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Allowable Load Tables Allowable Roof Loads (plQ-1.15 Load Duration Factor <br /> Example:Allowable Roof Loads <br /> Key-for each clear opening there are three rows of values: <br /> TL:Maximum total load in pounds per lineal foot(plf)with deflection <br /> limited to.1/180 <br /> LL:Maximum live load in pounds per lineal foot(plf)with deflection <br /> limited to 1/240 Ground Snow Load=30 psf <br /> BL: Required bearing length in inches Design Roof Snow Load=21 psf <br /> Roof Dead Load=10 psf <br /> Steps in Sizing Headers and Beams: Load Duration Factor=1.15 <br /> Roof Truss Span=26'+2'overhang <br /> I. Determine the required total load(live load+dead load)in plf. Clear Opening=10' <br /> 2. Determine the required live load in plf. <br /> 3. Select a clear opening and find columns where the plf value in the Total Load (2672+2')x(21 +10)psf 465 plf <br /> TL row equals or exceeds the required total load,and the plf value Live Load=(2672+2')x 21 psf=315 plf <br /> in the LL row equals or exceeds the required live load. Select the 10'clear opening in Tables 27-32.Read across the TL row in each table <br /> 4. Check required bearing lengths in the BL row. to fmd columns with total loads equal to or greater than the required 465 plf.Then <br /> 5. Find product size options at the to of the columns meeting the check the LL row in those columns to make sure the corresponding live loads are <br /> p p p g equal to or greater than the required 315 plf.Solutions include:from Table 27 for <br /> total load,live load and bearing length requirements. No.I SP lumber,select(2)2x 12s,(3)2x 10s or(4)2x8s;from Table 28 for No.2 SP <br /> lumber,select(3)2x12s or(4)2XIOs;from Table 29 for No.3 SP lumber,select(4) <br /> 2xl2s;from Table 30 for 2417-1.7E(V4)SP glulam,select a 3-1/2x9-1/4"beam; <br /> from Table 32 for 24F-1.8E(V3)SP glulam,select a 3-1/8x8-1/4"beam.All of the <br /> lumber solutions and the 24F-1.8E glularrt solution require a 1.5"bearing length, <br /> while the 24F-1.7E glulam solution requires a 3.0"bearing length. <br /> TableNo. I SouthernLumber <br /> Clear 1-ply 2-ply 3-ply 4-ply <br /> Opening 2 x 6 1 2x8 j2x10j2x12 2x6 I 2x8 2x10 2x12 2x6 I 2x8 12x1012xl2 2x6 I 2x8 2x10 2x12 <br /> TL 464 725 962 1296 928 1450 1925 2591 1590 2472 3266 4366 2120 3296 4355 5821 <br /> 4' LL 464 725 962 1296 928 1450 1925 2591 1590 2472 3266 4366 2120 3296 4355 5821 <br /> BL 1.5 3.0 3.0 4.5 1.5 3.0 3.0 4.5 1.5 3.0 3.0 4.5 1.5 3.0 3.0 4.5 <br /> TL 211 335 453 626 422 671 906 1252 726 1152 1552 2139 968 1536 2070 2852 <br /> 6' LL 211 335 453 626 422 671 906 1252 726 1152 1552 2139 968 1536 2070 2852 <br /> BL 1.5 1.5 3.0 3.0 1.5 1.5 3.0 3.0 1.5 1.5 3.0 3.0 1.5 1.5 3.0 3.0 <br /> TL 119 190 259 361 238 381 517 722 410 656 890 1240 547 875 1187 1654 <br /> 8' LL 119 190 259 361 238 381 517 722 410 656 890 1240 547 875 1187 1654 <br /> BL 1.5 1.5 1.5 3.0 1.5 1.5 1.5 3.0 1.5 1.5 1.5 3.0 1.5 1.5 1.5 3.0 <br /> TL 76 122 166 233 151 244 332 466 262 421 573 802 349 561 764 1069 <br /> 10' LL 73 122 166 233 146 244 332 466 219 421 573 802 292 561 764 1069 <br /> BL 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 3.0 1.5 1.5 1.5 3.0 <br /> TL 52 84 115 162 104 168 230 323 164 291 397 558 218 388 529 744 <br /> 12' LL 42 84 115 162 85 168 230 323 127 290 397 558 170 386 529 744 <br /> BL 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 <br /> TL 34 61 84 118 68 123 168 236 101 212 290 409 135 283 387 545 <br /> 14' LL 27 61 84 118 54 122 168 236 80 183 290 409 107 244 387 545 <br /> BL 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 <br /> TL 22 46 64 90 44 93 127 180 66 156 220 311 88 208 294 415 <br /> 16' LL 18 41 64 90 36 82 127 180 54 123 220 311 72 164 294 415 <br /> BL 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 <br /> TL 15 36 50 70 30 72 99 141 45 108 172 244 60 144 230 325 <br /> 18' LL 13 29 50 70 25 58 99 141 38 87 172 244 51 116 230 325 <br /> BL 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 <br /> (See Requirements for Use on page 23,and Key,Example and Notes on this page) <br /> Notes for Tables 27-32:Allowable Roof Loads(plf)-1.15 Load Duration Factor <br /> • Tabulated total loads(TL)and live loads(I.I.)represent the allowable uniformly distributed loads that a beam can support in addition to its own weight. <br /> Deflection is limited to.1/180 for total load and.1/240 for live load.To determine an allowable live load for a deflection limit other than 1/240,multiply <br /> the LL value by the ratio of 240 divided by the desired deflection constant.The result must not exceed the corresponding TL value far the same clear opening <br /> and product. <br /> • Tabulated bearing lengths(BL)reflect the number of 2x trimmers required at each end of the header or beam based on the corresponding plf loads(e.g., 1.5" <br /> =one trimmer,3.0"=two trimmers,etc.).Additional checks may be required for bearing length and trimmers. <br /> • See Assumptions for Table Development beginning on page 2 for details on design assumptions made to generate these tables. <br /> • Interpolation between clear openings is permitted. <br /> • The design span is assumed to be the clear opening plus 1/2 the required bearing length at each end. <br /> NEWN <br /> Southern Forest Products Association SOUTHERN PINE HEADERS&BEAMS I DESIGN <br /> SouthernPine.com Copyright 0 2013.Southern Forest Products Association.All rights reserved. 2013 Edition I 29 VALUES <br />