57.  Pick up the correct statement from the following :
A. Tacking rivets are used if the minimum distance between centres of two adjacent rivets exceeds 12 t or 200 mm, whichever is less
B. Tacking rivets are not considered to calculate stress
C. Tacking rivets are provided throughout the length of a compression member composed of two components back to back
D.(a) All the above.

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58.  When plates are exposed to weather, tacking rivets are provided at a pitch in line not exceeding, where t is the thickness of the outside plate.
A. 8 t
B. 16 t
C. 24 t
D. 32 t

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59.  When a large value of radius of gyration is not required
A. channels are placed back to back
B. channel flanges are kept inward
C. channel flanges are kept outward
D. none of these.

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60.  Outstanding length of a compression member consisting of a channel, is measured as
A. half of the nominal width
B. nominal width of the section
C. from the edge to the first row of rivets
D. none of these.

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61.  If the unsupported length of a stanchion is 4 metres and least radius of gyration of its cross-section is 5, the slenderness ratio of the stanchion, is
A.60
B.70
C.80
D.90

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62.  If the area of cross-section of a single angle discontinuous strut is 30 cm2 and allowable working stress cor-1 + 0.20 sec1 "I mfa r 4E where P. L and a are axial load, length of the beam and length of the column base respectively.
A. M = P(L ? a)
B. M = ?8 (L ? a)
C. M = ?3 (L + a)
D. none of these.

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63. The most commonly used sections in lateral system to carry shear force in built up columns, are
A. rolled steel flats
B. rolled angles
C. rolled channels
D. all the above.

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