Anchorage Efficiency Single Hole System 2018-10-15 PDF

TEST REPORT
STRUCTURAL ENGINEERING DIVISION
PROJECT : REPORT ON MONO ANCHORAGE

EFFICIENCY TEST
CLIENT : M/s NEKTOR ENGINEERS POST-

TENSIONING
CONSULTANT : PROF. B N RAO
ASSISTED BY : MANIKANDAN L
STRUCTURAL ENGINEERING DIVISION

DEPARTMENT OF CIVIL ENGINEERING
INDIAN INSTITUTE OF TECHNOLOGY, MADRAS
CHENNAI – 600 036
DATE: 15-10-2018
LABORATORY TEST REPORT
STRUCTURAL ENGINEERING LABORATORY
INDIAN INSTITUTE OF TECHNOLOGY MADRAS, CHENNAI- 600 036
Title: REPORT ON MONO ANCHORAGE EFFICIENCY TEST

Client: M/s NEKTOR ENGINEERS POST-TENSIONING
REPORT ON ANCHORAGE EFFICIENCY TEST
INTRODUCTION
M/s. NEKTOR ENGINEERS POST-TENSIONING had requested Structural
Engineering Laboratory, IIT Madras, to carryout on Mono Anchorage
Efficiency Test on Single Hole Anchorage System. Accordingly the test was
carried out in accordance with FIP – 1993 for the acceptance of post
tensioning systems. This report deals with the details of the test,
observations made and the result obtained from the test.
DESCRIPTION OF TEST SETUP

The test is based on the FIP Recommendations for the acceptance of
post-tensioning systems section 5.2.1, Static load test with tendon
anchorage assembly.
The test was carried out using an existing steel frame gadar assembly
shown in Figure 1. The tendons is made of 12.7 mm diameter strand. At the
active and passive sides, each of the anchor blocks was made to about on
steel fixture. The pre-stressing load was applied using hydraulic jack of 500
kN capacity, on single side of the frame. The applied load was measured
using 1000 kN capacity electrical load cell attached to each of the jack with
an accuracy of 1.25 kN. Elongation of the strand with respect to the bearing
plate and wedge/strand draw-in was measured using (Linear variable
differential transformer) LVDT of least count 0.001 mm. Readings of LVDT
were taken at each and every load step. Loads were applied in steps of 0.2
Fpk (Fpk-characteristic breaking load of tendon) until the breaking of the
tendon, which is generally taken as the breaking of the one of the ply of a
strand. For each increment, the load is increased at a constant load rate of
about 100 MPa per minute.
Date : 12-10-2018 1

TEST MATERIALS
Description : 12.7 mm, 7 ply LRPC strands according to IS 14268-1995
Specified values of the characteristics of the strands are given below:
Characteristic diameter of strand Øpk : 12.7 mm
Characteristic steel area Apk : 96.67 mm2
Characteristic breaking load Fpks : 183.7 kN
CHARACTERISTICS OF THE TENDONS

Number of strands in tendon - 01
Anchorage to Anchorage distance - 3500 mm
Characteristics breaking load of tendon Fpk - 183.7 kN
TEST PROCEDURE
Load steps are based on characteristics breaking load of the tendon,
Fpk= 183.7 kN and load was measured in the steps of 0.2 Fpk, which is 36.74
kN.
VARIOUS STEPS INVOLVED IN THE TESTING ARE LISTED BELOW.

 Installation of measuring equipments.
 Zero reading of all the load cells and LVDT.
 After zero reading, the load is increased in steps of 0.2 Fpk (36.74
kN) up to 0.8 Fpk (146.96 kN) and the LVDT readings were taken at
every stage.
 At 80% Fpk the load is transferred to steel frame gadar assembly and
is to be held for one hour.
 For every 15 minutes, wedge/strand reading are taken to ensure
stabilization.
 After one hour, the load is gradually increased until the failure of
the tendon (FTu).
Date : 12-10-2018 2

OBSERVATIONS
 The increase in the displacements between the anchorage
components as well as between the pre-stressing steel and
anchorage components were proportionate to increase in tendon
force.
 At 80% Fpk the load was kept for one hour, loss of load was observed
to be 115.5 kg (approximately 0.115 tonnes).
 At 80% Fpk of the load the wedge and strand insert on the anchor
head are 6.249 mm and 11.653 mm respectively.
 At nearly 100 % Fpk, all the tendons failed (as shown in Figure 2).
 At 100 % Fpk of the load the wedge and strand insert on the anchor
head are 6.496 mm and 13.800 mm respectively.
 The mode of failure was by pre-stressing steel tendon and it was
NOT by failure of anchorage components. No cracks were identified
in the Wedges (as shown in Figure 3).
CONCLUSIONS
Based on the anchorage efficiency test carried out on the specimen of
Mono Anchorage System, the supplied specimen was loaded up to 100 % of
total load approximately 18.74 tonnes, as per the test requirements of FIP.
Hence, the tendon anchorage assembly is COMPLYING with Acceptance
Standards for Post-Tensioning Systems.
Date : 12-10-2018 3

Figure 1. Test Setup
Figure 2. Failure of Anchor Tendons
Figure 3. Anchor Head after Failure

Date : 12-10-2018 4

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TEST REPORT

STRUCTURAL ENGINEERING DIVISION

PROJECT : REPORT ON MONO ANCHORAGE

CLIENT : M/s NEKTOR ENGINEERS POST-

CONSULTANT : PROF. B N RAO

STRUCTURAL ENGINEERING DIVISION

Title: REPORT ON MONO ANCHORAGE EFFICIENCY TEST

REPORT ON ANCHORAGE EFFICIENCY TEST

DESCRIPTION OF TEST SETUP

Title: REPORT ON MONO ANCHORAGE EFFICIENCY TEST

CHARACTERISTICS OF THE TENDONS

VARIOUS STEPS INVOLVED IN THE TESTING ARE LISTED BELOW.

Title: REPORT ON MONO ANCHORAGE EFFICIENCY TEST

Title: REPORT ON MONO ANCHORAGE EFFICIENCY TEST

Figure 1. Test Setup

Figure 2. Failure of Anchor Tendons

Figure 3. Anchor Head after Failure

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