?? ????? ??????? ??????? ??????? ?????? ?? ?????? ??? ??????? ???????? ??????? ?????? ???????? ?????? ??????. ?? ??? ?????? ??? ????? ??? ???? ??? ?? ???? ???? ?????? ?????? ???????? ??????? ?? ??? ???????? ?? ??????.
?? ?? ???? ??? ??? ????????
?? ??????? ??? ???? ??? ??????? ?? ????? ?????? ?? ???????. ????? ?? ????? ????? ?????? ???? ???? ???????. ??????? ?? ????? ???? ?????? ??? ??????? ????????? ??? ?? ?????? ???????.
???? ?????? ???????? ??????? ?? ????? ?? ????? ??????? ???????? ???? ????? ????? ????? ????? ???????? ?? ????? ??????? ??????? ?? ???????.
????? ????? ????? ??? ?????
???? ????? ????? ????? ????? ?????? ????? ??? ????? ??????:
1. ??? ???? ????? ????? ?? ????? ?????? (????? ?? ??? ??? ????? ??? ????? ?????? ??? ???????? ?? ?????? ??????? ????????) ?????? ???????. ?? ???????? ??? ??? ????? ??????? ??? 18-12? 12-10? 10-8? 8-6? ???. ?? ?? ???? ?? ??? ????? ????? ???? ?????? (?????????) ??? ??? ??? ? ??? γ 18 -12 ? γ 12-10 ? ??? ??? ????
2. ?????? ???? ?????? ??? ??? ???? (??? 18? 12? 10? 8? ???) ?? ????? ???? ?????? ?????? ??????? (??? 15? 11? 9? 7? ???) ??????? ??? ??? ?????? 18 ?? ?????? ?????? ?????? ??? ????? ???? ??? ?????? ??? ??? ???? ? ??? γ 18-12 ? γ 12-10 ? ??? ??? ????
3. ??? ?? ???? ???? ?????? ?????? ???????? ??????? ?? ??? ?????? ??????. ????? ?????? ??????? ??????? ???????? ?????? ?? ?????? ????????? ?????? ???????? ???????? ?? γ' D18 = γ 18-12 、γ' D12 = γ 12-10 、γ' D10 = γ 10-8 、γ' D8 = γ 8-6 ? ??? ??? ????
4. ???? ????? ?????? ???? ?????. ????? ???? ?????? ?????? ??????? ???? ?? ??????? ?????? ?????? ????? ????? ??? ??? ????? ?? ??????. ????? ???? ????? ????? ???????? ??? ????? ?????? ????? ?????? ???? ??????. ???? ????? ????? ?????? ??????? ??????? ??? ??? ???? ?? ??????? ??? γ D18 ? γ D12 ? γ D10 ? ??? ??? ????
5. ???? ?????? ??????? ??? ??? ???? ?? ??????.
?. ???? ?????? ????????? G ?????? ????? ??????:
G = π / 4 × D 2 × L × ? × δ
?? ??? ??????? G ???? ?????? ????????? ????? (t). D ?? ????? ??????? ???????? ????? ????? (?). L ?? ????? ?????? ???????? ??????? ??????? (?). ? ?? ???? ????? ??????? (?). ? δ ?? ??????? ???????? ????? (t /m 3 ).
?. ?? ???? ???? ?? ??? .
G D18 =G ? γ D18 ,G D12 =G ? γ D12 ,G D10 =G ? γ D10 ,G D8 =G ? γ D8 ,???.
???? ??? ????? ??? ??? ???????
???? ???? ????? ?? ???????? ?????? ?????? ??? ?????? ?????? ?? ????? ?????? ????? ? 1500mm×3000mm? ????? ???? ??????? ? = 50%? ?????? ???? ??? ??????? ??????? δ = 4.5 t/m 3 . ???? ??????? ??????? ??????? ????? ????? ???????.
1. ???? ?????? 1 ??????? ??? ????? ????? ??????? ????? ????? ????? ?? ????? ?????.
?????? 1
| ??? ?????? (??) | ??????? (?) | ??? ?????? (??) | ??????? (?) |
| 18-12 | ???? 18-12 =20 | 6-4 | ???? 6-4 =5 |
| 12-10 | ???? 12-10 = 40 | 4-2 | γ 4-2 =4 |
| 10-8 | ???? 10-8 = 15 | 2-1 | γ 2-1 =4 |
| 8-6 | ???? 8-6 =8 | 1-0 | γ 1-0 =4 |
2. ???? ??? ????? ????? ???? ?????? ???? ?? ???? ??? ??????? ??? ??????. ???? ?????? 2.
?????? 2
| ??? ?????? (??) | ??? ????? (??) | ??? ?????? (??) | ??? ????? (??) |
| 18-12 | ? 18 =120 | 6-4 | ? 6 =70 |
| 12-10 | ? 12 = 100 | 4-2 | ? 4 =60 |
| 10-8 | ? 10 = 90 | 2-1 | ? 2 =50 |
| 8-6 | ? 8 = 80 | 1-0 | ? 1-0 =40 |
3. ????? ??????? ????? ?????? ???????? ????? ?? ?????? 21.
?????? 21
| ??? ????? (??) | ???? ?????? (%) | ??? ????? (??) | ???? ?????? (%) |
| 120 | 20 | 70 | 5 |
| 100 | 40 | 60 | 4 |
| 90 | 15 | 50 | 4 |
| 80 | 8 | 40 | 4 |
??? ???? ??? ?? ????? ???? ???? ??? ?? 120 ?100 ?80 ?60? ????? ????? ???? 90 ?70 ?50 ?40 ??? ???? ????? ?????? ??????. ???? ??????? ??????? ???? ?????? ?? ?????? 3.
?????? 3
| ??? ????? (??) | ???? ?????? (%) | ??? ????? (??) | ???? ?????? (%) |
| 120 | 30 | 80 | 13 |
| 100 | 45 | 60 | 12 |
4. ???? ?????? ????????? G ?????? ???????:
G = π / 4 × D 2 × L × ? × δ = π / 4 × 1.5 2 × 3 × 0.5 × 4.5 = 11.928 (?)
5. ???? ???? ?? ??? ??? ??????? ??? ???.
? 120 = ? ? γ 120 = 11.928 × 30% = 3.58 (?)
? 100 = ? ? γ 100 = 11.928 × 45% = 5.37 (?)
? 80 = ? ? γ 80 = 11.928 × 13% = 1.55 (?)
? 60 = ? ? γ 60 = 11.928 × 12% = 1.43 (?)
6. ?? ???? ????? ????? ?????? ??????.
