1. For beams on the elastic half-space (the Gorbunow-Posadow procedure) calculate:
[m]
E B
EI
L 3 2
s P
G
(probably, you will get 4m …) and also
P G P
G 2 L
, L L 2 β B
2. First check if the beam belongs to a category of „long beams”. The Gorbunov-Posadov charts can be used only for such beams („short beams” have other charts).
One of the three conditions must be fulfilled:
0,01 < ≤ 0,15 & > 1,0 either 0,15 < ≤ 0,30 & > 2,0 either 0,30 < ≤ 0,50 & > 3,5.
3. Define = d/LG-P where the symbol d means distance from the force to the closest end of the beam. The charts are prepared for either doubly infinite beams (=+; >0 starts from the force position, dashed line) or for one-side finite beams (<+; >0 starts from this end).
4. For the value of just calculated, select one interval to which it belongs, for example = 0.18 belongs to Beta 0.1-0.2 (as a matter of fact, you will be using the charts for = 0.15 which are not very different). Read only from 4 charts grouped for Beta 0.1-0.2.
Ignore all clusters of charts M, Q, p, y for other intervals of which are not applicable here.
5. For each cross section , read dimensionless coefficients of influence (over-lined) and then use the following expressions:
beam moments:
100 L ) P ( M ) (
M GP
beam shearing forces:
P ) ( Q ) (
Q
subsoil reactions:
P
LG
10 ) P ( p ) ( p
beam settlements:
P G
s L
P E ) 1 ( Y ) ( y
.
6. If > 0 is „very large” (out off charts), assume simply that there is no influence, so take a zero value. Sometimes the chart is continued on the next page.
7. For all cross sections situated on the left from the force, change the sign of Q which is an odd function.
No such change is necessary for even functions M, p , y.
8. Correct the final moments at the beam ends if they are not zero.
Apply a linear correction on an interval :
= 1.2 for 0.01< 0.15
= 1.6 for 0.15< 0.50
= 2.0 for 0.50 < .
9. The Bleich method is not allowed here.
details on: www.ib.pwr.wroc.pl/brzakala in STUDIA II-go stopnia (magisterskie),
go to uzupełnienia , select wykresy Gorbunowa-Posadowa.
Example: for =0.18 read moments from Beta 0.10-0.20@M:
2 3 2 1. ) . (ξ= =
M for =+.