38B-108 (9) APPEND!)(
DESIGN 114G SEAMS 5Y US!NG FORMULAS
oft L"n 5F -h -
YR OCEDUR.E (Fos, a---1 G FOR mVLA5)
S?G P 1 - PICK TYPE OF WOOD, TABLE (p-1.
f= P3:
E= Psi
STEP Z—DETER HINE. TOTAL LOAD, W, AMD TYPE W LOAD
015TRIDUTIO14 (CASE I, 7Z_M,OK -W% APM11(DIX I).
w- lb.
STEP 3-DEFINE CLEAR 5PA14 L.
L = INCHES
STEP 4-CALCULATE 5EMDING MOMENT M-.X.-, FROM APPEI`PIX ?. -
1"1 MAX. ° Imc4 POUNDS
JTEY 5 -- f p = MMR FOR RECTANGULAR BEAMS. SU65TITU'I"E?
ID / IN THE EQUATION BELOW, THE VALUE f, THE
VALUE MMgx, FROM STEP 4, AND 'THE ASSUMED
DEPTH, d, AND SOLVE FOR WIDTH; b.
b = M MAX.
# dam_
RECALCULATE IF MECE55ARY TO GIVE BEAM
APPROXIMATE.LV 5QUARE 5HAPE.
STEP b- CALCULATE QKA%. FROM APPENDIX I. FIRST CALCULATE
;'IOI�Et;T vr� IC ERTiA, i, IN T-—L- THEN I StSI3 sTITUTr�
VALUE 7U CALCULATE DMA X.
STEP 7- iALCiSL yT� DA,ax= T Flij d-Iii-T 8E LESS THA' 1360
FOR FLOORS AND LE.55 THAN Yi+IO FOR ROOFS. IF
NOT, INCREASE W1917H, b, OR DEPTH, d, OF SEAM
AND RECALCULATE
STET B- CHECK 5HEARi HtiAx., IN APPENDIX I. IS HMA%.
LE55 THAN ALLOWABLE 5HEP►K, h? IF YE5, BEAM
15 0K. OTHERWISE, INCREASE 15EAN WIDTH OR
DEPTH AND RECHE-CK SHEAR.
f
198
PAPPEUIEN 1^4 1
5EAH DE51GH FORMULA5 (POP, KECTAHGULAR 5EAM5)
LORI) W mmAy- WL
CASE 1.
UNIFORM LOAD
!RF=W/2 w
L
bd
MAIA.
CASE U. M 3
7WO-PUNT LOAP -rrt�_�j
(q5 5 H Ow H) Dm4x, Z7
1 '41,_=R,
L----------------- a
HMAX. - J5
LOAD %4 m WL
CASE DI. W/2 14
01ME-P01417 UGAD WO
(CENTERED) d_k �aL I
T, W
f %
RF L Htwx. = -75
wt_
w = W
CAH-T!LtE_VcR
POINT LOAD D11A X
HAX.
DEFRNIT)ONS MAXIMUM bEhDING MOMENT (Ihr-" 7, lb .s!
W= TOTAL LOAD (POUNP5) DtIAX.- MAXIMUM DEFLY-C710H OF 15LAM '�Jlricj"
(5EE CHAPTER b, "C-_XkLCtjLA_TlNc, timpa.-MAXMUM HOP,%-ZONT.A.1- -AF-Afl, -57rKESS
LOADS Ch IAHBEPVS*). )?i BEAM
L C-LEAK 5FPN, 014C.Pc "A),- ALL0\VA?,LE F.,eF-K 5-1-ft'Ess IN
1.51� F
E—HOPULV5 OF ELWMIT'i (psi). 5emolvAc, (f(psi) k,5EF- TADLE 31
1= riolittvl- OF rtiEmrp, frw REC- h- MA)" ALLOWA5LE: 'rAOK%Z0NT;kL 3"EAR
-TANGULAfk MM5) = b43 R
QNC"F_54)� 5-TRES5 (psi) (SEE —, bLF- b-il
—,:x- RF_ArM6N FoRM
b=\vmTH or BEnH (*4CHF_%-
A= DEPTH OF BE V'! X O'T F_
_,i = FouND'S PER 5qVAKE INCH.
197
TABLE III-1 SPAN OF DEPTH OF TIMBER(d)* c
BEAM DESIGN LOADS TIMBER(L) (inches)
(feet) 6 7 8 9 10 12 14 16
(POUNDS PER INCH
OF BEAM WIDTH) 6 Floor 1066 1399 1599 1799 1999 2399 2799 3199
Roof 1066 1399 1599 1799 1999 2399 2799 3199 ;
OAK CASE I,
7 Floor 870 1244 1599 1799 1999 2399 2799 8199 .
UNIFORM LOAD Roof 914 1244 1599 1799 1999 2399 2799 3199 1�
Design Values: Table 6-1 8 Floor 666 1058 1422 1799 1999 2399 2799 3199
Allowable Deflection: Roof 799 1088 1422 1799 1999 2399 2799 3199
Floor: 1/360 9 Floor 526 836 1248 1599 1975 2399 2799 3199
Roof: 1/240 Roof 711 967 1264 1599 1975 2399 2799 3199
LORD 10 Floor 426 677 1011 1439 1777 2399 2799 3199
Roof 639 871 1137 1439 1777 2399 2799 3199
p..
-- d 11 Floor 352 559 836 1190 1616 2327 2799 3199
t Roof 528 791 1034 1309 1616 2327 2799 3199 s
SPA H �
� L i 12 Floor 296 470 702 999 1371 2133 2799 3199
CASE I Roof 444 705 948 1199 1481 2133 2799 3199
UNIFORM LOAD 13 Floor 252 400 598 852 1168 1969 2680 3199
Roof 378 601 875 1107 1367 1969 2680 3199
14 Floor 217 345 515 734 1007 1741 2488 3199
Roof 326 518 773 1028 1269 1828 2488 3199 h
15 Floor 189 301 449 639 877 1517 2322 3034
Roof 284 451 674 959 1185 1706 2322 3034 f
16 Floor 166 264 395 562 771 1333 2117 2844
Roof 249 396 592 843 1111 1599 2177 2844
17 Floor 147 234 349 498 683 1181 1875 2677
Roof 221 351 524 747 1025 1505 2049 2677
18 Floor 131 209 312 444 609 1053 1672 2497
Roof 197 313 468 666 914 1422 1935 2528
iYU
TABLE 111-2 6 Floor 800 1088 1422 1799 1999 2399 2799 3199
Roof 800 1088 1422 1799 1999 2399 2799 3199 ',
BEAM DESIGN LOADS 7 Floor 638 933 1219 1542 1904 2399 2799 3199
(POUNDS PER INCH Roof 685 933 1219 1542 1904 2399 2799 3199
OF BEAM WIDTH)
l OAK CASE II, 8 Floor 489 776 1066 1350 1666 2399 2799 3199 N,
TWO POINT LOAD Roof 600 816 1066 1350 1666 2399 2799 3199 .
9 Floor 386 613 916 1200 1481 2133 2799 3199
Design Values: Table 6-1 Roof 533 725 948 1200 1481 2133 2799 3199 '%
Allowable Deflection: 10 Floor 313 497 742 1056 1333 1920 2613 3199
Floor: 1/360 Roof 469 653 853 1080 1333 1920 2613 3199
W Roof: 1/240 '°
11 Floor 258 410 613 873 1197 1745 2375 3103
Yz WAD )iLOAD Roof 388 593 775 981 1212 1745 2375 3103
�y' Lj3 L[ 12 Floor 217 345 515 733 1006 1600 2177 2844
Roof 326 517 711 900 1111 1600 2177 2844
13 Floor 185 294 439 625 857 1476 2010 2625 -
SPA tj
t Roof 277 441 656 830 1025 1476 2010 2625
All
CASE II 14 Floor 159 253 378 539 739 1277 1866 2438
TWO P01" LOAD Roof 239 380 567 771 952 1371 1866 2438
15 Floor 139 220 329 469 644 1113 1742 2275 3=
Roof 208 331 494 704 888 1280 1742 2275
16 Floor 122 194 289 412 566 978 1553 2133
Roof 183 291 434 619 833 1200 1633 2133
17 Floor 108 172 256 365 501 866 1376 20073
Roof 162 258 385 548 752 1129 1537 2007
18 Floor 96 153 229 326 447 772 1227 1832
a
Roof 144 230 343 489 670 1066 1451 1896
T
*Actual Size, Not Nominal Size
200
r u_:
s 4
.,,I,P„ Attno,+niflY
•.. ._ r e a;rr;!t+ �ilt4'ra.T r �'�. tr�noa
Fa= Tdbi3
i200
•° ... _ `.s e•Pt•„' ,t,dtYP..P.111 iii vn°
'liije ar F5 Y lF
Y. ri 'l e]Tr! t iiV !1111 i elFO.L'on vFii
S �(7yrh t7)rt ICS a1W YYYW Vai,
•.�'
eirTe af.. g ,
�wi,.- "-`'e't`�.3'r elen'ie�ita3'�
b
t?1aa 1: s ,, .;� '�.�; �� .;.. � a eel iiaL had. ssna d, �ntroduction.11 You n-ve>,eC�"2n2Cal knowledge,
for r�S an €'Ir rri�ei � ii ii
Say, .,€' ae�ed their this Win be an op
portunrty to reYleW the
failure of i4; m the st9 ess-Straw curve") basic principles of the phyS1CS Of fo also wish t to and
11 0 loo
were pines, heado s, and other softwoods. structural design. You may
The hardwoods,such as oak and maple,were at the design equations in Appendices I and
still erect,and some,sirc.h as I i.r`ch and beech, 2. (We give beam design tables for sizing
were bowed to the gro"I'd, w itho-rt'sreaking.. timbers later in this chapter and in Ap-
On the wavy bacl;from the stream, as I was pendix 3.) These tables are applicable to the
L this in and t eahz inn hovF� Dell this framing methods shown in this book. If you
illustrated the variation in strengths of dif- have a unique framing system,you may wish
crent species of wood,ap;.ne branch snapped to have an engineer check your design.
off and fell across the path behind me,it was In most parts of the country, your work
time to viev,, nai:ua°e's example of structural on frame design—including joinery specifl-
characteristics of wood from the safety of the cations and the sizing of timbers—will not be
cabin complete until it has met with the approval
Perhaps it was from ice storms and simi- of the local building inspector. Before you
lar natural sitiia%ioas such as this one that meet with him, make sure you fully under-
;he early colonial settlers acquired their in- stand all the elements of the frame. He may
tuitive unt;erstar�zir.�; of tl�e ;iiffe tc:3ces in have specific questions about how your struc-
�rr era las ar icn a carious spa ciPS of wood. ture will carry the loads and resist the forces
stren, hs ate3ac� �, for enample, worrlr �-e as described in his building code. Because
that a pine lea�rr be of a lsrger dinnen- there is some discrepancy in the matter, he
' the c?37je load. may also want to know what wood values
Sr03?than. .lrl (1k beam bearing c1t Ili
aiit-i
z4;•� ,..7 Fn rnta3e �a.t,3 f.
- _ <♦ r ..1-b._ ev.�^.�_ i_ Pli-i k` C.(,il D-4'E i.<a::�. 4 . _. ...-
lalfftl4Mal tl! —
APPENDIX
DESIGNING DEANS Uh1 USING FORMULAS
(FOF� RLC7AMGULAR 5tAtA5)
EYAMPLE.; CONTINUING ExAMPLE I. 'CALCULATING WADS ON IMIDEfikS'
57cp I— WOOD IS vAK.
= 1,600p5i
E= 1.6 X tot,psi = 1,00^,,0010
h= 150 psi CP SE 1. LOADING,
s]!E--r 2— LOA D, W = +},54.+0 lb.
UINI firRM L.CAD CASE Is r_�_4 3t_i k a
SPAN L= 1z° �
STLP 3— 5PAN, 1.= 144 INCi-iE.S, �� (tqy IricH�S)
■
82,080 INCIA d P}
Q
571CP 5*— b= b "MAX. _ (a X 82,060
d2 f d-L X 1600
A55UME d=g". SU55TrrtJ-rC: 114TO EQUATION
AND SOLVE ;LI :. �_ ';a° 11'Ir�?E� i�n'� 5 IIM04I_S�.
STEP 6— CALC'UL R-TE_ Vmp,)C.
S is 1✓ _ S% 4,560 x Stir$
VtlAX. 3S4 Ef _384 X I;b+GO,000 X z.3
bd3
a
a
i IE�Er:`f E; Vv,viA-4.
a
c j j y
itttka — nct' �r�aaea s`i
`JTE1' -?---
OO .S r.a—r--H Ma si Y i-^`�}i j�-� A LL.vi&A NLE t__�_'E VL C.T 4Zj:`I
} L�
0;7- .-a . .... _ .
D S
D PF%p Tin
�y
a
-H AN
�-
n
R t 1
-
x
Y
R
(34�.a
f
f' E
V,
WAP
1
rt50 Ib
30 LL N P _ - 0,CA �7 lm(lca
kk
_ l _
Nsv1
Cl -
II
lD VL
l w+ 1/ p
L
1,, 'PA \ L a 1
V �(
� t
r►��°J 3 2
aW