slabsBeamDetailing

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1

Design and drawing of RC
Structures

CV61

Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore
-
570 008

Mob: 9342188467

Email: gss_nie@yahoo.com

2

DETAILING OF

BEAM &SLAB

3

Learning out Come


Review of detailing of beams


Continuous rectangular beams


Cantilever rectangular beams


Flanged beams


Introduction to detailing of slab


One way slab

4

5

PROBLEM No. 3


Draw the Longitudinal section and two cross sections one near the
support and other near the mid span of a RCC continuous beam with
the following data:

Clear span of beams = 3m each

Width of beam = 200mm

Overall depth of beam = 300mm

Width in intermediate supports = 200 mm

Main reinforcement = 4 Nos
-
12 mm diameter bars with 2 bars bent up

Anchor/hanger bars= 2
-
10 mm diameter

Stirrups = 6 mm diameter @ 300 mm c/c.

Materials : HYSD bars and M20 grade concrete

6

PROBLEM No. 3

7

PROBLEM No. 4


A rectangular beam of cross section 300 x 450 mm is
supported on 4 columns which are equally spaced at 3m
c/c. The columns are of 300 mm x 300 mm in section. The
reinforcement consists of 4 bars of a6 mm diameter (+ve
reinforcement) at mid span and 4 bars of 16 mm diameter at
all supports (
-
ve reinforcement). Anchor bars consists of a
2
-
16 mm diameter. Stirrups are of 8 mm diameter 2 legged
vertical at 200 c/c throughout. Grade of concrete is M20 and
type of steel is Fe 415.

Draw longitudinal section and important cross sections.

8

PROBLEM No. 4

9

10

PROBLEM No. 5


Draw to scale of 1:20 the Longitudinal section and two cross
-
section of a cantilever beam projecting 3.2 from a support using
following data

Clear span



=3.2m

Overall depth at free end

= 150 mm

Overall depth at fixed end

= 450 mm

Width of cantilever beam

= 300 mm


Main steel = 4
-
28 mm dia with two bars
curtailed at 1.5m from support

Anchor bars



= 2 Nos. 16 mm dia

Nominal stirrups


= 6mm dia at 40 mm c/c

Bearing at fixed end


= 300 mm

Use M20 concrete and Fe 415 steel

11

PROBLEM No. 5

12

PROBLEM No. 6

A cantilever beam with 3.2m length is resting over a masonry wall and
supporting a slab over it. Draw to a suitable scale Longitudinal section,
two cross
-
sections and sectional plan with the following data:

Size of beam = 300 mm x 350 mm at free end and 300 mm x 450 mm at
fixed end and in the wall up to a length of 4.8m

Main steel: 4 nos. of 25 mm dia bars, two bars curtailed at 1.2m from
free end

Hanger bars: 2 nos. 16mm.

Stirrups: 6mm dia 2 legged stirrups @ 200 mm c/c the support length
and @100 mm c/c from fixed end up to length of 1m @ 150mm c/c up to
curtailed bars and remaining @ 200 c/c.


Use M20 concrete and Fe 415 steel


13

PROBLEM No. 2

14

15

PROBLEM No. 7


A beam has following data


Clear span = 4m


Support width = 300mm


Size of web = 350 x 400


Size of flange = 1200 x 120mm


Main reinforcement in two layers : 3
-
20 tor + 3
-
16 tor and to be
curtailed at a distance 400 mm from inner face of support


Hanger bars: 3
-

20 tor


Stirrups: 2L
-
8 tor @ 200 c/c


Use M20 concrete and Fe 415 steel

Draw longitudinal and cross section if the beam is

1.
T
-
beam

2.
Inverted T
-
beam

3.
L
-
Beam

16

PROBLEM No. 5

17

Dr.G.S.Suresh

18

Introduction


Used

for

covering

spaces

in

the

form

of

roof

or

floor



Slab

may

be

supported

on

walls

or

beams

or

columns

.



Slab

supported

directly

by

columns

are

called

flat

slab



One

Way

Slab



Two

Way

Slab


Dr.G.S.Suresh

19

Introduction


Slabs

could

be

simply

supported,

continuous

or

cantilever



In

two

way

slab

the

corners

may

be

held

down

by

restraints

or

may

be

allowed

to

lift

up



Additional

torsion

reinforcement

is

required

at

corners

when

it

is

restrained

against

uplifting

as

shown

in

Fig

Dr.G.S.Suresh

20

Introduction

Dr.G.S.Suresh

21

Introduction


Thickness

of

the

slab

is

decided

based

on

span

to

depth

ratio

specified

in

IS
456
-
2000
.

Min

reinforcement

is

0
.
12
%

for

HYSD

bars

and

0
.
15

%

for

mild

steel

bars
.



The

maximum

diameter

of

bar

used

in

slab

should

not

exceed

1
/
8

of

the

total

thickness

of

slab



Maximum

spacing

of

main

bar

is

restricted

to

3

times

effective

depth

or

300

mm

which

ever

is

less



For

distribution

bars

the

maximum

spacing

is

specified

as

5

times

the

effective

depth

or

450

mm

which

ever

is

less


Dr.G.S.Suresh

22

Introduction


Generally

15

mm

to

20

mm

cover

is

provided

for

the

main

reinforcements



Alternate

main

bars

can

be

cranked

near

support

or

could

be

bent

at

1800

at

the

edge

and

then

extended

at

the

top

inside

the

slab

as

shown

in

Fig



Curtailment

and

cranking

of

bars

and

is

shown

in

Fig


Dr.G.S.Suresh

23

Introduction

Dr.G.S.Suresh

24

Introduction


Torsion

Reinforcement

shall

be

provided

as

shown

in

Fig
.


Dr.G.S.Suresh

25

Torsion Reinforcement

Dr.G.S.Suresh

26

Torsion Reinforcement

Dr.G.S.Suresh

27

Typical One Way slab

Dr.G.S.Suresh

28

Typical Two Way slab

29

PROBLEM


Prepare a detailed structural drawing of one way continuous slab for a
hall of clear dimensions 7m wide and 11.77 m long, use following data


Centre to centre distance of supporting beams = 3.0 m


Span of the beams = 7.23m


Beams are supported on walls of 0.23 m thickness


C/s of beam = 230 x 450 mm


Grade of concrete : M20


Type of steel : Fe415


Clear cover : 20 mm


Slab thickness: 150 mm


Beam depth is inclusive of slab depth, The hall is having walls on
all 4 sides



30

PROBLEM


Main positive reinforcement @ end span = 8mm
diameter @100 c/c


Main reinforcement in other interior panels = 8 mm
diameter @ 200 c/c


Negative reinforcement @ all supports = 8mm diameter
@ 200 c/c


Distribution steel= 8mm diameter @ 200 c/c

31

PROBLEM

32

33

No. 1

34

No. 2

35

No. 3

36

No. 4

37

No. 5

38

Do it Yourself


1
.

Draw

the

longitudinal

section

and

typical

cross

sections

(

at

centre

and

support),

and

show

the

reinforcement

details

in

a

simply

supported

rectangular

beam

of

size

300

mm

x

500

mm,

clear

span

5
m

supported

on

walls

of

0
.
3
m,

use

a

suitable

scale


Reinforcements
:


Main
:

4

No
.

16
mm

dia

with

2

No
.

cranked

at

1
m

from

centre

of

support
.

Stirrup

holders

2

Nos
.

of

12

mm

dia


Stirrups
:

2

legged

8

mm

dia

stirrups

at

250

mm

c/c

in

the

central

2
m

span

and

2

legged

8

mm

dia

stirrups

at

150

mm

c/c

in

the

remaining

portion
.

Assume

concrete

M

20

grade

and

steel

Fe

415
,

and

suitable

cover
.

Prepare

the

bar

bending

schedule

and

calculate

quantity

of

steel

and

concrete

required
.


39

Do it Yourself


2
.

Prepare

the

bar

bending

schedule

and

estimate

quantity

of

steel

and

concrete

after

drawing

the

longitudinal

and

cross

section
.

Other

details

are


Span

of

beam

=

4
.
2

m


Cross

section

at

support

end

300

x

600

mm

and

cross

section

at

free

end

300

x

150

mm


Reinforcements
:


Main

tension

steel
:

4
-
20

mm

dia,

2

bars

are

curtailed

at

a

distance

of

2
m

from

free

end


Hanger

bars
:

1
-
12

mm

dia


Two

legged

stirrups

8
mm

dia

@

140

mm

c/c

for

full

length
.


40

Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore
-
570 008

Mob: 9342188467

Email: gss_nie@yahoo.com