Design of steel and timber structure

measlyincompetentUrban and Civil

Nov 29, 2013 (3 years and 8 months ago)

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1

POKHARA UNI VERSI TY


Level:
Bachelor

Semester


Fall

Year :
2010

Programme:
BE

Full Marks: 100

Course: Design of Steel and Timber Structure
s

Pass Marks: 45

Time : 3hrs.


Candidates are required to give their answers in their own words

as far
as practicable.

The figures in the margin indicate full marks.

Attempt all the questions.


1.


Find the maximum stress on rivet due to load of 75kN inclined at 70
0

to
the horizontal in a bracket connection as shown in fig
ure

if the rivet used
are 8
-
20mm dia power driven shop rivets and the plates connected are 12
mm thick. All
dimensions

in figure are in cm.







15

2.


Design an end connection for a tension member
MC300@36.3kgf/m

with
a 12 mm thick gusset plat
e using lug angles and 20 mm dia.
p
ds rivets.
The design load on the channel is 560 KN.

15

3.


A strut in a roof truss carries an axial compressive load of 200 KN.
Design suitable double angle section for the compression member. The
length of strut between c
/c of intersection is 2.3m. Assume f
y
= 250MPa.

15

4.


Design base
plate of

a column section I.S.H.B. 350 @ 674 N/m subjected
to an axial load of 1100 KN and bending moment of 70 KN
-
m. The safe
bearing pressure of concrete is 4000 KN/m
2
. Assume permissible b
ending
stress in slab base is 185 MPa.

15

5.


Design a beam girder with 6.5m effective span, carrying a udl of 40kN/m
inclusive of self
-
weight over the entire span. The overall depth of the
beam is restricted to 350mm. The compression flange of the beam is
l
aterally supported throughout.

15


2

6.


A fitched beam 20 cm × 24 cm is made by joining two wooden joists each
10cm × 24cm and symmetrically placing a steel plate 2cm × 20cm deep
into grooves cut in the inner faces of the joists. The steel plate is firmly
atta
ched to both the wooden joists. Calculate the moment of resistance of
the combined section and the maximum stress in steel Maximum
permissible flexural stress in timber is 84.0 Kg/cm
2
, E
s

= 2×10
6

kg/cm
2

and E
w

= 1.25 × 10
5

Kg/cm
2
.






15

7.


Write short not
es on: (
Any Two
)

a)

Failure of riveted joints

b)

Advantages and disadvantages of steel structure

c)

Design of purlins in a roof truss

2×5