UFC 4-023-03
25 January 2005
Table 4-4 Deformation Limits for Reinforced Concrete
AP for Medium and
AP for Low LOP
High LOP
Rotation,
Rotation,
Component
Degrees
Degrees
()
()
(θ)
(θ)
Slab and Beam Without Tension MembraneA
Single-Reinforced or Double-
-
3
-
2
Reinforced w/o Shear ReinforcingB
Double-Reinforced w/
-
6
-
4
Shear ReinforcingC
Slab and Beam With Tension MembraneA
Normal Proportions (L/h ≥ 5)
-
20
-
12
Deep Proportions (L/h < 5)
-
12
-
8
Compression Members
Walls and Seismic ColumnsD,E
3
-
2
-
Non-Seismic ColumnsE
1
-
0.9
-
A
Requirements for developing tension membrane response are provided in
Park and Gamble 1999 and UFC 3-340-01; the tension membrane effect is
an extension of the yield line theory of slabs and it increases the ultimate
resistance. It cannot be developed when the slab has a free edge.
B
Single-reinforced members have flexural bars in one face or mid-depth only.
Double-reinforced members have flexural reinforcing in both faces.
C
Stirrups or ties meeting ACI 318-02 minimums must enclose the flexural bars
in both faces, otherwise use the response limits for Double-Reinforced w/o
shear reinforcing.
D
Seismic columns have ties or spirals in accordance with ACI 318-02 Chapter
21 seismic design provisions for special moment frames.
E
Ductility of compression members is the ratio of total axial shortening to axial
shortening at the elastic limit.
4-9
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