Question 7.5: A single storey shear frame shown in Fig 7.15a is subjected ......
A single storey shear frame shown in Fig 7.15a is subjected to El Centro ground excitation as shown in Fig. 7.15c. The simplified model is shown in Fig. 7.15b. The rigid girders support a load of 25.57 kN/m. Assuming a damping factor ρ = 0.02 for steel frame, E = 200 GPa. Write a computer program for the Wilson-θ method to evaluate dynamic response of the frame and plot u(t), v(t) and a_t(t) in the interval.
\begin{aligned}& \omega_n=9.53 rad / s \\& T_n=0.659 s \\ & \rho=0.02\end{aligned}
\ddot{u}+2 \rho \omega_n \dot{u}+\omega_n^2 u=-\ddot{u}_g 7.70
Once u, v and a_{ t } have been determined
a_t=a_n+\ddot{u}_gThe absolute acceleration can be obtained. The program using Wilson-θ method is given below for ground movement. The displacement, velocity and acceleration (total) response are shown in Fig 7.16.
