7.12 Frequency Domain Analysis of Direct Frequency Response Method
305
7.10 An idealised building is excited by ground motion x = X cos ωt. Find the
steady-state shear force at the base, considering only the response in the
fundamental mode.
Prob. 7.10
7.11 A reinforced concrete chimney idealised as lumped mass cantilever is
subjected at the top level to a step force F(t) = 4500 kN with m = 7000 kgs
2 /cm. EI = 2.305 × 10
10 kN-m
2 . Solve by any numerical technique the
equations of motion after transforming them to the first two modes by the
lower acceleration method with = 0.1 s.
Prob. 7.11
7.12 For the system whose spring–mass–damper representation is shown in the
figure, the different quantities have the following values:
F
(t)
1 = P 1 cos ωt, k 1 = 1000, k 2 = 500, m = 1
c 1 = 0.5, c 2 = 0.05
Determine the response of the masses.
Prob. 7.12
305
7.10 An idealised building is excited by ground motion x = X cos ωt. Find the
steady-state shear force at the base, considering only the response in the
fundamental mode.
Prob. 7.10
7.11 A reinforced concrete chimney idealised as lumped mass cantilever is
subjected at the top level to a step force F(t) = 4500 kN with m = 7000 kgs
2 /cm. EI = 2.305 × 10
10 kN-m
2 . Solve by any numerical technique the
equations of motion after transforming them to the first two modes by the
lower acceleration method with = 0.1 s.
Prob. 7.11
7.12 For the system whose spring–mass–damper representation is shown in the
figure, the different quantities have the following values:
F
(t)
1 = P 1 cos ωt, k 1 = 1000, k 2 = 500, m = 1
c 1 = 0.5, c 2 = 0.05
Determine the response of the masses.
Prob. 7.12