Prestressing cable strand system

1. INTRODUCTION

It is a bundle of wires with a central core and surrounding wires with uniform twist step of a cable not less than 12 times and not more than 16 times the nominal diameter of cable strand with the number of wires and other protection methods together..

2. CLASSIFICATION

Based on the structure of prestressed cable strand, it can be divided into the following types:

2.1 Prestressed cable strands without sheath

• Structure consisting of cable wires with a core in the middle and surrounding wires with uniform twisting steps not less than 12 times and not larger than 16 times the nominal diameter of strands with the sizes of 9.53; 12.7; 12.9; 15.24; 15,7 (for 7 wires type) and others on request.
• Compliant with BS 5896 standards; ASTM A416; AS 1311; GB / T 5224 and JIS 3536 or equivalent international standards.
• Widely applied in transport, civil and irrigation works: Prestressed concrete beams, prestressed slab system, box girder, retaining wall structure, dam door structure, ...

2.2 Prestressed cable strand with PE sheath

2.2.1 Normal strand with PE sheath:

• The structure is made of bare strand surrounded by anti-rust lubricating layer and outside is HDPE sheath with thickness from 1mm to 2mm.
• The cable strand in accordance with ASTM A416. Cover, grease according to FIB-30 standard
• Applicable for: External prestressing cable system for repair works.

2.2.2 Galvanized cable strand with PE sheath:

• The structure consists of galvanized strand surrounded by anti-rust lubricating layer and outside is HDPE sheath with thickness from 1mm to 2mm.
• The strand is in accordance with ASTM A416. Cover, grease according to FIB-30 standard.
• Applicable for: External prestressing cable systems, the system includes parallel PSS strands for cable-stayed bridges, Extradosed bridges.

2.3 Epoxy coated cable strand

2.3.1 Cable strand with epoxy coated single cable wire:

• High strength 7 wires cable strand, each single wire is covered with an epoxy layer by electrostatic painting method as cover layer.
• The thickness of an epoxy coating is usually 120 - 280 micrometers
• The cable strand conforming to TCVN 10952: 2015.

Apply for:

+ External prestressing cable system.

+ Bracing cable systems for arched steel pipe arch bridges.

+ The Cable bundles include PSS parallel strands for cable-stayed bridges, Extradosed bridges.

2.3.2 Epoxy filled cable strand:

• The 7-wires strand with molten epoxy coating is applied by electrostatic sedimentation method, the gap between the wires is completely filled with epoxy coating to prevent the movement of corrosive substances by capillary action or by other hydrostatic pressure.
• Thickness of epoxy coating usually from 380 - 1140 micrometres.
• The strand conforms to the following standards: ASTM A882, ISO 14655.

- Apply for:

+ External prestressing cable system.

+ Bracing cable systems for arched steel pipe arch bridges

+ The cable bundles include PSS parallel strands for cable-stayed bridges, Extradosed bridges.