written 6.2 years ago by | • modified 2.8 years ago |
Subject :- Structural Analysis II
Title :- Analysis of Indeterminate truss
Difficulty :- Hard
written 6.2 years ago by | • modified 2.8 years ago |
Subject :- Structural Analysis II
Title :- Analysis of Indeterminate truss
Difficulty :- Hard
written 6.2 years ago by |
Degree of static indeterminacy :-
$D_{SE}$ = r-3 = 4-3 = 1
$D_{Si}$ = M-(2j-3) = 9(2(6)-3) = 0
$D_S$ = 1+0 = 1
Selecting redundant force(R)
Let R = $H_E$(->)
Convert hinged int roller
P-Analysis:
Σ$M_A$ =0(+ve)
203 + 407 - $V_E$*7 =0
Σ$F_Y$ =0(+VE)
$V_A$ - 0 + 48.57 =0
$V_A$ = -8.54KN
Joint A:-
Σ$F_Y$ =0(+ve)
-8.57 + $P_{AC}$Sin(36.86) =0
$P_{AC}$ = 14.28KN (T)
Σ$F_Y$ =0(+ve)
$P_{AF}$ - 20 +(14.28cos38.86) =0
$P_{AF}$ = 8.57KN (T)
Joint E:-
Σ$F_Y$=0(+ve)
48.57 - 40 + $P_{EC}$sin45 =0
$P_{EC}$ = -12.11KN
$P_{EC}$ = 12.11 KN(C)
K-Analysis:
Table:-
Member | P | K | L | PKL | $K^2$L | R | RK | $P_f$=P+PK |
---|---|---|---|---|---|---|---|---|
AB | 0 | 0 | 3 | 0 | 0 | 8.57 | 0 | 0 |
BC | -20 | 0 | 4 | 0 | 0 | 8.57 | 0 | -20 |
CD | 0 | 0 | 3 | 0 | 0 | 8.57 | 0 | 0 |
DE | -40 | 0 | 3 | 0 | 0 | 8.57 | 0 | 40 |
EF | 8.57 | 1 | 3 | 25.71 | 3 | 8.57 | -8.57 | 0 |
FA | 8.57 | 1 | 4 | 34.28 | 4 | 8.57 | -8.57 | 0 |
AC | 14.28 | 0 | 5 | 0 | 0 | 8.57 | 0 | 14.28 |
CE | -12.11 | 0 | 4.24 | 0 | 0 | 8.57 | 0 | -12.11 |
CF | 0 | 0 | 3 | 0 | 0 | 8.57 | 0 | 0 |
Σ59.99 | 7 |
R = -[$\frac{\frac{ΣPKL}{AE}}{\frac{K^2L}{AE}}$]
= -[$\frac{60}{7}$] = -8.57
R = i.e = -8.57KN
He= 8.57KN<-
Actual $H_A$ = 20-8.57
$H_A$ = 11.43KN