Powers Fasteners MINI-UNDERCUT+ Installation Manual

GENERAL INFORMATION

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MECHANICAL ANCHORS

GENERAL INFORMATION

MINI-UNDERCUT+

Internally Threaded Undercut Anchor

PRODUCT DESCRIPTION

The Mini-Undercut+ anchor is an internally threaded, self-undercutting anchor designed for
performance in cracked and uncracked concrete. Suitable base materials include post-tension
concrete (PT slabs), hollow-core precast concrete, normal-weight concrete, sand-lightweight concrete
and concrete over steel deck. The Mini-Undercut+ anchor is installed into a pre-drilled hole with
a power tool and a setting tool. The result is an anchor which can provide consistent behavior at
shallow embedments as low as 3/4 of an inch. After installation a steel element is threaded into the
anchor body.

GENERAL APPLICATIONS AND USES

• Tension zones, seismic and
wind loading applications

• Suspended Conduit

FEATURE AND BENEFITS

+ Ideal for precast hollow-core plank and post-tensioned concrete slabs
+ Cracked concrete tested alternative to a mini dropin anchor
+ Redesigned ANSI carbide stop bit with enlarged shoulder for accurate depth
+ Anchor design allows for shallow embedment as low as 3/4 of an inch
+ Internally threaded anchor for easy adjustment and removability of threaded rod or bolt
+ Drill and drive the anchor with one tool for fast anchor installation

APPROVALS AND LISTINGS

• International Code Council, Evaluation Service (ICC-ES), ESR-3912 for Concrete and Hollow-Core
precast slabs, Code Compliant with the 2015, IBC, 2015 IRC, 2012 IBC, 2012 IRC, 2009 IBC,
and 2009 IRC.

• Qualifi ed according to ACI 355.2 (including ASTM E 488) for use in concrete

• FM Approvals (Factory Mutual) – File No. J.I. 3059197

GUIDE SPECIFICATIONS

CSI Divisions: 03 16 00 - Concrete Anchoring and 05 05 19 - Post Installed Concrete Anchors.
Expansion anchors shall be Mini-Undercut+ as supplied by DEWALT, Towson, MD. Anchors shall be
installed in accordance with published instructions and the Authority Having Jurisdiction.

™

• Fire Sprinkler & pipe supports

• Cable Trays and Strut

• Suspended Lighting

SECTION CONTENTS

General Information.........................1

Installation Instructions .................. 2

Reference Data (ASD) ...................... 3

Strength Design (SD) ....................... 4

Ordering Information ....................... 6

MINI-UNDERCUT+

THREAD VERSION

• UNC Thread

ANCHOR MATERIALS

• Zinc plated carbon steel

ANCHOR SIZE RANGE (TYP.)

• 3/8"

SUITABLE BASE MATERIALS

• Post-Tension Concrete

• Precast Hollow-Core Plank

• Normal-weight concrete

N

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Z

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S

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D

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code listed

ICC-ES ESR-3912

CONCRETE

TECH MANUAL – MECHANICAL ANCHORS ©2017 DEWALT – REV. C

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INSTALLATION INSTRUCTIONS

INSTALLATION PROCEDURE (USING SDS PLUS SYSTEM)

Using the required stop
drill bit, drill a hole into
the base material to the
required depth using
the shoulder of the
drill bit as a guide. The
tolerances of the drill
bit used must meet the
requirements of ANSI
Standard B212.15.

Remove dust and
debris from hole
(e.g. suction,
forced air) remove
loose particles left
from drilling.

Attach the required
SDS setting tool
to the hammer­drill. Mount the
open end of the
anchor onto the
setting tool. Drive
the anchor into
the hole until the
shoulder of the
anchor is flush with
the base material.

INSTALLATION INSTRUCTIONS

Insert threaded rod
or bolt full depth
into the
Mini-Undercut+,
taking care
not to exceed
the maximum
tightening torque
of the steel insert
element, T

.

max

Installation Information for Mini-Undercut+ Anchor

Anchor Property/Setting Information Symbol Units

Anchor outside diameter d

Internal thread diameter (UNC) d

Nominal drill bit diameter d

Minimum nominal embedment depth h

Effective embedment depth h

Hole depth h

Overall anchor length (before setting)

Approximate tool impact power (hammer-drill)
Minimum diameter of hole clearance in fixture for

steel insert element (following anchor installation)
Minimum member thickness in normal-weight

concrete
Minimum cover thickness in hollow core concrete

slabs (see Hollow-Core concrete figure)

Critical edge distance c

Minimum edge distance c

Minimum spacing distance s

Maximum installation torque T

Effective tensile stress area
(undercut anchor body)

Minimum specified ultimate strength f

Minimum specified yield strength f

Uncracked concrete

Mean axial stiffness

For SI: 1 inch = 25.4 mm, 1 ft-lbf = 1.356 N-m.

1. The information presented in this table is to be used in conjunction with the design criteria of ACI 318-14 Chapter 17 or ACI 318-11 Appendix D, as applicable.

2. For installation detail for anchors in hollow-core concrete slabs, see Hollow-Core concrete figure.

3. The embedment depth, h

4. Mean values shown, actual stiffness varies considerably depending on concrete strength, loading and geometry of application.

4

Cracked concrete

nom

, is measured from the outside surface of the concrete member to the embedded end of the anchor.

ℓ

h

min,core

β

a

bit

nom

ef

o

anch

-

d

h

h

min

ac

min

min

max

A

se

uta

ya

uncr

β

cr

1,2,3

Nominal Anchor Diameter (inch)

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)

J 2.1 to 2.8

in. 7/16

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)

in.

(mm)
ft.-lb.

(N-m)

2

in.

(mm2)

psi

(N/mm2)

psi

(N/mm2)

lbf/in. 50,400

lbf/in. 29,120

3/8

0.625
(15.9)

3/8

(9.5)

5/8

ANSI

3/4

(19)
3/4

(19)
3/4

(19)

15/16

(24)

2-1/2

(64)

1-1/2

(38)

2-1/4

(57)

2-1/2

(64)

2-3/4

(70)

5

(7)

0.044
(28.4)

95,000

(655)

76,000

(524)

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REFERENCE DATA (ASD)

d

bit

h

nom

MECHANICAL ANCHORS

Mini-Undercut+ Anchor Detail

d

bit

d

bit

STOP DRILL BIT

h

min

ℓ

anch

d

a

h

nom

h

o

Before After

h

min

h

o

d

a

h

ef

h

nom

MINI-UNDERCUT+

SETTING TOOL

Mini-Undercut+ Anchor Installed with Steel Insert Element

d

bit

h

h

o

d

a

ef

h

min

h

o

d

a

d

h

Do not exceed

h

h

ef

h

nom

T

max

min

h

o

d

a

d

Do not exceed

REFERENCE DATA (ASD)

Ultimate and Allowable Tension Load Capacities for Mini-Undercut+ in Normal-Weight Concrete

Nominal

Rod/

Anchor

Diameter

3/8

Minimum

Nominal

Embed.

d

in.

Depth

in.

(mm)

3/4
(19)

Tension

lbs

(kN)

1,535

(6.8)

f'c = 3,000 psi (20.7 MPa) f'c = 4,000 psi (27.6 MPa)

Ultimate Allowable Ultimate Allowable

Shear

lbs

(kN)

1,975

(8.8)

1. Tabulated load values are for anchors installed in concrete. Concrete compressive strength must be at the specified minimum at the time of installation.

2. Allowable load capacities are calculated using an applied safety factor 4.0.

3. Linear interpolation may be used to determine allowable loads for intermediate compressive strengths.

Minimum Concrete Compressive Strength

Tension

lbs

(kN)

385
(1.7)

Shear

lbs

(kN)

495
(2.2)

Tension

lbs

(kN)

1,770

(7.9)

Shear

lbs

(kN)

2,275
(10.1)

h

d

bit

1,2,3

Tension

lbs

(kN)

445

(2.0)

Tmax

h

ef

h

nom

Shear

lbs

(kN)

570
(2.5)

Tension

lbs

(kN)

2,345
(10.4)

1,2,3

Shear

lbs

(kN)

3,275
(14.6)

Tension

lbs

(kN)

585
(2.6)

Shear

lbs

(kN)

820
(3.6)

Ultimate and Allowable Tension Load Capacities for Mini-Undercut+ in Hollow-Core Plank

Nominal

Anchor

Diameter

TECH MANUAL – MECHANICAL ANCHORS ©2017 DEWALT – REV. C

Rod/

d

in.

3/8

Minimum

Nominal

Embed.

Depth

in.

(mm)

3/4
(19)

f'c = 5,000 psi (34.5 MPa) f'c = 6,000 psi (41.4 MPa) f'c = 8,000 psi (55.2 MPa)

Ultimate Allowable Ultimate Allowable Ultimate Allowable

Tension

lbs

(kN)

1,855

(8.3)

Shear

lbs

(kN)

2,590
(11.5)

Tension

lbs

(kN)

465
(2.1)

Shear

lbs

(kN)

650
(2.9)

Minimum Concrete Compressive Strength

Tension

lbs

(kN)

2,035

(9.1)

Shear

lbs

(kN)

2,835
(12.6)

Tension

lbs

(kN)

510
(2.3)

Shear

lbs

(kN)

710
(3.2)

1. Tabulated load values are for anchors installed in concrete. Concrete compressive strength must be at the specified minimum at the time of installation.

2. Allowable load capacities are calculated using an applied safety factor 4.0.

3. Linear interpolation may be used to determine allowable loads for intermediate compressive strengths.

Mini-Undercut+ Installed Detail for Anchor in the Underside of Hollow-Core Concrete slabs

3

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12"

Max.

8-1/2"

Max.

1-1/2"

2-1/4"

Min.

5"

Max.

3/4"

Mini-Undercut+ (Typ)

STRENGTH DESIGN (SD)

STRENGTH DESIGN (SD)

Tension Design Information for Mini-Undercut+ Anchors in the Underside of
Normal-weight Concrete and the Underside of Hollow-Core Concrete Slabs

Design Characteristic Notation Units

1,2,3,4,5,6,7

Nominal Anchor Size / Threaded Rod Diameter (inch)

code listed

ICC-ES ESR-3912

3/8

Anchor category 1, 2 or 3 - 1

Nominal embedment depth h

Steel Strength In Tension (ACI 318-14 17.4.1 or ACI 318-11 D.5.1)

Steel strength in tension N

Reduction factor for steel strength

Concrete Breakout Strength In Tension (ACI 318-14 17.4.2 or ACI 318-11 D.5.2)

Effective embedment h

Effectiveness factor for uncracked concrete k
Effectiveness factor for cracked concrete k
Modification factor for cracked and

uncracked concrete

Critical edge distance c

Reduction factor, concrete breakout strength

3

Pullout Strength In Tension (ACI 318-14 17.4.3 or ACI 318-11 D.5.3)

Pullout strength, uncracked concrete N

Pullout strength, cracked concrete N

Reduction factor, pullout strength

Pullout Strength In Tension For Seismic Applications (ACI 318-14 17.2.3.3 or ACI 318-11 D.3.3.3)

Characteristic pullout strength, seismic N

Reduction factor, pullout strength, seismic

For SI: 1 inch = 25.4 mm, 1 ksi = 6.894 N/mm2; 1 lbf = 0.0044 kN.

1. The data in this table is intended to be used with the design provisions of ACI 318-14 Chapter 17 or ACI 318-11 Appendix D, as applicable; for anchors resisting seismic load combinations the
additional requirements of ACI 318-14 17.2.3 or ACI 318-11 D.3.3, as applicable, shall apply.

2. Installation must comply with manufacturer’s published installation instructions and details.

3. All values of

4. The threaded rod or bolt strength must also be checked, and the controlling value of

5. Select the appropriate effectiveness factor for cracked concrete (k

6. The characteristic pullout strength for concrete compressive strengths greater than 2,500 psi for anchors may be increased by multiplying the value in the table by (f’c / 2,500)
(f’c / 17.2)
in the table by (f’c / 6,000)

7. Reported values for characteristic pullout strength in tension for seismic applications are based on test results per ACI 355.2, Section 9.5.

φ

are applicable with the load combinations of IBC Section 1605.2, ACI 318-14 Section 5.3, or ACI 318-11 Section 9.2.

0.5

. For hollow-core concrete slabs the characteristic pullout strength for concrete compressive strengths greater than 6,000 psi for anchors may be increased by multiplying the value

0.5

for psi or (f’c / 41.4)

0.5

.

nom

sa

φ

ef

uncr

cr

Ψ

c,N

ac

φ

p,uncr

p,cr

φ

p,eq

φ

cr

) or uncracked concrete (k

in.

(mm)

lb

(kN)

- 0.65

in.

(mm)

- 24

- 17

- 1.0 (see note 5)

in.

(mm)

- 0.40

lb

(kN)

lb

(kN)

- 0.40

lb

(kN)

- 0.40

Nsa

φ

between the anchor and rod must be used for design.

uncr

) and use

c,N

ψ

= 1.0.

3/4

(19)

4,180
(18.6)

3/4

(19)

2-1/4

(57)

See note 7

455

(2.0)

410

(1.82)

0.5

for psi or

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STRENGTH DESIGN (SD)

MECHANICAL ANCHORS

Shear Design Information for Mini-Undercut+ Anchors in the Underside of
Normal-weight Concrete and the Underside of Hollow-Core Concrete Slabs

Design Characteristic Notation Units

Anchor category 1, 2 or 3 - 1

Nominal embedment depth h

Steel strength in shear V

Reduction factor, steel strength

Steel Strength in Shear for Seismic (ACI 318-14 17.2.3.3 or ACI 318-11 D.3.3.3)

Steel strength in shear, seismic V

Reduction factor, steel strength in shear, seismic

Concrete Breakout Strength in Shear (ACI 318-14 17.5.2 or ACI 318-11 D.6.2)

Load bearing length of anchor in shear ℓ

Nominal outside anchor diameter d

Reduction factor for concrete breakout strength

Coefficient for pryout strength k

Effective embedment h

Reduction factor, pryout strength

For SI: 1 inch = 25.4 mm, 1 lbf = 0.0044 kN.

1. The data in this table is intended to be used with the design provisions of ACI 318-14 Chapter 17 or ACI 318-11 Appendix D, as applicable; for anchors resisting seismic load combinations the

additional requirements of ACI 318-17 17.2.3 or ACI 318-11 D.3.3, as applicable shall apply

2. Installation must comply with manufacturer’s published installation instructions and details.

3. All values of

4. The strengths shown in the table are for the Mini-Undercut+ anchors only. Design professional is responsible for checking threaded rod strength in tension, shear, and combined tension and

shear, as applicable.

5. Reported values for steel strength in shear are based on test results per ACI 355.2, Section 9.4 and must be used for design in lieu of the calculated results using equation 17.5.1.2b of ACI

318-14 or equation D-29 in ACI 318-11 D.6.1.2.

6. Reported values for steel strength in shear for the Mini-Undercut+ anchors are for seismic applications and based on test results in accordance with ACI 355.2, Section 9.6 and must be used

for design.

φ

are applicable with the load combinations of IBC Section 1605.2, ACI 318-14 Section 5.3, or ACI 318-11 Section 9.2.

1,2,3,4,5,6

Nominal Anchor Size / Threaded Rod Diameter (inch)

nom

Steel Strength in Shear (ACI 318-14 17.5.1 or ACI 318-11 D.6.1)

sa

φ

sa, eq

φ

e

a

φ

Pryout Strength in Shear (ACI 318-14 17.5.3 or ACI 318-11 D.6.3)

cp

ef

φ

in.

(mm)

lb

(kN)

- 0.60

lb

(kN)

- 0.60

in.

(mm)

in.

(mm)

- 0.45

- 1.0

in.

(mm)

- 0.45

code listed

ICC-ES ESR-3912

3/8

3/4
(19)

985

(4.4)

895

(4.0)

3/4
(19)

0.625
(15.9)

3/4
(19)

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ORDERING INFORMATION

Mini-Undercut+

Cat. No. Anchor Size Rod/Anchor Dia. Drill Diameter Overall Length Box Qty. Ctn. Qty.

PFM2111820 3/8" x 3/4" 3/8" 5/8" 3/4" 100 600

Accu-Bit™ for DEWALT Mini-Undercut+

Cat. No. Mini-Undercut+ Size

Rod/Anchor

Dia.

PPA2431720 5/8" x 3/4" Stop Drill Bit - PT Anchor 3/8" 5/8" 3/4" 1

Drill

Diameter

Drill Depth Std. Pack

ORDERING INFORMATION

SDS Plus Setting Tool for DEWALT Mini-Undercut+

Cat. No. Mini-Undercut+ Size

PFM2101720 3/8" SDS+ Setting Tool - PT Anchor 3/8" 1

Rod/Anchor

Dia.

Std. Pack

Mini-Undercut+ Ordering Matrix

™

Description Anchor Cat No.

3/8" x 3/4" Mini-Undercut+ PFM2111820 PPA2431720 PFM2101720

Accu-Bit

Cat. No.

Setting Tool

SDS Plus

Cat. No.

Recommended SDS

Hammer-Tools (DEWALT)

DCH273, DCH133, D25133, D25262

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