Bajrang Wire Products (India) Pvt Ltd – Manufacturers of High Carbon Steel Wire from India
LRPC Strands
Build Stronger and Safer Concrete Structures
Rely on Bajrang LRPC Strands
LRPC strands or HT Strands is short for Low Relaxation Pre-Stressed Concrete Steel Strands which are used in pre-stressing of concrete for different kinds 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.
What is meant by Low Relaxation?
The low relaxation property is achieved by a process called "Stabilizing". This is essentially a hot stretching process, in which pre-stressing strand is subjected to a predetermined tension during stress-relieving heat treatment. This results in linear hardening of the steel which substantially increases the resistance to creep and thereby reduces the relaxation losses.
A low relaxation strand, when initially loaded to 70 percent of the specified minimum breaking strength of the strand, shall have relaxation losses of not more than 1.8 percent after 100 hours and not more than 2.5 percent after 1000 hours when tested under the controlled temperature of 20 degrees centigrade. To ensure that these strands meet the most demanding specifications with excellent mechanical properties, high carbon wire rods of premium quality are selected for manufacturing LRPC strands.
| Product Range | 6.35 mm to 18.00 mm |
|---|---|
| Standards | IS 14268:2022, ASTM A416-2018, BS 5896:2012, AS/NZS 4672:2017, AS 1311:1987, EN 10138-3:2012, JIS G 3536:2014 |
| License | IS 14268:2022 |
Our Capabilities
- Premium quality High Carbon wire rods as raw material
- Cutting Edge Technology employed for production
- State-of-the-art manufacturing lines from Europe
- Complete product range (6.35 mm to 18.00 mm)
- Coil weights up to 5 MT
- IS/AS/NZS/ASTM/BS/EN International Standards
- Advanced relaxation testing facilities, meets Fatigue test
- Hi-tech metallurgical lab
ISO 9001:2015 Certified by TUV Nord
BS5896/EN1038/ASTM/AS/NZS Standards
IS 14268:2022
Fatigue and deflected tensile tests
Premium Quality Wire Rods ensure Zero Defects
Premium quality Wire rods are used and every delivery of raw material is closely inspected by our team for the highest quality assurance. Digital-controlled SCADA automation systems ensure optimized parameters which promote uniform mechanical properties of strands.
Perfected Performance
We focus on developing new production processes and testing procedures to satisfy the emerging needs and requirements of our customers. Various online automated production controls ensure world-class product quality
Advanced Relaxation Test Facilities
Every process adheres to rigorous global quality standards which are audited by internationally accredited bodies to ensure consistent output of the highest quality steel wires.
Advantages of Low Relaxation Strand
- Up to 15% savings in construction cost (lower consumption of concrete and steel with shorter lead times in construction)
- Stable Modulus of elasticity, High bonding force
- Better performance at ambient and elevated temperatures
- Uniform stress-strain relationship, higher breaking load, and Proof stress loads
- Higher fatigue and corrosion resistance
- Consistent physical properties with uniform winding
- Close tolerances on Unit mass to length ratio
- High reliability - failure of the strand on site is mitigated as the strand is tested online during manufacturing
- Larger slab spans construction with fewer columns
- Helps to construct stable and crack-resistant structures
- Significant reduction in building weight versus a conventional concrete building
- Reducing distortion and construction weight
- Low relaxation property of wire allows up to 10% savings in steel
- Enables to construct strong, safe, and lighter structures with high speed of construction
- Long-span cable stay bridges can be constructed without intermediate supports
- Enhance the life of cable stay bridges ~ 100 Years
- Minimizes impact on the environment
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. Bajrang follows highly automated control procedures from online production control to extensive lab testing.
Applications of LRPC Strands
Bajrang manufactures LRPC strands that undergoes strict quality assurance test and have earned a reputable name in it market owing to its several benefits. Low Relaxation PC strands are widely used in pre-stressed concrete girders for road, river and railway bridges, flyovers, pre-stressed atomic reactor domes, slabs, silos, hangars, aqueducts, high-rise buildings, viaducts and railway sleepers.
Cable Stay Bridges
Flyovers & Interchanges
Metro Rail
LNG Tanks
Atomic Reactors
Commercial Buildings
High Speed Rail – Bullet Train
Wind Mills
Dam Gates
Rock Anchoring
Precast Construction
Cement Plant Silos
Storage & handling of strands at Site
Handling and Storage
It's important to take proper care during the storage and usage of strands at the project sites. Failure to observe these simple precautions against damage and corrosion can cause adverse impacts at later stages.
- Care should always be taken to protect strands from mechanical damage. Abrasions, scrapers, or gouges on strands can reduce their breaking strength
- Strands should be stored in a dry, covered shed to prevent rusting and pitting
- For temporary storage outdoors, coils should be stored on wooden support covered with a waterproof sheet. It should never be placed on bare soil
- Ensure air circulation is there to avoid condensation on the coils
- Water soluble oil is used to protect the strand during storage, which can easily be washed away with water during use
Care before tensioning work
- When pulling strands from the inside coil, a well-made tight fitting strand payoff cage should be used. Spacers/ Wood blocks may be used between the strand coil and the payoff cage to ensure a light fit
- Advisable to use cutting grinder to cut the strand after stressing
- Welding and heating of pre-stressing materials must not be done
- Care should be taken to use good quality of anchoring grips for the strand, as strand is subjected not only to tensile stress, but also to shearing stress in the gripped direction
Pull Direction and space considerations
- Place strand pack in a strand cage so that the arrow pull direction faces the opening
- There should be less than 2" of space between strand pack and the frame or strand cage prior to the cutting or steel straps
- When there is space, insert spacers (such as wooden boards) prior to cutting of steel banding straps
Cutting of strands
- Strand cutting should be done with disc cutters
- Use of flame cutters/torch is not advisable as it adversely affects strand hardness and also change the characteristics/properties of steel
- Excessive expansion or pack may cause entanglement of strand
Storage & handling of strands at Site
Handling and Storage
It's important to take proper care during the storage and usage of strands at the project sites. Failure to observe these simple precautions against damage and corrosion can cause adverse impacts at later stages.
- Care should always be taken to protect strands from mechanical damage. Abrasions, scrapers, or gouges on strands can reduce their breaking strength
- Strands should be stored in a dry, covered shed to prevent rusting and pitting
- For temporary storage outdoors, coils should be stored on wooden support covered with a waterproof sheet. It should never be placed on bare soil
- Ensure air circulation is there to avoid condensation on the coils
- Water soluble oil is used to protect the strand during storage, which can easily be washed away with water during use
Care before tensioning work
- When pulling strands from the inside coil, a well-made tight fitting strand payoff cage should be used. Spacers/ Wood blocks may be used between the strand coil and the payoff cage to ensure a light fit
- Advisable to use cutting grinder to cut the strand after stressing
- Welding and heating of pre-stressing materials must not be done
- Care should be taken to use good quality of anchoring grips for the strand, as strand is subjected not only to tensile stress, but also to shearing stress in the gripped direction
Pull Direction and space considerations
- Place strand pack in a strand cage so that the arrow pull direction faces the opening
- There should be less than 2" of space between strand pack and the frame or strand cage prior to the cutting or steel straps
- When there is space, insert spacers (such as wooden boards) prior to cutting of steel banding straps
Cutting of strands
- Strand cutting should be done with disc cutters
- Use of flame cutters/torch is not advisable as it adversely affects strand hardness and also change the characteristics/properties of steel
- Excessive expansion or pack may cause entanglement of strand
