1.The constant β in βAg0fy/γm0 for tensile strength of angle section does not depend on :
a) area of unconnected leg
b) size of outstanding leg
c) ultimate stress of material
d) thickness of outstanding leg
Explanation: β = 1.4 – 0.076[(bs/Lc)(w/t)(fy/fu)] , where fu and fy are ultimate and yield stress of material, w and t are size and thickness of outstanding leg respectively, bs is the shear distance from edge of outstanding leg to nearest line of fasteners, Lc is the length of end connection measured from centre of first bolt hole to centre of last bolt hole in the end connection.
2. Which of the following is correct?
a) β ≥ fuγm0/fyγm1
b) β ≥ fuγm1/fy γm0
c) β ≤ fuγm0/fyγm1
d) β ≤ fuγm1/fy γm0
Explanation: Tdn = (0.9Ancfu/γm1) + βAg0fy/γm0, where β = 1.4 – 0.076[(bs/Lc)(w/t)(fy/fu)] and β ≤ fuγm0/fyγm1, β ≥ 0.7.
3. What is the maximum value of β in βAg0fy/γm0 for tensile strength of angle section?
a) 1.2
b) 0.9
c) 1.4
d) 0.7
Explanation: Tdn = (0.9Ancfu/γm1) + βAg0fy/γm0, where β = 1.4 – 0.076[(bs/Lc)(w/t)(fy/fu)] and β ≥ 0.7.
4. What is the value of partial factor of safety for material α for preliminary design for angle section as per IS code for three bolts in connection?
a) 0.6
b) 0.7
c) 0.8
d) 1.0
Explanation: As per IS code, the equation for preliminary design of angle tension member with partial factor of safety for material is given by Tdn = αAnfy/γm1, where α = 0.6 for one or two bolts, 0.7 for two bolts, 0.8 for four or more bolts in the end connection or equivalent weld length.
5. Which of the following statement is correct?
a) strength of members with punched holes is less than members with drilled holes
b) strength of members with drilled holes is less than members with punched holes
c) strength of members with punched holes is greater than members with drilled holes
d) strength of members with punched holes is equal to members with drilled holes
Explanation: Strength of members with punched holes may be 10-15% less than the members with drilled holes. This is due to strain hardening effect of material around punched holes and consequent loss of ductility.
6. The presence of holes _____ the strength of tension member
a) does not affect
b) improves
c) reduces
d) doubles
Explanation: The bolt holes reduce the area of cross section available to carry tension and hence reduce the strength of tension member
7. Staggering of holes __________ the load carrying capacity of tension member
a) reduces
b) improves
c) does not affect
d) halves
Explanation: Staggering of holes improves the load carrying capacity of tension member for given number of bolts. The failure paths may occur along sections normal to axis of member, or they may include zigzag sections when more than one bolt hole is present and staggering of holes may help to make the net area minimum.
8.The actual failure mode in bearing depends on
a) length of metal plate
b) length of bolt
c) hole diameter
d) bolt diameter
Explanation: The actual failure mode in bearing depends on end distance, bolt diameter and thickness of the connected material
9. The shear lag effect _____ with increase in connection length
a) increases
b) reduces
c) does not change
d) doubles
Explanation: The shear lag effect increases with increase in connection length. The shear lag reduces the effectiveness of component plates of tension member that are not connected directly to gusset plate.
10. Which of the following statement is correct?
a) increase in ductility reduces strength of member
b) reduction in ductility increases strength of member
c) increase in ductility does not affect strength of member
d) reduction in ductility reduces strength of member
Explanation: Reduction in ductility tends to reduce strength of member. An increase in ductility tends to increase net section strength by allowing better plastic redistribution of stress concentration over cross section.