OUTLINE introduction classification loads materials used Type of reinforcement RCC construction methods in RCC Analysis and design Detailing Basic Rules Site visit video

1. BEAM
S

2.  Beams are an important class of
structural element, and are
normally horizontal.
 The primary function of building
structures is to support the major
space enclosing elements:
commonly these are floors, roofs
and walls. The total behavior of
any building structure can be
complicated but frequently two
types of sub-structure can be
identified; vertical elements
(associated with walls) and
horizontal elements (associated
with floors and roofs).
 Vertical elements are columns,
walls and lift cores etc.
Horizontal elements include
slabs, trusses, space frames and
most importantly beams.
IntroductionIntroduction

3.  A beam is a structural
element that is capable of
withstanding load primarily
by resisting against bending
(tension). It forms a vital part
of any RCC structure.
 But beams have been around
for many ages. In fact, the
concept of beams is
estimated to have evolved in
most civilizations as early as
construction of dwellings
itself.
 Obviously, they have evolved
and developed with the
passage of time due to the
change in techniques,

4.  The primary purpose of beams is
to transfer the loads from the
superimposed structure onto the
columns or foundation as the
case may be.
 These loads may be both vertical
(e.g. self weight of slab or beam,
live loads) or in some cases
horizontal (e.g. wind,
earthquake) .
 Accordingly, it becomes
necessary to classify beams
according to the imposed loads,
types of joints at their ends
(supports) , materials used in
construction etc.

5. Classification based on loads
 Simplysupported- This is a beam
supported on the ends which are free
to rotate and have no moment
resistance. The deflections though
are zero at both the ends. Therefore
it has two reactions at the supports
to resist the imposed load.
 Fixed - A beam supported on both
ends and restrained from rotation. It
has both its ends fixed rigidly into
the support. Hence, deflection,
bending moment and slope of the
beam are all zero at the ends. This is
the most commonly used type of
beam in construction. In total there
are 6 reactions.

6.  Over hanging - A simple beam
extending beyond its
support on one end. A part
of the beam acts as a
simple cantilever or free
end. The free end has
maximum deflection.
 Double overhanging - A simple
beam with both ends
extending beyond its
supports on both ends. This
beam has two overhangs
instead of one as in the
previous case.

8.  Continuous - A beam
extending over more than
two supports. It cannot be
analyzed by conventional
techniques and hence
requires several specially
designed techniques to
solve due to insufficient
conditions of equilibrium.
 Cantilever - a projecting
beam fixed only at one end
while the other is free and
unsupported.
 Trussed - a beam
strengthened by adding a
cable or rod to form a truss.

9. classification based on shape
 Any structure requires beams to transfer the
imposed loads to the vertical members.
Moreover, structural limitations specify certain
necessary conditions of shape, geometry and
locations of beams. Hence, different beam sizes
and shapes are prevalent in constriction
nowadays. some of the moist common are -
 1. Rectangular - Most commonly used beam and
has cross section in the shape of a rectangle of
specific breadth (b) and depth (d). The ratio of
b/d is limited based upon the code of practice.
 2. T- Beam - This beam was developed and
effectively used to reduce the cost of
construction by placing the beams along with
the slab during concrete placement. It has two
major zones, the flange and web. The flange is
usually located in the slab while the web
protrudes like the conventional rectangular
beam. This effectively decreases the amount of
concrete required for bearing the same imposed
Rectangular beamT beam

10. L Beams - This is same in principle to that of
T beam but used in cases where
architectural limitations impose
restrictions on flange width for a T beam.
I section - this is the most commonly used
beam made of steel. It has two flanges
and a central vertical web connecting the
two. The dimensions and design of the
beam is done according to the code
being used.
Channel section - Commonly known as a C
section, this is used in corners or
situations which do not require complete
flange width. In certain cases, two C
sections may be held together back to
back to form an I section.
Angles - Steel angles are usually used for
bracket connections under tension or in

11. Classifications based on material used
 As beams have been around for quite a
long time, they have evolved
continuously with the latest materials
that have been used for construction in
various times.
 Therefore, according to the primary
material used, beams are classified as
under -
 1. Wooden beam - herein wood is the
primary material, still widely used for
cheaper and temporary structures.
widely prevail-ant in USA
 2. Stone beams - Obsolete nowadays, but
used extensively in various historical
buildings and monuments.

12. 3. Fletched beam - a combination of
wood and metal caps.
4. Steel or Metal beams - Made of
steel or Aluminum. These are a
recent innovation compared to the
other materials, and they provide
more strength for lesser cross
section than wooden or concrete
beams. Usually are prefabricated
off site and are assembled at the
site.
5. RCC beams - These are the most
prevailing type of beams. They
consist of concrete sections that
have steel reinforcement in them
to provide tensile strength

13. Classification based on type of reinforcement
 Singly Reinforced Beam- This has
steel reinforcement only one side,
that is tension face. It is used
when there is no restriction o n the
depth of the beams. It is
practically rare to find situations
where this can be effectively done.
This beam is designed based on
the assumption that the depth of
concrete section is enough to
resist the maximum bending
moments that are induced due to
the imposed load condition.
 Doubly Reinforced Beams - This
contains steel in both tension and
compression zones. The depth of
the beams is not sufficient to
withstand the external moments
and hence extra steel is provided
in the compression zone. This is
practically more common.

14. RCC
 Concrete is good in resisting compression
but is very weak in resisting tension.
 Hence reinforcement is provided in the
concrete whenever tensile stress is
expected.
 The best reinforcement is steel, since tensile
strength of steel is quite high and the bond
between steel and concrete is good.
 Reinforcements are usually in the form of
mild steel of ribbed steel bars.
A cage of reinforcement is thus prepared as
per design requirements, kept in a formwork
and then concrete is poured.
 After the concrete hardens, the formwork is
removed. The composite material of steel
and concrete is now called RCC. It acts as a
structural member and can resist tensile as
well as compressive stress very well.

15. Construction Methods in RCC Beams
 Cast in site- Refers to the construction which
is carried out the building site. For
reinforced concrete beam, Reinforcing
steel bars are placed within the
formwork and then the concrete is
poured. Plastic tipped metal, or plastic
bar chairs are used to hold the
reinforcing steel bars away from the
bottom and sides of the frame work, so
that when the concrete sets its.
 Precast - Concrete beam and block floors
are constructed using prestressed
concrete beams supporting standard
concrete blocks spanning between ‘T’
beams. These are available in a range of
sizes to suit various spans and loads.
Individual concrete blocks are laid
between the precast beams to form an

16. Analysis and design
 The basic function if any structure or
construction is to provide a safe and useful
enclosure. Obviously, this requires
resistance to various loads on behalf of the
structure.
 As we have seen in the initial slides, there
can be many types of loads, based on
magnitude, point of application, and nature
of action etc.
 As architects it is essential to understand
the mechanism involved in structures and

17. Analysis
 As we have understood, it is very essential to
understand the various loads acting on the structure and
the combined effect that they produce on the beam. This
process of evaluation is known as analysis.
 IN simple words Structural analysis is the determination
of the effects of loads on physical structures and
their components.
 There are innumerous methods to analyze structure and
specifically beams. Each of these has its own
advantages and disadvantages, and can be used based
on the type of beam, load conditions and the degree of
accuracy required. Some of the most commonly used
methods are
 1.Slope Deflection Method
2. Moment Distribution Method
3. Kani's Method
4. Double Integration Method
5. Matrix Methods

18. Design
 Once the analysis is dealt with, it is necessary to design and create
a beam or member that can withstand the various loads imposed
upon it for a sufficient and significant amount of time without
undergoing failure.
 The three most important failure modes in beams can be
enumerated as -
1. Bending
2. Shear
3. Deflection
 Accordingly, a beam must be designed to withstand and resist
these forces.
 While bending is caused due to moment in the beam, shear is
caused by the action of shear forces and deflection by moments or
forces as the case may be.
 The design of beam, or any other member for that matter, is to be
done based on certain codes of practice or regulations. These code
of practice are governed and managed by organizations that are
entrusted with the duty of assessing, managing and changing as
and when required the various rules and regulations to be followed

19. Detailing

Detailing is one of the most important and fundamental
aspect of any construction. It requires careful
assessment and arrangement of the various
components of RCC members, on behalf of the
architect.
 Good detailing of reinforcements with proper drawings
are essential at the site to provide good construction
process. These drawing generally also include a bar
bending schedule. The bar bending schedule describes
the length and number, position and the shape of the
bar.
The detailing of beams is normally associated with:
 i) Size and number (or spacing) of bars,
ii) Lap and curtailment (or bending) of bars,
iii) Development length of bars,
iv) Clear cover to the reinforcement and
v) Spacer and chair bars.

20.  Steel used in beams may belong to different categories
based on its intended purpose as -
 i) Longitudinal reinforcement at tension and
compression face (Min of two 12 mm diameter bar is
required to be provided in tension) in single or multiple
rows are provided.
 ii) Shear reinforcements in the form of vertical stirrups
and or bent up longitudinal bars are provided. ( The bar
bent round the tensile reinforcement and taken into the
compression zone of an RCC beams are called stirrups)
 iii) Side face reinforcement in the web of the beam is
provided when the depth of the web in a beam exceeds
750 mm. (0.1% of the web area and shall be distributed
equally on two faces at a spacing not exceeding 300 mm
or web thickness whichever is less)

21. Basic rules
 The IS456 has specific rules and guidelines pertaining to various
parameters involved in RCC design.
 EFFECTIVE SPAN
 (a) For simply supported beam and slab: The effective span of a simply
supported beam or slab is taken as the distance between the centre
to centre of support or the clear distance between the supports plus
the effective depth of the beam of slab whichever is smaller.
 (b) For continuous beam or slab: In case of a continuous beam or slab,
where the width of the support is less than 1/12 the clear span, the
effective span shall be worked out by following the rule given in (a)
above.
 In case the supports are wider than 1/12 of the clear span or 600 mm
whichever is less, the effective span shall be taken as under.
 (i)For end span with one end fixed and the other continuous or for
intermediate spans, the effective span shall be the clear span
between supports.
 (ii) For end span with one end free and the other continuous, the
effective span shall be equal to the clear span plus half the effective
depth of the beam or slab or the clear span plus half the width of the
discontinuous support, whichever is less.

22.  Control on deflection is also necessary to prevent structural
behavior of the member being different from the assumption
made in the design. As per Code for beams and slabs, the
vertical deflection limits may be assumed to be satisfied,
provided that the span to depth ratio are not greater than the
values obtained as below.
 (a) Basic values of span to effective depth ratios for spans up to
10m.
 (i) Cantilever 7
 (ii) Simply supported 20
 (iii) Continuous 26
 For spans above 10m, the values in (a) may be multiplied by
10/span in meters, except for cantilever in which case deflection
calculations

23. Maximum Spacing of Sheer Reinforcement
 Maximum spacing of shear reinforcement
measured along the axis of the member
shall be as under
 (i)
 For vertical stirrups
 0.75d or 450mm whichever is less
 (ii)
 For inclined stirrups at 45˚
 d or 450mm whichever is less

24. Site visit
 Location of the site– Jubilee
hills road no.92
 Type of building- Residential

26. Formwork for slab

30. Formwork for the slab.

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