ASSIGNMENT
Submitted To:
Engr. Waqas Aziz
Submitted By:
Wajid Hafeez
Roll#
BSTCV-023R17-09
Subject:
Prestressed & Precast Concrete
Class:
BS.Civil Tech. (6th)
Assignment No.
Date
Total Marks___________
02
04-05-2020
Obtained Marks___________
End Anchorages
End anchorages are mechanical device used to transmit prestressing force to the reinforced
concrete in a posttensioned member.
End anchorages are used at non stressing end of a tendon. They are used where the end of
a prestressing cable is buried in concrete or is inaccessible during the stressing operation of
the tendon. The end anchorage configurations is same as the standard anchorage as it uses
the same tube unit to guide the strands.
Types of End Anchorages
Different types of end anchorages are mentioned below:
End VSL type H anchorage:
This 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.
End VSL type H anchorage
End VSL type U anchorage:
With this type of anchorage, the transmission of prestressing force is realized 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.
End VSL type U anchorage
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.
End VSL type P anchorage
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 Ushape tendon duct having a circular cross-section. Soft reinforcement is inserted to avoid
development of cracks in the concrete behind the anchorage.
End VSL type L anchorage
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.
End VSL type AF anchorage
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. This anchorage is used in slab
system.
End VSL type H and P anchorage