Masonry structure are widely used to its low cost and easy construction specially in developing country. By retrofitting of building we ensure the stability and earthquake resistance houses.
Explain the various method of retrofitting in the masonry buildings
Retrofitting of Building:
Due to weak structure, every year many casualty happen due to collapsing house or building during earthquake. So it is clear that retrofitting of the existing house stock is urgent successful company oriented in this direction are scane and inexistent.
The existing methods of retrofitting technique can be categorised in
- Grout and epoxy injection
- Surface coatings
- Rainforced and post-tensioned course
- Addition of structure elements
Retrofitting method proposal:
The proposed retrofitting method is based on polypropylene band (pp-band) using cement mortar overlay in mesh orientation.
These bands, which are used worldwide for packing are inexpensive, resistant and easy to handle.
Check: Green Building Design
The retrofitting installation procedure is as follows:
- The PP- bands are arranged in mesh fashion and connected at their crossing points.
- At the mesh borders, which coincide with the wall top and bottom, two Steel rods are installed. Because it is difficult to paste the PP band with the other material such as brick or concrete, these bars are used to anchor the mesh at the foundation and wall top edge in retrofitting.
- The walls are cleaned and if possible the paint is removed. Any loose Brick piece are removed and replaced.
- 6 mm diameter holes are drilled through the wall at approximately 250 to 300 mm pitch. AP masonry units are relatively strong, it is preferable to place the holes at the week motor interface. The drilled holes are cleaned with water spray or air.
- The meshed are installed on both sides of the wall and wrapped around the corners and wall edge. An overlapping length of approximately 300 mm is needed.
- Wire is passed through the previously drilled holes and used to connect the meshes on both wall sides of reftrofitting bulding area. In order to prevent the wire from cutting the PP band mesh, a plastic piece or any other stiff element is placed between the band and wire. It is desirable to have connectors close to the wall intersections and wall edges.
- The top and bottom mesh edges, where Steel bars are installed, are pasted to the foundation and the wall top border utilizing epoxy. The epoxy is used to connect the bars and the wall and it is not directly applied to the mesh.
- The mesh overlapping length are pasted to the adjacent to wall meshes. In this way, the reinforcement system continuity is enhanced. This step concludes the setting of PP-bend mesh in retrofitting.
- In order to protect the mesh from the ultraviolet radiation, rain and eventually vandalism, a mortar layer is placed on the retrofitted wall of building.
Retrofitting of building is a techniques by which we provide strength to existing building and ensure the stability of building against earthquake and any natural disaster.
different types of retrofiting in building are Grout and epoxy injection, Surface coatings, Rainforced and post-tensioned course and Addition of structure elements