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Simpsons Strong-Tie THA hangers for underslung joists

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April 27, 2018

Re: Allowable Loads for Simpson Strong-Tie

®

THA Hangers Supporting Joists That Hang Below the Header

This letter provides allowable loads for the face-mount installation of Simpson Strong-Tie THA adjustable truss hangers when the supported member hangs either partially or entirely below the header as shown in Figures 1 and 2.

For top-flange installation options, refer to the

Wood Construction Connector

catalog.

The table below provides allowable loads for alternate THA face-mount fastening schedules that are not shown in the

Wood Construction Connectors

catalog. Also included is the THAI-2 maximum nailing configuration. Tabulated allowable loads are for downward gravity loads only. For applications involving suspended wood joists from a header above the joists, bracing or other means of lateral and torsional support must be provided. Design of bracing systems must be in full compliance with governing building code requirements and must be performed by a qualified design professional when required by the jurisdictional authority.

Allowable Loads for Face-Mount Installation with Joist Hanging Below Header

Dimensions (in.) Fasteners Allowable Loads (lbs.)

Joist

Size

Model

No.

W H Face Joist

Floor

DF/SP

Snow Roof Floor

SPF/HF

Snow Roof

(100) (115) (125) (100) (115) (125)

2x Truss/

Joist

THA213

THA218

1 5

/

8

1

5

/

8

3

1

/

8

13 5

/

16

17

3

/

16

17

11

/

16

(10) 10d

(10) 10d

(4) 10dx1 ½”

(4) 10dx1 ½”

(6) 10dx1 ½”

(6) 10dx1 ½”

(4) 10dx1 ½”

(6) 10dx1 ½”

(6) 10dx1 ½”

(6) 10dx1 ½”

(2) 10dx1 ½”

1,180

1,180

2,440

2,440

2,440

2,440

3,225

1,200

1,200

2,485

2,485

2,485

2,485

3,225

1,200

1,200

2,485

2,485

2,485

2,485

3,225

1,020

1,020

1,160

1,160

1,200

1,200

2-2x

Truss/

Joist

4x Truss/

Joist

3”-5 ¼”

THA218-2

THA222-2

THA413

THA418

THA422

THA426

THAI-2

3 1

/

8

3 5

/

8

3 5

/

8

3

3

5

5

3 1

/

8

/

/

8

8 to

5

5

/

16

22

17

22

26

21

3

13 5

/

1

1

1

11

/

/

/

/

/

16

16

2

16

16

16

(20) 10d

(20) 10d

(10) 10d

(20) 10d

(20) 10d

(30) 10d

(30) 10d

1,180

3,780

1,200

4,260

1,200

4,425

2,100

2,100

1,020

2,100

2,100

2,770

3,270

2,140

2,140

1,160

2,140

2,140

2,770

3,540

2,140

2,140

1,200

2,140

2,140

2,770

3,540

1.

Loads are based on a min. 2-ply 2x carrying member (multiple plies must be fastened together independently of the hanger fasteners to act as one unit to resist the applied load). 10dx2 ½” nails may be used instead of the specified 10d commons at 0.85 of the table load. For single-ply 2x or 1 ¾” wide carrying members, use

10dx1 ½” nails and use 0.77 of the table value. Alternately, SD #9 x1 1/2" screws may be used in place of the specified header and joist nails for full table loads.

2.

At least half of the face fasteners must be installed into the upper half of the header, unless some other means of mechanical reinforcement is used to resist the tension perpendicular to grain stresses. Nails must have a minimum 1/2” edge distance.

3.

THA models: the joist nails should be installed straight into the carried member by straightening the THA double shear nailing tabs. When used to support 2x4 joists, the THA213 or THA218 may be installed with (2)10dx1 ½” nails into the joist (one each side).

4.

THAI-2: Specify W dimension for hanger width needed; W should be ordered 1/16” to 1/8” greater than the joist width.

5.

For installations with fewer face fasteners than specified, reduce the allowable load as follows:

Allowable load = No. of Face Nails Used/No. Face Nails in Table x Table Load

6.

NAILS:

10d = 0.148" dia. x 3" long, 10dx1 1/2" = 0.148" dia. x 1 1/2" long.

Figure 1 – THA218 Supporting Suspended Joist

Figure 2 – THA422 supporting floor truss that is deeper than the header

Page _ 1 _ of _ 2 L-C-THAALT18

Simpson Strong-Tie Company Inc.

5956 W. Las Positas Boulevard Pleasanton, CA 94588 Phone: 925.560.9000 Fax: 925.847.1605 www.strongtie.com

Example 1: 24” deep floor truss with 2000-lb. reaction framing into 1 ¾” x 11 7/8” LVL Ledger

Try THA418 (Allowable load = 2,440 lbs.)

Step 1 - Check Strap Length

(footnote 2):

THA418: Straps do not extend beyond the centerline of the carrying member NG

Try THA422: Straps extend past the centerline by enough distance to install 16 face fasteners (8 ea strap) above the centerline

Step 2 - Determine allowable load based on number of face fasteners that can be installed

(footnotes 2 and 5):

THA422: Allowable load with 20 face fasteners = 2, 440 lbs.

Step 3 - Adjust allowable load for single-ply header

(footnote 1):

THA422 with (20) 10dx1 ½” nails

0.77 = 1,879 lbs. < 2000 lbs.

NG

Allowable load = 2, 440 x

Allowable load = 2, 440 lbs. > THA422 with (20) SD#9x1 ½

2000 lbs.

OK

Example 2: 2x10 joist with 800-lb. reaction suspended from 2-2x10 SPF Header

Try THA213 (Allowable load = 1,020 lbs.)

Step 1 - Check Strap Length

(footnote 2):

THA213: Straps do not extend beyond the centerline of the carrying member NG

Try THA218: Straps extend past the centerline by enough distance to install 4 face fasteners (2 ea strap) above the centerline

Step 2 - Determine allowable load based on number of face fasteners that can be installed

(footnotes 2 and 5):

THA218: Allowable load with 8 face fasteners = 8/10 x 1,020 lbs. =

816 lbs. > 800 lbs.

OK

(Note: Bracing or other means of lateral and torsional support must be provided for joist)

The information in this letter is valid until

4/30/2019

when it will be re-evaluated by Simpson Strong-Tie. Please visit www.strongtie.com for additional pertinent information. If you have questions or need further assistance regarding this matter, please contact the Simpson Strong-Tie engineering department at 800.999.5099.

Sincerely,

SIMPSON STRONG-TIE COMPANY INC.

Page _ 2 _ of _ 2 L-C-THAALT18

Simpson Strong-Tie Company Inc.

5956 W. Las Positas Boulevard Pleasanton, CA 94588 Phone: 925.560.9000 Fax: 925.847.1605 www.strongtie.com

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