Indian Agricultural Research Institute (IARI) 2007 Diploma Civil Engineering Theory of Structures- I -- Question Paper
BCE-032
Diploma In Civil Engineering Term-End Examination June, 2007
BCE-032 : THEORY OF STRUCTURES-I
Time : 2 hours Maximum Marks : 70
Note : Question no. 1 is compulsory. Attempt any four questions from the remaining. Total number of questions to be attempted are five. Assume suitable data wherever necessary and mention it clearly. Use of calculator and steel tables is permitted.
1. Choose the most appropriate answer from the given
alternatives : 7x2=14
(i) In determining the bearing strength of a double cover butt joint the thickness of the plate is taken as
(a) the thickness of the main plates connected
(b) the total thickness of both the cover plates
(c) least of (a) or (b)
(d) None of these .
(ii) If T is the actual length of a fillet weld and s is its size, the effective length of the fillet weld is
(a) (/-4s)
(b) (/-2s)
(c) 0-8 /
(d) 0-7 /
(iii) In tension members composed of two flats, angles or tees tacking rivets are provided at a pitch in line not exceeding
(a) 2000 mm
(b) 1800 mm
(c) 1500 mm
(d) 1000 mm
(iv) The maximum slenderness ratio of a compression member carrying compressive loads resulting from dead arid superimposed loads should not exceed
(a) 180
(b) 250
(c) 350
(d) 400
(v) Lacings or battens in compound columns are designed for a transverse shear force of
(a) 1*5% of the axial load
(b) 2-0% of the axial load
(c) 2-5% of the axial load
(d) 3*0% of the axial load
(vi) Rolled steel I-sections are most commonly used as beams because they provide
(a) greater lateral stability
(b) large moment of inertia with less sectional area
(c) large moment of resistance when compared with other sections
(d) All the above
(vii) An I-section purlin of span 4 m in a roof truss is subjected to a uniformly distributed load of 1250 N/m. The purlin will be designed for a maximum bending moment of
(a) 2000 Nm
(b) 2500 Nm
(c) 3000 Nm
(d) 3600 Nm
2. (a) Determine the strength and efficiency of a single rivetted lap joint of 8 mm thick plates using 27 mm diameter rivets at a pitch of 80 mm. Sketch the plan and elevation of the joint. Allowable stresses in rivets in shear 90 MPa, Bearing 270 MPa and Tearing
150 MPa.
7
(b) A single U-butt weld joins two plates of 20 mm and 16 mm thickness. Find the strength of the joint in tension if the width of the plates is 150 mm. Sketch the plan and elevation of the joint. Adopt allowable
tensile stress in butt weld = 142 MPa.
7
3, (a) Draw the influence line diagrams for shear force and
bending moment for a cantilever beam of span 5 m at a section X which is at 3 m from the free end of the beam. 7
(b) For the beam in question 3(a), determine the maximum shear force and bending moment at X when two connected wheel loads of 10 kN each at a fixed distance of 3 m rolls from left to right. 7
4. Analyse the continuous beam shown below and draw the bending moment and shear force diagrams. Calculate the support reactions also. 14
12 kN
2 kN/m
YWVYYYYVVVV-YyN
..... ..........tB
M-3
m
6 m
-x
6 m
5. (a) A tension member consists of two ISA , 150 x75x10 which are connected by their longer legs to a 12 mm thick gusset plate by 16 mm diameter rivets (single row). Find the net effective area of the tension member under the following conditions : 3x3=9
(i) The angles are connected on the same side of the gusset plate and tack rivetted.
(ii) The angles are connected on the same side of the gusset plate without tack rivets.
(iii) The angles are connected on the opposite sides of the gusset plate and are tack rivetted.
(b) Find the strength of the tension member in the
above mentioned three conditions (f = 250 MPa). 5
6. Calculate the safe load carrying capacity of a column shown below. Effective length of the column is 6 m and
steel is of grade f = 250 MPa.
MS Plate 500 x 14 TH
ISMC 400 @ 49-4 kg/m
, 300
ISMC 400 @ 49-4 kg/m
MS Plate 500 x 14 TH
500
The allowable axial compressive stresses for different slenderness ratios are as below :
|
l/r |
o ac |
|
10 |
150 |
|
20 |
148 |
|
30 |
145 |
|
40 |
139 |
|
50 |
132 |
|
60 |
122 |
|
70 |
112 |
|
80 |
101 |
|
90 |
90 |
|
100 |
80 |
|
110 |
72 |
|
120 |
64 |
7. State the two moment area theorems.
A simply supported beam AB of 6 m span carries a load of 12 kN/m over the entire span. Using these moment area theorems calculate the slopes and deflection at the supports and centre of the beam. Adopt E = 2 x 105 MPa and I = 30 x 106 mm4. 14
8. In a trussed roof building, steel trusses are supported on RCC columns. Show the key plan and elevation of the building and explain the following terms : 14
(i) Pitch
(ii) Truss spacing
(iii) Ridge line
(iv) Top chord
(v) Eaves line
(vi) Bottom chord
(vii) Purlin
BCE-032 6 1,000
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Attachment: |
| Earning: Approval pending. |
