Shear walls

 Shear walls are vertical elements of the horizontal
force resisting system.
 Shear walls are constructed to counter the effects
of lateral load acting on a structure.
 When shear walls are designed and constructed
properly, and they will have the strength and
stiffness to resist the horizontal forces.
 Shear walls are especially important in high-
rise buildings subjected to lateral wind and seismic
forces.
 Shear wall buildings are usually regular in plan and
in elevation.

 Shear walls are not only designed to resist gravity /
vertical loads, but they are also designed for lateral
loads of earthquakes / wind.
 Shear wall structural systems are more stable.
 Walls have to resist the uplift forces caused by the pull
of the wind. Walls have to resist the shear forces that
try to push the walls over. Walls have to resist the
lateral force of the wind that tries to push the walls in
and pull them away from the building.
Purpose of constructing shear walls

COMPARISIONS OF SHEAR WALL WITH
CONSTRUCTION OF CONVENTIONAL LOAD
BEARING WALLS
 Load bearing masonry is very brittle material. Due to different kinds of
stresses such as shear, tension, torsion, etc., caused by the
earthquakes, the conventional unreinforced brick masonry collapses
instantly during the unpredictable and sudden earthquakes.
 The RCC framed structures are slender, when compared to shear wall
concept of box like three-dimensional structures. Though it is possible
to design the earthquake resistant RCC frame, it requires extraordinary
skills at design, detailing and construction levels, which cannot be
anticipated in all types of construction projects.

 On the other hand even moderately designed
shear wall structures not only more stable, but
also comparatively quite ductile. In safety terms it
means that, during very severe earthquakes they
will not suddenly collapse causing death of people.
They give enough indicative warnings such as
widening structural cracks, yielding rods, etc.,
offering most precious moments for people to run
out off structures, before they totally collapse.

FORCES ON SHEAR WALL
Shear walls resist two types of forces:
 shear forces : Shear forces are
generated in stationary buildings
by accelerations resulting from
ground movement and by external
forces like wind and waves. This
action creates shear forces
throughout the height of the wall
between the top and bottom shear
wall connections.

 uplift forces : Uplift
forces exist on shear
walls because the
horizontal forces are
applied to the top of the
wall. These uplift forces
try to lift up one end of
the wall and push the
other end down. In
some cases, the uplift
force is large enough to
tip the wall over. Uplift
forces are greater on
tall short walls and less
on low long walls.

CLASSIFICATION OF SHEAR WALLS
 Simple rectangular
types and flanged
walls (bar bell type)
•Coupled shear walls

 Rigid frame shear
walls
•Framed walls with in
filled frames

 Column supported
shear walls
•Core type shear walls

METHODS OF DESIGN OF SHEAR WALL
 Segmented shear wall method
The segmented shear wall method uses full
height shear wall segments that comply with
ratio requirements and are usually
restrained against overturning by hold down
devices at the ends of each segment.

 Force transfer –ground openings method
The second method force transfer-ground openings
method consider the entire shear wall with openings
and the wall piers adjacent to openings are
segments. The method requires the forces around
the perimeter of the openings to be analyzed,
designed, and detailed. With this method, the hold-
down devices generally occur at the ends of the
shear wall, not at each wall pier, and special
reinforcement around the opening is often required.

 Perforated shear wall
method
The third and newest
method is the
perforated shear wall
method which is an
empirical approach that
does not require special
detailing for force
transfer adjacent to the
openings. The
perforated shear wall
method, however,
specifically requires
hold-down devices at
each end of the
perforated shear wall.

 Ludlow Castle School, undergoing retrofit.
After structural retrofitting and earthquake
preparedness training for faculty, staff,
students and parents, Ludlow Castle School
was officially designated a "model safe
school" by the Indian government.

TYPES OF SHEAR WALLS
 RC SHEAR WALL
It consists of reinforced concrete walls and reinforced concrete slabs. Wall thickness
varies from 140 mm to 500 mm, depending on the number of stories, building age,
and thermal insulation requirements. In general, these walls are continuous
throughout the building height; however, some walls are discontinued at the street
front or basement level to allow for commercial or parking spaces.
 PLYWOOD SHEAR WALL
Plywood is the traditional material used in the construction of Shear Walls. The
creation of pre-fabricated shear panels have made it possible to inject strong shear
assemblies into small walls that fall at either side of a opening in a shear wall. As
well as the use of a sheet steel, and steel-backed shear panel (i.e. Sure-Board) in the
place of structural use plywood in shear walls, has proved to be far stronger in
seismic resistance when used in shear wall assemblies.
Plywood shear walls consist of:
• Plywood, to transfer shear forces
• Chords, to resist tension/compression generated by the over turning moments
• Base connections to transfer shear to foundations.

MIDPLY SHEAR WALL
The MIDPLY shear wall is an improved timber shear wall that was developed by
redesigning the joints between sheathing and framing members, so that the failure
modes observed in standard wall testing are virtually eliminated at lateral load levels
high enough to cause failures in standard walls.
In MIDPLY shear wall design, one ply of sheathing material is placed at the center of
the wall between a series of pairs of studs oriented in a 90° rotated position relative to
those in standard shear walls
RC HOLLOW CONCRETE BLOCK MASONRY WALLS
RHCBM walls are constructed by reinforcing the hollow concrete block masonry, by
taking advantage of hollow spaces and shapes of the hollow blocks. It requires
continuous steel rods (reinforcement) both in the vertical and horizontal directions at
structurally critical locations of the wall panels, packed with the fresh grout concrete in
the hollow spaces of masonry blocks.
MIDPLY
SHEAR
WALL RHCBM

STEEL PLATE SHEAR WALL
In general, steel plate shear wall system consists of a
steel plate wall, boundary columns and horizontal floor
beams. Together, the steel plate wall and boundary
columns act as a vertical plate girder. The columns act
as flanges of the vertical plate girder and the steel plate
wall acts as its web. The horizontal floor beams act,
more-or-less, as transverse stiffeners in a plate girder.
Steel plate shear wall systems have been used in recent
years in highly seismic areas to resist lateral loads.

ADVANTAGES OF STEEL PLATE SHEAR WALL TO
RESIST LATERAL LOADS:

1. The system, designed and detailed properly is very ductile and has
relatively large energy dissipation capability. As a result, steel shear
walls can be very efficient and economical lateral load resisting
systems.
2. The steel shear wall system has relatively high initial stiffness, thus
very effective in limiting the drift.
3. Compared to reinforced concrete shear walls, the steel shear wall is
much lighter which can result in less weight to be carried by the
columns and foundations as well as less seismic load due to reduced
mass of the structure.
4. By using shop-welded, field-bolted steel shear walls, one can speed-
up the erection process and reduce the cost of construction, field
inspection and quality control resulting in making these systems even
more efficient.


5. Due to relatively small thickness of steel plate shear walls
compared to reinforced concrete shear walls, from
architectural point of view, steel plate shear walls occupy
much less space than the equivalent reinforced concrete
shear walls. In high-rises, if reinforced concrete shear walls
are used, the walls in lower floors become very thick and
occupy large area of the floor plan.
 6. Compared to reinforced concrete shear walls, steel plate
shear walls can be much easier and faster to construct when
they are used in seismic retrofit of existing building.

ARCHITECTURAL ASPECTS OF SHEAR WALLS
 Most RC buildings with shear walls also have
columns; these columns primarily carry gravity
loads (i.e., those due to self-weight and
contents of building). Shear walls provide large
strength and stiffness to buildings in the
direction of their orientation, which significantly
reduces lateral sway of the building and thereby
reduces damage to structure and its contents.

 Since shear walls carry large horizontal
earthquake forces, the overturning effects on
them are large. Thus, design of their foundations
requires special attention. Shear walls should be
provided along preferably both length and width.
However, if they are provided along only one
direction, a proper grid of beams and columns in
the vertical plane (called a moment-resistant
frame) must be provided along the other direction
to resist strong earthquake effects.

 Door or window openings can be provided in shear walls, but
their size must be small to ensure least interruption to force
flow through walls. Moreover, openings should be
symmetrically located. Special design checks are required to
ensure that the net cross-sectional area of a wall at an
opening is sufficient to carry the horizontal earthquake force.
Shear walls in buildings must be symmetrically located in
plan to reduce ill effects of twist in buildings. They could be
placed symmetrically along one or both directions in plan.
Shear walls are more effective when located along exterior
perimeter of the building – such a layout increases
resistance of the building to twisting.

ADVANTAGES OF SHEAR WALLS IN BUILDINGS
 Properly designed and detailed buildings with shear
walls have shown very good performance in past
earthquakes. Shear walls in high seismic regions require
special detailing. However, in past earthquakes, even
buildings with sufficient amount of walls that were not
specially detailed for seismic performance (but had
enough well-distributed reinforcement) were saved from
collapse. Shear wall buildings are a popular choice in
many earthquake prone countries, like Chile, New
Zealand and USA.

 Shear walls are easy to construct, because
reinforcement detailing of walls is relatively
straight forward and therefore easily implemented
at site.
Shear walls are efficient, both interims of
construction cost and effectiveness in minimizing
earthquake damage in structural and
nonstructural elements like glass windows and
building contents.

CONCLUSION
 Thus shear walls are one of the most effective
building elements in resisting lateral forces
during earthquake. By constructing shear walls
damages due to effect of lateral forces due to
earthquake and high winds can be minimized.
Shear walls construction will provide larger
stiffness to the buildings there by reducing the
damage to structure and its contents.

Shear walls

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Shear walls