SHEAR WALL METHOD:-
Shear walls are vertical elements of the horizontal force resisting system. They are typically wood frame stud walls covered with a structural sheathing material like plywood. When the sheathing is properly fastened to the stud wall framing, the shear wall can resist forces directed along the length of the wall. When shear walls are designed and constructed properly, they will have the strength and stiffness to resist the horizontal forces.
CONCEPT OF SHEAR WALL METHOD:-
In structural engineering, a shear wall is a structural system composed of braced panels (also known as shear panels) to counter the effects of lateral load acting on a structure. Wind and seismic loads are the most common loads that shear walls are designed to carry. Under several building codes, including the International Building Code (where it is called a braced wall line) and Uniform Building Code, all exterior wall lines in wood or steel frame construction must be braced. Depending on the size of the building some interior walls must be braced as well. Shear walls resist in-plane loads that are applied along its height. The applied load is generally transferred to the wall by a diaphragm or collector or drag member. They are built in wood, concrete, and CMU (masonry).
Plywood is the conventional material used in shear walls, but with advances in technology and modern building methods, other prefabricated options have made it possible to inject shear assemblies into narrow walls that fall at either side of an opening. Sheet steel and steel-backed shear panels in the place of structural plywood in shear walls has proved to provide stronger seismic resistance.
TYPES OF SHEAR WALL METHOD:-
In shear wall method we provide a wall parallel to damaged portion of the building(structure) so as to provide the damage part strength so,if in future earthquake occurs then it is limited to only the shear wall and the interior main wall does not gets affected.
Shear wall can be provided in two ways:-
1. Infill shear wall.
2. External shear wall.
- INFILL SHEAR WALL:-
In the strengthening method with infill walls, the existing partition walls in the building are removed and high strength reinforced concrete shear walls are built instead. In such a strengthening application, the shear walls bear majority of the earthquake loads and limits the displacement behaviour of the building while the frame system resists very low amounts of the earthquake loads. Reinforced concrete infill walls can also be used as partial walls and wing walls. Door and window openings may also be provided in these walls to allow the building to deliver its architectural functions although they reduce stiffness and strength of the wall. In such applications preventing the construction of infill walls in the form of a full-fill wall, many experimental studies indicated that these walls develop more brittle damages compared to full-fill walls.
(Fig-1:- Infill shear wall)
- EXTERNAL SHEAR WALL:-
In cases where pile foundation is not applied for the shear wall foundation, such shear walls are effective in only one direction. In order to create a positive effect on earthquake resistance of the building, they must be installed at opposite facades. This increases the required amount of shear walls and costs. For all these reasons, external shear walls that located perpendicular to the external facade are not preferred in the application. The more preferred form of the external shear walls is the application where they are installed in parallel with the building façade. An example of the application of a external shear wall located in parallel with the building facade is seen in Figure 2.
(Fig-2:- External shear wall)