Table 4 Aspects of structural strengthening of architectural heritage

1

Structural interventions related to the foundations

(a) Improvement of the ground soil

Bearing soil improvement techniques mainly use the effects of increased adhesion between soil particles, condensation and enhancement to achieve one or more of the following elements: increase strength to improve stability, reduce deformation due to deformation or compression of soil mass, reduce liquefaction and reduce soil natural fluctuations

There are many ways to modify and improve the earth around the world now, including geotextiles, stone columns, micropiles, water dewatering, and pressure, preloading with and without vertical drains, Jet injection, deep mixing, and deep condensation and soil enhancement

Among many ground improvement techniques, the stone column has gained much popularity since it was properly documented in the middle of the last century. Potential applications of stone columns include the stabilization of basic soils, supporting structures, stabilization of the soil, and reduction of soft sanding potential

(b) Improving the behaviour of foundations by enlargement and/or consolidation

(c) Strengthening of the foundation by underpinning using micro piles isolated or in group or in row

2

Local interventions for structural improvement

(a) Masonry walls Pozzolanic grouting or stitching in cracks.

(b) Strengthening roof diaphragms with plywood and steel ties

(c) Vertical and Transversal anchorage (Cintec stitching anchors) in walls

(d) Strengthening masonry columns with jacketing (e.g. FRPs Jacketing like CFRP laminates)

(e) Repair of damaged wood elements

3

Global interventions for structural improvement

(a) Strengthening of masonry walls with reinforced cement coating (shotcrete or jacketing)

(b) Strengthening of masonry walls with polypropylene meshing

(c) Strengthening of floors and improving the connection floor/wall

(d) Strengthening of masonry walls with composite materials (CFRP and GFRP)

(e) The use of horizontal tie rods

(f) Retrofitting by post tensioning rodes

(g) Strengthening with ring beams

(h) Retrofitting by introducing RC shear walls

(i) Strengthening with RC or shear panel steel frames or braced frames (anti seismic techniques)