Shear Wall

A project report on
Design Of Shear Wall
(Using Staad Pro)
Submitted by
SABHAYA RUTVIK
17SOESE21007
DEPARTMENT OF CIVIL ENGINEERING
SCHOOL OF ENGINEERING,
RK UNIVERSITY
RAJKOT, GUJARAT-360020
April 2018

ii
CERTIFICATE
This is to certify that the report entitled Design Shear Wall
submitted by, Mr. Rutvik Sabhaya to the School of Engineering, RK
University, Rajkot towards partial fulfillment of the requirements for
the award of the Degree of master of Technology in STRUCTURAL
Engineering 17SOESE21007 respectively are bonafide record of the
work carried out by their under my/our supervision and guidance and
is to the satisfaction of department.
Date:
Place:
Signature and Name of Student:
Signature and Name of Examiner.:
Seal of Institute

iii
Index
No. Title Page no.
1. Introduction of walls 1
2. APPLICATION 4
3. ADVANTAGES & DISADVANTAGES 5
4. SHEAR WALL 6
5. Design Procedure 12
Design Procedure Of Shear Wall ( Staad Pro) 14
Design Procedure Of Shear Wall (Reference) 20
6. CONCLUSION 27
7. Reference 28

SCHOOL OF ENGINEERING, RK UNIVERSITY Page 1
CHAPTER-1 INTRODUCTION
1.1 INTRODUCTION
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. In residential construction, shear walls are straight external walls that
typically form a box which provides all of the lateral support for the building.
When shear walls are designed and constructed properly, and they will have the
strength and stiffness to resist the horizontal forces.
Lateral forces caused by wind, earthquake, and uneven settlement loads, in
addition to the weight of structure and occupants; create powerful twisting
(torsion) forces. These forces can literally tear (shear) a building apart. Shear
walls are especially important in high-rise buildings subjected to lateral wind and
seismic forces.
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.
In building construction, a rigid vertical diaphragm capable of transferring
lateral forces from exterior walls, floors, and roofs to the ground foundation in a
direction parallel to their planes. Lateral forces caused by wind, earthquake, and
uneven settlement loads, in addition to the weight of structure and occupants;
create powerful twisting (torsion) forces. These forces can literally tear (shear) a
building apart. Reinforcing a frame by attaching or placing a rigid wall inside it
maintains the shape of the frame and prevents rotation at the joints. Shear walls
are especially important in high-rise buildings subjected to lateral wind and
seismic forces.
Shear wall systems are one of the most commonly used lateral-load
resisting systems in high-rise buildings. Shear walls have very high in-plane
stiffness and strength, which can be used to simultaneously resist large horizontal
loads and support gravity loads, making them quite advantageous in many
structural engineering applications. There are lots of literatures available to design
and analyses the shear wall. However, the decision about the location of shear
wall in multi-storey building is not much discussed in any literatures.

1.2 PURPOSE OF CONSTRUCTING SHEAR WALLS
Shear walls are not only designed to resist gravity / vertical loads (due to
its self-weight and other living / moving loads), but they are also designed for
lateral loads of earthquakes / wind. The walls are structurally integrated with roofs
/ floors (diaphragms) and other lateral walls running across at right angles, thereby
giving the three dimensional stability for the building structures. Shear wall
structural systems are more stable. Because, their supporting area (total cross-
sectional area of all shear walls) with reference to total plans area of building, is
comparatively more, unlike in the case of RCC framed structures. 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.
1.3 COMPARISONS OF SHEARWALL 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., Becaused 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 walls 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. For structural purposes we consider the exterior walls as the
shear-resisting walls. Forces from the ceiling and roof diaphragms make their way
to the outside along assumed paths, enter the walls, and exit at the foundation.
1.4 FORCES ON SHEAR WALL:
Shear walls resist two types of forces: shear forces and uplift 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 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. Bearing walls have less uplift than non-
bearing walls because gravity loads on shear walls help them resist uplift.
Shear walls need hold down devices at each end when the gravity loads cannot
resist all of the uplift. The hold down device then provides the necessary uplift
resistance.
Shear walls should be located on each level of the structure including the
crawl space. To form an effective box structure, equal length shear walls
should be placed symmetrically on all four exterior walls of the building.
Shear walls should be added to the building interior when the exterior walls
cannot provide sufficient strength and stiffness. Shear walls are most efficient
when they are aligned vertically and are supported on foundation walls or
footings. When exterior shear walls do not provide sufficient strength, other
parts of the building will need additional strengthening. Consider the common
case of an interior wall supported by a sub floor over a crawl space and there
is no continuous footing beneath the wall. For this wall to be used as shear
wall, the sub floor and its connections will have to be strengthened near the
wall. For Retrofit work, existing floor construction is not easily changed.
That’s the reason why most retrofit work uses wall with continuous footings
underneath them as shear walls.

CHAPTER-2 APPLICATION
 Shear walls are not only designed to resist gravity / vertical loads but
designed for lateral loads of earthquakes / wind.
 walls are structurally integrated with roofs / floors (diaphragms)
 Other lateral walls running across at right angles, thereby giving the
three dimensional stability for the building structures.
 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 push the walls in
and away from the building
 Shear wall structural systems are more stable.
 Supporting area with total plans area of building, is comparatively
more, unlike in the case of RCC framed structures.

CHAPTER-3 ADVANTAGES & DISADVANTAGES
3.1 ADVANTAGES
1) Thinner walls.
2) Light weight.
3) Fast construction time.
4) Fast performance.
5) Enough well distributed reinforcements.
6) Cost effectiveness.
7) Minimized damages to structural and nonstructural elements.
8) Provides greater stiffness
3.2 DISADVANTAGES
1) Less energy dissipation.
2) Causes higher losses to non-structural components

CHAPTER-4 SHEAR WALL
4.1 GENERAL
When RC walls with very large in-plane stiffness are placed as shown in
Fig., they provide the needed resistance to the lateral loads, have the ability to
dampen vibration, and keep the lateral drift within limits. Such walls, often called
shear walls, generally act as deep vertical cantilever beams and resist the in-plane
shears and bending moments caused by lateral loads in the plane of the walls and
also carry vertical gravity loads, thus providing lateral stability to the structure. As
these walls predominantly exhibit flexural deformations and their strength is
normally controlled by their flexural resistance, their name is a misnomer,
although they are provided with shear reinforcement to prevent diagonal tension
failures.
Fig.1 Shear Wall
Hence, they are referred to as structural walls in ACI 318 and also in this
book, and sometimes as flexural walls. They have large strength and high stiffness
and provide greater ductility than RC framed buildings. Fintel (1991), based on
his observation of collapsed buildings during several earthquakes throughout the

world since 1963, concluded that structural walls exhibit extremely good
earthquake performance [it is interesting to note that the R value, which signifies
the ductility provided by the system, for ductile structural walls (designed as per
IS 13920) is given as 4.0 in Table 7 of IS 1893(Part1):2002, whereas for special
RC moment-resisting frame (SMRF) it is 5.0; only ductile shear wall with SMRF
has R = 5.0].
When a building has structural walls, it can be modelled in STAAD using
surface elements. The modelling can be done using a single surface element or a
combination of surface elements. The use of the surface element enables the
designer to treat the entire wall as one entity. It greatly simplifies the modelling of
the wall and adds clarity to the analysis and design output. The results are
presented by STAAD in the context of the entire wall rather than individual finite
elements, thereby allowing users to quickly locate required information.
4.1 Types of Structural Walls
structural walls can be constructed in a variety of shapes such as
rectangular, T-, C-, or L-shaped, circular, curvilinear, or box type. When the
flanges of T-, C-, or L-shaped walls are in compression, they exhibit large
ductility; however, T- and L-section walls have only limited ductility when the
flange is in tension. The structural walls must be provided symmetrically along
the length and width of the building, as shown in Figs 16.25(a) and (b), to avoid
torsional stresses and better performance during earthquakes. Structural walls
should also be continuous throughout the height. They are more effective when
located along the exterior perimeter of a building but need not extend over the full
width of the building (see Fig. 16.25a). They may be used to enclose stairwells,
elevators, or toilets even in this case, it is better to locate them symmetrically. It is
to be noted that such an arrangement of walls in the interior of a building may not
be as effective as the walls located on the periphery of the building; however,
because of the box shape they provide torsional resistance during earthquakes.

Fig.2 Types of structural walls (a) Rectangular shear walls (b) Structural wall around elevators and
stairwells (c) Coupled structural walls.
In many situations, it is not possible to use structural walls without some
openings in them for doors, windows, and service ducts. Such openings should be
placed in one or more vertical and symmetrical rows in the walls throughout the
height of the structure, as shown in Fig. 16.25(c). The walls on either side of the
opening are interconnected by short deep beams called coupling beams or link
beams. Such walls are called coupled structural walls. Walls with openings
arranged in a regular and rational pattern have very good energy dissipation
characteristics. Because of their low span to-depth ratio, typically between one
and four, the short beams require special detailing requirements to ensure
adequate deformation capacity during earthquakes
4.2 Behaviors of Structural Walls:
The behavior of walls will depend on their geometry. Based on the
geometry, walls may be classified as squat walls (with Hw/Lw < 2), intermediate
walls (with 2 < Hw/Lw < 3), and slender or cantilever walls (with Hw/Lw > 3).

Slender and squat/intermediate walls are shown in Fig. 3. Squat walls are
generally dominated by shear, whereas in slender walls lateral loads are resisted
mainly by flexural action; when the value of Hw/Lw is between two and three, the
walls exhibit a combination of shear and flexural behavior
.
Fig.3 Classification based on Hw/lw (a) Squat/Intermediate wall (b) Cantilever wall.
Five basic modes of failure are possible in slender walls. They are shown
in Fig.4 and are listed as follows (Paulay and Priestley 1992; Rohit, et al. 2011):
1. Ductile flexural tension failure with yielding of vertical steel as shown in
Fig.4(b)
2. Flexural shear failure with diagonal shear cracks in the web of wall as shown in
Fig. 4(c)

Fig.4 Failure modes in cantilever walls (a) Wall (b) Flexural tension (c) Flexural shear (d) Sliding
(e) Overturning (f) Flexural compression.
3. Horizontal sliding failure near wall foundation interface or at a construction
joint as shown in Fig. 4(d)
4. Overturning (stability) failure as shown in Fig.4(e)
5. Flexural compression failure with the crushing of concrete at the bottom
regions of the wall as shown in Fig. 4(f)
4.1 Function and Load Transfer Mechanism:
Function:
The main function of a shear wall can be described as follows:
1.provide lateral strength to a building
Shear wall must provide lateral shear strength to the building to resist the
horizontal earthquake forces, wind forces and transfer these forces to the
foundation.
2.providing lateral stiffness to building;
Shear walls provide large stiffness to building in the direction of their
orientation, which reduces lateral sway of the building and thus reduces damage to
structure.

Fig. 5 function of shear walls
Load transfer mechanism :
Shear walls carry horizontal seismic forces downwards to the foundations. The
overturning effects on shear walls are quite large. Thus, design of their
foundations requires special foundation. If, the shear wall is an exterior wall, then
it will also carry the wind load & then it should also be design to resist the wind
load and this load also get transfer to the foundation of the shear wall.
The various walls and co-existing frames in a building are linked at the
different floor levels by means of the floor system, which has the
distributes the lateral loads to these different systems appropriately. The
interaction between the shear walls and the frames is structurally advantageous in
that the walls restrain the frame deformations in the lower story, while frame
restrain the wall deformations in the upper storey, while frames restrain the wall
deformations in the upper storey. Frame-shear wall systems are generally
considered in the building up to about 40 storeys.

CHAPTER-5 Design Procedure
The following are the steps required in the design of rectangular RC
structural walls, after the moments, shear force, and axial forces are determined
using an FEM-based computer program. (the clauses given here pertain to IS
13920:1993):
Step 1: Check whether a boundary element is required. This can be determined
by calculating the stress in the wall using the following equation:
where Pu is the factored axial load, Mu is the factored moment acting on
the wall, Ag is the gross area of the wall, Lw is the length of wall, and I is the
moment of inertia of the wall = tw*Lw^3 /12. When this stress is greater than
0.2fck, boundary elements are to be provided (Clause 9.4.1). They may be
discontinued when the compressive stress is less than 0.15fck. It should be noted
that boundary elements need not be provided when the entire wall is provided
with special confining reinforcement as per Clause 9.4.6. However, the provision
of boundary walls will result in better performance during earthquakes. Clause
21.9.6.4 of ACI 318 suggests that the boundary element should extend
horizontally from the extreme compression fibre to a distance not less than the
larger of the xu − 0.1Lw and xu/2, where xu is the neutral axis depth.
Step 2: Check for section requirements of Clause 9.1.2. The thickness of the
wall should be greater than 150 mm.
Step 3: Check for minimum reinforcement and maximum spacing (as per
Clauses 9.1.4–9.1.7. Ast(min) = 0.0025twLw. If the thickness is greater than or
equal to 200 mm, reinforcement should be provided in two layers. The maximum
allowable spacing is the smallest of Lw/5, 3tw, and 450 mm. The chosen diameter

of the bar should be less than tw/10. The area of vertical reinforcement in the
boundary element should be greater than 0.6 per cent and less than 4 per cent
(Clause 9.4.4).
Step 4: Design for shear. Calculate the nominal shear stress,
where dw = 0.8Lw. Using Table 19 of IS 456, find the design shear strength of
concrete, Ʈc. In addition, find the value of Ʈc,max from Table 20 of IS 456 for the
chosen grade of concrete. If Ʈv ≥ Ʈc,max, then the thickness of the section should
be increased and the calculation repeated. If Ʈv ≤ Ʈc, the minimum percentage of
horizontal steel (0.25% of gross area) specified in Clause 9.1.4 is adequate. If the
Ʈv ≥ Ʈc, calculate the shear to be carried by the stirrups as
From this, the spacing of two-legged stirrups of chosen diameter can be calculated
as
where Ah is the area of the two legs of the chosen diameter of stirrup.
Step 5: Design for flexural strength. Calculate the moment of resistance of the
rectangular structural wall as per Annex A of IS 13920.
Calculate (xu*/Lw) and (xu/Lw). if(xu/LW)<(xu*/Lw) than calculate the
= Mn/fck *tw*Lw2
(Xu*/Lw)<(Xu/Lw)<1.0, than calculate the =Mn/fck *tw*Lw2
Using this calculate the Mn.if (Mn>Mu) then the moment (Mu-Mn) should be
resisted by the boundary elements.

Step 6: Design the boundary element. Calculate the c/c distance of boundary
element, Cw. The additional compressive force to be resisted by the boundary
element, in addition to its own axial force, Padd = (Mu − Mn)/Cw. Total load on
column, Pu1 = Pu + Padd. Assuming minimum steel (0.8% of gross area of
boundary element), calculate the nominal axial load capacity, Pn, of the boundary
element as a short column:
Check whether Pn < Pu1; if not, increase the area of steel or the size of boundary
element and repeat the calculation.
Special confining reinforcement should be provided throughout the
boundary element as per Clauses 9.4.6 and 7.4.8. The area of confining steel, Ash,
is given by the greater of
where s is the spacing of confining reinforcement, h is the longer
dimension of the rectangular confining hoop, and Ak and Ag are the area of
confined core and gross area of boundary element, respectively. The spacing s
should be greater than 75 mm and less than 100 mm (Clause 7.4.6). It should also
be less than one-fourth the size of boundary element or 6db, where db is the
diameter of the main bar.
Step 7: Detailing the reinforcement as per the derive.
5.1 Example Solved in Staad Pro.
EXAMPLE: Design the shear wall of a 11-storey building having a dual
system consisting of SMRF and structural walls. The floor to floor height is 33 m.
The design forces in the wall have been obtained from a computer analysis.
Design the structural wall assuming M25 concrete and Fe 415 steel. The following
sizes were assumed in the computer analysis: Length and height of wall are 3 m

and 3 m, respectively, wall thickness is 200 mm, boundary element (column) size
is 450 mm × 450 mm, and beam size is 300 mm × 450 mm.
The rigid characteristic of the pavement is connected with durability or
flexure energy or slab action so the load is distributed over a wide part of sub-
grade land. Rigid pavement is laid in slab with steel reinforcement.
Step 1: Geometry
Length = 3 m
Width = 3 m
Height = 3 m
No. of Storey = 11
Step 2: Define Properties

Step 3: Define Supports
Step 4: Define Loads And Load Combinations

Step 5: Define Shear wall Panels
Step 6: Define Shear Wall Parameters

Step 7: Analysis BM & SF

Step 8: Analysis Design
5.1 Example Solved in Manually.
EXAMPLE: Design the shear wall of a 10-storey building having a dual
system consisting of SMRF and structural walls. The floor to floor height is 3.1 m.
The design forces in the wall have been obtained from a computer analysis.
Design the structural wall assuming M25 concrete and Fe 415 steel. The following
sizes were assumed in the computer analysis: Length and height of wall are 4 m
and 31 m, respectively, wall thickness is 200 mm, boundary element (column)
size is 450 mm × 450 mm, and beam size is 300 mm × 450 mm.

Step 1 Check for boundary columns requirement. Although a boundary element
was considered in the analysis, let us check whether it is required, assuming a
rectangular wall of size 4000 mm × 200 mm.
From Table 16.8, maximum design forces at the base of the wall
Since the stress in the extreme fi bre exceeds the limit, boundary element should
be provided (Clause 9.4.1 of IS 13920). The boundary element provided in the
form of column of size 450 mm × 450 mm is shown in Fig.

Fig: Dimensions and stress distribution of structural wall
Step 2 Check for section requirements (Clause 9.1.2 of IS 13920).
Thickness of wall = 200 mm > 150 mm
Hence, minimum thickness is satisfied.
Step 3 Check for minimum reinforcement (Clause 9.1.4)
Thickness is 200 mm; hence, reinforcement should be provided in two layers
(Clause 9.1.5). Provide 8 mm bars at 200 mm c/c in the two layers in both
horizontal and vertical directions; area provided = 251 × 4 × 2 = 2008 mm2.
Maximum allowed spacing (Clause 9.1.7):
Smaller of Lw/5, 3tw, and 450 or 4000/5 = 800, 3 × 200 = 600, and 450
450 mm > 200 mm

Hence, the adopted spacing is adequate. As per Clause 9.1.6, diameter of bar
should be less than tw/10 = 200/10 = 20 mm > 8 mm. Hence, the adopted
diameter is sufficient.
Maximum area of vertical reinforcement in boundary element (Clause 9.4.4)
Step 4 Design for shear (Clause 9.2 of IS 13920).
Effective depth of wall dw = 0.8Lw = 0.8 × 4000 = 3200
As per Table 19 of IS 456, design shear strength for M25 concrete with 0.25 per
cent steel is 0.36 N/mm2.
tc,max (Table 20 of IS 456) = 3.1 N/mm2 > 1.925 N/mm2
Hence, shear has to be carried by shear reinforcement.

Step 5 Design for flexural strength (Annex A of 13920).
Axial load on wall, Pu = 3710 kN

The remaining moment, that is, Mu − Mn = 6559 − 5375.2 = 1183.8 kNm, should
be resisted by reinforcement in the boundary elements.
Step 6 Design the boundary elements. The maximum compressive axial load on
boundary element (column) as per Table16.8, Pu = 2132 kN c/c of boundary
element, Cw = 4 + 0.45 = 4.45 m Additional compressive force induced by
seismic force (Clause 9.4.2 of IS 13920)
Total axial load = 2132 + 266 = 2398 kN
Size of the boundary element = 450 mm × 450 mm
Ag = 450 × 450 = 202.5 × 103 mm2
Assuming minimum longitudinal reinforcement of 0.8 percent of gross area, as
per Clause 9.4.4 of IS 13920
As = × 0.008 × 202 5 1 × 0 1 3 3 = 1.62 ×10 mm2
Axial load capacity of boundary element acting as short column

Confining reinforcement in boundary element
Special confining reinforcement should be provided throughout the height of the
boundary element (Clauses 9.4.6 and 7.4.8 of IS 13920)
Fig Reinforcement details of structural wall

CHAPTER-6 CONCLUSION
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.
Not only had its strength, in order to accommodate huge number of
population in a small area tall structured with shear walls are considered to be
most useful.
Hence for a developing nation like India shear wall construction is
considered to be a back bone for construction industry.

CHAPTER-7 Reference
1. Design of-Reinforced-Concrete-Structures-2014 by N. Subramanian
2. Structural wall for resisting earthquake engineering by S.K. Duggal
3. Design of Concrete Structures by Author H. Nelson, David Darwin and
Charles W. Dolan 14th Edition.
4. Fintel, M. 1991, ‘Shear Walls: An Answer for Seismic Resistance?’,
Concrete International, ACI, Vol. 13, No. 7, pp. 48–53.
5. IS: 13920:1993 for Ductile detailing
6. IS: 875 Part 3 for wind load

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