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11
aDhesiVe anchors
STRENGTH DESIGN (SD)
TECH MANUAL – ADHESIVE ANCHORS ©2015 POWERS VOLUME 1 – 9/2015 – REV. G
Bond Strength Design Information for Threaded Rods and Reinforcing Bars in Holes Drilled with a
Core Drill and Diamond Core Bit (For use with load combinations taken from ACI 318 Section 9.2)
1
Design Characteristic Notation Units
Nominal Rod Diameter (inch) / Reforcing Bar Size
1/2" or #4 5/8" or #5 3/4" or #6 7/8" or #7 1" or #8
Minimum embedment h
ef,min
in.
(mm)
2-3/4
(70)
3-1/8
(79)
3-1/2
(89)
3-1/2
(89)
4
(102)
Maximum embedment
7
h
ef,max
in.
(mm)
10
(54)
12-1/2
(318)
15
(381)
17-1/2
(445)
20
(508)
75°F (24°C)
Maximum Long-Term
Service Temperature;
104°F (40°C)
Maximum Short-Term
Service Temperature
4,10
Characteristic bond strength
in uncracked concrete
5,8
t
k,uncr
psi
(N/mm
2
)
1,419
(9.8)
1,351
(9.3)
1,298
(9.0)
1,257
(8.7)
1,221
(8.4)
110°F (43°C)
Maximum Long-Term
Service Temperature;
140°F (60°C)
Maximum Short-Term
Service Temperature
2,4
Characteristic bond strength
in uncracked concrete
5,8
t
k,uncr
psi
(N/mm
2
)
1,133
(7.8)
1,075
(7.4)
1,033
(7.1)
1,022
(6.9)
975
(6.7)
110°F (43°C)
Maximum Long-Term
Service Temperature;
176°F (80°C)
Maximum Short-Term
Service Temperature
3,4
Characteristic bond strength
in uncracked concrete
5,8
t
k,uncr
psi
(N/mm
2
)
895
(6.2)
849
(5.9)
816
(5.6)
791
(5.5)
770
(5.3)
Permissible Installation
Conditions
6
Dry concrete
f
d
- 0.55 0.45 0.45 0.45 0.45
Water-saturated concrete
f
ws
- 0.45 0.45 0.45 0.45 0.45
κ
ws
- 1.0 1.0 1.0 1.0 1.0
Water-filled hole (flooded)
f
ws
- 0.45 0.45 0.45 0.45 0.45
κ
wf
- 0.94 0.95 0.95 0.95 0.96
For SI: 1 inch = 25.4 mm, 1 psi = 0.006894 MPa. For pound-inch units: 1 mm = 0.03937 inch, 1 MPa = 145.0 psi.
1. Bond strength values correspond to a normal-weight concrete compressive strength f'c = 2,500 psi (17.2 MPa). For concrete compressive strength, f'c between 2,500 psi and 8,000 psi
(17.2 MPa and 55.2 MPa), the tabulated characteristic bond strength may be increased by a factor of (f'c / 2,500)
0.12
[For SI: (f'c / 17.2)
0.12
].
2. The maximum short-term service temperature may be increased to 162°F (72°C) provided characteristic bond strengths are reduced by 10 percent. Long-term and short-term
temperatures meet the requirements of Section 8.5 of ACI 355.4 and Table 8.1, Temperature Category B.
3. Long-term and short-term temperatures meet the requirements of Section 8.5 of ACI 355.4 and Table 8.1, Temperature Category A.
4. Short-term base material service temperatures are those that occur over brief intervals, e.g. as a result of diurnal cycling. Long-term base material service temperatures are roughly
constant over significant periods of time.
5. Characteristic bond strengths are for sustained loads including dead and live loads.
6. Permissible installation conditions include dry concrete, water-saturated concrete and water-filled holes. Water-filled holes include applications in dry or water-saturated concrete where
the drilled holes contain standing water at the time of anchor installation.
7. Maximum embedment is limited to twelve anchor diameters for horizontal and upwardly inclined installations.
8. For structures assigned to Seismic Design Categories C, D, E or F, bond strength values for cracked concrete do not require an additional reduction factor applied for seismic tension
(
a
N,seis
= 1.0), where seismic design is applicable.
9. Bond strength values for uncracked concrete are applicable for structures assigned to Seismic Design Categories A and B only.
10. Room temperature range is not recognized by ACI 318-11 and does not meet the minimum temperature requirement of ACI 355.4, Table 8.1 and consequently is
not applicable to design under ACI 318-11 or current and past editions of the International Building Code (IBC). The tabulated values are provided for analysis and
evaluation of existing conditions only.
200
400
600
800
1000
1200
Uncracked Concrete
110°F Max Long-Term Service Temp,
140°F Max Short-Term ServiceTemp
110°F Max Long-Term Service Temp,
176°F Max Short-Term ServiceTemp
Core Drilled Hole
110°F Max Long-Term Service Temp,
140°F Max Short-Term ServiceTemp
Core Drilled Hole
110°F Max Long-Term Service Temp,
176°F Max Short-Term ServiceTemp
Cracked Concrete
110°F Max Long-Term Service Temp,
140°F Max Short-Term ServiceTemp
110°F Max Long-Term Service Temp,
176°F Max Short-Term ServiceTemp
0.250 0.375 0.500 0.625 0.750 0.875 1.000 1.125 1.250 1.375 1.500
Nominal Threaded Rod Or Reinforcing Bar Diameter (In.)
Characteristic Bond Strength (psi)