chp 5

Question 1

reason for required minimum bar spacing

Answer 1

to obtain adequate compaction and bond

Question 2

minimum horizontal pitch (for individual bars or pairs of bars)

Answer 2

• 75mm (space must be allowed for insertion of poker vibrator)
• 100mm (for pairs of bars)

Question 3

minimum vertical pitch (for individual bars or pairs of bars)

Answer 3

25mm or bar diameter, whichever greater

Question 4

maximum pitch distance (for individual bars or pairs of bars)

Answer 4

• tension bars - 165mm
• compression bars - 300mm

Question 5

for beam with 1000mm depth or more

Answer 5

bars 16ø should be placed along the sides inside the links at a maximum pitch of 250

Question 6

link spacing (min. pitch, max. pitch, max. lateral pitch of legs)

Answer 6

• min. pitch - 100mm or (50+12.5(No. of legs))mm, whichever greater
• max. pitch - 300mm or 0.75ø or 12ø of compression bar, whichever is smaller
• max. lateral pitch of legs - 600mm or 0.75ø

Question 7

limit state design

Answer 7

• ultimate limit state
• limit state of servicability

Question 8

describe ultimate limit state

Answer 8

the failure of the structure when subjected to extreme values of action

Question 9

describe limit state of servicability

Answer 9

the structure must remain functional for its intended use subject to routine loading

Question 10

types of loads

Answer 10

• permanent actions (g)
• variable actions (q)
• accidental actions (a)

Question 11

types of permanent actions

Answer 11

• self weight of structure
• fixed equipment
• road surfacing

Question 12

types of variable actions

Answer 12

• imposed load on building floors
• wind actions
• snow loads

Question 13

types of accidental actions

Answer 13

• explosion
• impact loads