min. 1 MT to max. 4 MT, ID-750mm, OD-1500mm & Length-1000 mtr. to 4000 mtr; so that the strands can be conveniently pulled from the center of the coil. If required coils can be supplied in special water soluble rust preventive oil for corrosion resistance. Coils are normally packed in the following manner. 1. Strapping of coils at six places. 2. Wrapping with VPI paper. 3. Wrapping with LD-Polythene film. 4. Wrapping with one side LD laminated bituminized jute. 5. Strapping. Storage, Handling and use Low relaxation strands for Pre-stressed concrete have superior mechanical & chemical characteristics and are utilized under very severe conditions close to the limit of their yield point. Thus best possible care is required in all stages of transportation, handling, storage and use. The following precautions are essential while handling and using pre stressing steel. 1. Steel cutting should be effected with abrasive disc cutters or shears and never with electric arc or gas flame. 2. The steel should be stored in a covered warehouse with good air circulation. For storage in the outdoors, stack reels above ground level, duly covered, however allowing good air condition to avoid condensation. 3. Avoid exposing steel to concentrated sources of heat as they can seriously alter the micro structure of the steel and hence change its characteristics and mechanical properties. 4. For long storage, it is advisable to apply protective coatings.

About prestressed concrete strand

High-strength steel strand tensioned inside concrete structures such as bridges and beams.