塔吊附墙杆选型及计算
1、附墙杆轴向力计算(包括剪力)
F n 1 | | F X | 1 | | COS | 28.36 | o | | F Y | 1 | | Sin | 28.36 o | | 391.93 | Kn(二根杆) |
| | 388.44 Kn(二根杆) |
F n | 2 | F X | 2 | | Sin | 40.57 | o | | F Y | 2 | | COS40.57 | o |
| | 14.97 Kn(二根杆) |
F V1 | F X | 1 | | Sin | 28.36 | o | | F Y | 1 | | COS28.36 | o |
| | 42.96 Kn(二根杆) |
F V2 | F X | 2 | | Sin | 40.57 | o | | F Y | 1 | | COS40.57 | o |
2、附墙杆选材
选Q235钢材,f=215N/mm2,fV=125N/mm2,fce=325N/mm2
所需的附墙杆截面面积为 | A | | | F n 1 | | 391.93 10 3 | | 911.47 | mm | 2 |
| | 需 | | 2 | f | | 2 215 | | | | |
3、附墙杆截面形式选择
选每根附墙杆由4个角钢组成,型号为L63×6,截面特性计算:
A=7.29×4=29.16cm2> | A需 | =911.4mm2 | 9788.68 cm | 4 |
Ix=27.12×4+7.29× | ( | 40 | | 1.78) | 2 | | 4 | |
2 | | | | | | | |
ix= | 9788.68 | | 18.32 cm |
29.16 |
附墙杆所受的外力计算(取附墙杆1所受的外力,附墙杆每米重量取为50Kg/m)
M | | | 1 | ql | 2 | | 1 | | 500 15.52 | 2 | | 15054.4 . N m |
| X | | 8 | | 8 | |
M | | 1 | ql | 2 | | 1 | | 500 15.52 | 2 | | 15054.4 . N m |
| X | | 8 | | 8 | |
N | | 1 | F n 1 | | 1 | | 391.93 | | 195.97 | N m |
| | 2 | 2 | |
V | | 1 | F V | | | 1 | | 42.96 | | 21.48 | Kn |
| | 2 | 1 | 2 | |
4、斜缀条受力计算(取斜缀夹角为45°)
假想剪力 | V | | Af | f | y | | 29.16 215 10 | 2 | | 7376 | N | | 7.38 | Kn | <实际剪力V= |
85 | 235 | 85 |
21.48Kn
缀条内力及长度计算:
| 45 o | | NC= | | | 21.48 | | 15.19 | KN |
| | 2 | | COS | 45 o | | | |
l | | 280 | 396 | mm |
| | cos45 o | | | | | | | |
选用L40×4角钢,A=3.09cm2,ix=1.22cm,
| 396 | | 32.46 | < | [ ] | 150 | ,取n=0.85,查表知, | 0.927 |
| 12.2 | | | | | | | |
验算缀条稳定:
N | C | | 15.19 10 3 | | | 53.03 | N mm | 2 | p | f | | 215 0.85 | | 183 | N mm | 2 |
A | | 0.927 3.09 10 | 2 | | | | | | | | | | | | |
所以缀条满足要求。
5、验算附墙杆弯距作用平面内的整体稳定。
x | l 0 | x | | 15520 | | 84.72 | |
i x | 183.2 | |
换算长细比, | 0 x | | x 2 | | 27 | A | | 84.72 | 2 | | 27 4 | | 85.36 | < | [ ] | 150 |
A 1 |
查附表(b 类截面),x | 0.652 |
NEX= | 2 | FA | | 2 | | 2.06 10 | 5 | | 29.16 10 | 2 | =73970N |
1.10 x | 2 | 1.1 85.36 | 2 | | |
取 | mx | | 1.0 | , | W | X | | I | X | | 9788.68 | | 4.43 cm | 3 |
y | 20 | 2 |
N | | W 1 | X | mx | M | X | ) | | 103.08 | | 15054.4 | | 103.04 | N mm |
X | A | (1 | | X | N | 4.43 10 | 3 | ( 0.72) | | |
N | EX | | |
<f=215N/mm2,所以满足要求。
5、大缀条验算
[ ] | 150 | ,取缀条最大长细比为130 | i | | 1500 | | 11.54 | mm | ,取L40×4 角钢 |
则有2500~1500 之间,所需缀条回转半径 |
x | | 130 | | | | |
( | i | | 1500 | | 12.20 | mm | ) |
| x | 130 | | | | | | | | | | | |
220
y
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