Tests on retrofitting wall ties

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Tests on retrofitting wall ties

Messali, F.; Paletti, E.

Publication date

2017

Document Version

Final published version

Citation (APA)

Messali, F., & Paletti, E. (2017). Tests on retrofitting wall ties. Delft University of Technology.

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Date 01 August 2017

Corresponding author Francesco Messali (f.messali@tudelft.nl)

TU Delft Large-scale testing campaign 2016

TESTS ON RETROFITTING WALL TIES

Authors: Francesco Messali, Elisa Paletti

Cite as: Messali, F. Paletti, E. (2017). Tests on retrofitting wall ties. Report number C31B67WP6-4, 01 August 2017. Delft University of Technology.

This document is made available via the website ‘Structural Response to Earthquakes’ and the TU Delft repository. While citing, please verify if there are recent updates of this research in the form of scientific papers.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system of any nature, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of TU Delft.

TU Delft and those who have contributed to this publication did exercise the greatest care in putting together this publication. This report will be available as-is, and TU Delft makes no representations of warranties of any kind concerning this Report. This includes, without limitation, fitness for a particular purpose, non-infringement, absence of latent or other defects, accuracy, or the presence or absence of errors, whether or not discoverable. Except to the extent required by applicable law, in no event will TU Delft be liable for on any legal theory for any special, incidental consequential, punitive or exemplary damages arising out of the use of this report.

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Version 01 - Final 01/08/2017

1 Introduction

The current document reports the outcomes of a series of tests performed on new wall ties. New wall ties can be considered as a retrofitting measure for non-structural elements and are generally applied to prevent collapse of the out-of-plane failure of the external leaf of cavity walls.

The performed tests aimed at providing a complete characterization of the behaviour of this typology of retrofitting system under either axial (tensile and compressive) or shear monotonic/cyclic loading. The obtained results may be used as inputs to calibrate the numerical models that simulate the interaction between the leaves of a cavity wall.

New wall ties are used to retrofit cavity walls either when the number of existing ties is not enough to provide an effective connection, or when old ties are corroded. Two different typologies of connectors are commonly adopted: mechanical (dry-fixed) or adhesive (resin bonded) connectors.

Helical mechanical anchors are usually manufactured from stainless steel. They do not require the use of grouts or resins and are driven into both the leaves of a cavity wall via a small pilot hole. Since the tie is fully recessed below the face of masonry, often the hole can be retrospectively sealed so that it is no longer visible in the façade. The installation process is easy and cheap. Adhesive chemical anchors are also manufactured from stainless steel, but they require a resin bonding at both the tie ends. Thanks to the resin, they are able to provide significantly larger resistances to pull-out. However, they are much more expensive and the installation is longer and more complex. Finally, their performance is also more sensitive to temperature fluctuations.

A comparison between the retrofitting performances provided by either helical mechanical anchors or adhesive connectors is presented in [1] and [2]. Also a discussion with TotalWall [3] confirmed that the mechanical anchors are currently (and, likely, in the future) the most used typology of retrofitting wall ties since they are cheap and easy to install, so that a large number of ties can be applied to improve the global behaviour of the wall. As a summary, mechanical anchors:

 Are cheap and easy to install;

 Even if they have a smaller pull-out resistance, they are as effective at improving the OOP cavity wall performance as adhesive ties [1];

 Do not require the use of large diameter bars [2];

 Are already suggested as common retrofitting system for cavity walls by engineering companies. Based on these remarks, the mechanical anchors Helifix DryFix (supplied in the Netherlands by TotalWall) were selected to be tested.

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2 Construction of the specimens

The samples were built in the Stevin II laboratory at the Delft University of Technology on 03/05/2017. The installation was completed by Marten de Jong (TotalWall).

The specimens were built by connecting one hollow clay brick (of the outer leaf) and one Calcium Silicate (CS) brick (of inner leaf) with the Helifix DryFix. During the installation procedure, the two bricks were clamped to avoid any splitting of the unit while drilling (Figure 1). The distance between the two units was 17cm and a Helifix tie with a diameter of 8mm and a length of 335mm was used.

To simulate the real installation of the tie, the tie was drilled through the whole thickness of the clay brick and then partially through the CS brick. After the installation, the tie was cut in the middle and two specimens with a tie 85 mm long were obtained. The usual distance between the two leaves is 80mm. but during the tests the tie was clamped for 30mm so that the final distance between the clamp and the brick was 55mm only. This choice was made because the use of longer helifix could cause inaccuracy in the installation (due to bending of the tie).

Examples of a specimen before and after cutting the DryFix tie are showed in Figure 2, and in Figure 3 and Figure 4, respectively.

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Version 01 - Final 01/08/2017 Figure 2 – Specimens connected by the DryFix tie

Figure 3 – CS specimen

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3 Axial tests

Testing procedure

Description of the specimens

The tests refer to cavity walls composed of two masonry leaves. Each leaf havea thickness of approximately 100mm and the cavity is 80mm wide.

To test a complete connection both the typologies of specimens (CS and Clay) are considered:  Calcium Silicate specimens;

 Clay specimens.

The specimens are shown in Figure 5.

The dimensions for each typology of specimen are provided in Table 1.

Figure 5 – CS and Clay specimens Table 1 – Dimensions of test specimens

Dimensions Calcium Silicate specimens Clay specimens

ls (mm) 210 210

hs (mm) 100 100

ts (mm) 70 50

Test set-up

The test apparatus is presented in Figure 6, and comprehends:

 Simple supports for the specimen, for both tensile and compressive applied forces. The support system consists of hardwood/steel bearers (6) placed on the top and bottom surfaces of the specimen (1). The bearers are contrasted by a horizontal steel plate (5) which is connected to the support beam (10) to prevent any vertical displacement of the supports. The hardwood bearers do not apply any restraint against splitting of the specimen (apart from the friction generated at the reaction due to the applied load, as suggested by EN 846-5:2012) since a central space is left free.  A means of applying and maintaining a constant compressive stress on the couplet. The force is

provided by a hydraulic jack (9) acting in the horizontal direction and perpendicular to the bed joint plane. The system is self-equilibrated by four threaded bars (7) connecting the vertical plates (4).

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Version 01 - Final 01/08/2017 The upper bar has been cut in the drawing in order to show the clamp; in real it continues as the bar below and as shown in Figure 7a.

 A test machine to apply the vertical load.The pull-out load acts in a vertical direction using displacement controlled apparatus. The apparatus is composed by a 4.5 tons jack and a double cylindrical joint (between the load cell and the clamp),which reduce possible eccentricities and prevent torsion failures of the tie during loading.The machine is provided with a clamp (3) for gripping efficiently the free end of the tie (Figure 7b).

Figure 6 – Scheme of the test apparatus

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Figure 7 – Set-up (a) and detail of the clamp (b) Loading scheme

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Version 01 - Final 01/08/2017 The test is completed on the base of the recommendations included in EN 846-5:2012. However, some changes (such as in the loading protocol) are introduced to fit the specific features of the tested specimens. Before testing, the specimen is placed in the test machine such that the tie body is axial and aligned at the center of the test machine. The tie is clamped so that it has a free distance from the couplet equal to 55 mm. During the tests, the specimen is kept under constant lateral pre-compression, while a pull-out load is applied to the tie. Two levels of pre-compression are investigated (0.1 ± 0.01 N/mm2_{and 0.3 ± 0.01 N/mm}2_). The pull-out load is applied in displacement control while the pre-compressive load is maintained constant by means of the manually operated hydraulic jack. Three different loading schemes are followed:

 Protocol A1 (monotonic tensile protocol): the pull-out behavior of the ties (tensile loading) is

determined by monotonically increasing the displacement with a rate of 0.1 mm/s up to failure.  Protocol A2 (monotonic compressive protocol): the push-out behavior of the ties (compressive

loading) will be determined by monotonically increasing the displacement with a rate of 0.1mm/s.  Protocol A3 (tensile-compressive protocol): the displacement is cyclically varied by applying both

tensile and compressive loads on the tie. The loading history for this test can be subdivided into two phases. In phase 1 three groups of three cycles of amplitude equals to 0.1 mm, 0.25 mm and 0.5 mm, respectively, are performed. In phase 2 each cycle is composed by two runs of increased displacements and two runs of reduced displacement. The reduced displacements are calculated as the 40% of the displacements of the two previous runs (Figure 8). The loading rate is chosen to maintain a constant duration of every cycle until reaching 1 mm/s. Afterwards it is kept constant. The name and number of the specimens tested for each loading protocol (for the axial tests) are listed in Table 2. 31 CS and 29 clay brick specimens were tested, respectively.

Figure 8 – Loading protocol 3 (cyclic protocol)

V e rt ic a l d isp la c e m e n t Group of cycles Phase 1 Phase 2 Phase 2-continues

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Version 01 - Final 01/08/2017 Table 2 – CS specimens tested for each loading protocol for axial loads

Name Tie embedment Load Loading protocol Lateral pressure[MPa] Name specimen

TUD_ANC-31 CaSi-brick Axial A1

0 MPa TUD_ANC-31-44 TUD_ANC-31-12 TUD_ANC-31-17 TUD_ANC-31-25 0.1 Mpa TUD_ANC-31-22 TUD_ANC-31-03 TUD_ANC-31-24 TUD_ANC-31-21 0.3 MPa TUD_ANC-31-49 TUD_ANC-31-56 TUD_ANC-31-40 TUD_ANC-31-58

TUD_ANC-32 CaSi-brick Axial A2

0 MPa TUD_ANC-32-15 TUD_ANC-32-04 TUD_ANC-32-16 0.1 MPa TUD_ANC-32-19 TUD_ANC-32-42 TUD_ANC-32-43 0.3 MPa TUD_ANC-32-09 TUD_ANC-32-60 TUD_ANC-32-46

TUD_ANC-33 CaSi-brick Axial A3 0 MPa

TUD_ANC-33-06 TUD_ANC-33-05 TUD_ANC-33-10 TUD_ANC-33-11 TUD_ANC-33-48 0.1 MPa TUD_ANC-33-₃₆

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Version 01 - Final 01/08/2017 TUD_ANC-33-53 TUD_ANC-33-37 0.3 MPa TUD_ANC-33-23 TUD_ANC-33-59

Table 3 – Clay specimens tested for each loading protocol for axial loads

Name _embedmentTie Axial _load _protocolLoading _pressureLateral [MPa]

Name specimen

TUD_ANC-41 Clay - brick Axial A1

0 MPa TUD_ANC-41-13 TUD_ANC-41-11 TUD_ANC-41-19 TUD_ANC-41-12 0.1 Mpa TUD_ANC-41-22 TUD_ANC-41-24 TUD_ANC-41-33 TUD_ANC-41-36 0.3 MPa TUD_ANC-41-21 TUD_ANC-41-31 TUD_ANC-41-40

0 MPa TUD_ANC-42-27 TUD_ANC-42-60 TUD_ANC-42-17 0.1 MPa TUD_ANC-42-48 TUD_ANC-42-38 TUD_ANC-42-28 0.3 MPa TUD_ANC-42-58 TUD_ANC-42-55

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TUD_ANC-42-42

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Experimental results on CS specimens (calcium silicate

masonry)

Monotonic tensile tests – TUD_ANC-31

The observed failure mechanism showed cracking and splitting of the calcium silicate for every compression level. Figure 9, Figure 10, and Figure 11 show an example of the specimens at failure for each precompression level.

In the following subsections, the force-displacment curve of each single test is reported and the overall behaviour discussed.

Figure 9 – Failure mechanism with a precompression level of 0 MPa

Figure 10 – Failure mechanism with a precompression level of 0.1 MPa

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Precompression level: 0 N/mm2

Figure 12 and Figure 13 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement (evaluated for a force equal to 20% of the resistance) are listed in Table 4.

Figure 12 – Force – displacement curves for a level of precompression 0 MPa

Figure 13 – Summary of the “Force – Displacement curves” for monotonic tensile loading of Calcium Silicate specimens at a level of precompression 0 MPa

0 1 2 3 4 5 6 7 0 5 10 15 20 25 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-44 0 1 2 3 4 5 6 7 0 5 10 15 20 25 V eri ca l fo rce (k N) Vertical displacement (mm) TUD_ANC-31-17 0 1 2 3 4 5 6 7 0 5 10 15 20 25 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-12 0 1 2 3 4 5 6 7 0 5 10 15 20 25 V er ica l fo rce (k N) Vertical displacement (mm) TUD_ANC-31-25 0 1 2 3 4 5 6 7 0 5 10 15 20 25 V er tic a l f o rc e [k N ] Vertical displacement [mm] TUD_ANC-31-44 TUD_ANC-31-17 TUD_ANC-31-12 TUD_ANC-31-25

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Version 01 - Final 01/08/2017 Table 4 – Summary of results for monotonic tensile loading of Calcium Silicate specimens at a level of

precompression 0 MPa

Specimen Peak force

[kN] Displacement [mm] Displacement at 50 % of peak force TUD-ANC-31-44 6.07 20.51 21.60 TUD-ANC-31-17 5.71 12.14 12.26 TUD-ANC-31-12 6.14 14.92 15.07 TUD-ANC-31-25 6.52 14.81 16.83 Average 6.11 15.60 16.44 Deviation 0.33 3.52 3.92 CoV [%] 5.45 22.55 23.85 Precompression level: 0.1 ± 0.01 N/mm2

Figure 14 and Figure 15 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement (evaluated for a force equal to 20% of the resistance) are listed in Table 5.

Figure 14 – Force – displacement curves for a level of precompression 0.1 MPa 0 1 2 3 4 5 6 7 0 10 20 30 40 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-22 0 1 2 3 4 5 6 7 0 10 20 30 40 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-24 0 1 2 3 4 5 6 7 0 10 20 30 40 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-21 0 1 2 3 4 5 6 7 0 10 20 30 40 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-03

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Version 01 - Final 01/08/2017 Figure 15– Summary of the “Force – Displacement curves” for monotonic tensile loading of Calcium Silicate

specimens at a level of precompression 0.1 MPa

Table 5 – Summary of results for monotonic tensile loading of Calcium Silicate specimens at a level of precompression 0.1 MPa

[kN] Displacement [mm] Displacement at 50 % of peak force TUD-ANC-31-22 5.52 11.03 20.01 TUD-ANC-31-24 6.18 12.98 14.64 TUD-ANC-31-21 4.31 8.12 8.21 TUD-ANC-31-03 5.55 - - Average 5.39 10.71 14.29 Deviation 0.78 2.45 5.91 CoV [%] 14.51 22.87 41.37

The specimen TUD_ANC-31-03 shows the peak force at 5.55 kN similar to the others but with a higher displacement around 24.69 mm; in order to obtain representative values it was’t considered in the calculation of the average of the displacement.

Precompression level: 0.3 ± 0.01 N/mm2

Figure 16 and Figure 17 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement (evaluated for a force equal to 20% of the resistance) are listed in Table 6.

The specimen TUD_ANC-31-58 shows the peak force at 5.65 kN similar to the others but with a higher displacement around 23.52 mm; in order to obtain representative values it was’t considered in the calculation of the average of the displacement.

0 1 2 3 4 5 6 7 0 5 10 15 20 25 30 35 40 Vert ica l f orce [k N] Vertical displacement [mm] TUD_ANC-31-22 TUD_ANC-31-24 TUD_ANC-31-21 TUD_ANC-31-03

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Version 01 - Final 01/08/2017 Figure 16 –Force – displacement curves for a level of precompression 0.3 MPa

Figure 17 – Summary of the “Force – Displacement curves” for monotonic tensile loading of Calcium Silicate specimens at a level of precompression 0.3 MPa

0 1 2 3 4 5 6 7 8 0 10 20 30 40 50 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-49 0 1 2 3 4 5 6 7 8 0 10 20 30 40 50 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-56 0 1 2 3 4 5 6 7 8 0 10 20 30 40 50 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-40 0 1 2 3 4 5 6 7 8 0 10 20 30 40 50 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-31-58 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-31-49 TUD_ANC-31-56 TUD_ANC-31-40 TUD_ANC-31-58

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Version 01 - Final 01/08/2017 Table 6 – Summary of results for monotonic tensile loading of Calcium Silicate specimens at a level of

precompression 0.3 MPa

Specimen Peak force _[kN] Displacement _[mm] Displacement at 50 % of peak force TUD-ANC-31-49 5.65 14.41 20.26 TUD-ANC-31-56 6.92 16.38 19.40 TUD-ANC-31-40 5.52 9.64 17.48 TUD-ANC-31-58 5.65 - - Average 5.94 13.48 19.05 Deviation 0.66 3.46 1.42 CoV [%] 11.06 25.71 7.47

Influence of the level of precompression

Table 7 reports a comparison between the average values of force and displacement at peak, and the ultimate displacement obtained for different levels of precompression. No significant trend can be identified for any of the reported results. However, with 0.3 MPa the failure of the specimen is generally less brittle.

Table 7 – Average of the peak vertical force and corresponding displacement for the three levels of precompression Precompression [MPa] Peak force [kN] Displacement [mm] Displacement at 50 % of peak force 0 6.11 15.60 16.44 0.1 5.39 10.71 14.29 0.3 5.94 13.48 19.05

Figure 18 – Summary of the peak vertical force and corresponding displacement for the three levels of precompression 0 1 2 3 4 5 6 7 0 5 10 15 20 V e r tic al for c e [kN] Vertical displacement [mm]

Influence of the level of precompression

Average-0.0MPa Average-0.1MPa Average-0.3MPa

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Version 01 - Final 01/08/2017 Monotonic compressive tests – TUD_ANC-32

Before performing the tests, a 3 cm long steel cylinder with a diameter of 8mm was glued to the end section of the tie to provide a better grip for the clamp. Sikadur glue was used. Figure 19 shows the specimen with the glued steel cylinder.

In the following subsections, the force-displacment curve of each single test is reported and the overall behaviour, including the failure mode, discussed.

Figure 19 – Detail of the specimen after gluing the steel cylinder

Two different failure mechanisms were observed: cracking and splitting of the calcium silicate unit for the specimens TUD_ANC-32-15 and 32-04 (Figure 20) or buckling of the tie for specimen TUD_ANC-32-16 (Figure 21). Figure 22 and Figure 23 report the force-displacement curves for each single performed test and a summary of the results.

Figure 20 – Failure mechanism of TUD_ANC-32-15 and TUD_ANC-32-04

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Version 01 - Final 01/08/2017 Figure 22 – Force – displacement curves for a level of precompression 0 MPa

Figure 23 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Calcium Silicate specimens at a level of precompression 0 MPa

0 1 2 3 4 5 6 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-15 0 1 2 3 4 5 6 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-04 0 1 2 3 4 5 6 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-16 0 1 2 3 4 5 6 0 3 6 9 12 15

Ver

tica

l f

o

rc

e

[k

N]

Vertical displacement [mm] TUD_ANC-32-15 TUD_ANC-32-04 TUD_ANC-32-16

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Version 01 - Final 01/08/2017 Table 8 – Summary of results for monotonic compressive loading of Calcium Silicate specimens at a level of

precompression 0 MPa

[kN] Displacement [mm] Displacement at 50 % of peak force TUD-ANC-32-15 4.29 2.79 2.81 TUD-ANC-32-04 5.67 3.90 3.92 TUD-ANC-32-16 4.30 5.03 7.71 Average 4.76 3.90 4.81 Deviation 0.80 1.12 2.57 CoV [%] 16.73 28.73 53.38 Precompression level: 0.1 ± 0.01 N/mm2

Buckling of the tie was observed for every specimen.

Figure 25 and Figure 26 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement are listed in Table 9.

It should be noted that the tests were stopped after the buckling of the tie when the tie touched the steel plate (no. 5 in Figure 6). Therefore, the evaluation of the ultimate capacity of the was not possible.

Figure 24 – Failure mechanism of the tie with precompression 0.1MPa

0 1 2 3 4 5 6 7 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-19 0 1 2 3 4 5 6 7 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-42

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Version 01 - Final 01/08/2017 Figure 25 – Force – displacement curves for a level of precompression 0.1 MPa

Figure 26 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Calcium Silicate specimens at a level of precompression 0.1 MPa

Table 9 – Summary of results for monotonic compressive loading of Calcium Silicate specimens at a level of precompression 0.1 MPa

Specimen Peak force [kN] Displacement [mm] TUD-ANC-32-19 5.71 3.68 TUD-ANC-32-42 3.67 8.11 TUD-ANC-32-43 6.21 5.20 Average 5.19 5.67 Deviation 1.35 2.25 CoV [%] 25.92 39.70 0 1 2 3 4 5 6 7 0 3 6 9 12 15 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-43 0 1 2 3 4 5 6 7 0 3 6 9 12 15 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-32-19 TUD_ANC-32-42 TUD_ANC-32-43

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Precompression level: 0.3 ± 0.01 N/mm2

Buckling of the tie was observed for every specimen (as for the 0.1 MPa precompression level), as shown in Figure 27.

Similarly to the previous case, the evaluation of the ultimate displacement capacity of the specimens was not possible.

Figure 27 – Failure mechanism of the tie with precompression 0.3 MPa

Figure 28 – Force – displacement curves for a level of precompression 0.3 MPa 0 1 2 3 4 5 6 0 5 10 15 20 25 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-09 0 1 2 3 4 5 6 0 5 10 15 20 25 V erica l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-60 0 1 2 3 4 5 6 0 5 10 15 20 25 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-32-46

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Version 01 - Final 01/08/2017 Figure 29 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Calcium

Silicate specimens at a level of precompression 0.3 MPa

Table 10 – Summary of results for monotonic compressive loading of Calcium Silicate specimens at a level of precompression 0.3 MPa

[kN] Displacement [mm] TUD-ANC-32-09 5.69 5.23 TUD-ANC-32-60 3.87 3.29 TUD-ANC-32-46 4.40 1.70 Average 4.65 3.40 Deviation 0.94 1.77 CoV [%] 20.11 51.96

The results summarised in Table 11 and shown in Figure 30 indicate that the influence of the level of precompression between 0.1 MPa and 0.3 MPa is not relevant: the peak vertical force and the corresponding displacement are similar, with only lightly higher force and displacement for 0.1 MPa.

Table 11 – Average peak vertical force and corresponding displacement for different precompression levels

Precompression

[MPa] Peak force [kN] Displacement [mm]

0 4.76 3.90 0.1 5.19 5.67 0.3 4.65 3.40 0 1 2 3 4 5 6 0 5 10 15 20 25 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-32-09 TUD_ANC-32-60 TUD_ANC-32-46

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Version 01 - Final 01/08/2017 Figure 30– Summary of the peak vertical force and corresponding displacement for the three levels of

precompression 0 1 2 3 4 5 6 0 2 4 6 8 10

V

er

tic

al

for

ce

[kN]

Vertical displacement [mm]

Influence of the level of precompression

Average - 0 Mpa Average - 0.1 Mpa Average - 0.3 Mpa

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Version 01 - Final 01/08/2017 Cyclic tests – TUD_ANC-33

The observed failure mode of the specimens is a combination of those described in the sections 3.2.1 and 3.2.2 for tensile and compressive loading, respectively.

Three specimens showed cracking and crushing (TUD_ANC-33-06, -11, -48), instead with TUD_ANC-33-10 and -05 buckling of the tie occurred. For TUD_ANC-33 the connection between the tube and the glue failed.

Figure 31 – “Force – Displacement curves” for monotonic cyclic loading of Calcium Silicate specimens at a level of precompression 0 MPa

-6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-06 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-11 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-48 -6 -4 -2 0 2 4 6 8 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-10 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo r ce (k N) Vertical displacement (mm) TUD_ANC-33-05

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Version 01 - Final 01/08/2017 Figure 32 – Hysteretic curve of CS specimens under axial cyclic loading at a precompression level of 0 MPa

Figure 33 – Indicative hysteretic and envelope curves of CS specimen under axial cyclic loading at a precompression level of 0 MPa

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 -6 -4 -2 0 2 4 6 8 10 12 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-33-06 TUD_ANC-33-11 TUD_ANC-33-48 TUD_ANC-33-10 TUD_ANC-33-05

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Version 01 - Final 01/08/2017 Figure 34 – Envelope tension and compression curves of a CS specimens under axial cyclic loading at a

precompression level of 0 MPa

Table 12 – Summary of results for cyclic loading of Calcium Silicate specimens at a level of precompression 0 MPa

Specimen Tension Compression

Peak vertical force [kN]

Displacement

[mm] Peak vertical force [kN]

Displacement [mm] TUD_ANC-33-05 3.59 4.66 4.86 3.54 TUD_ANC-33-06 3.45 4.32 2.14 2.49 TUD_ANC-33-10 3.91 6.26 5.48 4.75 TUD_ANC-33-11 4.16 4.87 5.49 4.80 TUD_ANC-33-48 2.91 5.53 3.75 4.98 Average 3.61 5.13 4.35 4.11 Deviation 0.48 0.77 1.42 1.07 CoV [%] 13.27 15.03 32.70 26.00 Precompression level: 0.1 ± 0.01 N/mm2

The observed failure mechanism showed cracking and splitting of the calcium silicate.

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Version 01 - Final 01/08/2017 Figure 35 – Failure mechanism of the tie with precompression 0.1 MPa

Figure 36 – “Force – Displacement curves” for monotonic cyclic loading of Calcium Silicate specimens at a level of precompression 0.1 MPa

-6 -4 -2 0 2 4 6 -16 -12 -8 -4 0 4 8 12 16 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-36 -6 -4 -2 0 2 4 6 -16 -12 -8 -4 0 4 8 12 16 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-53 -6 -4 -2 0 2 4 6 -16 -12 -8 -4 0 4 8 12 16 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-37

(30)

Version 01 - Final 01/08/2017 Figure 37 – Hysteretic curve of CS specimens under axial cyclic loading at a precompression level of 0.1 MPa

Figure 38 – Indicative hysteretic and envelope curves of CS specimen under axial cyclic loading at a precompression level of 0.1 MPa

-6 -4 -2 0 2 4 6 -16 -12 -8 -4 0 4 8 12 16 Ver tica l f o rc e [k N ] Vertical displacement [mm] TUD_ANC-33-36 TUD_ANC-33-53 TUD_ANC-33-37 -4 -3 -2 -1 0 1 2 3 4 5 6 -16 -12 -8 -4 0 4 8 12 16

V

er

tic

al

for

ce

[kN]

Vertical displacement [mm]

TUD_ANC-33-37

Envelope - tension

Envelope - compression

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Version 01 - Final 01/08/2017 Figure 39 – Envelope tension and compression curves of a CS specimens under axial cyclic loading at a

precompression level of 0.1 MPa

Table 13 – Summary of results for cyclic loading of Calcium Silicate specimens at a leve of precompression 0.1 MPa

Displacement

Displacement [mm] TUD_ANC-33-36 5.44 9.77 4.89 4.21 TUD_ANC-33-53 3.67 4.91 5.08 4.59 TUD_ANC-33-37 4.57 6.96 3.56 4.89 Average 4.56 7.21 4.51 4.56 Deviation 0.88 2.44 0.83 0.34 CoV [%] 19.39 33.89 18.31 7.46 Precompression level: 0.3 ± 0.01 N/mm2

The observed failure mechanisms showed cracking and crushing of the calcium silicate or the tie broken.

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Version 01 - Final 01/08/2017 Figure 41 and Figure 42 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement are listed in Table 14.

Figure 41 – “Force – Displacement curves” for monotonic cyclic loading of Calcium Silicate specimens at a level of precompression 0.3 MPa

Figure 42 – Hysteretic curve of CS specimens under axial cyclic loading at a precompression level of 0.3 MPa -6 -4 -2 0 2 4 6 -25 -20 -15 -10 -5 0 5 10 15 20 25 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-33-23 -6 -4 -2 0 2 4 6 -25 -20 -15 -10 -5 0 5 10 15 20 25 V er ica l fo rce (k N) Vertical displacement (mm) TUD_ANC-33-59 -8 -6 -4 -2 0 2 4 6 8 -30 -20 -10 0 10 20 30

Vert

ica

l f

orce

[k

N]

Vertical displacement [mm] TUD_ANC-33-23 TUD_ANC-33-59

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Version 01 - Final 01/08/2017 Figure 43 – Indicative hysteretic curve of CS specimen under axial cyclic loading at a precompression level

of 0.3 MPa

Figure 44 – Envelope tension and compression curves of a CS specimens under axial cyclic loading at a precompression level of 0.3 MPa

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Version 01 - Final 01/08/2017 Table 14 – Summary of results for cyclic loading of Calcium Silicate specimens at a level of precompression

0.3 MPa

Displacement

Displacement [mm] TUD_ANC-33-23 5.65 9.95 5.86 3.93 TUD_ANC-33-59 3.66 9.48 4.88 4.14 Average 4.65 9.71 5.37 4.04 Deviation 1.40 0.34 0.70 0.15 CoV [%] 30.18 3.49 12.96 3.69

Table 15 reports a comparison between the average values of force and displacement at peak, and the ultimate displacement obtained for different levels of precompression. No significant trend can be identified for any of the reported results. Only the displacement at peak for tensile loading increases for larger precompression levels.

Table 15 – Average peak vertical force and corresponding displacement for different precompression levels

Precompression [MPa] Tension Compression Peak vertical force [kN] Displacement

Displacement [mm]

0 3.61 5.13 4.35 4.11

0.1 4.56 7.21 4.51 4.56

0.3 4.65 9.71 5.37 4.04

Figure 45 – Summary of the peak vertical force and corresponding displacement for the three levels of precompression -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 -6 -4 -2 0 2 4 6 8 10 V er tic al for ce [kN] Vertical displacement [mm]

Average - 0 MPa

Average - 0.1 MPa

(35)

Experimental results on Clay specimens (Clay masonry)

Monotonic tensile tests – TUD_ANC-41

Indipendently of the applied precompression level the same failure mechanism was observed for every specimen, with splitting of the clay brick, as shown in Figure 46.

Figure 46 – Failure mechanism of the clay

Figure 47 – Force – displacement curves for a level of precompression 0 MPa 0 0,5 1 1,5 2 2,5 3 3,5 0 2 4 6 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-13 0 0,5 1 1,5 2 2,5 3 3,5 0 2 4 6 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-12 0 0,5 1 1,5 2 2,5 3 3,5 0 2 4 6 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-19

(36)

Version 01 - Final 01/08/2017 Figure 48 – Summary of the “Force – Displacement curves” for monotonic tensile loading of clay specimens

at a level of precompression 0 MPa

Table 16 – Summary of results for monotonic tensile loading of clay specimens at a level of precompression 0 MPa

[kN] Displacement [mm] Displacement at 50 % of peak force TUD_ANC-41-13 3.08 5.26 5.36 TUD_ANC-41-19 3.16 5.07 5.11 TUD_ANC-41-12 2.60 3.78 3.85 Average 2.95 4.71 4.77 Deviation 0.30 0.80 0.81 CoV [%] 10.25 17.10 16.96 Precompression level: 0.1 ± 0.01 N/mm2

Figure 49 and Figure 50 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement are listed in Table 17. 0 0,5 1 1,5 2 2,5 3 3,5 0 2 4 6 Ver tica l f o rc e [k N ] Vertical displacement [mm] TUD_ANC-41-13 TUD_ANC-41-19 TUD_ANC-41-12

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Figure 50 – Summary of the “Force – Displacement curves” for monotonic tensile loading of clay specimens at a level of precompression 0.1 MPa

0 0,5 1 1,5 2 2,5 3 3,5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-22 0 0,5 1 1,5 2 2,5 3 3,5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-24 0 0,5 1 1,5 2 2,5 3 3,5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-33 0 0,5 1 1,5 2 2,5 3 3,5 0 5 10 15 20 25 30 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-41-22 TUD_ANC-41-24 TUD_ANC-41-33

(38)

Version 01 - Final 01/08/2017 Table 17 – Summary of results for monotonic tensile loading of clay specimens at a level of precompression

0.1 MPa

[kN] Displacement [mm] Displacement at 50 % of peak force TUD_ANC-41-22 2.79 5.28 9.77 TUD_ANC-41-24 2.99 5.91 11.84 TUD_ANC-41-33 2.61 5.22 14.28 Average 2.79 5.47 11.96 Deviation 0.19 0.38 2.26 CoV [%] 6.81 7.02 18.87 Precompression level: 0.3 ± 0.01 N/mm2

Figure 51 – Force – displacement curves for a level of precompression 0.3 MPa 0 1 2 3 4 5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-21 0 1 2 3 4 5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-31 0 1 2 3 4 5 0 5 10 15 20 25 30 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-41-40

(39)

Version 01 - Final 01/08/2017 Figure 52 – Summary of the “Force – Displacement curves” for monotonic tensile loading of clay specimens

at a level of precompression 0.3 MPa

Table 18 – Summary of results for monotonic tensile loading of clay specimens at a level of precompression 0.3 MPa

[kN] Displacement [mm] Displacement at 50 % of peak force TUD_ANC-41-21 4.09 11.15 14.07 TUD_ANC-41-31 4.67 16.08 22.48 TUD_ANC-41-40 4.33 9.86 18.66 Average 4.37 12.36 18.40 Deviation 0.29 3.28 4.21 CoV [%] 6.66 26.56 22.88

Table 19 reports a comparison between the average values of force and displacement at peak, and the ultimate displacement obtained for different levels of precompression.

Large differences between the average results are obtained for the three precompression levels.

As for the peak force, similar values are obtained for no precompression or low (0.1 MPa) precompression levels, but the resistance is significantly larger for high (0.3 MPa) lateral precompression. The differences are more evident for the displacements at peak, for which a clear increasing trend is observed. Finally, the absence of precompression leads to brittle failure of the specimen.

0 1 2 3 4 5 0 5 10 15 20 25 30 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-41-21 TUD_ANC-41-31 TUD_ANC-41-40

(40)

Version 01 - Final 01/08/2017 Table 19 – Average of the peak vertical force and corresponding displacement for the three levels of

precompression

Precompression

[MPa] Peak force [kN] Displacement [mm] Displacement at 50 % of peak force

0 2.95 4.71 4.77

0.1 2.79 5.47 11.96

0.3 4.37 12.36 18.40

Figure 53 – Summary of the peak vertical force and corresponding displacement for the three levels of precompression 0 1 2 3 4 5 0 2 4 6 8 10 12 14 16 18 20 V er tic al for ce [ kN] Vertical displacement [mm]

Average - 0 Mpa

Average - 0.1 Mpa

(41)

Version 01 - Final 01/08/2017 Monotonic compressive tests – TUD_ANC-42

Also the clay brick samples were modified by gluing a steel cylinder to the tie (similar to what described in section 3.2.2).

Independently of the applied precompression level, the same failure mechanism was observed for every test, with buckling of the steel tie.

Figure 54 – Failure mechanism of wall ties embedded in clay for compressive loadings

Figure 55 – Force – displacement curves for a level of precompression 0 MPa 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-17 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-27 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-60

(42)

Version 01 - Final 01/08/2017 Figure 56 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Clay

specimens at a level of precompression 0 MPa

Table 20 – Summary of results for monotonic compressive loading of Clay specimens at a level of precompression 0 MPa

Specimen Peak force [kN] Displacement [mm] Displacement at 50 % of peak force TUD_ANC-42-17 4.02 7.96 11.69 TUD_ANC-42-27 4.20 6.47 8.75 TUD_ANC-42-60 4.27 6.76 8.60 Average 4.16 7.06 9.68 Deviation 0.13 0.79 1.74 CoV [%] 3.10 11.19 18.00 Precompression level: 0.1 N/mm2

Figure 57 and Figure 58 report the force-displacement curves for each single performed test and a summary of the results.

Similarly to the case of the calacium silicate specimens, the tests were stopped after the buckling of the tie when the tie touched the steel plate (no. 5 in Figure 6). Therefore, the evaluation of the ultimate capacity of the was not possible.

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 2 4 6 8 10 12 14 16 18 20 V er tica l f o rc e [k N ] Vertical displacement [mm] TUD_ANC-42-17 TUD_ANC-42-27 TUD_ANC-42-60

(43)

Figure 58 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Clay specimens at a level of precompression 0.1 MPa

0 1 2 3 4 5 0 5 10 15 20 V er ica l fo rce (k N) Vertical displacement (mm) TUD_ANC-42-48 0 1 2 3 4 5 0 5 10 15 20 V erica l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-38 0 1 2 3 4 5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-28 0 1 2 3 4 5 6 0 2 4 6 8 10 12 14 16 18 Ver tica l f o rc e [k N] Vertical displacement [mm] TUD_ANC-42-48 TUD_ANC-42-38 TUD_ANC-42-28

(44)

Version 01 - Final 01/08/2017 Table 21 – Summary of results for monotonic compressive loading of Clay specimens at a level of

[kN] Displacement [mm] TUD_ANC-42-48 3.81 8.81 TUD_ANC-42-38 4.77 8.56 TUD_ANC-42-28 4.10 9.06 Average 4.23 8.81 Deviation 0.49 0.25 CoV [%] 11.55 2.84 Precompression level: 0.3 N/mm2

Figure 59 and Figure 58 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak, and the ultimate displacement are listed in Table 22. Again, the ultimate displacement could not be measured.

Figure 59 – Force – displacement curves for a level of precompression 0.3 MPa 0 1 2 3 4 5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-58 0 1 2 3 4 5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-55 0 1 2 3 4 5 0 5 10 15 20 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-42-42

(45)

Version 01 - Final 01/08/2017 Figure 60 – Summary of the “Force – Displacement curves” for monotonic compressive loading of Clay

specimens at a level of precompression 0.3 MPa

Table 22 – Summary of results for monotonic compressive loading of Clay specimens at a level of precompression 0.3 MPa

[kN] Displacement [mm] TUD_ANC-42-58 4.01 9.36 TUD_ANC-42-55 4.20 10.15 TUD_ANC-42-42 3.88 12.74 Average 4.03 10.75 Deviation 0.16 1.77 CoV [%] 3.99 16.45

Table 23 reports a comparison between the average values of force and displacement at peak, and the ultimate displacement obtained for different levels of precompression. No influence of the lateral precompression on the peak force is detected, whereas a small increase of the displacement at peak is observed.

Table 23 – Average vertical force and corresponding displacement for the three levels of precompression

Precompression

[MPa] Peak force [kN] Displacement [mm]

0 4.16 7.06 0.1 4.23 8.81 0.3 4.03 10.75 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 0 2 4 6 8 10 12 14 16 18 Ver tica l f o rc e [k N ] Vertical displacement [mm] TUD_ANC-42-58 TUD_ANC-42-55 TUD_ANC-42-42

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Version 01 - Final 01/08/2017 Figure 61 – Summary of the peak vertical force and corresponding displacement for the three levels of

precompression 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 2 4 6 8 10 12 14 16

V

er

tical

for

ce

[k

N]

Vertical displacement [mm]

Influence of the level of precompression

Average - 0 Mpa

Average - 0.1 Mpa

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Version 01 - Final 01/08/2017 Cyclic tests – TUD_ANC-43

For every specimen the same failure mechanism was observed, with splitting of the clay bricks.

Figure 62 – Failure mechanism for cyclic loadings

Figure 63 – “Force – Displacement curves” for monotonic cyclic loading of Clay specimens at a level of precompression 0MPa -3 -2 -1 0 1 2 3 4 5 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-30 -3 -2 -1 0 1 2 3 4 5 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-45 -3 -2 -1 0 1 2 3 4 5 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-29

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Version 01 - Final 01/08/2017 Figure 64 – Hysteretic curve of Clay specimens

Figure 65 – Indicative hysteretic curve of Clay specimen under axial cyclic loading at a precompression level of 0 MPa -3 -2 -1 0 1 2 3 4 5 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 Vert ica l f o rce [k N ] Vertical displacement [mm] TUD_ANC-43-30 TUD_ANC-43-45 TUD_ANC-43-29

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Version 01 - Final 01/08/2017 Figure 66 – Envelope tension and compression curves of a Clay specimens under axial cyclic loading at a

precompression level of 0 MPa

Table 24 – Summary of results for cyclic loading of Clay specimens at a level of precompression 0 MPa

Peak force [kN] Displacement[mm] _{Peak force [kN]} Displacement [mm]

TUD_ANC-43-30 4.53 7.27 1.93 4.99 TUD_ANC-43-45 2.09 2.80 0.08 2.50 TUD_ANC-43-29 2.74 3.66 0.40 4.25 Average 3.12 4.57 0.81 3.91 Deviation 1.27 2.37 0.99 1.28 CoV [%] 40.60 51.83 123.47 32.64 Precompression level: 0.1 N/mm2

For every specimen the same failure mechanism was observed, with splitting of the clay brick.

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Version 01 - Final 01/08/2017 Figure 68 and Figure 69 report the force-displacement curves for each performed test and a summary of the results, respectively. The force and displacement at peak are listed in Table 25.

Figure 68 – “Force – Displacement curves” for monotonic cyclic loading of Clay specimens at a level of precompression 0.1 MPa

Figure 69 – Hysteretic curve of Clay specimens -3 -2 -1 0 1 2 3 4 5 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-20 -3 -2 -1 0 1 2 3 4 5 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V er ica l fo rce (k N) Vertical displacement (mm) TUD_ANC-43-41 -3 -2 -1 0 1 2 3 4 5 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-51 -3 -2 -1 0 1 2 3 4 5 6 -25 -20 -15 -10 -5 0 5 10 15 20 25 V er tic al for ce [kN] Vertical displacement [mm] TUD_ANC-43-20 TUD_ANC-43-41 TUD_ANC-43-51

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Version 01 - Final 01/08/2017 Figure 70 – Indicative hysteretic curve of Clay specimen under axial cyclic loading at a precompression level

of 0.1 MPa

Figure 71 – Envelope tension and compression curves of a Clay specimens under axial cyclic loading at a precompression level of 0.1 MPa

-3 -2 -1 0 1 2 3 4 5 -25 -20 -15 -10 -5 0 5 10 15 20 25 V er tic al for ce [ kN] Vertical displacement [mm] TUD_ANC-43-51 Envelope - tension Envelope - compression

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Version 01 - Final 01/08/2017 Table 25 – Summary of results for cyclic loading of Clay specimens at a level of precompression 0.1 MPa

Peak force [kN] Displacement[mm] _{Peak force [kN]} Displacement [mm]

TUD_ANC-43-20 4.79 7.96 2.54 4.76 TUD_ANC-43-41 2.55 4.90 1.83 4.95 TUD_ANC-43-51 4.18 9.80 1.98 4.90 Average 3.84 7.56 2.12 4.88 Deviation 1.16 2.48 0.37 0.10 CoV [%] 30.18 32.75 17.61 1.99 Precompression level: 0.3 N/mm2

For every specimen the same failure mechanism was observed. No splitting of the brick occurred, but the top part of the clay brick broke.

Figure 73 and Figure 74 report the force-displacement curves for each single performed test and a summary of the results, respectively. The force and displacement at peak are listed in Table 26.

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Version 01 - Final 01/08/2017 Figure 73 – “Force – Displacement curves” for monotonic cyclic loading of Clay specimens at a level of

Figure 74 – Hysteretic curve of Clay specimens -6 -4 -2 0 2 4 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-55 -6 -4 -2 0 2 4 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V eri ca l fo rce (k N ) Vertical displacement (mm) TUD_ANC-43-46 -6 -5 -4 -3 -2 -1 0 1 2 3 4 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V er ica l fo rce (k N) Vertical displacement (mm) TUD_ANC-43-44 -6 -5 -4 -3 -2 -1 0 1 2 3 4 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V er tic al for ce [kN] Vertical displacement [mm] TUD_ANC-43-55 TUD_ANC-43-46 TUD_ANC-43-44

(54)

Version 01 - Final 01/08/2017 Figure 75 – Indicative hysteretic curve of Clay specimen under axial cyclic loading at a precompression level

of 0.3 MPa

Figure 76 – Envelope tension and compression curves of a Clay specimens under axial cyclic loading at a precompression level of 0.3 MPa

-6 -5 -4 -3 -2 -1 0 1 2 3 4 -21 -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 21 V er tic al for ce [kN] Vertical displacement [mm] TUD_ANC-43-44 TUD_ANC-43-44 Tension TUD_ANC-43-44 Compression

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Version 01 - Final 01/08/2017 Table 26 – Summary of results for cyclic loading of Clay specimens at a level of precompression 0.3 MPa

Peak force [kN] Displacement[mm] Peak force [kN] Displacement [mm]

TUD_ANC-43-55 2.70 6.61 2.81 9.97 TUD_ANC-43-46 3.73 9.66 5.17 9.18 TUD_ANC-43-44 3.54 9.97 4.17 9.93 Average 3.33 8.75 4.05 9.69 Deviation 0.54 1.85 1.18 0.45 CoV [%] 16.36 21.19 29.21 4.60

Table 27 reports a comparison between the average values of force and displacement at peak, and the ultimate displacement obtained for different levels of precompression. For positive loading no influence of the lateral precompression on the peak force is detected, whereas a small increase of the displacement at peak is observed. On the other hand, larger precompression levels lead to both larger forces and displacements.

Table 27 – Average of the peak vertical force and corresponding displacement for the three levels of precompression Precompression [MPa] Tension Compression Peak vertical force [kN] Displacement

Displacement [mm] 0 3.12 4.57 0.81 3.91 0.1 3.84 7.56 2.12 4.88 0.3 3.33 8.75 4.05 9.69 Figure 77 - Peak vertical force and corresponding displacement for the three levels of precompression

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 -10 -8 -6 -4 -2 0 2 4 6 8 10 V er tic al for ce [kN] Vertical displacement [mm] Influence of the level of precompression

Average - 0 MPa

Average - 0.1 MPa

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4 Shear tests

Testing procedure

Description of the specimens

The tests refer to cavity walls composed of two masonry leaves. Each leaf have a thickness of approximately 100mm and the cavity space is 80mm wide.

To test a complete connection both the typologies of specimens (CS and Clay) are considered:  Calcium Silicate specimens;

 Clay specimens.

The specimens are shown in Figure 78.

The dimensions for each typology of specimen are provided in Table 1.

Figure 78 – CS and Clay specimens Table 28 – Dimensions of test specimens.

Dimensions Calcium Silicate specimens Clay specimens

ls (mm) 210 210

hs (mm) 100 100

ts (mm) 70 50

Test set-up

The test apparatus adopted for shear tests is similar to that used for the axial tests (section 3.1.2).

The setup was moved eccentrically of 10 cm so that the clamp was able to apply the shear load simply moving upwards and downwards (Figure 79).

Besides, the specimen was surrounded by Teflon sheets to alow it to slide towards the clamp when large shear displacements were applied and avoid pull-out forces due to the second order effects.

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Figure 79 – New position of the specimen with respect to the clamp

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Version 01 - Final 01/08/2017 Figure 81 – View of the set-up from the side of the clamp

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Version 01 - Final 01/08/2017 Loading scheme

The test is completed on the base of the recommendations included in EN 846-5:2012. However, some changes (such as in the loading protocol) are introduced to fit the specific features of the tested specimens. The specimen is placed in the test machine such that the tie body is horizontal and aligned at the center of the test machine. The tie is clamped so that it has a free distance from the couplet equal to 80 mm. The specimen is kept under constant lateral pre-compression, while a shear load is applied to the tie. Two levels of pre-compression are investigated (0.1 ± 0.01 N/mm2_{and 0.3 ± 0.01 N/mm}2_).

The shear load is applied in displacement control while the pre-compressive load is maintained constant by means of the manually operated hydraulic jack. Two different loading schemes are followed:

 Protocol S1 (monotonic shear protocol): the shear behavior of the ties is determined by

monotonically increasing the displacement with a rate of 0.1mm/s up to failure.

 Protocol S2 (cyclic shear protocol): the displacement is cyclically varied by applying both upward

and downward (shear) loads on the tie, as described for Protocol A3 (Axial loading) and is depicted in Figure 83.

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Version 01 - Final 01/08/2017 Table 29 and Table 30.

Figure 83 – Loading protocol S2 ( cyclic protocol)

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 0 1 2 3 4 5 6 7 8 V erti ca l D is pa lcem ent Group of cycles

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Version 01 - Final 01/08/2017 Table 29 – CS specimens tested for each loading protocol for shear loads

Name Tie

embedment

Axial

load Loading protocol

Lateral pressure

Name specimen

TUD_ANC-34 CaSi-brick Shear S1

0 MPa TUD_ANC-34-57

TUD_ANC-34-38 0.1 MPa TUD_ANC-34-26 _{TUD_ANC-34-13} TUD_ANC-34-27 0.3 MPa TUD_ANC-34-31 _{TUD_ANC-34-07} TUD_ANC-34-30

TUD_ANC-35 CaSi-brick Shear S2

0 MPa TUD_ANC-35-14 _{TUD_ANC-35-18} TUD_ANC-35-08 0.1 MPa TUD_ANC-35-35 _{TUD_ANC-35-34} TUD_ANC-35-39 0.3 MPa TUD_ANC-35-28 _{TUD_ANC-35-29} TUD_ANC-35-01 Table 30 – Clay specimens tested for each loading protocol for shear loads

Name Tie embedment Axial load Loading protocol Lateral pressure Name specimen

TUD_ANC-44 Clay - brick Shear S1

TUD_ANC-45 Clay - brick Shear S2

0 MPa TUD_ANC-45-04 TUD_ANC-45-39 TUD_ANC-45-37 0.1 MPa TUD_ANC-45-50 TUD_ANC-45-47 TUD_ANC-45-07 0.3 MPa TUD_ANC-45-14 TUD_ANC-45-08 TUD_ANC-45-34 TUD_ANC-45-32

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Experimental results on CS specimens (calcium silicate

masonry)

Monotonic tests – TUD_ANC-34

For every specimen the same failure mechanism was observed independently on the applied precompression level. At failure, the Helifix tie yields in two points. The ultimate displacement evaluate for a residual strength equal to 20% of the peak load could not be measured for most of the specimens.

Figure 84 – Precompression level 0 MPa

Figure 85 – Precompression level 0.1 MPa

Tests on retrofitting wall ties

Tests on retrofitting wall ties

Messali, F.; Paletti, E.

Publication date

2017

Document Version

Final published version

Citation (APA)

Messali, F., & Paletti, E. (2017). Tests on retrofitting wall ties. Delft University of Technology.

Important note

To cite this publication, please use the final published version (if applicable).

Please check the document version above.

TU Delft Large-scale testing campaign 2016

TESTS ON RETROFITTING WALL TIES

Authors: Francesco Messali, Elisa Paletti

Table of Contents

1 Introduction

2 Construction of the specimens

3 Axial tests

Testing procedure

Experimental results on CS specimens (calcium silicate

masonry)

Influence of the level of precompression

Ver

tica

l f

o

rc

e

[k

N]

V

er

tic

al

for

ce

[kN]

Vertical displacement [mm]

Influence of the level of precompression

V

er

tic

al

for

ce

[kN]

Vertical displacement [mm]

TUD_ANC-33-37

Envelope - tension

Envelope - compression

Vert

ica

l f

orce

[k

N]

Experimental results on Clay specimens (Clay masonry)

V

er

tical

for

ce

[k

N]

Vertical displacement [mm]

Influence of the level of precompression

4 Shear tests

Testing procedure

Experimental results on CS specimens (calcium silicate

masonry)