Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

Downloaded From : www.EasyEngineering.net
P c
= F c
A where F c
is given by the following equation
⎡
2
⎤
F c
= F* ⎢ F F* c- + F F*
c [1 +( ce / c )]/2 ⎡
⎣ [1 ( ce / c )]/2 c⎤
⎦ - ( F ce / F*
c )/ c ⎥
⎣
⎦
Effective
length, ft
F* c
= 1,650
E’ min
= 580,000
F * c = 1,552
E’ min
= 580,000
F * c = 1,495
E’ min
= 470,000
F * c = 1,322
E’ min
= 510,000
4 ë 4 S4S 4 ë 4 S4S 4 ë 4 S4S 4 ë 4 S4S
4 16,484 15,755 14,433 13,537
5 13,846 13,425 11,811 11,608
6 11,076 10,883 9,333 9,462
7 8,792 8,681 7,252 7,581
8 7,020 6,948 5,761 6,090
9 5,519 5,656 4,655 4,952
10 4,688 4,672 3,819 4,098
11 3,919 3,897 3,206 3,428
12 3,318 3,338 2,697 2,904
13 2,851 2,841 2,315 2,487
14 2,462 2,461 1,999 2,162
15 l e
/d>50 l e
/d>50 l e
/d>50 l e
/d>50
Effective
F * = 1,600
c
E’ min
= 580,000
F * = 1,485
c
E’ min
= 580,000
F * = 1,430
c
E’ min
= 470,000
F * = 1,265
c
E’ min
= 510,000
Length, ft 4 ë 6 S4S 4 ë 6 S4S 4 ë 6 S4S 4 ë 6 S4S
4 25,334 17,646 22,831 20,551
5 21,442 14,922 18,202 17,796
6 17,267 12,258 14,396 14,639
7 13,727 9,952 11,315 11,810
8 10,993 8,154 9,014 9,499
9 8,891 6,711 7,278 7,758
10 7,337 5,599 5,991 6,391
11 6,163 4,747 5,006 5,370
12 5,388 4,047 4,240 4,523
13 4,476 3,481 3,635 3,891
14 3,891 3,010 3,139 3,401
15 l e
/d>50 l e
/d>50 l e
/d>50 l e
/d>50
ww.EasyEngineering.n
Notes:
1. Calculated values are based on Eqs. (5-61) and (5-62).
2. Values are calculated using c = 0.8 for sawn lumber, and minimum cross-sectional
dimension d = 3½ in.
3. No adjustments have been made for moisture, temperature, load-duration, or other conditions;
additional adjustments may be necessary for a particular job.
4. Values of F ∗ and E’ are in lb per sq in.
c min
5. Lumber is considered in dry condition, moisture content < 19%.
6. For wood members the slenderness ratio l e
/d should not exceed 50.
TABLE 5-5 Allowable Load of Rectangular Solid Wood 4 × 4 and 4 × 6 S4S
Columns Members, Based on Stipulated Values of F ∗ c and E’ min
Downloaded From : www.EasyEngineering.net
133