## 44. Bearing For Beams

When the ends of beams rest upon walls, cast or wrought iron bed plates should be used to distribute the pressure over a greater surface. For buildings stone beds are generally used, but when the pressure is great both plates and stone. Beams have seldom less than 8 inches bearing or more than 12 inches; if less than 8 feet long, 6 inches will be sufficient.

## 45. Pressure On Brick And Stone Work

The pressure per square foot for brickwork should not exceed six tons, and for stone twelve to twenty tons, according to its character.

## 46. Knees For Beam Connections

The following sizes of knees are commonly used for beam connections:

 24" into 24" beam = 6 X 4 X 1/2" angles, 20" long; 20" " 20" " = 6 X 4 X 1/2" " 16" " 15" " 15" " = 6X4X1/2" " 11" " 12" " 12" " = 6 X 4 X 1/2 " 8" " 10 1/2" " 10 1/2" " = 6 X 4 X 7/16" " 6 1/2" "
 10" into 10" beam = 6 X 4 X 7/16" angles, 6" long; 9" " 9" " = 6X4X7/16" " 5" 8" " 8" " = 5 X 3 1/2 X 3/8" " 4 1/2" " 7" " 7" " = 5 X 3 1/2 X 3/8" " 3 1/2" " 6" " 6" " = 5 X 3 1/2 X 3/8" " 3" " 5" " 5" " = 5 X 3 1/2 X 3/8" " 2 1/2" " 4" " 4" " = 3 1/2 X 3 1/2 X 3/8" " 2 1/4" "

## 47. Bolts And Rivets For Beam Connections

The number of bolts and rivets is determined by shearing and bearing strain. See article on "Bolts and Rivets".

## 48. Tee Irons As Beams

The following table gives:

### Safe Load, In Pounds, Uniformly Distributed, For Tirons, Including Weight Of T

Maximum Strain 12,000 Pounds per Square Inch.

 Size of T. Weight per yard. Coefficient forTransverseStrain. Distance between Supports, in feet. 4 5 6 7 8 9 I0 11 12 flange stem th'kness lbs. 5 X3" X1/2" 38.1 7480 1870 1500 1250 1070 940 830 750 680 620 4 1/2 X3 1/2 x11/16 46.5 6010 1502 I200 IOOO 860 750 670 600 550 500 4 X5 X 1/2 45.6 24,800 6200 4960 4130 3540 3I00 ,2770 2480 2250 2070 4 X4 1/2 X1/2 42.9 20,400 5100 4080 3400 2910 2550 2270 2040 1860 1700 4 X4 X1/2 37.5 I5,800 3950 3l60 2633 2257 1975 1755 1580 1435 1325 4 X3 XI 27.3 7070 1705 1414 1178 IOIO 884 785 707 634 589 3 1/2 X3 1/2 x1/2 27.O 9530 2382 1900 1590 1360 II90 IO60 950 870 790 3 1/2 X4 X3/8 29.1 12,380 3095 2476 2064 1770 I550 1380 1240 1130 1030 3 1/2 X3 x1/2 22.5 5790 1418 1l60 970 830 720 640 580 530 480 3 X4 x1/2 34.8 15,480 387O 3I00 2580 2210 1940 1720 I550 1410 1290 3 X3 1/2 x1/2 32.1 11,910 2975 2380 1990 1700 1490 1320 1190 1080 990 3 X3 x 5/16 19.5 5900 1475 Il80 980 840 740 650 590 540 490 3 X 2 1/2 X5/16 18.0 4100 I025 820 680 590 5IO 460 410 370 340 3 X 2 x 5/16 14.6 2540 637 508 423 363 317 283 254 231 212 2 1/2 X2 1/2 x 5/16 16.2 4000 I000 800 670 570 500 440 400 360 330 2 1/2 X3 x5/16 18.0 6110 1527 I220 1020 870 760 680 610 560 510 2 1/4 X 2 1/2 X9/32 11.90 2811 703 560 469 402 352 312 281 254 234 2 X 2 x1/4 9.4 I970 493 394 328 282 246 218 197 179 164 1 3/4 X 1 3/4 x1/4 9.0 1550 39° 310 260 220 190 170 155 140 130 1 1/2 X 1 1/2 x1/4 6.68 1033 258 207 172 147 129 115 103 94 86 I 1/4 XI 1/4 x7/32 4.87 596 149 119 98 85 75 66 59 54 49 I X I x5/32 2.80 268 67 53 45 38 36 29 26 24 22

## 49. Angle Irons As Beams

The following table gives:

### Safe Load, In Pounds, Uniformly Distributed, For Equal-Leg Angles, Including Weight Of Angles

Maximum Strain 12,000 Pounds per Square Inch.

 Size ofAngle. Weight yard. Coefficient for TransverseStrength. Distance between Supports, in feet. 4 5 6 7 8 9 10 XX 12 inches. lbs. 6 X6 X7/16 50.6 32,560 8140 6510 5430 4650 4070 3620 3260 2960 2715 6 X6 X1/2 57.5 36,900 9225 7400 6150 5270 4612 4100 3690 3354 3075 5X5X 3/5 36.0 19,360 4840 3870 3230 2770 2420 2150 1940 1760 1618 4 1/2 X 4 1/2 X A 37.5 18,000 4500 3600 3000 2571 2250 2000 1800 1633 1500 4 X4 XI 28.6 12,184 3046 2437 2031 1740 1523 1354 1218 1107 1015 3 1/2 X 3 1/2 X 3/8 24.8 9200 2300 1840 1530 1310 1150 I020 920 840 770 3 X3 X 1/4 14.4 4611 "53 922 767 658 576 512 461 419 384 2 5/4 X 2 3/4 X 5/16 16.2 4710 1177 942 785 672 589 522 471 428 393 2 1/2 X 2 1/2 X 1/4 11.9 3156 789 631 526 45T 394 344 317 287 263 2 1/4 X 2 1/4 X 1/4 10.6 2530 633 506 422 362 316 281 253 230 211 2 X 2 x 7/32 8.3 1752 438 350 292 250 219 195 175 159 146 1 3/4 x 1 3/4 x 3/16 6.21 II50 287 230 I92 164 144 128 "5 104 96 1 1/2 x 1 1/2 x 3/16 5.27 832 208 164 139 119 104 92 83 76 69 1 1/4 X 1 1/4 X 1/8 2.97 393 98 78 65 56 49 44 39 36 33

## 50. Safe Load For Unequal-Leg Angles, The Longer Leg Vertical

Maximum Strain 12,000 Pounds per Square Inch.

 Size ofAngle. Weight per yard. Coefficient for TransverseStrength. Distance between Supports, in feet. 4 5 6 7 8 9 10 11 12 inches. lbs. 6 X4 X 7/16 41.8 30,680 7670 6136 5113 4383 3834 3409 3068 2789 2556 6 X4 X3/8 36.1 26,560 6640 53IO 4430 3790 3320 2950 2660 2410 22I0 6 X 3 1/2 X 3/8 34.2 26,000 6500 5200 4330 3710 3250 2890 2600 2360 2I70 5 X4 X3/8 32.3 18,720 4680 3740 3I20 2670 2340 2080 1870 1700 I560 5 X3 1/2X 3/8 30.5 18,353 4590 3671 3059 2622 2294 2038 1835 1668 1528 5 X3 X 3/8 28.6 17,840 4460 3570 2970 2550 2230 1980 1784 1620 I490 4 1/2X3 X3/8 26.7 14,580 3645 2916 2430 2083 1823 1620 1458 1325 I217 4 X3 1/2X 3/8 26.7 I2,000 3000 2400 2000 1710 1500 I330 I200 I090 1000 4 X3 X5/16 20.9 9850 2462 1970 1641 1407 1231 I094 985 895 821 3 1/2X3 X5/16 19.3 7680 1920 I540 1280 1100 960 850 770 700 640 3 1/2 X 2 1/2 X 1/4 14.4 6000 I500 I200 10000 860 750 670 600 540 500 3 X 2 1/2 X 1/4 I3.I 4480 1120 900 750 640 560 500 450 410 370 3 X2 X1/4 II.9 4320 1080 860 720 620 540 480 430 390 360 2 1/2X2 x3/16 8.1 2320 580 460 390 330 290 260 230 210 190

## 51. Beams Not Uniformly Loaded And Beams Not Supported At Both Ends

(a) For a beam fixed at one end and loaded at the other as a cantilever, coefficient/8L. Safe load in lbs. =

(6) For a beam fixed at one end and uniformly loaded, coefficient/4L Safe load in lbs. =

(c) For a beam supported at both ends, load concentrated at any point,

Safe load in lbs. =(coefficient/L)x (L2/(8AxB)

A = distance from load to one support; B = distance from load to the other support.

Note. - The beams, channels and other shapes treated of in this chapter are selezcted from the hand-books of the Passaic Rolling Mill Co., Phoenix Iron Co., Columbia Iron and Steel Co., and Pottsville Iron and Steel Co.