Which one of the following values represents the maximum slenderness ratio of any connection member which normally acts as a tie in a roof truss but can be subjected to possible reversal of stresses from the action of wind or seismic force?
The permissible bending stress in slab base is (fy = 250 N/mm2)
Consider the following stipulations in designing a laced column:
1. Single lacing systems on opposite planes shall preferably be in the same direction so that one is the shadow of the others
2. Lacing bar should be a flat section
3. The slenderness ratio of the lacing bars for compression shall not exceed 180.
4. Laced compression members are to be provided with tie plates at ends.
Which of these observations is/are correct?
The lacing bar may be a flat or angle section. The purpose of lacing is to hold the various parts of a column straight, parallel at a correct distance apart and to equalize the stress distribution between its various parts. The slenderness ratio of the lacing bars for compression shall be less than 145.
Slenderness ratio for single angle single riveted strut should be less than
In ISMC 400 channels placed back to back at a spacing of 26 cm carry an axial load of 160 tonnes. The lacing system should be designed to resist a transverse shear of
The lacing system is designed for a load which is 2.5% of the axial load i.e.,
The thickness of lacing bars for single lacing, system should not be less than
where l = length between the inner end of connections.
Minimum thickness of lacing bars,
for single lacing
for double lacing riveted or welded at intersection.
Which of the following is not a compression member?
Strut is a compression member used in the roof truss and bracing.
Rafter or principal rafter is a top chord member in a roof truss.
Boom is the principal compression member in a crane.
Tie rods are sag rods provided at the crown of truss used in industrial sheds. These cut as tension members and resist the tangential components from the two sides of roof truss.
Permitted maximum slenderness ratio of a steel, column under dead load and live load is
Two ISMC 400 are placed back to back at a spacing of 300 mm and carry an axial ioad.of 160 kN. As per IS : 800 1984 its lacing system should be designed to resist a transverse shear of
Lacing is designed to resist a transverse shear of V = 2.5% of axial force in the member,
Slenderness ratio of the splices for compression members is
Splices used in compression members are assumed to act as short columns with zero slender ness ratio.