Special Steel Bars

High Strength Alloy Steel (HSA) and Heat-Treated Stress Relieved (HTSR) tensioning bars are manufactured using specific industrial processes including heat treatment (quench & tempered) that ensures increased mechanical characteristics.

The resulting ductility, tensile and yield strengths are greater than typical threaded bars (the bars may be bent 90 degrees at tight radii without fracture).

Applications of HSA and HTSR tensioning bars include heavy lifting, lifting tie downs and structural connections where their greater yield strength allows for more compact solutions. HSA and HTSR tensioning bars are also well suited for structures subject to seismic loadings and possess excellent cold temperature properties.

Application Areas

• Temporary and definitive post-tensioning
• Seismic protection
• Anchoring
• Heavy lifting
• Pile testing
• Wind Turbines

Advantages

HSA and HTSR tensioning bars present many advantages over typical tensioning bars:

• Consistent mechanical properties throughout the entire cross section
• Consistent Modulus of Elasticity for bars, with a tolerance of +/- 725 ksi (5 GPa)
• Enhanced Fatigue Performance and Strength (success testing according to ETAG -013 in 30 up to 75mm) High Ductility
• Guaranteed Resilience for cold temperature applications
• Length between 1m and 15m

Technical Characteristics of HSA

Threading is performed by cold rolling, in accordance with ISO 965-1. The main mechanical characteristics of the HSA are the following:

• Modulus of Elasticity: E = 200 GPa (29,000 ksi)
• Minimum Guaranteed Rupture Strength: fpk = 1,070 MPa
• Minimum Guaranteed Yield Strength: fp0.2k = 870 MPa
• Minimum Guaranteed Elongation at Rupture: E% ≥ 12

The guaranteed characteristic of Resilience for HSA is indicated below:

• Resilience at 20°C : 50 J

Technical Characteristics of HTSR

Threading is performed by cold rolling, in accordance with ISO 965-1. The main mechanical characteristics of the HTSR are the following:

• Modulus of Elasticity: E = 200 GPa (29,000 ksi)
• Minimum Guaranteed Rupture Strength: fpk = 1,200 MPa (174 ksi)
• Minimum Guaranteed Yield Strength: fp0.2k = 1,050 MPa (152 ksi)
• Minimum Guaranteed Elongation at Rupture: E% ≥ 10

The guaranteed characteristics of Resilience for HTSR are indicated below:

• Resilience at 20°C : 50 J
• Resilience at 0°C : 30 J
• Resilience at -20°C : 20 J

Resilience characteristics at lower temperatures (-40°C, -70°C) can be provided upon request. Tests conducted following EN ISO 6892-1 and EN ISO 148-1.

Quality Assurance

Production of HSA and HTSR tensioning bars is carried out under a strict Quality Assurance System in compliance with ISO 9001: 2008. Each delivery is accompanied by a Certificate of Conformity 3.1 in compliance with the standard EN 10204 for each heat treatment lot. Each bar is individually marked with its heat treatment lot number.

Corrosion Protection

Permanent protection of the bars may be provided onsite through the use of flexible filler materials (petroleum wax, grease) or by means of a bonded filler material (cementitious grout, epoxy). The bars can also be provided with a factory applied corrosion protection system:

• Lamellar zinc coating
• Epoxy coating
• Specific paint
• Denso protection
• Heat-shrink sleeves.

Depending on specific project requirements, other corrosion protection systems may be proposed.

For more information on Special Steel Bars, please follow the related link on the left, download our Ground Anchorages Brochure or contact us.