PRELIMINARY DESIGN OF PRECAST / PRESTRESSED CONCRETE STRUCTURES
CHAPTER 3
3
3.5 Pretopped Double-Tee Load Tables (cont.)
Strand Pattern Designation
15'-0" × 34"
Number of strand (20)
S = straight D = depressed
Section Properties
Normalweight
A = 1185 in.2
I =109,621in.4
yb = 25.65 in.
yt = 8.35 in.
Sb = 4274 in.3
St =13,121 in.3
wt = 1234 lb/ft
DL =
82 lb/ft2
V/S = 2.45 in.
208- D1
Lightweight
Number of depression points
Diameter of strand in 16ths
Because these units are pretopped and are typically
used in parking structures, safe loads shown do not
include any superimposed dead loads. Loads shown
are live load. Long-time cambers do not include live
load.
Key
1185
109,621
22.65
8.35
4274
13,121
946
63
2.45
in.2
in.4
in.
in.
in.3
in.3
lb/ft
lb/ft2
in.
fc' = 5000 psi
174 – Safe superimposed service load, lb/ft2
0.3 – Estimated camber at erection, in.
0.4 – Estimated long-time camber, in.
fpu = 270,000 psi
/2-in.-diameter regular strand
1
Check with regional producers for availability.
15DT34
Table of safe superimposed service load, lb/ft2, and cambers, in.
Strand
pattern
Normalweight — No Topping
Span, ft
ys
in.
32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88
88-S
7.00
128-S
5.83
168-S
5.69
208-S
5.95
248-S
6.42
174 147 124 105
0.3 0.3 0.3 0.3
0.4 0.4 0.4 0.4
198
0.6
0.8
89
0.3
0.4
173
0.6
0.9
75
0.3
0.4
151
0.7
0.9
63
0.2
0.3
132
0.7
0.9
197
1.1
1.4
52
0.2
0.3
116
0.7
1.0
175
1.1
1.5
43
0.2
0.2
101
0.7
1.0
156
1.1
1.6
35
0.1
0.2
89
0.7
1.0
139
1.2
1.6
185
1.6
2.2
27
0.1
0.1
77
0.7
0.9
124
1.2
1.7
167
1.6
2.3
67
0.6
0.9
110
1.2
1.7
150
1.7
2.3
58
0.6
0.8
98
1.2
1.7
135
1.8
2.4
50
0.6
0.7
87
1.2
1.7
122
1.8
2.4
43
0.5
0.6
77
1.2
1.7
110
1.8
2.4
36
0.4
0.5
69
1.2
1.6
99
1.8
2.5
30
0.3
0.3
61
1.1
1.5
89
1.8
2.5
53
1.1
1.4
80
1.8
2.5
105
2.4
3.2
47
1.0
1.3
72
1.8
2.4
95
2.4
3.2
41
0.8
1.1
64
1.7
2.4
86
2.4
3.2
35
0.7
0.9
57
1.7
2.3
78
2.4
3.2
30
0.5
0.6
51
1.6
2.1
71
2.3
3.1
25
0.3
0.3
45
1.4
1.9
64
2.3
3.0
40
1.3
1.6
57
2.2
2.9
35
1.1
1.3
52
2.1
2.8
30
0.8
1.0
46
1.9
2.6
25
0.6
0.6
40 34 29
1.7 1.5 1.2
2.3 1.9 1.5
15LDT34
Table of safe superimposed service load, lb/ft2, and cambers, in.
Strand
pattern
ys
in.
88-S
7.00
128-S
5.83
168-S
5.69
208-S
5.95
248-S
6.42
Lightweight — No Topping
Span, ft
32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94
188 161 139 120 103 89 77 67 57 49 42 35 30
0.4 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.4 0.4 0.3
0.6 0.6 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.5 0.4
187 166 147 130 116 103 92 81 72 64 57 50 44
1.0 1.1 1.2 1.2 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.2
1.4 1.5 1.6 1.7 1.7 1.8 1.8 1.8 1.9 1.8 1.8 1.7 1.6
189 170 153 138 125 112 102 92 83 75
1.8 1.9 2.0 2.1 2.2 2.2 2.3 2.3 2.4 2.4
2.5 2.6 2.7 2.8 2.9 3.0 3.0 3.1 3.1 3.2
200 181 164 150 136 124 113 103
2.6 2.7 2.8 3.0 3.1 3.2 3.3 3.4
3.5 3.7 3.9 4.0 4.2 4.3 4.4 4.5
39
1.1
1.5
68
2.4
3.2
94
3.4
4.5
34
1.0
1.3
61
2.3
3.1
86
3.5
4.5
29
0.8
1.1
55
2.3
3.1
79
3.5
4.5
25
0.7
0.8
49
2.2
3.0
72
3.5
4.5
44
2.1
2.9
65
3.5
4.5
39
2.0
2.7
60
3.4
4.5
35
1.8
2.4
54
3.4
4.4
31
1.6
2.1
49
3.3
4.3
62
4.5
5.8
27
1.4
1.8
45
3.2
4.2
56
4.5
5.7
40
3.0
4.0
51
4.4
5.6
36
2.9
3.8
47
4.3
5.5
32
2.6
3.4
43
4.2
5.3
29
2.3
3.0
40
4.0
5.2
26
1.9
2.4
36 33
3.8 3.6
4.9 4.6
Strength is based on strain compatibility; bottom tension is limited to 12 fc' ; see pages 3–8 through 3–11 for explanation.
Shaded values require release strengths higher than 3500 psi.
3–30
First Printing/CD-ROM Edition
PCI DESIGN HANDBOOK/SEVENTH EDITION