ceen 3304 t4 one-way slab - tamuk.eduusers.tamuk.edu/kfgfa00/ceen 3304/lectures/ceen 3304 t4...
TRANSCRIPT
1
Page 1
CEEN 3304 Concrete Design
One-way slabs
Francisco AguíñigaAssistant Professor
Civil and Architectural Engineering ProgramTexas A&M University – Kingsville
Page 2
Slab types
2
Page 3
Slab types
Page 4
Slab types
3
Page 5
One-way slab behavior
Page 6
Two-way slab deformation
4
Page 7
Two-way slab deformation
If ll/ls = 2 ws = 16 wl
EIlw ll
l 3845 4
=ΔEIlw ss
S 3845 4
=Δ
4
⎟⎟⎠
⎞⎜⎜⎝
⎛=
s
l
l
s
ll
ww
Page 8
Slab reinforcement
Main reinforcementUsed to resist moment
Shrinkage and temperature reinforcement
Used to prevent cracking due to contraction of the concrete resulting from shrinkage and temperature changes
5
Page 9
Slab reinforcement
Minimum reinforcementShrinkage and temperatureFor fy = 40 to 50 ksi As(S&T) = 0.002bhFor fy = 60 ksi As(S&T) = 0.0018bhFor fy > 60 ksi As(S&T) = (0.0018x60xbh)/fy >= 0.0014bhb = 12 in. (1 foot wide strip)h = Slab thickness (in.)
Page 10
Minimum cover
ACI 7.7.71 (if not exposed to weather or in contact with soil)
¾ in. for # 11 and smaller1.5 in. for # 14 and # 18 bars
6
Page 11
Maximum spacing
Main reinforcementACI 10.5.4S < smaller of (3 h or 18 in.)ACI 10.6.4
Using min cover of ¾ in. and fs = 2/3fy=2/3(60000) = 40,000 psiS = 12 in.
Shrinkage and Temp. reinforcementACI 7.12.2.2Smax (S&T) = min(5h or 18 in.)
⎟⎟⎠
⎞⎜⎜⎝
⎛≤−⎟⎟
⎠
⎞⎜⎜⎝
⎛=
sc
s fc
fs 40000125.24000015
Page 12
Example
7
Page 13
Example
Page 14
Example
8
Page 15
Example
Page 16
Design example
Determine the reinforcement at midspan and at the supports
9
Page 17
Design example
Page 18
Design example
#6
10
Page 19
Design example
Page 20
Design example
11
Page 21
Design example
Page 22
Design example
12
Page 23
Design example
Page 24
Design example