FLOOD02929

• County: Statewide
• Community: na
• Basin: Statewide
• Title: Manufactured Home Installation in Flood Hazard Areas
• Date: 9/1/1985
• Prepared By: FEMA
• Floodplain - Doc Type: Educational/Technical/Reference Information

Cross Bracing
To improve the lateral stability of an elevated
foundation system using vertical members brac-
ing will be needed along the length of the elevated
foundation between vertical members as shown
in Figure 4.42. This becomes increasingly more
important as the ~~ight above grade increases.
Tables 4.18 and 4.19 provide minimum recom-
mended sawn timber sizes for cross bracing. The
number of spans between vertical members (bays)
needing cross bracing is shown along with the
minimum sawn timber size. The required net area
of the cross bracing is calculated using the
allowable working stress in tension parallel to grain
for the wood type used as follows:

An p
=
Ft
Where:
An = Net area (sq. in.)
p = Axial load (Ibs.)
Ft = Allowable working stress in tension
parallel to grain (psi)

Based on a Ft of 531.3 psi (550 psi corrected
for service condition, treatment and load duration
factors), the minimum sawn timber sizes shown

Table 4.17

MINIMUM SAWN LUMBER HORIZONTAL BEAM

Vertica.l MenDer Manufactured Home Width (ft.)
Spacing (ft.) 12' 14
Wind Load = 15 O1assis I-Beam SDacin~ (in.)
Roo f Li ve Load = 20 ps f 75 1/2 82 99 75 1/2 82 99
5 2@ 3"xI2" 20 311x12" 20 211xt41l 2@ 311x1411 2@ 3"x14" 20 311x14"
6 4@ 2"xI2" 2{!. 3"x1211 2{!. 2"x 411 4@ 2"x14" 4@ 2"x14" 2@ 3"xI4"
7 20 311x14" Z{!. 3"x14n 2C} 3"xI211 4@ 3"xI2" 4@ 3"x12" 4@ 2"xI4"
8 4@ 2"XI411 2@ 3"XI4" 4@ 2"XI2" 4@ 3"x141t 4@ 311x12" 4@ 2"xI4"
9 4@ 2"x14" 4@ 2"x14" 2@ 3"x14" 40 3"x14" 4@ 3"xI4" 4@ 3"xI2"
10 2@ 3"XI6" 4C 3"X14" 2@ 3"X141r 40 311x14" 40 3"x14T1 4@ 31lx14"
Wind Load = 25 psf
Roof Live Load = 20 psf
5 Z{!. 3"x1211 2@ 3hx12" 2@ Jllxl2" 4@' 2"xI4" 2@ 3"xI4" 4~ 211X121T
6 4@ 2"x121f 20 3"x12" 40 2"xIO" 4@ 2"xI4" 2@ 3"xI4" 40 21'X 12"
7 40. 211x12" 2{!. 3"x14" 4@ 211x1211 4@ 3t'x12" 40 3"x121l 40 2"x1411
8 4@ 2"XI2" 2@ 3"XI4" 4@ 2"XI2" 4@ 311x14" 4@ 311x12" 4@ 2"xI4"
9 4@ 3"x12" 4@ 2"xI4" 2@ 3"x14" 4e. 3"x 14" 4@ 3"xI4" 4@. 3"xI2"
10 4@ 3"XI2" 40 2"X1411 2@ 3"X14" 4@ 311x14" 4@ 3"xI4" 4@ 3"xI4"
Roo f Li ve Load = 30 psf
5 Ze 3"xI4" 2@ 3"x12" 2@ 211x14" 4@ 2"xI411 40 2"xI4" 2@. 311x14"
6 2@ 3"x'14" 2@. J"xl4n 4@ 2"xI2" 4@ 3"xI2" 4@ J"xI2" 4@. 211x14"
7 40. 21lx14" 40 211x14n 2@ J"xI4" 4e 311x141l 4@ 3"xI2" 4@. 3"xI2f1
8 4@. 3"X12" 4@ 2"X1411 2@ 3"XI4" 4@ 3"xI4" 4@ JlIxl4" 4@ 311x14"
9 4C} J"xI2f1 4@ J1fx1211 4@ 2"xI4" 4@ J"xI4f1 4@ Jllxl4" 4@ 311x141t
10 4@ 3"XI4" 4@ 3"XI4" 4@ 3"XI2" 4@ J"x1611 40 3"x16" 403"xI4"
Roof Ll ve Load = 40 psf
5 2e 311x14" 2@ 3"xI4" 2@ 311x12" 4C J".x12" 4@ 21'.x14" 2@ 3"x14"
6 40. 2"xI411 20. J"xI4" 4@ 211x12" 4@ 3"xI4" 4@ 3"xI4" 2@ 311x16"
7 4@ 3"x12 4C 2"xI411 20 Jllxl4" 4@ 31fx141T 4@ 3"x14" 4@ 31fx12"
8 4@ 3"xI2f1 40 3"xI2" 4@. 2"XI4" -- 40 3"xI4" 4e 3"xI4"
9 4~ 3"xI411 40. JIIX 1211 4e 2"xI4" -- -- 4@ 3"xI4"
10 40 311x14" 4e 311x14" 4@ 3"xI211 -- -- --

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