Post-Tensioning

Anchorages for multistrand system

Live VSL type CS 2000 anchorage

This anchorage type is lightweight and compact. The bearing plate is made of cast iron and high-strength mortar and is completed with a plastic trumpet. The anchorage is lightweight and easy to install. The local zone reinforcement may be formed by a spiral or orthogonal reinforcement, or combination of both. CS 2000 anchorage may be used also as a non-tensioned – dead-end anchor.

Live VSL type GC anchorage

This type of anchorage enables rapid transmission of prestressing force to the structure through a single-flange cast-iron anchor. This is a compact and relatively lightweight anchorage. The local zone reinforcement is formed by a spiral and orthogonal reinforcement. Type GC anchorage may be used also as a non-tensioned, dead-end anchor.

Live VSL type E anchorage

The prestressing force is evenly transmitted through the steel anchor plate to concrete. The local zone reinforcement may be formed by a spiral or orthogonal reinforcement, or combination of both. After a minor modification, type E anchorage may be used as a non-tensioned – dead-end anchor.

Dead-end VSL type H anchorage

This dead-end anchorage presents a technically easy and economical solution to transmission of the prestressing force to the structure. Considering that the prestressing force is introduced through the bond between the reinforcement and surrounding concrete, the force transmission is extremely even. The tension O-ring eliminates transverse forces in the anchor root. Reinforcement network in the end area serves as a space grid for individual strands. This type of anchorage is used for tendons in flat duct, too.

Dead-end VSL type U anchorage

With this type of anchorage, the transmission of prestressing force is realised partly through bond between prestressing strands and surrounding concrete, and partly through the cast-in U-plate. The tension O-ring and spiral eliminate the transverse forces in the anchor root. This anchorage may be fitted into the structure both horizontally and vertically. If the number of strands in the anchorage is odd, the odd strand is turned around U-plate and introduced back into the duct. Because there is a need of special device for bending the strands, it is necessary to manufacture this type of anchorage prior to being placed into the structure.

Dead-end VSL type P anchorage

This anchorage type is used where the prestressing force has to be transferred to the structure in the shortest possible distance from the end of the tendon duct, or where respectively the entire force has to be introduced into the end of the post-tensioned element. The anchorage consists of a curved anchor plate, to which strands are anchored using compression fittings. Strands are locked in required positions using distance plates. This type of anchorage is used also for tendons in flat duct.

Dead-end VSL type L anchorage

In this way of anchoring, the prestressing steel is bent at 180 degrees within a relatively small space, so that it can be led back close to its initial point. The anchorage consists of U-shape tendon duct having a circular cross-section. Soft reinforcement is inserted to avoid development of cracks in the concrete behind the anchorage.

Dead-end VSL type AF anchorage

This type of anchorage is used for vertical tendons when it is useful to install prestressing strands once the structure is concreted. First, the compression fittings are installed onto strands and then strands are inserted into the tendon duct and bonded into the anchorage with a special high-performance mortar. Once the mortar has achieved a sufficient strength, the tendon can be stressed and then grouted.

VSL type K coupler

This coupler is used for connections to a tendon that has already been installed and stressed. The connection is easy; the strands are anchored using compression fittings onto the coupling head grooves.

VSL type V coupler

This coupler is used for connecting to a tendon that has already been installed but not stressed. The connection is easy; the strands are anchored using compression fittings onto the coupling head grooves as with the type K coupler.

Intermediate VSL type Z and ZU anchorage

Intermediate anchorages of type Z and ZU are used in cases where stressing has to be done from the intermediate point for constructional reasons. The anchor head is placed in the stressing area between the parts of a tendon. Intermediate anchorages of type Z and ZU are used particularly:

  • For pressure shaft and pressure tunnel ring tendons, avoiding the use of internal buttresses.
  • For silo and reservoir circular and cylindrical structure ring tendons, avoiding the use of external buttresses.
  • For transverse tendons in bridge deck slabs wherever stressing pockets along the bridge deck perimeter are undesirable for aesthetic or other reasons.
  • For tie rod and beam tendons wherever the stressing cannot be done from the face of the prestressed element.

Anchorages for slab systems

Live VSL type S 6-4, Si 6-4 anchorage

It is mainly used for post-tensioning of floors, transverse prestressing of bridge decks and other thin slab structures, where the eccentricity of tendon has to be used to the maximum extent. The strands are anchored into the cast-iron anchor head using the standard wedges. The head is placed into the plastic recess of the “trumpet” and distributes the prestressing force to the structure.

Dead-end VSL type H and P anchorage

This type of anchorage is used to make a bond between the prestressing steel and surrounding concrete. Different finish of prestressing strand ends makes it possible to reduce the length of transmission of prestressing force from the tendon to the structure.

VSL type SK coupler

This type of coupler is used in combination with the oval tendon duct. This coupler is used for connections to a tendon that has already been concreted and stressed. The connection is easy; the strands are anchored using compression fittings onto the coupling head grooves.

Live VSL type S 6-1 PLUS/Si 6-1 PLUS anchorage, embedded VSL type SF 6-1 PLUS anchorage

It is a very economical system with enhanced corrosion protection. A plastic coat covers the external faces of the anchorage casing in continuity of the plastic sleeve. Anchorages can be used for anchoring single unbonded strands (S 6-1 PLUS) or single bonded strands (Si 6-1 PLUS). The prestressing force is transmitted through wedges to a one-flange cast-iron anchor and then further to the structure. The wedges are protected with plastic grease and equipped with a cap for the unbonded system to provide a watertight seal, the anchorage system certainly solves also the corrosion protection of the point where the strand accesses the anchor. The anchorage is either live, type S 6-1 PLUS/Si 6-1 PLUS, or embedded, non-stressed SF 6-1 PLUS anchorage.

Live VSL type S 6-1/Si 6-1 anchorage, embedded VSL type SF 6-1 anchorage,  SK 6-1 coupler

This type of anchorage is designed for anchoring single unbonded strands (S 6-1) or single bonded strands (Si 6-1). The prestressing force is transmitted through wedges to a two-flange cast-iron anchor and then further to the structure. The wedges are protected with plastic grease and equipped with a cap for the unbonded system to provide a watertight seal, the anchorage system certainly solves also the corrosion protection of the point where the strand accesses the anchor. The anchorage is either live, type S 6-1/Si 6-1, or embedded, non-stressed SF 6-1 anchorage. Single strands in the structure can be connected using the SK 6-1 coupler. New strand is connected once the previous strand is stressed.