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TitleStructural strengthening manual.pdf
TagsFibre Reinforced Plastic Composite Material Chemistry Materials
File Size4.6 MB
Total Pages92
Document Text Contents
Page 1

Cutting-edge systems and solutions for the
repair and static / seismic upgrading
of buildings using fibre reinforced composites

Products & Applications

Structural strengthening manual

ADHESIVES • SEALANTS • CHEMICAL PRODUCTS FOR BUILDING

Page 2

Cover picture:
The Church of San Bernardino in L’Aquila - Italy

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44

5.2.1. Laboratory testing: “Diagonal compression tests on tuff
masonry panels strengthened with CMF: PLANITOP HDM +
MAPEGRID G 220”

Testing was carried out on tuff masonry panels made with specially prepared
construction mortar to reproduce the mechanical characteristics of the
pozzolan-based mortar used on ancient monuments and buildings in the south
of Italy’s area. Strengthened panels and panels without strengthening were
then subjected to diagonal compression tests. The strengthening system was
made of a pre-primed, alkali-resistant (A.R.) glass fibre mesh (MAPEGRID G
220) and a matrix based on a two-component, high ductility, fibre reinforced,
pozzolanic-reaction cementitious mortar (PLANITOP HDM).

TEST RESULTS
The results of the tests demonstrated that the strengthening offered considerable
benefits in terms of shear strength and ductility, and also had the capacity
to distribute loads to limit the extremely fragile post-peak behaviour of the
strengthened member, with significant advantages in the event of seismic
activity. On the panels without strengthening, the tension induced by the loads
generated cracks mainly along the surface of the tuff/mortar interface rather
than in the direction of the load applied.
Failure was characterised by the beds of mortar slipping from the tuff stones.
The presence of strengthening materials on both wall faces, on the other hand,
modified the failure mode of the panels, moving the shear failure caused by the
mortar slipping to shear failure characterised by widespread cracking in the
direction of the compressive load, with small to medium size cracks intercepting
both the layers of mortar and the tuff stones.

Figure 5.4 - A panel with
a strengthening system
applied: MAPEGRID G220 +
PLANITOP HDM

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45

Structural
strengthening manual

The strengthening on both faces of the wall, therefore, managed to change
the distribution of the tension over the entire surface of the wall. The tensile
properties of the strengthening system were clearly visible through the presence
of widespread micro cracking along the outer layer of mortar distributed on both
faces of the wall, with a sub-vertical trend along the compressed diagonals
of the wall. Graph 1 shows the stress-deformation behaviour of each sample

5.5 5.6

5.7 5.8

Figure 5.7 - The behaviour
of a strengthened

masonry panel

Figure 5.8 - The behaviour
of a masonry panel without

strengthening

Figures 5.5 and 5.6 -
Diagonal compressive

strength test

Page 92

MAPEI SpA
Via Cafiero, 22 - 20158 Milan - Tel. +39-02-37673.1 - Fax +39-02-37673.214
Internet: www.mapei.com - E-mail: [email protected]

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