Design a Wall Flashcards
1
Q
How to Design a Wall
A
- Robustness
- Loads
- Capacity
- Design Options
2
Q
Robustness
A
- confinement
- containment
- boundary elements
- shear
3
Q
Loads
A
- tension shifted moment diagram
- linear to allow for higher mode responses
- jd = lw
4
Q
Capacity
A
- coupling effect accounts for 40-60%
5
Q
Design Options
A
- conventionally reinforced
- diagonally reinforced cage
6
Q
conventionally reinforced
A
- only appropriate for small EQ forces and displacements
- more appropriate for slender coupling beams
- performs very badly under large shear
7
Q
diagonally reinforced cage
A
- detail diagonal cages as mini columns (<= 6db)
- extend at least 1.5 Ld into wall for anchorage
- wedges of concrete not required for strength so services
- require basketing to stop diagonal wedges falling out (anchor 100 - 150 mm)
8
Q
containment
A
- extra ties in web for containment of core and preventing buckling of long. bars
- <= lw/3 or 300
- ensures load path maintained when concrete crushed up and prevents falling out
9
Q
confinement
A
- lots of stirrups to confine core
- increase compressive strain (0.008)
- also increases ductility, compressive strength and prevents inward buckling
10
Q
boundary elements
A
- end sections of wall: 0.15 lw
- designed like columns (min 8 bars and h/4 spacing)
- more steel in boundary elements than middle
- ensure multiple cracks and fan cracking
- lumping steel for yielding and elongation of bars
- cracking steel run full height
- enlarged BEs
- staggered lapping
11
Q
shear
A
- horizontal spacing lw//3, 3t, 450
- vertical spacing lw/5, 3t 450
- limit nominal shear stress to prevent diagonal compression failure in PPHZ (< 0.2 f’c or 8 MPa)
