Seismic resistant retrofitting for buildings
Practical Action
The welded mesh should be attached to the longitudinal bars with binding wire. The strip should
then be attached with 100-150mm (4-6”) nails with the nails driven into the mortar joints.
Spacers should be provided to allow at least 15mm (1/2”) thickness between the wall and the
mesh, to ensure the mesh is completely covered by the cement plaster. The ratio of cement:
sand should be 1:3.
For a random rubble wall, L-shaped shear connectors should be cast as depicted in Figure 3(b)
made of reinforced concrete. These should be installed every 1.25-1.5m (4-5ft) and once the
concrete has set, the protruding dowel bar can be attached to the welded mesh strip with binding
wire. 100mm (4”) square headed nails should be used to attach the welded mesh to the wall in
the fashion described previously.
Step-by-step instructions including illustrations can be found on pages 64-67 of Manual for
Restoration and Retrofitting of Rural Structures in Kashmir. Recommendations for vertical mesh
reinforcement are covered in pages 68-72.
Table 1 - Reinforcement recommendations for horizontal seismic belts (National Disaster
Management Division, Govt. of India, 2006)
Length of Wall (m)
<5
6
Cat. D
Gauge
g10
g10
N
8
10
H
230
280
7 g10
10
280
With 2 bars of 6 mm Ø
8 g10
10
280
With 2 bars of 8mm Ø
Cat. E
Gauge
N
H
g10 10
280
g10 10
280
With 2 bars of 6 mm Ø
g10 10
280
With 2 bars of 8 mm Ø
g10 10
280
With 3 bars of 8 mm Ø
Table 2 - Reinforcement recommendations for vertical reinforcement (National Disaster
Management Division, Govt. of India, 2006)
No. of storeys
One One
Two Top
Bottom
Three
Top
Middle
Bottom
Cat. D
Single Bar, mm
Mesh (g10)
NB
10 10 300
10 10 300
12 14 400
10 10 300
12 14 400
12 14 400
Cat. E
Single Bar, mm Mesh (g10)
NB
12 14 400
12 14 400
16 14 400
With 1 bars of
12mm Ø
12 14 400
16 14 400
With 1 bars of
12mm Ø
16 14 400
With 1 bars of
12mm Ø
4