780 CMR, 2306.7
Shear walls sheathed with portland cement plaster, gypsum lath, gypsum sheathing or gypsum board shall be designed and constructed in accordance with AF & PA SDPWS. Shear walls sheathed with these materials are permitted to resist horizontal forces using the allowable shear capacities set forth in Table 2306.7. Shear walls sheathed with portland cement plaster, gypsum lath, gypsum sheathing or gypsum board shall not be used to resist seismic forces in structures assigned to Seismic Design Category E or F.
TABLE 2306.7ALLOWABLE SHEAR FOR WIND OR SEISMIC FORCES FOR SHEAR WALLS OF LATHAND PLASTER OR GYPSUM BOARD WOOD FRAMED WALL ASSEMBLIES
| TYPE OF MATERIAL | THICKNESS OF MATERIAL | WALLCONSTRUCTION | FASTENER SPACINGb MAXIMUM (inches) | SHEAR VALUEa, e(plf) | MINIMUMFASTENER SIZEc, d, j, k |
1. Expanded metal or woven wire lath and portland cement plaster | 7/8" | Unblocked | 6 | 180 | No. 11 gage 11/2" long, 7/16" head No. 16 gage galv. staple, 7/8" legs |
2. Gypsum lath, plain or perforated with vertical joints staggered | 3/8" lath and 1/2" plaster | Unblocked | 5 | 180 | No. 13 gage galv. 11/8" long, 19/64" head, plasterboard nail |
| 3/8" lath and | Unblocked | 5 | 100 | No. 16 gage galv. staple 11/8" long, | |
3. Gypsum lath, plain or perforated | 1/2" plaster | 0.120" nail min.3/8" head, 11/4 long | |||
| 1/2" × 2" × 8" | Unblocked | 4 | 75 | No. 11 gage, 13/4" long, 7/16" head, diamond-point, galvanized | |
| 1/2" × 4" | Blockedd Unblocked | 4 7 | 175 100 | ||
4. Gypsum sheathing | 16 Ga. Galv. Stable, 13/4" long | ||||
| 5/8" × 4" | Blocked | 4" edge/7" field | 200 | 6d galvanized 0.120' Nail, min.3/8" head, 13/4" long | |
| Unblockedf | 7 | 75 | |||
| Unblockedf | 4 | 110 | |||
| Unblocked | 7 | 100 | 5d cooler (15/8" × 0.086") or wallboard 0.120" nail, min.3/8× head, 11/2" long No. 16 gage galv. staple, 11/2" long | ||
| Unblocked | 4 | 125 | |||
| Blockedg | 7 | 125 | |||
| 1/2" | Blockedg | 4 | 150 | ||
| Unblocked | 8/12h | 60 | |||
| Blockedg | 4/16h | 160 | |||
| Blockedf, g | 4/12h | 155 | No. 6-11/4" screwsi | ||
| Blockedg | 8/12h | 70 | |||
5. Gypsum board, gypsum veneer base or water-resistant gypsum backing board | Blockedg | 6/12h | 90 | ||
| 7 | 115 | ||||
| Unblockedf | 4 | 145 | 6d cooler (17/8" × 0.092") or wallboard | ||
| 0.120" nail, min. 3/8" head, 13/4" long | |||||
| Blockedg | 7 | 145 | No. 16 gage galv. staple, 11/2" legs, 15/8" long | ||
| 4 | 175 | ||||
| 5/8" | Blockedg Two-ply | Base ply: 9 Face ply: 7 | 250 | Base ply-6d cooler (17/8" × 0.092") or wallboard 13/4" × 0.120" nail, min. 3/8' head 15/8" 16 gage galv. staple Face ply-8d cooler (23/8" × 0.113") or wallboard 0.120" nail, min.3/8 " head, 23/8" long No. 15 gage galv. staple, 21/4" long | |
| Unblocked | 8/12h | 70 | No. 61/4"-1screwsi | ||
| Blockedg | 8/12h | 90 |
| For SI: 1 inch = 25.4 mm, 1 pound per linear foot = 14.5939 N/m. |
| a. These shear walls shall not be used to resist loads imposed by masonry or concrete walls (see Section 4.1.5 of AF & PA SDPWS). Values shown are for short-term loading due to wind or seismic loading. Walls resisting seismic loads shall be subject to the limitations in Section 12.2.1 of ASCE 7. Values shown shall be reduced 25 percent for normal loading. |
| b. Applies to fastening at studs, top and bottom plates and blocking. |
| c. Alternate fasteners are permitted to be used if their dimensions are not less than the specified dimensions. Drywall screws are permitted to substitute for the 5d (15/8" × 0.086"), and 6d (17/8" × 0.092")(cooler) nails listed above, and No. 6 11/4 inch Type S or W screws for 6d (17/8" × 0.092) (cooler) nails. |
| d. For properties of cooler nails, see ASTM C 514. |
| e. Except as noted, shear values are based on a maximum framing spacing of 16 inches on center. |
| f. Maximum framing spacing of 24 inches on center. |
| g. All edges are blocked, and edge fastening is provided at all supports and all panel edges. |
| h. First number denotes fastener spacing at the edges; second number denotes fastener spacing at intermediate framing members. |
| i. Screws are Type W or S. |
| j. Staples shall have aminimum crown width of 7/16 inch, measured outside the legs, and shall be installed with their crowns parallel to the long dimension of the framing members. |
| k. Staples for the attachment of gypsum lath and woven-wire lath shall have a minimum crown width of 3/4 inch, measured outside the legs. |
780 CMR, 2306.7