DCS-II.pdf

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Code

trto. SLR-UM

-

56

r ilililt

il1il

lilltll

llllllll

lll

lllll

lllllill

Seat

No.

Seat

No.

Centre

For Otfice

Use

Only

Code

No.

Seat

No. in words

Signature

of Jr. Supervisor

B.E.

(Civil)

(Part

-

ll) Examination,2014

DESIGN

OF CONCRETE

STRUCTURES

-

II

Day and

Date

:

Tuesday,

27'5'2014

Time :

10.00 a.m.

to

1.00

p.m. Max. Marks:

100

Day &

Date

Language

of

Answer

Examination

Paper

No.

Subject

Marks

-

Out

of

Signature

of

Examiner

Examination

(Paper

For Office

Use

only

Code No.

lnstructions:

.

Question

No.

1

is MCQ,

which is compulsory

and

to be

solved

in

30

min.,

while

solving

MCQ

lS 456-2000

andl.S.

1343

are

not allowed

to

refer.

Write the correct

option

of

each

question.

S/.

No.

1

to

1 1

carries

one

mark

each

and

Sl.

No. 13

to

15

carries

two

marks and Sl.

No.

12

three

marks.

For solving

MCQ

l.S.

456and

l.S.

1343 are

not allowed.

o

a

P.T.O.



ililIIililIilI

flilililfltilII

ilflfi

ilfl

IilI

-68*

*s*$u**

\\

h-\LJ-

Q*'"

MCQ/Objective

Type

euestion

paper

Duration

:30

Minutes

1.

Write

the

correct

option

in

the

box

given

t

I

:

1)

ln

case

of 2-way

slab,

the

limiting

defrection

of

srab

is

I

a)

Primarily

a

function

of

long

span

b)

Primarily

a

function

of

short

span

c)

lndependent

of

long

span

and

short

span

d)

Dependent

on

both

long

span

and

short

span

2)

Effective

span

of

continuous

beam,

if

the

width

of

support

is

greater

than

1/12

0t

crear

span

or

600

mm

whichever

is

ress

for

end

span

with

one

end

free

and

other

continuous

shall

be

t

a)

crear

span

+

d/2

--

t

b)

Clear

span

+

d

Marks:20

n

T

J

v

?-

)

Clear

span

+

1/2width

of

discontinuous

support

d)

crear

span

+

d/20r

crear

span

+

1/2width

of

discontinuous

support

whichever

is

less

3)

The prestressed

concrete

beam

is

suitable

for

a)

Largespans

b)

Short

spans

c)

Both

large

and

short

spans

d)

None

of

these

a)

The profire

of

cabre

in

prestressed

concrete

beam

is

usuaily

similarto

a)

Shear

force

diagram

c)

Noneofa)andb)

b)

Bending

moment

diagram

d)

T.

M.

diagram



ililril il]t l]ll ll

ilililI l]

lllll

llllllll

5)

ln

two

way

restrained slab the middle strip being

times width.

b) 3t4

d)

112

6)

ln

pre

stressed

concrete

section

the

section

is

effective.

a)

Above

N.A.

b)

Below

N.A.

c)

Partially above and

below

d)

Entire section

7) For

two

way slab for

max. B.M.

per

unit

width

in

a

slab in longer

direction

is

a)

crrWl*2

b)

crrw(

d)

cr*Wlfr

)

u*wlf

B)

The

stability

of a

retaining

wall

is

checked

for

which

of

the

following condition

-3- SLR.UM

-

56

a) 1lB

c)

114

9)

ln

design

of rectangular

P.S.C. beam

the

eccentricity

of

tendons

is

given

by

a)

2 Md +Mll2p

c)

2

Md

+2Mllp

10)

The

safe stress

in

concrete

at

transfer

is

fck

a)

Overturning about toe

c)

Both of

above

a)

0.3

c)

0.5

b) Overturning about heal

d)

None

of

the

above

b)

Md +

2Mll2p

d)

Noneoftheabove

b)

0.4

d)

0.6

11)

How is the deflection

in RC beam controlled as

per

lS 456

a)

By

using

large aspect ratio

b) By

using small

modular

ratio

c)

By

controlling

span to depth ratio

d) By

moderating

water

cement

ratio



j

rilIililillll

lllllIllllllllllllllllllllllll

SLR-UM

-

56

12)

Asimply

supported

isotropically reinforced square slab

of

side 4

m

is subjected

to

a

service

load

of 6

kPa

with

thickness

120

mm

the

moment

of reistance

required

as

per

yield

line

theory

is

t

b)

9

kNm/m

d)

13.2

kNm/m

13)

ln a load

balanced

Prestressed

Concrete

beam

under

self-load

the

cross

section

is subjected

to

t

b)

Bending

stress

d)

Axialand

bending

stress

14)

From

limiting

deflection

point

of

view,

use

of

high

strength

steel

in RC

beam

results

in

a)

Reduction

in

dePth

c)

lncrease

in dePth

15)

tn

case of

pre

tensioned

RC

beams

a) Shrinkage

of

concrete

is

of

order

3x104

b)

Relaxation

of

steelcan

be

ignored

c)

Only

one

wire can

be

stretched

at a

time

d)

Even

mild steel

can be

used

for

pre

stressing

a)

9

kN-m

c)

13.2

kNm

a)

Axial

stress

c)

Axial

and

shear

stress

b)

d)

No change

in

depth

lncrease

in width

,



I[]iltil]tilll

llllllllllllllllll

llilllll

Seat

No.

Day

and

Date :Tuesday,

27-5-2014

Time

:

10.00

a.m. to

1.00

p.m.

SLR-UM

-

56

B.E.

(Givil)

(Part

-

ll) Examination,

2014

DESIGN

OF

CONCRETE

STRUCTURES

-

II

Marks

:80

-5-

ll.

lnstructions

:

o

Answer

any

three

questions

from each

Section.

o

lJse

of

l.S.

456 and

non-programmable

calculator

is allowed.

o

Draw

neat

sketch's

where

required

and

assume suitable

data

with clear

notification.

SECTION

_

I

Design an open

well type stair

for

a college

building

using

the following

data

:

Floor

to floor

height

=

3.6

m

No. of

flights

per

floor

=

3

Size

of steps

=

150 mm riser and 300

mm tread

Landings

are supported all around

by

walls and by beams

of

width 300

mm at

floor levels.

Thickness

of

wall

=

300

m

Use M20

concrete

and

Fe-500

steel.

13

Design

a reinforced

concrete

slab

for a room

of

clear

dimension

3.65

m

x

5.0

m.

The slab

is

supported

all around on

walls of

width

300

mm. The

slab

has

to carry

a

live load of

4 kN/m2 and

floor finish

1

kN/m2.

Use

M20 concrete

and Fe-500

steel.

Assume corners are

held down. Sketch the

details

of

reinforcement.

13

Design the stem slab

of a counterfort

retaining

wall, if the

height of

wall above

the

ground

level

is

5

m.

SBC

of

soil

is

200 kN/m2, angle of

internal friction

is

30'

and

unit weight

of

back fill

is 18 kN/m2. Keep spacing

of

counterfort as 3

m.

Coefficient

of

friction between soil and

concrete

is

0.5. Use

M20 mix and

Fe

500

grade

of steel.

14

v-

ilt.

lv.



SLR.UM

-

56

1 ililil1

ililililililililililil

ililililililt

V.

Design

a

three span

continuous

rectangular beam

of

span 6.50

m

each

to

catry

a

dead

load

of

15

kN/m

and

live load

of

9.5 kN/m.

The

beam is

supported

by

columns.

Use M20

mix

and

Fe

500

grade

of

steel.

Sketch

the reinforcement

details.

13

SECTION

_

II

Vl.

A

P.S.C.

rectangular

beam

400

mm

x

600 mm

carries

a UDL of

35 kN/m

with

span

6

m.

The

beam

is

applied

with

a

prestressing

force

of

1000

kN

along

a

tendon having parabolic profile with eccentricity

100

mm at center and zero

at

:-

supports.

Calculate the

extreme

stresses

for

the

mid

span

section

by

using

strength

concept,

stress

concept

and load

balancing

concept.

13

Vll.

A PSC

beam 230

mm

wide

and 450

mm

deep

has

a

span

of

10

m. The

beam

is

prestressed

by

steel

wires

of

area

350

mm2

provided

at a

uniform

eccentricity

of

75

mm

with

an

initial

prestress

of

1250

N/mm2.

Determine

the

percentage

loss

of

stress

in the

wire

if

the

beam

is

post

tensioned.

tr

-ox1O5N/mm2

s-a

tr

-

e.5

x

105

N/mm2

c-o

.

Relaxation

loss

percentag

e 5"/o,

esh

=

1 .9

x

1O-a

Creep

strain

25

x

10-6 N/mm2

of

stress

Anchorage

slip

=

1.25

mm

-_

Friction

coefficient

=

0.00015/m.

Vlll.

Design

a PSC

I

section

beam

for

the

following

:

Span =

16

Ir,

superimposed

load

=

35 kN/m, cube

strength

of

concrete

at

28

days

is

35

N/mm2.

Safe stress

in

concrete

at transfer

is

0.5 f.n

Allowable

tensile

stress

in

concrete

is

0.279

(l"x)1t2

Safe

stress

in

steel

is 1500

Mpa

Total

loss

of stress

20%

Ultimate

stress

in

steel

i

500

N/mm2.

13

14



rf

s

ll

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llll llll

SLR.UM

-

56

lX.

Figure

1 shows

a

PSC beam 400

mm

wide and 800 mm

deep.

Determine

the

horizontal,

vertical

and

shear

stresses

at

the

point

Q

in

the end

block.

Find

also

the

principal

stresses

at

Q.

The

tendons

are

placed

at

an

eccentricity

of

100

mm.

The

anchor

plate

is

300

mm

wide and

200

mm deep.

Prestressing

force

in

.

tendons

is 1000

kN.

Assume

Kq

-

0.251,Kr=-2.47.

T

$$mm

i

trI

tt0*nr

,L

I

,

? 0$n1

I

t

P{6arm

J-

-.{-600rnrr

(;)

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