Structures Flashcards
0
Q
Scaffolds: rope or wire
A
Rope or wire’s F => 6 intended load
1
Q
Rope Breaking Strength for Block & Tackle
A
B=((W+LWS)/S)F B: rope breaking strength W: weight to be lifted L: frictional loss per part S: #parts or sheaves F: safety factor
2
Q
Scaffolds: Height
A
> 10’: guard, mid, & toe rails
4-10’: only guard rail needed
3
Q
Intended Load, #Parts
A
W/S =< .2B
4
Q
Ramps
A
Recommended: <= 15deg
Never exceed 20deg
5
Q
Pulley Mechanical Advantage
A
free cords running to moving pulley
6
Q
Block & Tackle Rule of Thumb
A
Absent of other info, rule of thumb is for working load to be =< 20% of rope breaking strength.
7
Q
Block & Tackle Default Safety Factor
A
5
