3 Rd Sem Design of Earth Quake Resistant Structures-Jan2010

8/11/2019 3 Rd Sem Design of Earth Quake Resistant Structures-Jan2010

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MSTR

1M

SN

, S

M S RAMAIAH INSTITUTE OF TECHNOLOGY

AUTONOMOUS INSTITUTE

,

AFFILIATED TO VTU)

NG LORE

560 054

SEMESTER END EXAMINATIONS - JANUARY 2010

Course & Branch M.Tech (

Structural Engineering

) Semester: III

Subject

Design of Earthquake Resistant Structures Max. Marks: 100

Subject Code

MSTR3 Duraon 3Hs

Instructions to the Candidates:

1) Answer one full question from each unit

2) Any data missing can be suitably assumed and indicated

3) Relevant IS Codes are permitted

a) Explain the occurrenc

UNIT I

e of earthquakes using plate tectonics theo

ry.

(5)

b) What are plate bound

aries? Discuss briefly the various plate b

oundaries

(15)

2

with sketches.

a) Discuss elastic rebou

nd theory with sketches and its relation

with plate

(15)

tectonics,

b) What are seismic hazards? Discuss the phenomenon of liq uefaction

(5)

3

briefly.

a) Construct a pseudo -

UNIT II

acceleration elastic design spectra with a

damping

(10)

ratio of 2 on a log -

log scale. Adopt asps=4.38 - 1.04 In ; a

sp = 3.38

- 0.67 In and asd

ground conditions.

b) A rigid steel portal fr

= 2.73 - 0.45 In c. Adopt PGA = 0.8g

ame shown in fig.(3b) is subjected to PG

and firm

A = 0.5g.

(10)

Calculate the total displacement at the top and maximum BM in the

column. = 2 , MI for each column is 100 E 06 mm4 and E = 200 Gpa.

L 5Ole N

w w

M r

8 nN --mil

Fig. 3b)

4. a) Compare an elastic design spectra with a response spectra for a specified (10)

ground motion.

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b) Discuss the effects of yielding and damping on the responses during an (10)

earthquake.

UNIT III

5. a) What is base isolation? Discuss different systems used in base isolation. 10)

b) Discuss the effects of infill masonry on rigid frame in resisting lateral 10)

forces.

6. An inner beam - column joint in the ground floor roof of a 12 - storeyed 20)

building located in zone 5 is subjected to the following forces:

Axial load in the column, Pti, = 2000 kN

BM in upper column, M = 225 kNm

BM in lower column, M = 450 kNm

BM in left beam, M = 300 kNm at ends

BM in right beam, M = 200 kNm at ends

Grade of concrete and rebars are M25 and Fe415 respectively

Span of left and right beams are 5m and 4m respectively

Height of column = 3.5m

DL on the beam = 30 kN/m

IL on the beam = 8 kN/m

Design the joint as a strong column-weak beam with the confining steel

and sketch the reinforcement details.

UNIT - IV

7. Calculate the lateral forces on a two storey mathematical model shown in 20)

Fig.7 adopting response spectrum method. The natural periods and

mode shapes shall be obtained by stiffness method. Adopt I = 1.5, R =

3.0 and Z = zone IV. Assume the soil to be medium. Use

CQC method for combining the modal forces. Combined stiffness of each

floor is Kl = 40 E 06 N/m and K2 = 60 E 06 N/m. Masses lumped at each

level is ml = 40 E 03 kg and m2 = 20 E 03 kg. Damping ratio is 5 .

Fig

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8. Explain linear elastic Time-History method of analyzing structural systems 20)

with complete derivations. Discuss the advantages and limitations of the

method.

UNIT - V

9. a) What is steel panel zone? Discuss the behavior and detailing of panel 15)

zone for seismic resistance along with the relevant expressions for

design.

b) Dscuss box action and bands in masonry buldngs. 5)

10. A 14-storeyed building has plan dimensions as shown in fig.10 Two shear 20)

walls are provided in each directions to resist the seismic forces. The

height between the floors is 3.2m and the first floor is 5.2m from the

foundation level with thickness of slab 200mm, floor and roof finishes =

1.8 kN/m2, weight of light partitions = 1.0 kN/m2 and IL = 3.0 kN/m2.

The soil can be taken as hard and the building is located in Bengaluru.

The size of all the beams is 300 x 600 mm and all the columns are

400mm square.. The axial load on each shear wall can be taken as 5500

kN excluding the self weight of the wall. Grade of concrete is M30 for all

the elements and Grade of Rebars are Fe 415. Design the shear wall and

sketch the details. Use equivalent lateral force method.

MLY

r

14r

M

L_J

Fig. 10

J

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3 Rd Sem Design of Earth Quake Resistant Structures-Jan2010