DOUBLE TEES - Technical Data
Design Topics
Span-Load Tables
Design Criteria for the Span Load Tables
Manufacturing Tolerances
Strand Locations for Prestressing
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USE OF DOUBLE TEE SPAN LOAD TABLES ATTENTION: The Span-Load Tables included herein were derived from
computer-calculated data, are intended as aids to preliminary sizing, and must be interpreted using sound engineering judgement.
INTRODUCTION - These Span-Load Tables present three distinct types of Double Tee flexural members: the "standard" thin-flange Double Tee, with and without composite topping (pages 8-21 ); and the thick-flange Double Tee (pages 22-28).
The "standard" thin-flange Double Tee without composite topping is commonly used for lightly loaded applications (not exceeding 80 psf), such as roof structures.
The "standard" thin-flange Double Tee with composite topping, and the thick-flange Double Tee, are used for moderately loaded applications, such as floors for most warehouses, office buildings, schools, shopping malls and parking garages. Cast-in-place concrete topping provides a smooth, level floor surface that serves as the horizontal diaphragm. The alternative untopped thick-flange Double Tee provides a plant-produced wearing surface that exhibits superior durability when compared to typical field-placed concrete topping. In this case, the horizontal diaphragm is provided by welded flange connectors.
Flanges thicker than four inches are also available for heavily loaded surfaces, such as bridges and piers.
DESIGN CRITERIA FOR DEVELOPMENT OF THE SPAN-LOAD TABLES
The Span-Load Tables were developed in accordance with the provisions of the "Building Code Requirements for Reinforced Concrete", ACI 318-89, as described below:
COMPRESSION - The extreme fiber stress in both the Double Tee flange and topping slab under the application of full service load is limited to 0.45f'c [ACI 318-89, Section 18.4.2(a)].
TENSION - The extreme fiber stress in the precompressed tensile zone under the application of full service load is limited to 6 c [ACI 318-89, Section 18.4.2(b)]. If service is to be in a corrosive environment (salt water, certain industrial chemicals, etc.), or if full design loads are likely to be sustained for extended periods (such as in warehouses), designers should consider using an allowable tensile stress of less than 6 c.
ULTIMATE STRENGTH - The nominal flexural strength, øMn, exceeds the required ultimate strength Mu - 1.4Md + 1.7Ml [ACI 318-89, Section 9.2.1]. The stress in the prestressed reinforcement at nominal strength (fps) was calculated as set forth in ACI 318-89, Section 18.7.2(a), and all superimposed loads were considered as live loads. When ultimate strength governs the design, a more rigorous analysis based on strain compatability will increase the span-load capacity, as will superimposed loads comprised of dead and live load combinations.
SHEAR - The nominal shear strength, øVn, exceeds the required ultimate shear Vu = 1.4Vd + 1.7Vl [ACI 318-89, Sections 9.2.1 and 11.1.1]. Web and flexure shear strengths were calculated as set forth in ACI 318-89, Section 11.4.2. Additional web shear capacity can be obtained by computing the shear force corresponding to dead and live loads that result in a principal tensile stress of 4 c at the centroidal axis of the member.
Values above and to the right of the bold type in all Span-Load Tables are based on Double Tees without shear reinforcement. For all of these values, the shear strength of the concrete section equals or exceeds the ultimate shear.
Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. The shear capacity provided by the steel (Vs), does not exceed 8 c bwd [ACI 318-89, Section 11.5.6.8].
Full scale load tests have been performed at Concrete Technology Corporation to verify the shear capacity of Double Tees without web reinforcement. Test results also confirm that, with a rough screeded top flange, full composite action is achieved without the use of mechanical ties to develop the horizontal shear requirements of ACI 318-89, Section 17.5.
CONCRETE RELEASE STRENGTH and TOP FLANGE TENSION REINFORCEMENT requirements have been checked for conformance to ACI 318-89, Section 18.4.1, and are reflected in the Span-Load Tables.
CONCRETE STRENGTH varies depending on the total amount of prestress and the length of the Double Tees. All unhighlighted values in the Span-Load Tables use f'ci = 4000 psi at release and f'c - 6000 psi at 28 days. For composite Double Tees, the strength of the topping at 28 days is a minimum 3000 psi. Designs using higher values of f'c for both the Double Tees and topping slab are also possible. PRESTRESSING STEEL is ½" diameter, 270 ksi, 7 wire, Iow-relaxation strand. Initial jacking stress is 0.7fpu = 189 ksi. Long term losses are estimated at 35 ksi, for a final effective stress of 154 ksi.
HARPED STRAND DESIGNS are calculated for a midpoint harp and a single row of stacked strands (see page 5). For heavily stranded Double Tees, significant improvement in eccentricity may be achieved by using a double row harp design. However, little capacity improvement is achieved by two-point harping at 0.4L, so the single point harp is recommended for economy. Strand sleeving for control of concrete stresses at release is also available. Contact CTC's Marketing Department for economical alternate strand configurations.
HIGHLIGHTING of the values in the Span-Load Tables represent the following requirements:
12 Double Tees in this span range weigh in excess of 54 kips.
234 f'ci is between 4000 - 5000 psi, f'c = 6000 psi
345 f'ci is greater than 5000 psi, f'c = 7000 psi
456 Top flange tension reinforcement is required in addition to the flange mesh. For thick-flange Double Tees, this will exceed the minimum reinforcement required for temperature.
COMPOSITE DOUBLE TEE DESIGNS have already considered the weight of the cast-in-place topping. This should not be deducted from the allowable superimposed load. Double Tees which are designed with composite topping will have a rough screeded top to insure good bond to the topping.
STRUCTURAL LIGHTWEIGHT CONCRETE, with unit weights as low as 110 pcf and 28 day strengths of 5000 psi, can be used where reduced dead load can be of advantage. In considering its use, the designer should be aware of the reduced elastic modulus resulting in cambers approximately twice the value of those estimated for normal weight concrete. Large differential cambers often result from large absolute cambers. Variation in camber also results from less precise control of the concrete mix due to the inherent fluctuation of density, gradation, and moisture content in the lightweight aggregate. SPECIAL WIDTHS are available, although it is desirable to maintain the 10' nominal width to minimize cost. If a layout suggests a non-standard width be used, it is most economical to use as many 10' units as
possible, and fill the remainder with non-standard widths. The minimum width of a Double Tee is 6'-2".
The Span-Load Tables are calculated for the standard 10' nominal width. Narrower widths will allow heavier loading conditions than are reflected in the tables for a given span. In these cases, special consideration must be given to the prestressing profile, shear and end-bearing reinforcement, and the top flange thickness. Contact CTC's Marketing Department for span-load capacities of special-width Double Tees.
THE FIRE RESISTANCE RATING of Double Tees varies depending on many factors, including but not limited to cover over the prestressing, type and thickness of topping slab and/or roofing, normal or lightweight concrete, etc. In many cases, additional prestressed or mild reinforcement can be added to improve the fire resistance rating. Two excellent design guides are the PCI Design Handbook, and PCI MNL-124-77, "Design for Fire Resistance of Precast Prestressed Concrete".
CAMBER (net upward deflection) due to the eccentricity of the prestressing force should be recognized and accounted for in the design process. Many variables affect camber, including the quality of concrete and strength at release, member length, number and placement of strands, placement of supports for storage, differential temperature, age of member prior to erection and placement of superimposed loads, relative humidity, etc. Associated building elements which may be affected by camber should be placed with adequate tolerances. It is not practical to deflect the formwork to produce desired cambers.
DOUBLE TEES MANUFACTURING TOLERANCES
Double Tees - Span-Load Tables
Thin Flange Double Tees No Topping
Thin Flange Double Tees 2½" Topping
Thick Flange Double Tees 4" Flange
12" Untopped 12" Topped 14" Thick Flange
16" Untopped 16" Topped 18" Thick Flange
20" Untopped 20" Topped 22" Thick Flange
24" Untopped 24" Topped 26" Thick Flange
28" Untopped 28" Topped 30" Thick Flange
3
DOUBLE TEES MANUFACTURING TOLERANCES
4" Thick Flange
36" Untopped 36" Topped 38" Thick Flange
12" DOUBLE TEE
SECTION PROPERTIESI = 4573 in4 Zt = 1398 in3 Zb = 524 in3 A = 398 in2
W = 43 psf Yt = 3.27 in Yb = 8.73 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 20 22 24 26 28 30 32 34 36 38 40 42
4 (straight) 80 67 50 38 27
4 (harped) 76 58 44 33 24
6 (straight) 80 77 60 47 35 26
6 (harped) 80 79 63 50 39 29 22
8 (harped) 80 71 57 46 36 28 21
10 (harped) 80 72 59 48 38 30 23
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases.
16" DOUBLE TEE
SECTION PROPERTIESI = 10238 in4 Zt = 2235 in3 Zb = 896 in3 A = 454 in2
W = 49 psf Yt = 4.58 in Yb = 11.42 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56
4 (straight) 80 67 52 40 30 22
4 (harped) 80 74 58 45 35 26
6 (straight) 80 70 57 45 36 28 21
6 (harped) 80 69 57 46 37 30 23
8 (straight) 77 63 51 40 32 24
8 (harped) 80 71 59 49 39 31 25
10 (harped) 80 78 66 55 46 37 30 24
12 (harped) 80 69 58 49 41 34 27 22
14 (harped) 80 69 59 50 42 35 29 23
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
20" DOUBLE TEE
SECTION PROPERTIESI = 18787 in4 Zt = 3142 in3 Zb = 1340 in3 A = 507 in2
W = 55 psf Yt = 5.98 in Yb = 14.02 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 34 38 42 46 50 54 58 62 66 70
6 (straight) 71 48 31
6 (harped) 80 57 38 24
8 (straight) 70 49 32
8 (harped) 80 63 45 30
10 (straight) 80 61 41 27
10 (harped) 80 63 45 30
12 (harped) 79 59 42 29
14 (harped) 80 72 54 39 27
16 (harped) 80 64 48 35 24
18 (harped) 73 56 42 30 21
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
24" DOUBLE TEE
SECTION PROPERTIESI = 30486 in4 Zt = 4114 in3 Zb = 1838 in3 A = 557 in2
W = 60 psf Yt = 7.41 in Yb = 16.59 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 38 42 46 50 54 58 62 66 70 74 78 82
6 (straight) 67 46 30
6 (harped) 77 54 36 23
8 (straight) 80 71 51 35 22
8 (harped) 80 63 46 31
10 (straight) 80 67 48 32 20
10 (harped) 80 66 48 33 22
12 (harped) 80 63 47 33 22
14 (harped) 78 60 45 32 22
16 (harped) 80 72 56 42 31 21
18 (harped) 80 65 50 38 28
20 (harped) 74 58 45 34 24
22 (harped) 80 66 52 40 30 21
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
28" DOUBLE TEE
SECTION PROPERTIESI = 45509 in4 Zt = 5136 in3 Zb = 2378 in3 A = 604 in2
W = 65 psf Yt = 8.86 in Yb = 19.14 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 42 46 50 54 58 62 66 70 74 78 82 86 90 94
6 (straight) 62 42 28
6 (harped) 69 49 33 20
8 (straight) 80 69 50 35 23
8 (harped) 80 60 44 31
10 (straight) 80 69 50 35 22
10 (harped) 80 66 48 34 22
12 (harped) 80 65 49 35 24
14 (harped) 80 63 47 35 24
16 (harped) 76 59 45 34 24
18 (harped) 80 70 56 43 32 23
20 (harped) 80 65 51 39 29 21
22 (harped) 73 59 46 36 26
24 (harped) 80 66 53 41 32 23
26 (harped) 73 59 47 37 28 20
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
32" DOUBLE TEE
SECTION PROPERTIESI = 63952 in4 Zt = 6209 in3 Zb = 2947 in3 A = 648 in2
W = 70 psf Yt = 10.30 in Yb = 21.70 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 46 50 54 58 62 66 70 74 78 82 86 90 94 98 102
8 (straight) 80 64 47 33 22
8 (harped) 75 56 41 28
10 (straight) 80 68 50 35 22
10 (harped) 80 64 47 33 22
12 (straight) 80 63 46 32 21
12 (harped) 80 64 48 35 24
14 (harped) 80 63 48 36 25
16 (harped) 77 61 47 35 25
18 (harped) 80 73 58 45 34 24
20 (harped) 80 68 54 42 32 23
22 (harped) 78 63 50 40 30 22
24 (harped) 80 71 58 46 36 27
26 (harped) 79 65 53 42 33 24
28 (harped) 80 72 59 47 38 29 21
30 (harped) 78 64 53 42 33 25
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
36" DOUBLE TEE
SECTION PROPERTIESI = 85827 in4 Zt = 7323 in3 Zb = 3535 in3 A = 689 in2
W = 75 psf Yt = 11.72 in Yb = 24.28 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 54 58 62 66 70 74 78 82 86 90 94 98 102 106 110 114
10 (straight) 80 65 48 34 21
10 (harped) 80 77 60 44 31 20
12 (straight) 80 62 46 32 21
12 (harped) 80 62 46 34 23
14 (harped) 79 62 47 35 25
16 (harped) 80 76 60 47 35 25
18 (harped) 80 73 58 46 35 25
20 (harped) 80 69 56 44 33 24
22 (harped) 80 65 53 42 32 23
24 (harped) 74 61 49 39 30 22
26 (harped) 80 69 56 45 36 27 20
28 (harped) 76 63 52 42 33 25
30 (harped) 80 70 58 47 38 29 22
32 (harped) 76 63 52 42 34 26
34(harped) 57 47 38 30 22
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement is 80 psf. The maximum safe concentrated load is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
12" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI = 7397 in4 Ztc = 2605 in3 Zif = 4207 in3 Zbc = 722 in3
w = 74 psf Ytc = 4.26 in Yif = 1.76 in Ybc = 10.24 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 20 22 24 26 28 30 32 34 36
4 (straight) 96 65 38
4 (harped) 107 78 49 27
6 (straight) 141 99 67 41 22
6 (harped) 181 137 99 69 45 26
8 (harped) 247 190 143 107 78 55 36 20
10 (harped) 304 234 181 139 105 78 56 38 23
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
16" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI = 15061 in4 Ztc = 4265 in3 Zif = 5385 in3 Zbc = 1141 in3
w = 80 psf Ytc = 5.30 in Yif = 2.80 in Ybc = 13.20 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 24 26 28 30 32 34 36 38 40 42 44 46 48 4 (straight) 83 61 44 27
4 (harped) 91 68 49 33
6 (straight) 140 110 82 58 39 23
6 (harped) 163 129 102 78 56 38 23
8 (straight) 185 142 108 81 59 40 25
8 (harped) 229 185 150 119 92 70 51 36 22
10 (harped) 290 237 195 158 126 100 78 60 44 30
12 (harped) 345 284 236 192 156 127 102 81 63 48 34 22
14 (harped) 393 325 270 222 182 150 122 99 80 63 48 35 24
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
20" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI = 26389 in4 Ztc = 6151 in3 Zif = 6707 in3 Zbc = 1643 in3
w = 86 psf Ytc = 6.43 in Yif = 3.93 in Ybc = 16.07 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 26 30 34 38 42 46 50 54 58
6 (straight) 157 100 62 28
6 (harped) 176 114 73 40
8 (straight) 212 141 90 51 22
8 (harped) 250 170 117 74 42
10 (straight) 257 173 111 68 36
10 (harped) 319 222 157 106 68 39
12 (harped) 384 270 195 136 92 59 34
14 (harped) 443 315 230 164 115 78 50 28
16 (harped) 497 356 261 189 135 95 64 40 20
18 (harped) 546 392 290 211 154 110 77 51 30
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
24" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
,
SECTION PROPERTIESI = 41627 in4 Ztc = 8192 in3 Zif = 8127 in3 Zbc = 2205 in3
w = 91 psf Ytc = 7.62 in Yif = 5.12 in Ybc = 18.88 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 30 34 38 42 46 50 54 58 62 66 70 6 (straight) 134 88 55 29
6 (harped) 149 99 64 38
8 (straight) 189 130 89 53 26
8 (harped) 218 153 107 73 42
10 (straight) 235 167 115 74 43 20
10 (harped) 283 203 148 105 69 42 20
12 (harped) 344 251 186 136 95 64 39
14 (harped) 402 296 222 166 120 84 57 34
16 (harped) 457 339 256 194 143 104 73 49 29
18 (harped) 507 378 287 219 164 122 89 62 41 23
20 (harped) 414 316 243 184 139 103 75 52 33
22 (harped) 264 202 154 116 86 61 41 24
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
28" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI = 60971 in4 Ztc = 10339 in3 Zif = 9609 in3 Zbc = 2816 in3
w = 96 psf Ytc = 8.84 in Yif = 6.34 in Ybc = 21.66 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 30 34 38 42 46 50 54 58 62 66 70 74 78 6 (straight) 169 114 75 47 26
6 (harped) 184 125 84 54 32
8 (straight) 236 166 117 81 52 26
8 (harped) 266 189 135 96 67 39
10 (straight) 296 213 154 112 74 45 22
10 (harped) 344 250 184 136 100 67 41 20
12 (harped) 418 308 231 174 131 93 64 40 21
14 (harped) 490 363 275 211 161 119 86 59 37
16 (harped) 558 416 317 245 190 143 107 77 53 33
18 (harped) 621 466 357 278 217 166 126 94 68 46 29
20 (harped) 513 394 308 243 188 145 110 82 59 40 23
22 (harped) 337 267 208 162 125 95 71 50 33
24 (harped) 227 178 139 108 81 60 41 26
26 (harped) 152 118 91 68 49 32
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion.
5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2) top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
32" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI = 84445 in4 Ztc = 12571 in3 Zif = 11147 in3 Zbc = 3457 in3
w = 101 psf Ytc = 10.08 in Yif = 7.58 in Ybc = 24.42 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 34 38 42 46 50 54 58 62 66 70 74 78 82 86 90 8 (straight) 203 146 104 73 47 23
8 (harped) 225 164 119 85 59 35
10 (straight) 259 191 141 103 71 44 22
10 (harped) 297 221 165 124 92 62 38
12 (straight) 310 231 174 130 91 61 37
12 (harped) 365 275 210 161 124 89 61 39 20
14 (harped) 431 328 253 197 154 115 83 58 37 20
16 (harped) 494 378 294 231 183 140 105 77 54 35
18 (harped) 554 427 334 264 211 164 126 95 70 49 31
20 (harped) 610 473 372 296 237 186 146 112 85 62 43 27
22 (harped) 407 325 262 208 164 129 100 75 55 37 23
24 (harped) 286 228 182 144 113 88 66 47 31
26 (harped) 199 159 126 99 76 56 40 25
28 (harped) 138 109 85 65 47 32
30 (harped) 73 54 39 25
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table.
3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the application of this information to specific design cases.
4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in "Design Criteria..." for discussion.
5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2) top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
36" DOUBLE TEE Composite with 2½" Concrete Topping (f'c = 4000 psi)
SECTION PROPERTIESI =112008 in4 Ztc = 14865 in3 Zif = 12725 in3 Zbc = 4118 in3
w = 106 psf Ytc = 11.30 in Yif = 8.80 in Ybc = 27.20 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98
10 (straight) 170 127 94 65 40 20
10 (harped) 195 148 112 83 56 34
12 (straight) 210 160 122 87 59 36
12 (harped) 247 191 148 114 83 57 36
14 (harped) 296 232 183 144 108 79 55 36
16 (harped) 344 272 217 173 133 101 75 53 34
18 (harped) 390 311 250 201 157 122 93 69 49 32
20 (harped) 435 348 281 228 181 143 111 85 63 45 29
22 (harped) 477 383 311 253 203 162 129 101 77 57 40 25
24 (harped) 339 278 225 181 145 115 90 69 50 35 21
26 (harped) 245 199 161 129 103 80 61 44 29
28 (harped) 176 143 115 91 70 53 37 24
30 (harped) 101 79 61 45 31
32 (harped) 69 52 37 24
34 (harped) 30
NOTES:
1. The standard top flange reinforcement is WWF 8x4-W2.9/W2.9, and the maximum safe uniform load on the flange with this reinforcement, without the topping, is 80 psf. The maximum safe concentrated load without the topping is 500 lbs.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
14" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 7383 in4 Zt = 2012 in3 Zb = 715 in3 A = 638 in2
W = 69 psf Yt = 3.67 in Yb = 10.33 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 20 22 24 26 28 30 32 34 36 38 40
4 (straight) 96 69 49 33 21
4 (harped) 107 78 57 40 26
6 (straight) 149 113 86 64 45 30
6 (harped) 180 139 108 83 63 46 32 20
8 (harped) 247 192 151 118 92 71 54 40 28
10 (harped) 299 235 186 148 118 94 74 58 44 32 22
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
18" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 15203 in4 Zt = 3269 in3 Zb = 1139 in3 A = 693 in2
W = 75 psf Yt = 4.65 in Yb = 13.35 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 4 (straight) 85 63 46 32 20
4 (harped) 92 69 51 37 25
6 (straight) 142 111 87 68 52 39 28
6 (harped) 164 130 104 82 65 50 38 28
8 (straight) 187 150 121 97 78 61 46 34 23
8 (harped) 231 188 153 125 103 84 67 53 40 29 20
10 (harped) 294 241 199 165 137 112 92 75 60 48 37 27
12 (harped) 351 290 240 199 166 138 115 95 79 64 52 41 32 23
14 (harped) 400 330 274 229 192 161 136 114 96 80 66 54 43 34 26
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
22" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 26782 in4 Zt = 4666 in3 Zb = 1647 in3 A = 746 in2
W = 81 psf Yt = 5.74 in Yb = 16.26 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 26 30 34 38 42 46 50 54 58 62 6 (straight) 158 102 65 38
6 (harped) 177 117 76 47 27
8 (straight) 214 144 98 65 41 21
8 (harped) 252 173 120 82 55 34
10 (straight) 261 179 125 86 56 34
10 (harped) 323 226 161 116 82 55 34
12 (harped) 390 276 200 147 105 74 50 32
14 (harped) 453 323 237 174 127 93 66 45 28
16 (harped) 511 367 268 199 148 110 80 57 39 24
18 (harped) 564 404 297 221 166 125 93 68 49 32
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
26" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 42411 in4 Zt = 6164 in3 Zb = 2218 in3 A = 796 in2
W = 86 psf Yt = 6.88 in Yb = 19.12 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 30 34 38 42 46 50 54 58 62 66 70 74 6 (straight) 137 91 58 35
6 (harped) 151 102 67 42 23
8 (straight) 192 133 93 63 40 23
8 (harped) 220 156 110 77 53 33
10 (straight) 240 171 122 87 61 39 21
10 (harped) 287 207 152 111 81 57 37 20
12 (harped) 350 257 191 144 108 78 55 36 21
14 (harped) 411 304 229 174 132 98 72 51 34 20
16 (harped) 468 349 265 203 155 117 88 65 46 30
18 (harped) 522 390 298 228 176 135 104 78 58 41 27
20 (harped) 430 327 252 196 152 118 91 69 50 35 22
22 (harped) 274 214 168 131 102 79 59 43 29
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
30" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 62255 in4 Zt = 7724 in3 Zb = 2838 in3 A = 843 in2
W = 91 psf Yt = 8.06 in Yb = 21.94 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per tee 30 34 38 42 46 50 54 58 62 66 70 74 78 82 86 6 (straight) 171 117 78 50 29
6 (harped) 186 128 87 58 36
8 (straight) 239 170 121 85 58 38 22
8 (harped) 268 192 138 100 70 48 30
10 (straight) 300 217 159 116 84 60 40 23
10 (harped) 347 254 188 140 104 77 55 37 21
12 (harped) 424 314 236 179 137 104 79 56 37 22
14 (harped) 498 371 282 217 168 131 99 74 53 36 22
16 (harped) 569 426 326 253 198 155 120 91 69 50 34 21
18 (harped) 636 479 368 288 226 177 139 108 83 63 46 31
20 (harped) 529 408 320 251 199 157 124 97 75 56 41 28
22 (harped) 349 276 219 175 139 110 87 67 50 36 24
24 (harped) 238 191 153 123 97 76 59 44 31 20
26 (harped) 166 134 108 85 67 51 37 26
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
34" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI = 86363 in4 Zt = 9337 in3 Zb = 3489 in3 A = 887 in2
W = 96 psf Yt = 9.25 in Yb = 24.75 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per
tee 34 38 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98
8 (straight) 206 149 108 76 52 34
8 (harped) 228 167 122 89 63 42 26 10
(straight) 263 195 145 108 79 56 38 23
10 (harped) 300 225 169 128 96 71 51 35 20
12 (straight) 315 237 179 136 103 77 56 37 21
12 (harped) 370 281 215 166 128 99 75 54 37 22
14 (harped) 438 335 260 203 160 126 98 73 53 37 23
16 (harped) 504 387 303 239 190 151 118 91 69 51 35 22
18 (harped) 567 438 344 273 219 174 138 109 85 65 48 33 21
20 (harped) 627 486 384 307 246 197 158 126 100 78 60 44 31
22 (harped) 422 337 270 218 176 142 114 91 71 54 40 27
24 (harped) 294 238 194 157 128 103 82 64 49 35 24
26 (harped) 211 172 141 114 92 73 57 43 31 20
28 (harped) 153 125 102 82 65 50 37 26
30 (harped) 90 72 57 44 32 22
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
38" THICK-FLANGE DOUBLE TEE
SECTION PROPERTIESI =114680 in4 Zt = 10985 in3 Zb = 4161 in3 A = 929 in2
W = 101 psf Yt = 10.44 in Yb = 27.56 in
ALLOWABLE SUPERIMPOSED LOAD (in pounds per square foot) SIMPLE SPAN (in feet)
Number of ½" Ø strands per
tee 42 46 50 54 58 62 66 70 74 78 82 86 90 94 98 102 106
10 (straight) 175 132 99 73 52 35 21
10 (harped) 199 152 116 87 65 46 31
12 (straight) 215 165 127 97 73 54 36 21
12 (harped) 251 196 153 119 92 70 52 35 20
14 (harped) 303 238 189 150 119 93 71 52 35 22
16 (harped) 352 280 224 180 145 114 89 68 50 35 22
18 (harped) 400 320 258 209 168 135 107 84 64 48 34 21
20 (harped) 447 359 291 236 191 155 124 99 78 60 45 32 20
22 (harped) 492 396 322 261 213 174 141 115 92 73 56 42 29
24 (harped) 350 285 234 192 158 129 105 84 66 51 38 26
26 (harped) 254 210 173 143 117 95 77 59 46 34 23
28 (harped) 188 156 129 106 86 69 54 42 30 20
30 (harped) 116 95 78 62 48 37 26
32 (harped) 86 69 55 43 32 22
34 48 37 27
(harped)
NOTES:
1. The minimum top flange reinforcement is WWF 4x4-W2.9/W2.9, and the maximum safe uniform load on the flange with minimum reinforcement is 180 psf. Additional flange reinforcement will be required for loads in excess of 180 psf.
2. Interpolation between values shown is acceptable. Do not extrapolate values into the blank spaces of the table. 3. These Span-Load Tables are intended as an aid to preliminary sizing. Sound engineering judgement is required for the
application of this information to specific design cases. 4. Values in the lower left of the table in bold type represent conditions where shear reinforcement is required. See SHEAR in
"Design Criteria..." for discussion. 5. Values in the lower left of the table in bold red type represent conditions where (1) shear reinforcement is required and (2)
top flange tension reinforcement is required in addition to the standard flange mesh.
6. See "Design Criteria..." for definitions of HIGHLIGHTING. Highlighting not visible on printed copy (screen only).
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